testing formats

CORPORATE OPERATION SERVICES
POWER GRID CORPORATION OF INDIA LTD.
GURGAON
Pre-Commissioning Procedures
& Formats for
Switchyard Equipments
FOR INTERNAL CIRCULATION ONLY

POWER GRID CORPORATION OF INDIA LTD.
CORPORATE OPERATION SERVICES
PRE-COMMISSIONING PROCEDURES AND FORMATS FOR
SWITCHYARD EQUIPMENTS
DOC: D-2-01-03-01-03
Revision Department Date Signature Signature
00 CC/OS 25.04.1995 Sd/- Sd/-
01 CC/OS 05.11.1999 Sd/ Sd/
02 CC/OS 22.04.2008 Sd/ Sd/
03 CC/OS 01.04.2011 Sd/ Sd/
Proposed Checked Reviewed Recommended Approved
Sumit S.H Ray
Engineer(OS)
V.K.Bhaskar
Ch. Manager
(OS)
S.V.P.Selvakumar
AGM (OS)
P.N.Dixit
GM (OS)
Sanjeev Singh
ED(OS)
Anant Shukla
Engineer(OS)
G Agrawal
Manager(OS)
S.No. Pages Revision Remarks
01 All Pages 03 All pages replaced

CONTENTS
PRE-COMMISSIONING PROCEDURES FOR SWITCHYARD EQUIPMENTS 1
TRANSFORMER AND REACTOR 1
PRE-COMMISIONING CHECKS/ TESTS FOR TRANSFORMER & REACTOR
CHECK LIST FOR ENERGISATION OF TRANSFORMER/ REACTOR 35
2.1 Checks after receipt of Transformer/Reactor at site 4
2.2 Insulating oil 5
2.3 Internal Inspection 6
2.4 Precautions during erection 7
2.5 Final tightness test with vacuum (i.e. leakage test or Vacuum Drop Test) 9
2.6 Oil filling 10
2.7 Hot oil Circulation using High Vacuum Filter Machine 13
2.8 Procedure for Dry Out of Wet Winding of Transformer/Reactor by Vacuum 14
Pulling,N2 filling and Heating
2.9 Relation between different units (conversion of units) 16
3.1 Core Insulations Check 19
3.2 Earth Pit Resistance Measurement 19
3.3 Insulation Resistance (IR) Measurement 20
3.4 Capacitance & Tand Measurement of Bushing 21
3.5 Capacitance and Tand measurement of windings 24
3.6 Turns ratio (Voltage ratio) measurement 25
3.7 Vector Group & Polarity 25
3.8 Magnetic Balance test 26
3.9 Floating Neutral point measurement 27
3.10 Measurement of Short Circuit Impedance 27
3.11 Exciting/Magnetising current measurement 28
3.12 Operational checks on OLTCs 28
3.13 Tests/Checks on Bushing Current Transformer (BCT)s 29
3.14 Operational checks on Protection System 29
3.15 Stability Test of Differential, REF of Transformers/Reactor 30
3.16 Frequency Response Analysis (FRA) measurement 32
3.17 Winding resistance measurement 33
3.18 Dissolved Gas Analysis (DGA) of oil sample 34
4.1 Preliminary checks 35
4.2 Checking of auxiliary and protective ciruits 36
17
SL.NO. PARTICULARS
PAGE
NOS
Doc No. D-2-01-03-01-03
v

SL.NO PARTICULARS
PAGE
NOS
POST COMMISSIONING CHECKS/ TESTS FOR
TRANSFORMERS AND REACTORS 38
PRE-COMMISSIONING CHECKS/ TESTS FOR OTHER
SWITCHYARD EQUIPMENTS 39
BUS BAR PROTECTION 59
PRE-COMMISSIONING FORMATS FOR SWITCHYARD EQUIPMENT
5.1 Thermovision scanning (IR thermography) 38
5.2 Online Moisture Measurement 38
5.3 Vibration measurement of Oil- immersed reactor 38
6.1 Capacitance & Tand Measurement of CT, CVT, CB voltage
grading capacitor & Surge Arresters 43
6.2 Checks/ tests applicable for Cts 43
6.3 Checks/ tests application for Circuit Breakers 47
6.4 Checks / Test applicable for CVTs 54
6.5 Checks/ tests applicable for Isolator 55
6.6 Checks/ tests applicable for Surge Arrester 55
6.7 Checks/ tests applicable for other areas/equipments 56
7.1 High Impedance Protection 59
7.2 Low Impedance Protection 60
7.3 Primary injection and bus bar differential stability test (New Substation) 61
7.4 Primary injection and bus bar differential stability test (Bay Extension in the old substation) 62
7.5 Scheme Checking of bus bar protection & DC trip logic. (New substation & Bay extension) 64
7.6 AMP Testing of bus bar protection and scheme 65
7.7 Double main transfer scheme (400kV/220kV) 66
7.8 Scheme checking of bus bar protection & DC trip logic. (New substation & Bay extension) 73
7.9 AMP testing of bus bar protection and scheme 74
1 No. CF/ICT/01/ R-3 DATED 01/04/2011 ICT 75
2 No. CF/SR/02/ R-3 DATED 01/04/2011SHUNT REACTOR 101
3 No. CF/CB/03/ R-3 DATED 01/04/2011 CIRCUIT BREAKER 117
4 No. CF/CT/04/R-3 DATED 01/04/2011 CURRENT TRANSFORMER 130
5 No. CF/CVT/05/R-3 DATED 01/04/2011 CVT 140
6 No. CF/BAY/06/R-3 DATED 01/04/2011 BAY/FEEDER 145
7 No. CF/ISO/07/ R-3 DATED 01/04/2011 ISOLATOR/GROUND SWITCH 154
8 No. CF/SA/08/ R-3 DATED 01/04/2011 SURGE ARRESTER 159
9 No. CF/WT/09/ R-3 DATED 01/04/2011WAVE TRAP 162
10 No. CF/C&P/10/R-3 DATED 01/04/2011 CONTROL & PROTECTION 164
Doc No. D-2-01-03-01-03
vi

Doc No. D-2-01-03-01-03
Pre-Commissioning Procedures For Switchyard Equipments 1
1.1 Purpose
1.2 Commissioning Team
This document is to provide guidance to POWERGRID personnel in carrying out Pre-
commissioning checks along with formats for recording the test data and subsequently
chargingofSubstation Bayequipmentsalongwithassociatedauxiliaryequipments.
Pre-commissioning checks/ tests are the activities carried out to ascertain the correctness,
completeness of installation and healthiness of the equipment before its charging. These
checks/ tests are to be carried out by Contractor's representative in the presence of
POWERGRID's authorizedrepresentative.
1.2.1 Constitution of Commissioning team: After completion of erection in all respects, a
commissioning team may be constituted (as per procedures laid down in Works &
Procurement Policy and Procedures -Clause C2.15.4.6 of WPPP Vol. II), to oversee/
coordinate with erection agency/ manufacturer of the equipment for the pre-commissioning
tests and subsequently charging of the equipment. In case of Substation, Commissioning
teammayconsistoffollowing:
(I) I/C of Substation
(ii) O&M executive not below Manager
(iii) T&C executive not below Sr. Engineer
1.2.2 Role of Commissioning team: The Commissioning Team shall examine the following
statutory and other clearances obtained by Execution Site prior to clearance for test charging
of theequipment/transmissionlineatratedvoltage:
StatutoryClearances:
a) Electrical Inspector's Clearance (provisional or final) for charging transmission
line/bayequipmentasperI.E.rules.
b) P.T.C.C.clearance.
c) Copyofnotificationinformingpublic/administrationregardingchargingoftheline.
d) ForestClearance
OtherClearances:
a) CharginginstructionfromSEFGroupofCorporateEngineering.
PRE-COMMISSIONING PROCEDURES
FOR SWITCHYARD EQUIPMENTS

Doc No. D-2-01-03-01-03
Pre-Commissioning Procedures For Switchyard Equipments2
b) RelaysettingdetailsfromCorporateEngineering.
(ClauseC2.15.4.8(v)ofWPPPVol-II)
1.2.3 Responsibilities of Commissioning team The responsibilities of the commissioning team
are to go through statutory clearances and standing instructions before initial charging of
new equipment, witness Pre-Commissioning tests after erection of individual equipment as
per requirement of guidelines issued by Corporate OS or in line with manufacturer's
recommendation and test charging, investigate failure of equipment during test charging,
declare commencement of trial operation and evaluate guaranteed test results and
recommend acceptance as may be provided in the contract, list out deviations/ exception/
incomplete work, for acceptance/ rejection (Clause C2.15.4.7 of WPPP Vol-II). Proper
documentation also to be ensured by the Commissioning team based upon the observations
fortheaboveforfuturereference.
1.2.4 The Team shall also go through the factory test reports. If such tests have been repeated
during pre-commissioning, the Team shall list out deviations, if any, in the results of pre-
commissioningtestswithrespecttothefactorytests.
(ClauseC2.15.4.8(vii)ofWPPPVol-II)
1.2.5 After all pre-commissioning checks and tests are found to be acceptable taking into account
permissible deviation limits, the commissioning team, in consultation with regional O&M,
shallgiveclearanceforcommissioning/charging.
Please Note: In case ofTransformers & Reactors, commissioning team shall forward the Pre-
Commissioning report along with their recommendations to RHQ-OS and CC-OS for
charging clearance and CC-OS shall give the final charging clearance after reviewing of the
testresults.
All measures and precautions should be undertaken to prevent occurrence of unsafe acts.All
the personnel involved should be thoroughly apprised about the safe procedures to be
adoptedwhileperformingvariousactivitiesincludingcarryingouttestsintheswitchyard.
Adequate fire-fighting system as per procedures and their healthiness is to be ensured before
charging.
Warning signs and Safety barriers should be positioned in conformity to IE rules as amended
fromtimetotime.
All the equipment after erection/assembly at site, should be tested in order to check that it has
not been damaged during transport, erection/assembly to such an extent that its future
operation will be at risk. The significance of various tests with brief procedure has been
elaborated in the subsequent sections of this document. Regarding the detailed testing
methods / procedures for conducting various pre-commissioning tests refer to Doc. No. D-2-
03-XX-01-01: Maintenance Procedures for Switchyard Equipments-Part 1: EHV
Transformers & Reactors and Doc No. D-2-03-XX-01-01 –Part 2: Other Switchyard
Equipments.
1.3 Safety
1.4 GeneralProceduresduringPre-commissioningofSwitchyardEquipment

Doc No. D-2-01-03-01-03
Sl.
No. FORMAT NO. EQUIPMENT
1. No. CF/ICT/01/ R-3 DATED 01/04/2011 ICT
2. No. CF/SR/02/ R-3 DATED 01/04/2011 SHUNT REACTOR
3. No. CF/CB/03/ R-3 DATED 01/04/2011 CIRCUIT BREAKER
4. No. CF/CT/04/R-3 DATED 01/04/2011 CURRENT TRANSFORMER
5. No. CF/CVT/05/R-3 DATED 01/04/2011 CVT
6. No. CF/BAY/06/R-3 DATED 01/04/2011 BAY/FEEDER
7. No. CF/ISO/07/ R-3 DATED 01/04/2011 ISOLATOR/GROUND SWITCH
8. No. CF/SA/08/ R-3 DATED 01/04/2011 SURGE ARRESTER
9. No. CF/WT/09/ R-3 DATED 01/04/2011 WAVE TRAP
10. No. CF/C&P/10/R-3 DATED 01/04/2011 CONTROL & PROTECTION
These formats have all the tests recordings to be performed at site before energization/
charging. Switching and operational activities will be recorded in regular manner in the
operator's log. Copies of this log, notes on special observations from inspections and other
measurements will constitute the test records. The test records had to be signed by the
responsible personnel from the OEM, the supplier, the erection agency and the
POWERGRID representative. The test formats/records are to be distributed to Regional
O&MofficeandConcernedSub-Stationlibrary.
1.5 Documentation
The results of the test shall be documented on the test record formats as mentioned below,
whicharealsopartofthisdocumentation:

A1
A2
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.5
0.05
0.05
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5
Lb / in 2
-30 -20 -10 0 10 20 30 40 50
Temperature in ° C
GaugePressure–Kg/Cm2
Graph showing variation of Pressure v/s Temperature of
gas for gas filled unit during Transport or storage
Example: For 40 °C Temperature (Depending upon the pressure of gas at the time of filling),
- minimum pressure of gas can be 0.185 Kg/ Cm 2
at point A1
- maximum pressure of gas can be 0.32 Kg/ Cm 2 at point A2
A1
A2
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.5
0.05
0.05
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5
Lb / in 2
-30 -20 -10 0 10 20 30 40 50
Temperature in ° C
at point A1
0
-0.05
Permissible
Range
A1
A2
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.5
0.05
0.05
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5
Lb / in 2
-30 -20 -10 0 10 20 30 40 50
Temperature in ° C
at point A1
A1
A2
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.5
0.05
0.05
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5
Lb / in 2
-30 -20 -10 0 10 20 30 40 50
Temperature in ° C
at point A1
0
-0.05
Permissible
Range
2.1 Following points to be checked after receipt of transformer / reactor at Site:
2.1.1 N pressure and Dew point to be checked after receipt of transformer at Site. It should be2
withinpermissibleband(aspergraphprovidedbymanufacturer&givenbelowinFig-1)
2.1.2 Core Insulation Test shall be carried out to check insulation between Core (CC&CL) and
Ground. (Not applicable for Air Core Reactors)
2.1.3 The data of impact recorder shall be analyzed jointly in association with the manufacturer. In
case the impact recorder indicates shocks of ≥3g during shipment, further course of action
for internal inspection shall be taken jointly with the manufacturer/ supplier. Impact
Recorder should be detached from the Transformer/ Reactor preferably when the main unit
hasbeenplacedonitsfoundation.
As present day impact recorders are of electronic type, analysis of impact recorder
along with dew point and Core insulation tests to be performed on trailer itself. In case,
the test results are not meeting permissible limits, same to be informed to OEM, CC-Engg. &
CC-OSforfurthercourseofaction.
Fig. 1
TRANSFORMER AND REACTOR
Doc No. D-2-01-03-01-03

2.1.4 Unpacking and inspection of all accessories to be carried out taking all precautions so that
the tools used for opening do not cause damage to the contents. Proper storage of all
accessories are to be ensured after unpacking. Fragile instruments like oil level gauge,
temperature indicators, etc. are to be stored indoor. Any damaged or missing components
should be reported to equipment manufacturer and insuring agency so that the same can be
investigatedorshortagemadeupaspertheterms/conditionsofthecontract.
2.1.5 Storageofthemainunitandtheaccessoriesatsite:
ØIf erection work can not start immediately due to some reasons, then accessories
shouldberepackedintotheirowncratesproperlyandpackinglistshouldberetained.
ØAll packing cases should be kept above ground by suitable supports so as to allow
free air flow underneath. The storage space area should be such that it is
accessible for inspection, water does not collect on or around the area and
handling/transport would be easy. Proper drainage arrangement in storage areas to
be ensured so that in no situation, any component gets submerged in water due to
rain,floodingetc.
ØIt is preferable to store the main unit on its own location/foundation. If the foundation
is not likely to be ready for more than three (3) months, then suitable action plan has
tobetakenfromthemanufacturerregardingproperstorageoftheMainUnit.
ØIf the transformer/ Reactor is to be stored up to three (3) months after arrival at site, it
can be stored with N filled condition. N pressure to be monitored on daily basis so2 2
that chances of exposure of active part to atmosphere are avoided. In case of drop in
N pressure, dew point of N has to be measured to check the dryness of the2 2
Transformer/ Reactor. If there is drop in dew point, fresh nitrogen need to be filled.
Leaks are to be identified and rectified and Nitrogen to be filled to the required
pressure.
ØIn case the transformer/ reactor is to be stored for more than 3 months, it needs to be
stored in oil filled condition. Processed oil to be filled which complies the required
specification and ppm ≤5ppm and BDV ≥70kV. In case of storage of transformer in
oil-filled condition, the oil filled in the unit should be tested for BDV and moisture
contents once in every three months. The oil sample should be taken from bottom
valve. If BDVis less and moisture content is more than as given for service condition
thenoilshouldbefiltered.
When oil is dispatched to site separately it is usually in sealed steel drums. In some of the
cases, oil is supplied in tankers also. The oil to be used to filling and topping up must comply
with oil specification given in POWERGRID Technical Specification for acceptance
criteria. Oil Samples shall be taken from oil drums/ tanker received at site and sent to our
12
nearest oil Lab for oil parameter testing (BDV > 50 kV, ppm<40, Resistivity > 150 x 10
Ohm-cm & Tan delta < 0.0025 @ 90 °C). The latter is important since dirty transportation
vessels can significantly contaminate the oil. High dielectric losses cannot be removed by
filter treatment, such lots have to be rejected. If the oil is supplied in railroad or trailer tanks,
one or two samples are sufficient. If the oil is delivered in 200 litres drums, the following
schemeforcheckingisrecommended.
2.2 InsulatingOil
Doc No. D-2-01-03-01-03

Numberofdrumsdelivered No.ofdrumstobechecked
2to5 2
6to20 3
21to50 4
51to10 7
101to200 10
201to400 15
In case any doubt arises, number of drums to be checked needs to be increased. However,
before filling oil, each drum has to be physically checked for free moisture and appearance.A
register needs to be maintained indicating the number of drums supplied in each lot as per
LOAand number of drums of each lot used in filling a particular Transformer/ Reactor. The
oiltestresultscarriedoutasaboveshouldalsoberecorded.
The copy of test certificate of routine testing at oil refinery should be available at site for
comparisonoftestresults.
2.2.1 Samples from Oil Drum
Check the seals on the drums. The drum should first be allowed to stand with bung (lid)
vertically upwards for at least 24 hours. The area around the bung should be cleaned & clean
glass or brass tube long enough to reach to within 10mm of the lowermost part of the drum
should be inserted, keeping the uppermost end of the tube sealed with the thumb while doing
so. Remove the Thumb thereby allowing oil to enter the bottom of the tube. Reseal the tube
and withdraw an oil sample. The first two samples should be discarded. Thereafter, the
sample should be released into a suitable receptacle. Samples to be collected preferably in
clean glass bottles. The bottles are to be rinsed with the same oil and to be without any air
bubble.
Before starting erection, thorough internal inspection of Transformer/ Reactor is to be
carriedoutbyPOWERGRIDengineeralongwithmanufacturer'srepresentative.
Internal inspection should be preferred in dry and sunny weather and should be finished as
quicklyaspossibletoavoidingressofmoistureadmittingdryair.
Prior to making any entry into the transformer tank, establish a foreign material exclusion
programmetoavoidthedangerofanyforeignobjectsfallingintothetransformer:
ØLoose articles should be removed from the pockets of anyone working on the
transformercover.
ØAlljewellery,watches,pens,coinsandknivesshouldberemovedfrompockets.
ØProtectiveclothingandcleanshoecoversarerecommended.
ØToolsshouldbetiedwithcleancottontapeorcordsecurelyfastened.
ØPlatedtoolsortoolswithpartsthatmaybecomedetachedshouldbeavoided.
ØAn inventory of all parts taken into transformer should be recorded and checked
beforeclosinginspectioncovertoassureallitemswereremoved.
2.3 InternalInspection
Doc No. D-2-01-03-01-03

If any object is dropped into the transformer and cannot be retrieved, the manufacturer
shouldbenotified.
Theinspectionshouldinclude:
ØRemovalofanyshippingblockingortemporarysupport.
ØExaminationforindicationofcoreshifting.
ØTestsforunintentionalcoreorcoreclampgrounds.
ØVisual inspection of windings, leads, and connections including clamping, bracing,
blocking,spaceralignment,phasebarriers,oilboxes,andcoilwraps.
ØInspectionofDETCandin-tankLTCsincludingcontactalignmentandpressure.
ØInspectionofcurrenttransformers,includingsupportsandwiringharness.
ØChecksfordirt,metalparticles,moisture,orotherforeignmaterial.
In case of any abnormality noticed during internal inspection, same to be referred to
manufacturer,CC-Engg.&CC-OSimmediatelybeforestartingerectionactivities.
Detailed photographs of all visible parts/ components as per above are to be taken during
internalinspectionandtobeattachedwithpre-commissioningreport.
During erection, efforts to be made to minimize the exposure of active parts (core and coils)
of transformer/ reactor. Moisture may condense on any surface cooler than the surrounding
air. Excessive moisture in insulation or dielectric liquid lowers its dielectric strength and
maycauseafailureofTransformer/Reactor.
Further, either dry air generator should be running all the time or dry air cylinders may be
used to minimize ingress of moisture. The transformer should be sealed off after working
hours. Transformer/ reactor shall never be allowed to be opened without application of
dryair.
Remarks: As N2 is heavier than air, application of Vacuum to be ensured and thereafter dry
air to be admitted before entering inside Transformer after shipment in N2 filled condition.
Oxygen content should be between 19 % and 25 % prior to any entry. During inspection, dry
airtobepurgedcontinuously.
It is practical to apply a slight overpressure overnight with dry air or N2 inside – less than 300
mbar (30 kPa or 0.3 atmospheres). Next day the pressure is checked and suspected leaks may
be detected with leak detection instruments/ with soap water or with plastic bags tightened
aroundvalves(beinginflatedbyleakingair)
For oil filled units whenever oil is drained out below the inspection covers, job will be treated
as exposed.Otherexposureactivitiesareasbelow:
1) Bushingerections
2) JumperconnectionsofBushings
3) Fixingbushingturrets
4) Coreinsulationchecking(incasethecheckingpointnotaccessibleoutside)
5) Buchholzrelaypipeworkfixingoncover
6) Gasreleasepipes/equalizerpipefixing
7) Enteringinsidethetankforconnections/inspectionetc
2.4 Precautionsduringerection
Doc No. D-2-01-03-01-03

For oil filled units depending upon the level up to which the oil is drained decides the
exposure time. All such exposure time should be recorded in a log sheet to decide the oil
processing(drying)andoilfillingoftransformer.
"GET THE TRANSFORMER UNDER OIL AS SOON AS POSSIBLE!" It is good practice to
proceed with the erection in such a sequence that all fittings and auxiliaries with oil seals to
the tank are assembled first. The oil filling will then be performed as easily as possible. The
"active part" inside - core and coils - is then impregnated and protected. It has good time to
soak properly, before the unit shall be energized, while remaining fittings are assembled on
theunit,andcommissioningcheckscarriedout.
For transformers with a gas pressure of 2.5- 3 PSI, the acceptable limits of dew point shall be
asunder:(Courtesy:BHEL,Bhopal)
TABLE 1- Variation of Dew Point of N2 Gas Filled in Transformer Tank w.r.t
Temperature
Temperature of
Insulation in°F
Permissible dew
point in°F
Temperature of
Insulation in°C
Permissible dew
point in°C
0 -78 -17.77 -61.11
5 -74 -15.0 -58.88
10 -70 -12.22 -56.66
15 -66 -9.44 -54.44
20 -62 -6.66 -52.22
25 -58 -3.33 -49.99
30 -53 -1.11 -47.22
35 -48 +1.66 -44.44
40 -44 +4.44 -42.22
45 -40 +7.44 -39.39
50 -35 +9.99 -37.22
55 -31 12.77 -34.99
60 -27 15.55 -32.77
65 -22 18.33 -29.99
70 -18 23.11 -27.77
75 -14 23.88 -25.55
80 -10 26.66 -23.33
85 -6 29.44 -21.11
90 -1 32.22 -18.33
95 +3 34.99 -16.11
100 +7 37.75 -13.88
110 +16 43.33 -8.88
120 +25 48.88 -3.88
130 +33 54.44 +0.55
140 +44 59.99 +5.55
Doc No. D-2-01-03-01-03

2.5 Finaltightnesstestwithvacuum(i.e.leakagetestorVacuumDropTest)
Before oil filling is started, a final check is made for the tightness of the transformer tank by
applying vacuum. When vacuum is applied to a transformer without oil, a leakage test must
be carried out to ensure that there are no leaks in the tank which would result in wet air being
drawnintothetransformer.Thefollowingprocedureistobeadopted:
ØConnect the vacuum gauge to a suitable valve of the tank. (Vacuum application and
measurement should be performed only on top of the main tank) -Avacuum gauge of
Mc Leod type or electronic type, with a reading range covering the interval - 1 kPa (1
-10mmmercury)tobeused
ØConnectthevacuumpumptoanotheropening.
ØEvacuate the transformer/ reactor tank until the pressure is below 3 mbar ( 0.3 kPa or
about2mmofHg)
ØShutthevacuumvalveandstopthepump.
ØWaitforanhourandtakeafirstvacuumreading–sayP1
ØTakeasecondreading30minuteslater-sayP2
ØNote the volume of the tank (quantity of oil required according to the rating plate)
3
andexpressasvolume,V,inm
ØTake the difference between P2 and P1, and multiply this with the oil quantity V. If
3
the pressures are expressed in kPa, and the oil quantity in m , then the product shall be
lessthan3.6.
(P2–P1)xV<3.6
The transformer is then considered to be holding sufficient vacuum and is tight.
Continuereading(atleast2to3)atsuccessive30minintervalstoconfirmtheresult.
ØIf the leak test is successful, the pumping will be continued, until the pressure has
come down to 0.13 kPa (1 Torr) or less. The vacuum shall then be held for the time
giveninTable-3beforetheoilfillingstarts.
ØIf the specified vacuum cannot be reached, or if it does not hold, the leak in the
transformersystemshallbelocatedandcorrected.
In case the transformer is provided with an On Load Tap Changer (OLTC), while evacuating
the main transformer tank, the diverter switch compartment may also be evacuated
simultaneously so that no undue pressure is allowed on the tap changer chamber. While
releasing vacuum, the tap changer chamber vacuum should also be released simultaneously.
For this one pressure equalizer pipe should be connected between main tank and tap changer.
Manufacturer's instruction manual should be referred to protect the air cell/diaphragm in the
conservatorduringevacuation.
This vacuum must be maintained for the time specified as per the voltage class in Table-3
before and should also be maintained during the subsequent oil filling operations by
continuousrunningofthevacuumpumps.
Doc No. D-2-01-03-01-03

2.6 Oil Filling
Once the oil is tested from the drums and found meeting the requirements, the oil is
transferredtooilstoragetankforoilfiltrationbeforefillinginsidethetransformer.
The drums ortrailertanks shall not be emptied to the last drop - a sump of an inch orso
isleft,toavoidpossiblesoliddirtorwaterinthebottom.
Before being used, the tanks and hoses are visually inspected inside for cleanness. Any
liquid residue from earlier use will be carefully removed, and the container flushed
withasmallquantityofnew oil,whichisthendiscarded.
Afterfiltration,oilsampleistestedformeetingPOWERGRIDspecificationfornewoil.
Prior to filling in main tank at site and shall be tested for:
1. Break Down voltage (BDV) : 70kV (min.)
2. Moisture content : 5 ppm (max.)
3. Tan-delta at 90 °C : Less than 0.01
4. Interfacial tension : More than 0.035 N/m
For transformer dispatched with gas (N2) filled from the works, the filling of oil inside the
tank is done under vacuum. Transformer of high voltage ratings and their tanks are designed
to withstand full vacuum. Manufacturer's instructions should be followed regarding
applicationoffullvacuumduringfillingtheoilinthetank.
When filling a transformer with oil it is preferable that the oil be pumped into the
bottom of the tank through a filterpress orotherreliable oil drying and cleaning device
shouldbeinterposedbetweenthepumpandthetank(pleasereferFig-2).
The oil flow at the entry valve must be controlled to maintain a positive pressure above
atmospheric and to limit the flow rate if necessary to 5000 litres / hour, or a rise in oil level in
thetanknotexceedingonemeter/hour(asmeasuredontheoillevelindicator)
Continue oil filling until the level reaches approximately 200 mm above the ambient oil level
indicated on the magnetic oil level gauge in the expansion vessel. Then, release the vacuum,
withdryairofdewpoint-40degCorbetter.
The diverter tank can now be topped up at atmospheric pressure. Reconnect oil outlet hose to
valve on flange on tap changer diverter head. Reinstate breather and very slowly top up the
diverter switch such that the correct level is reached in the diverter expansion vessel. In the
event the expansion vessel is overfull drain oil from flange into a suitable container until the
correctlevelisreached.
Doc No. D-2-01-03-01-03

TRANSFORMER
TANK
FILTER
MACHINEOIL
STORAGE
TANK
VACUUM
PUMP
SUMP
D.O.F. Filter Valve
If not, then BTM Filter Valve
B
A C
B.R.
Top Filter
Valve
Compound Pressure
& Vacuum gauge
Filter on any 1”
Sampling or 2” Filter
Valve
Valve near B. RELAY
towards Conservator
Tank Oil Gauge/
Transparent hose for
Level monitoring
When the vacuum filling of the transformer and diverter tank is complete, the cooling system/
Radiator bank can be filled (WITHOUT VACUUM) at atmospheric pressure, via an oil processing
plant. Oil must be admitted, very slowly, through the bottom cooler filter valve, with the cooler
vented at the top and the top cooler filter valve unblanked and open to atmosphere. As the oil level
reachesthetopvent,thentopvalveto beclosedandtheprocessingplantcanbeshutdown.
Note:Caremustbetakennottopressurizethecoolers/radiators.
Upon completion, open the top cooler isolating valve in order to equalize the pressure in the cooler
with the transformer tank. This will also allow contraction or expansion of the oil as the ambient
temperaturechanges.
Before filling oil into the conservator, the air cell/ bellow to be inflated to 0.5 PSIG i.e. 0.035kg/cm2
max. by applying pressure (N2/Compressed dry air) so that it can take shape. After releasing
pressure, breather pipe is to be fitted however it is recommended not to fit breather in position,
instead a wire mesh guard over and flange of the pipe to prevent entry of any insect inside the pipe.
Thiswillensurefreeairmovementfromtheaircelltotheatmosphere.
Use flow meter / indicator on outlet of filter machine and regulate the flow using the valve to limit oil
fillingrateto2000litresperhour(max.)incasefiltercapacityismore.
Figure-2 : Arrangement for Evacuation and Oil filling upto tank Oil gauge & Conservator
Doc No. D-2-01-03-01-03

Oil to be pushed slowly into conservator through the transformer via valve No. 5 (valve 2,3 & 4 to
remain open) till the oil comes out first through valve Nos.2 & 3 (close these valves) and then
through valve No. 4. Allow some oil to come out through valve No.4. Oil should come out freely
into the atmosphere. This will ensure that air inside the conservator is expelled out and the space
surrounding the air cell is full of oil. (Close valve No. 4). During all these operations valve No.1
shallbein closedposition.
Excess oil from the conservator is to be drained by gravity only through valve No. 1 or through drain
valve of the transformer via valve No. 5. Do not use filter machine for draining oil from the
conservator. Also do not remove buchholz relay and its associated pipe work, fitted between the
conservatorandthetransformertankwhiledrainingoil.
Stop draining oil till indicator of magnetic oil level gauge reaches position-2 on the dial, which is
corresponding to 30C reading on the oil temperature indicator. Fill the conservator according to the
oiltemperatureandnottheatmospherictemperature
Figure-3 : General Arrangement For Oil Conservator
After Oil filling, Hot Oil Circulation has to be applied to all theTransformers/ Reactors except under
the circumstances when active part of Transformer/ Reactor gets wet. Following conditions can be
consideredtodefinetheTransformer/Reactorwet:
1. IfTransformer/ReactorreceivedatsitewithoutpositiveN2pressure.
2. IfDryairnotusedduringexposurewhiledoingerectionactivities
3. Overexposure of active part of Transformer/ Reactor during erection
(Overexposurewhenexposure>12Hrs)
Underabove mentioned conditions, Manufacturershall take necessary action foreffective dry
out of the Transformer/ Reactor. However general guidelines for dry out in such cases is given
insection2.8
Doc No. D-2-01-03-01-03

2.7 HOTOILCIRCULATIONUSINGHIGHVACUUMOILFILTERMACHINE
To ensure proper dryness and absorption of possible trapped gas bubbles, the oil in the tank is
circulatedthroughthevacuumfilterandwithcirculationdirectionasshowninFig.-4.
Thecirculationprocedureforthemaintankisasfollows.
2.7.1 The Transformer/ Reactor is connected to the oil filter machine in a loop through the upper
and lower filter valves. The direction of circulation shall be from the filter to the
transformer at the top and from the transformer to the filter at the bottom. (Please note that at
theinitialoilfillingtimethedirectionisreversetoavoidairbubbleformation).
2.7.2 The temperature of the oil from the filter to the Transformer should be around 60 °C and in
nocaseitshouldgobeyond70°Cotherwisethismaycauseoxidationofoil.
2.7.3 The circulationshall proceed until a volume of oil has passed through the loop corresponding
to 2 times the total oil volume in the tank. (At freezing ambient temperature the circulation
time is increased, circulate 3 times the volume at temperature down to minus 20 °C, increase
to4timesbelowthattemperature).
The oil sample from the transformer tank, after filling in tank before commissioning should
meet the following specifications (as per latest POWERGRID Revision) given in table-2
below.
1. Break Down voltage (BDV) : 70 kV (min.)
3. Tan-delta at 90 °C : 0.01 (max.)
4. Total Gas Content : < 1%
12
5. Resistivity at 90 °C : 6 X 10 ohm-cm (min.)
6. Interfacial tension : 0.035 N/m (min.)
7. *Oxidation Stability (Test method as per IEC 61125 method C, Test duration: 500
hour for inhibited oil)
a) Acidity : 0.3 (mg KOH /g) (max.)
b) Sludge : 0.05 % (max.)
c) Tan delta at 90 °C : 0.05 (max.)
8. * Total PCB content : Not detectable (2 mg/kg total)
* For Sr. No. 7 & 8 separate oil sample shall be taken and test results shall be submitted
within 45 days after commissioning for approval of Powergrid.
Table-2
Doc No. D-2-01-03-01-03

Figure-4: Arrangement for Hot Oil Circulation and Filtration
2.8 PROCEDUREFORDRYOUTOFWETWINDING OFTRANSFORMER/
REACTORBYAPPLICATIONOFVACUUM,N2FILLINGANDHEATING
The drying of a new Transformer/ Reactor is required when the moisture gets absorbed by
the solid insulation used in Transformers/ Reactors due to various reasons. The process of
drying out a transformer requires care and good judgment. If the drying out process is
carelessly or improperly performed, a great damage may result to the transformer insulation.
In no case shall a transformer be left unattended during any part of the dry out period unless
on-line dryout process is adopted which incorporates all necessary safety features. The
transformer should be carefully watched throughout the dry-out process and all observations
tobecarefullyrecorded.
When the transformer is being dried out, it is necessary to ensure that fire fighting equipment
is available near the transformer as a precaution as there are chances of fire as we are dealing
withheatandinflammableoil.
2.8.1 IsolationRequired
All the openings of transformer main tank like openings for coolers/radiators, conservator,
OLTCetc.istobeproperlyisolatedandtotallyblanked.
2.8.2 Procedure
a. Fill the main transformer/ reactor tank with Nitrogen (Use only Dry N2 gas as per IS:
1747 with less than 50 ppm moisture and 1% oxygen by volume) until it comes to a
2.
positive pressure of 0.15 Kg/cm It is kept for about 48 hrs.At the end of 48 hrs, dew
point of N at outlet is measured. If the dew point is not within acceptable limits as per2
Table-I,dryoutmethodshouldbecontinued.
Doc No. D-2-01-03-01-03

b. While N2 circulation is in progress, the heaters are to be installed around the
transformer tank. The heaters are to be kept ON until we achieve a temperature of
about 75–80 deg C of the core & winding of transformer as measured by top oil
temperatureinthetransformer.
c. After ascertaining that there is no leakage, pull out vacuum and keep the
transformer/reactor under near absolute vacuum (1-5 torr) and keep under vacuum
for about 96 hours running the vacuum pump continuously. The duration of vacuum
can vary between 48 to 96 hrs depending upon the dew point being achieved. Keep
vacuum machine ON and collect condensate for measurement. Observe the rate of
condensate collection on hourly basis. Depending on the value of rate of condensate
(lessthan40ml/hrfor24hrs),continuationoffurthervacuumshallbedecided.
d. Then the vacuum is broken with dry nitrogen.The dew point of nitrogen at the inlet is
0
to be measured and should be of the order of - 50 C or better. When the nitrogen
comes to the positive pressure of 0.15 kg/cm2, it is stopped and kept for 24 hours.
Heating from outside is to be continued while N2 circulation is in progress. Then the
nitrogen pressure is released and the outlet nitrogen dew point is measured. If the
dew point is within acceptable limits as per Table-I then the dryness of transformer is
achieved. If not again the transformer is taken for vacuum treatment and then
nitrogen is admitted as mentioned above and tested. The cycle is to be continued till
desireddewpointasperTable-1isachieved.
e. Periodicity of vacuum cycle may vary between 48-96 hrs. Initially two N2 cycles
may be kept for 24 hrs.After that it may be kept for 48 hrs depending upon dew point
beingachieved.
After completion of drying process, oil filling and hot oil circulation is to be carried out
before commissioning. Please ensure standing time as per table-3 given below before
charging.
Note: If already known that the transformer is wet based on the tests or exposure time,
then (a) above can be skipped to save time.
Transformer HV
Rated Voltage
(in kV)
Application of Vacuum &
holding for (before oil filling)*
(in Hours)
STANDING TIME After Oil
circulation and before energising
(in Hours)
Up to 145kV 12 HRS 12 HRS
145 kV and up to
420kV
24 HRS 48 HRS
Above 420 kV 36 HRS 120 HRS
*Without running the vacuum pump and leakage rate to be ≤40mbar-lit/sec
Table-3
After the expiry of this time, air release operation is to be carried out in Buchholz relays,
turretsandotherreleasepointsgivenbythemanufacturersbeforecharging.
For subsequent activities, proceed to format no. CF/ICT/01/ R-3 Dated 01/01/2011 for ICT
& format No. CF/SR/02/ R-3 Dated 01/01/2011 for Reactor. Refer pre-commissioning test
proceduresgiveninnextsectionforallrequiredteststobeperformed.
Doc No. D-2-01-03-01-03

RELATION BETWEEN DIFFERENT2.9 UNITS (CONVERSION OF UNITS):
Pressure
1 bar = 105
Pa = 750 Torr = 14.5 psi = 1.02kg/cm2
1 Torr = 1.33 mbar = 0.133 kPa
1 kPa(kilo-Pascal) = 103
Pa = 10 mbar = 7.501 Torr(mm of mercury)
1 MPa = 106
Pa
1 atmosphere=0.1 MPa=1.02kg/cm2
= 14.5 psi
Force
1 kp = 9.807 N
Weight
1 ton=1000 kg=2200 lbs
Temperature
° C =
5
9
* (° F - 32)
° F =
9
5
* (° C )+ 32
Volume
1m3
= 1000 litres=260 US gallons=220 Imp gallons
1 litre =0.26 US Gallons
1 US Gallons = 3.78 litres
1 litre =0.22 Imp Gallons
1 Imp Gallons
Benchmarks
1-mm mercury (Torr) is about 1 millibar or 0.1 kPa
1 m3
of oil weights 0.9 tons –say 1 ton
1000 US gallons of oil weights 3.5 tons
Doc No. D-2-01-03-01-03

Once oil filling is completed, various pre-commissioning checks/ tests are performed to ensure the
healthiness of the Transformer/ Reactor prior to its energization. Various electrical tests are to be
performedandtheirsignificanceisgivenbelow
Sr.
No.
Name of Test/
Check point
Purpose of test/ check
3.1 Core insulation tests Allows for investigating accidental grounds which results in
circulating currents if there is more than one connection between
the core and ground.
3.2 Earth pit resistance
measurement
To check the resistance of earth pit provided for Transformer. In
case, the resistance is more, proper treatment is to be given.
3.3 Insulation
Resistance (IR)
measurement
Test reveals the condition of insulation (i.e. degree of dryness of
paper insulation), presence of any foreign contaminants in oil
and also any gross defect inside the transformer (e.g. Failure to
remove the temporary transportation bracket on the live portion
of tap-changer part)
3.4 Capacitance and
Tanä measurement
of bushings
Measurement of C1 & C2 Capacitance and Tanä in UST mode.
Changes in the normal capacitance of an insulator indicate
abnormal conditions such as the presence of moisture layer,
short -circuits or open circuits in the capacitance network.
3.5 Capacitance and Tan
ä measurement of
windings
Dissipation factor/Loss factor and capacitance measurement of
winding is carried out to ascertain the general condition of the
ground and inter-winding insulation
3.6 Turns ratio (Voltage
ratio) measurement
To determine the turns ratio of transformers to identify any
abnormality in tap changers/ shorted or open turns etc
3.7 Vector Group &
Polarity
To determine the phase relationship and polarity of transformers
3.8 Magnetic Balance
test
This test is conducted only in three phase transformers to check
the imbalance in the magnetic circuit
3.9 Floating Neutral
point measurement
This test is conducted to ascertain possibility of short circuit in a
winding.
3.10 Measurement of
Short Circuit
Impedance
This test is used to detect winding movement that usually occurs
due to heavy fault current or mechanical damage during
transportation or installation since dispatch from the factory.
PRE- COMMISSIONING CHECKS/TESTS
FOR TRANSFORMERS AND REACTORS
Doc No. D-2-01-03-01-03

3.13 Tests/ Checks on
Bushing Current
Transformers (BCTs)
To ascertain the healthiness of bushing current transformer at the
time of erection
3.14 Operational Checks
on protection System
Operational checks on cooler bank (pumps & Fans), Breathers
(Silicagel or Drycol), MOG, temperature gauges (WTI/OTI), gas
actuated relays (Buchholz, PRD, SPR etc.) and simulation test of
protection system
3.15 Stability of
Differential, REF of
Transformer/ Reactor
This test is performed to check the proper operation of
Differential & REF protection of Transformer & Reactor by
simulating actual conditions. Any problem in CT connection,
wrong cabling, relay setting can be detected by this test.
3.16 Frequency Response
Analysis (FRA)
measurement
To assess the mechanical integrity of the transformer.
Transformers while experiencing severity of short circuit current
looses its mechanical property by way of deformation of the
winding or core. During pre-commissioning this test is required
to ascertain that Transformer active part has not suffered any
severe impact/ jerk during transportation.
3.17 Winding resistance
measurement
To check for any abnormalities due to loose connections, broken
strands and high contact resistance in tap changers
3.18 Dissolved Gas
Analysis (DGA) of
oil sample
Oil sample for DGA to be drawn from transformer main tank
before commissioning for having a base data and after 24 hrs. of
charging subsequently to ensure no fault gas developed after first
charging. DGA analysis helps the user to identify the reason for
gas formation & materials involved and indicate urgency of
corrective action to be taken
3.11 Exciting/Magnetising
current measurement
To locate defect in magnetic core structure, shifting of windings,
failures in turn to turn insulation or problems in tap changers.
These conditions change the effective reluctance of the magnetic
circuit thus affecting the current required to establish flux in the
core
3.12 Operational checks
on OLTCs
To ensure smooth & trouble free operation of OLTC during
operation.
Doc No. D-2-01-03-01-03

3.1 COREINSULATIONTEST
3.2 Earthpitresistancemeasurement
This test is recommended first after receiving the equipment at site and to be performed on
trailer itself. Thereafter, before the unit is placed in service or following modifications to the
transformer that could affect the integrity of its core insulation and at other times, when
indicated by DGA(key gases being ethane and/or ethylene and possibly methane) or usually
duringamajorinspection.
For core-insulation to ground test, remove the cover of the terminal block, Disconnect the
closing link that connects the two terminals CL-G. Apply 1.0 kV direct voltage between CL
andCC+G(coregroundingstrap). Thetankshallbegroundedduringthetest.
Acceptable Limit: The insulation value after 1min. should be minimum 10 M for new
transformer at the time of commissioning. Core insulation resistance is generally more than
100Mfornewassembledtransformerwhentestedatfactory.
Earth tester is used for measurement of Earth resistance. If earth resistance is more, proper
treatment is to be given. For measurement of earth pit resistance, pit earthing connection
should be disconnected from main grid.Thereafter, measurement is to be carried out by three
pointmethod.
Working of EarthTester: -There is hand operated D.C.generator. While feeding current to
spike, D.C. current is converted intoA.C. current by the converter andA.C. current received
from spike is again converted in D.C. current by the help of rectifier, while going to
generator. A.C. current is fed to the spike driven in earth because there should not be
electrolyticeffect.
Measurement of Earth Resistance (Three point method):-
Figure-5
Doc No. D-2-01-03-01-03

In this method, earth tester terminals C1 & P1 are shorted to each other and connected to the
earth electrode (pipe) under test. Terminals P2 & C2 are connected to the two separate
spikes driven in earth. These two spikes are kept in same line at the distance of 25 meters and
50 meters due to which there will not be mutual interference in the field of individual spikes.
Ifwerotategeneratorhandlewithspecificspeedwegetdirectlyearthresistanceonscale.
AcceptableLimit:Valueofearthpitresistanceshouldbelessthanorequalto1? .
IR measurements shall be taken between the windings collectively (i.e. with all the windings
being connected together) and the earthed tank (earth) and between each winding and the
tank, the rest of the windings being earthed. Before taking measurements the neutral should
be disconnected from earth. Following table gives combinations of IR measurements for
auto-transformer,three-windingtransformer&ShuntReactor
3.3 INSULATIONRESISTANCE(IR)MEASUREMENT
For Auto-transformer For 3 winding
transformer
For Shunt Reactor
HV + IV to LV HV + IV to LV HV to E
HV + IV to E HV + LV to IV
LV to E HV + IV +LV to E
Rated Voltage class of
winding
Minimum desired IR value at 1 minute
(Meg ohm)
11kV 300 M?
33kV 400 M?
66kV & above 500 M?
Difference in temperatures ( °C) Correction Factor (k)
10 1.65
20 2.6
30 4.2
40 6.6
50 10.5
WhereHV-Highvoltage,IV-Intermediatevoltage,LV-Lowvoltage/Tertiaryvoltagewindings,E-Earth
Acceptable Limits: Unless otherwise recommended by the manufacturer, the following IR
values as a thumb rule may be considered as the minimum satisfactory values at 30°C (one
minutemeasurements)atthetimeofcommissioning.
Insulation resistance varies inversely with temperature and is generally corrected to a
standard temperature (usually 20°C) using table (Source: BHEL instruction Manual) as
givenbelow:
(The measured value to be multiplied by the factor k i.e T20 = k*T measured)
Doc No. D-2-01-03-01-03

The ratio of 60 second insulation resistance to 15 second insulation resistance value is called
dielectric absorption coefficient or Index (DAI). For oil filled transformers with class A
insulation,inreasonablydriedconditiontheabsorptioncoefficientat30°Cwillbemorethan1.3.
The polarization index test is performed generally by taking mega ohm readings at 1min and
10mim insulation resistance value. The polarization index is the ratio of the 10 min to the 1
minmegaohmreadings.
PI=R /R (dimensionless),WherePIisPolarizationIndexandRisresistance10 1
Thefollowingareguidelinesforevaluatingtransformerinsulationusingpolarizationindexvalues
Polarization Index Insulation Condition
Less than 1 Dangerous
1.0-1.1 Poor
1.1-1.25 Questionable
1.25-2.0 Fair
2.0 – 4.0 Good
Above 4.0 Excellent
A PI of more than 1.25 and DAI of more than 1.3 are generally considered satisfactory for a
transformer when the results of other low voltage tests are found in order. PI less than 1 calls
for immediate corrective action. For bushings, an IR value of above 10,000 MÙ is
consideredsatisfactory.
DissipationFactor
Dissipation factor/loss factor (Tan delta) is defined as the ratio of resistive component (I ) ofr
currenttothatofcapacitivecurrent(I )flowinginaninsulatingmaterial.c
PowerFactor
Power factor is the ratio of resistive current to that of total current. For very low value of
resistivecurrents,valuesofdissipationfactorandpowerfactoraresame(upto2%).
UST
Test set connected for Ungrounded Specimen Test mode. This is used when specimen is
isolated from earth e.g. Transformer bushing, CTs with test tap, CVTs and CB voltage
grading capacitors. The test mode is often used to reduce the effect of stray capacitance
lossestoground,andtoreducetheeffectofinterferencepickupfromenergizedapparatus.
GST
Test set connected for grounded specimen test mode. This is used when specimen do not
have two specific points (isolated from ground) for Tan delta measurement e.g.
Transformer/Reactorwinding,CTswithouttesttapetc.
GSTg
This test is used to separate the total values of a GST test into separate parts for better analysis.
OftenthistestisusedwithGSTtesttoconfirmthetestreadingsmadeusingtheUSTmode
3.4 CapacitanceandTan ämeasurementofBushings
Doc No. D-2-01-03-01-03

Figure-6
TESTEQUIPMENT
10 KV or 12 KV fully automatic Capacitance and Tan delta test kit to be used for accurate
measurementandrepeatabilityoftestresults.
TESTINGPROCEDURE
TypicalarrangementforTan dmeasurementisgivenbelow:
Doc No. D-2-01-03-01-03

PRECAUTIONS
a) Thereshouldbenojointsintestingcables.
b) HV lead should be screened with double shield and shields should not have internal shorting
otherwise tests in GST/GSTg modes, shall not be possible. Check the same by Insulation
Tester(100V)
c) Testleadsshouldnottouchanylivepart.
d) Neverconnectthetestsettoenergizedequipment
e) Thegroundcablemustbeconnectedfirstandremovedatlast
f) Highvoltageplugsshouldbefreefrommoistureduringinstallationandoperation.
g) Testingmustbecarriedoutbyexperienced/certifiedpersonnelonly.
h) After testing with high voltage (10 kV), test terminals must be grounded before being
touchedbyanypersonnel.
ØFor 3-Ph auto-transformer, short togetherall400kV, 220kVandNeutral(isolatedfromearth)
Bushings.Alsoshortall33kVBushingsandearththesame.
Measurement of C1 Capacitance and Tand: Connect the crocodile clip of the HV cable to
the top terminal of the shorted HV/IVbushings. Unscrew the test tap cover, Insert a pin in the
hole of the central test tap stud by pressing the surrounding contact plug in case of 245 kV
OIPBushing and remove the earthing strip from the flange by unscrewing the screw (holding
earth strip to the flange body) in case of 420 kVOIPBushing. Connect the LVcable to the test
tap (strip/central stud) of the bushing under test to the C & TANdKIT through a screened
cable and earth the flange body. Repeat the test for all Bushings by changing only LV lead
connectionofthekittotesttapoftheBushingwhichistobetested
Measurement of C2 Capacitance and Tand: HV lead to be connected to the test tap of the
bushing under test (if requiredadditionalcrocodiletype clipmay be used) and LVof the kit to
be connected to the ground. HVof the bushing is to be connected to the Guard terminal of the
testkit.TesttobecarriedoutinGSTgmodeat1.0kV.
ØFor measurement of 33kV Bushing Tan Delta, earth HV/IV Bushings (already shorted).
Apply HV lead of the Test kit to shorted 33kV Bushings and connect LV lead of the test kit to
TesttapoftheBushingundertest.
ØMeasurements shall be made at similar conditions as that of a previous measurement. The
oil-paper insulation combination of bushings exhibit fairly constant tan delta over a wide
range of operating temperature. Hence, effort is to be made for testing at temperature near to
previoustestandcorrectionfactorneednotbeapplied.
ØDo not test a bushing (new or spare) while it is in its wood shipping crate, or while it is lying
on wood. Wood is not as good an insulator as porcelain and will cause the readings to be
inaccurate.Keepthetestresultsasabaselinerecordtocomparewithfuturetests.
ØIt is to be ensured that C& Tan ä measurement of bushings and testing of turrets carried out
before installation.This will prevent installation of bushings having C&Tan ä values beyond
permissiblelimits.
Doc No. D-2-01-03-01-03

Ø
measurements for that particular Bushing and earthing of test tap to be ensured by carrying
outcontinuitytest.
AcceptableLimits:BushingTanäshouldbelessthan0.5%foralltypeofbushings.
The combination for C & tan measurement of winding is same as that of measurement of
IR value. The summery of probable combination is given below.
It is to be ensured that Test Tap points are earthed immediately after carrying out the
3.5 CAPACITANCEANDTANäMEASUREMENTOFWINDINGS
LV2 to Ground GSTg
Auto-
Transformer
(Two winding)
Test
Mode
Shunt
Reactor
Test
Mode
3 winding
Transformer
Test
Mode
HV + IV to LV UST HV to E GST HV to LV1 UST
HV + IV to E GSTg HV to LV2 UST
LV to E GSTg LV1 to LV2 UST
HV to Ground GSTg
LV1 to Ground GSTg
Test
No.
Winding
Combination
Test
mode
Cap
Symbol Test lead Connection Remarks
1. HV-IV/LV UST C HL HV lead of test kit to
HV/IV bushings of
transformer
LV lead of test kit to LV
bushing of transformer
2. HV-IV/ LV+G GST C HL +C HG -do-
3. HV-IV / LV with
Guard
GSTg C HG -do- LV to be
Guarded
4 HV-IV/LV UST C HL LV lead of test kit to
HV/IV bushings of
transformer
HV lead of test kit to LV
bushing of transformer
5 LV/ HV-IV +G GST C HL +C LG -do-
6. LV/ HV-IV with
Guard
GSTg C LG -do- HV to be
Guarded
Table 4: Combination for C & tan measurement of winding for various transformers/ Shunt Reactor
Ø
Bushings isPre-RequisiteforC&TanäMeasurementofWindings.
ØFor ICTs (Auto-Transformers): Shorting of all three phase Bushings (400kV&220kV)
and neutral to be done. In case of single phase, 400kV, 220kV and neutral Bushings to be
shorted Capacitance and Tan measurement of windings should be done in following
combinations.
Ensure that test specimen is isolated from other equipments. Removal of Jumpers from
Table 5:.Winding combination for C & tan ä measurement for auto transformer
Doc No. D-2-01-03-01-03

· Measurement inter-check can be done by calculating C = C -C & C = C - C &1 2 3 4 5 6
DF =C DF -C DF / C -C = C DF -C DF / C -C Where C stands for capacitance and DF1 2 2 3 3 2 3 4 4 5 5 4 5
for dissipation factor or tan ä and attached suffix (1…6) denotes the sr. no. of test in above
table.
· For Reactors: All 400kV and neutral Bushings to be shorted. HV of the test kit to be
connected to shorted Bushings and LV of the test kit to be connected to Earth connection.
Measure the Capacitance and tan Delta in GSTmode. Neutral connection with earth/ NGR to
beisolatedbeforethetest.
AcceptableLimit:WindingTanäshouldbelessthan0.5%inallcombinations.
Ratio measurements must be made on all taps to confirm the proper alignment and operation
of the tap changers. The test should preferably be performed by automatic Transformer turns
ratio(TTR)meter.
Open turns in the excited winding will be indicated by very low exciting current and no
output voltage. Open turns in the output winding will be indicated by normal levels of
exciting current, but no or very low levels of unstable output voltage.The turns-ratio test also
detects high-resistance connections in the lead circuitry or high contact resistance in tap
changersbyhigherexcitationcurrentandadifficultyinbalancingthebridge.
Acceptable Limit: Results of the voltage ratio are absolute, and may be compared with the
specified values measured during factory testing. The turns-ratio tolerance should be within
0.5 % of the nameplate specifications. For three phase Y connected winding this tolerance
applies to phase to neutral voltage. If the phase-to-neutral voltage is not explicitly indicated
in the nameplate, then the rated phase-to-neutral voltage should be calculated by dividing the
phase-to-phasevoltagebyÖ3.
Polarity and phase-relation tests are of interest primarily because of their bearing on
paralleling or banking two or more transformers. Phase-relation tests are made to determine
angular displacement and relative phase sequence. Phase-relation or vector group
verification test is performed on a three phase transformer or on a bank of three single-phase
transformers. The details of Additive and Subtractive polarity are given in IS: 2026-Part 1
andIEC60076-1.
3.6 TURNS RATIO(VOLTAGERATIO)MEASUREMENT
3.7 VECTORGROUPANDPOLARITY
Figure-7
1.1
1.2
Doc No. D-2-01-03-01-03

For a single-phase transformer having a ratio of transformation of 30 to 1 or less, the polarity
test shall be done as follows. The line terminal of high voltage winding (1.1) shall be
connectedtotheadjacentlineterminallow-voltagewinding(2.1)asshowninfigure7.
Any convenient value of alternating voltage shall be applied to the full high-voltage winding
and readings shall be taken of the applied voltage and the voltage between the right-hand
adjacenthigh-voltageandlow-voltageleads.
Whenthelaterreadingisgreaterthantheformer,thepolarityisadditive.
When the later reading is less than the former (indicating the approximate difference in
voltage between that of the high-voltage and low-voltage windings), the polarity is
subtractive.Thetestshallbeconductedwith3phase,415Vsupply.
By the measured voltage data, it should be verified that the desired conditions of vector
groupandpolarityarefulfilled
Example for Y D11
1R1
3R1
3Y1
2R1
2B1 2Y1
1B1 1Y1
3B1
- Connectneutralpointand LVphasewithEarth
- Join1R1&3R1Terminals
- Apply415,3-ösupplytoHV
- Ensure2R1-N=2Y1-N=2B1-N=Constant
- If 3R1-N>3Y1-N>3B1-N, and 3Y1-1B1>3Y1-
1Y1
Vector group Yna0d11 is confirmed and polarity
verified.
3.8 MAGNETICBALANCETEST
This test is a low voltage test conducted at factory and site by applying single phase voltage
between phase and neutral of a winding and measuring voltage induced in other two phases
ofthesamewinding.Thistestiscarriedoutonlyinthreephaseunits.
Keep the tap in nominal tap position. Disconnect transformer neutral from ground. Apply
single phase 230 V across one phase of Highest Voltage (HV) winding terminal and neutral
(call it v1) then measure voltage in other two HV terminals across neutral (call them v2 and
v3 respectively). Repeat the test for each of the three phases. Repeat the above test for
Intermediate Voltage (IV) winding also. The identical results confirm no damage due to
transportation.Thefollowingpointsmaybenoted.
Transformerneutralshouldbedisconnectedfromground
(i) No winding terminal should be grounded, otherwise results would be erratic and
confusing.
(ii) Zero voltage or very negligible voltage induced in any of the other two phases
shallbeinvestigated.
(iii) It is proposed that a set of readings should be taken for information and comparison
laterduringserviceofthetransformer.
Please Note: Most of the auto transformers in POWERGRID are of Yd11configuration.
Doc No. D-2-01-03-01-03

Acceptable Limit: Also the applied voltage may be expressed as 100% voltage and the
induced voltage may be expressed as percentage of the applied voltage. This will help in
comparison of the two results when the applied voltages are different. The voltage induced
in the centre phase shall be 50 to 90% of the applied voltage. However, when the centre
phase is excited then the voltage induced in the outer phases shall be 30 to 70% of the
appliedvoltage.
Zero voltage or very negligible voltage induced in the other two windings should be
investigated.
This test is conducted by applying 3 phase 415 volt supply across HV windings or IV
winding as the case may be after disconnecting the transformer neutral from the ground. For
a healthy transformer, when 3 phase balance voltage is applied, the voltage between neutral
and ground is zero or otherwise a negligible voltage will appear. But in case there is a short
circuited winding, the voltage between the neutral and the ground is appreciable. This test
will also help in detecting the gradual deterioration or development of fault in the winding
duringservice.
Acceptable Limit For a healthy transformer the voltage between neutral and ground should
be zero or negligible. In case, significant voltage appears between neutral and ground,
mattertobereferredtothemanufacturer.
This test is used to detect winding movement that usually occurs due to heavy fault current or
mechanicaldamageduringtransportationorinstallationsincedispatchfromthefactory.
Ensure the isolation of Transformer from High Voltage & Low voltage side with physical
inspection of open condition of the concerned isolators/ disconnectors. In case tertiary is also
connected,ensuretheisolationofthesamepriortocommencementoftesting
The measurement is performed in single phase mode. This test is performed for the
combination of two windings.The one of the winding is short circuited and voltage is applied
to otherwinding.Thevoltageandcurrentreadingarenoted.
The test shall be conducted with variac of 0-280 V, 10 A, precision RMS voltmeter and
ammeter. The conductors used for short-circuiting one of the transformer windings should
have low impedance (less than 1m-ohm) and short length. The contacts should be clean and
tight.
Acceptable Limit: The acceptable criteria should be the measured impedance voltage
having agreement to within 3 percent of impedance specified in rating and diagram
nameplate of the transformer. Variation in impedance voltage of more than 3% should be
consideredsignificantandfurtherinvestigated.
3.9 FLOATINGNEUTRALPOINTMEASUREMENT
3.10 MEASUREMENTOFSHORTCIRCUITIMPEDANCE
Doc No. D-2-01-03-01-03

3.11 EXCITING/MAGNETISINGCURRENTMEASUREMENT
3.12 OPERATIONALCHECKSONOLTC
This test should be done before DC measurements of winding resistance as saturation of
winding due to the application of DC voltage may alter the test results. If there is suspected
residual magnetism in the winding, transformer under test may be demagnetized before
commencementofmagnetizingcurrenttest.
Three-phase transformers are tested by applying Single-phase 10 kV voltage to one phase
(HV terminals) and keeping other winding open circuited and measuring the current at
normal,minimumandmax.tappositions.
Keep the tap position in normal position and keep HV and LV terminals open.Apply 1phase
10kV supply on IV terminals. Measure phase to phase voltage between the IV terminals and
currentoneachoftheIVwindings.
Acceptable Limit: The set of reading for current measurement in each of the tap position
should be equal. Unequal currents shall indicate possible short circuits in winding. Results
between similar single-phase units should not vary more than 10 % .The test values on the
outside legs should be within 15 % of each other, and values for the centre leg should not be
more than either outside for a three-phase transformers. Results compared to previous tests
made under the same conditions should not vary more than 25%. If the measured exciting
current value is 50 times higher than the value measured during pre-commissioning
checks, then there is likelihood of a fault in the winding which needs further analysis.
The identical results confirm no damage due to transportation.The availability of test data of
normalconditionandfaultyconditionresultshelpustoanalyzetheprobleminfuture.
Followingchecksshouldbecarriedoutduringpre-commissioning:
ØManual Operation: The tap changer has to be run manually by the hand crank
through the total operating cycle. In each operating position, the position indicators
of motordriveand tap changer (OnTC head)show the same position.
ØMotor drive for step by step tap changing operation: Push button to be kept pressed
till the motor stops i.e. driving motor should be automatically switched off when the
tap changer has performed one switching operation be seen through the inspection
glassinthetapchangerheadcover).
(Note: At the time of change over selector operation (i.e. 9b to 10 & vice-versa), higher
torqueisrequired.Tapchangerendpositionshouldbecheckedthatthesameisnotoverrunto
avoid any failure during operation. Same can be seen through the inspection glass in the tap
changerheadcover).
With the tap-changer fully assembled on the transformer the following sequence of
operationsshallbeperformed:
a. With the transformer un-energized, one complete cycles of operations (a cycle of
operation goes from one end of the tapping range to the other, and back again). Check
Doc No. D-2-01-03-01-03

continuity of winding during this test. Ensure that the voltmeter needle does not
deflecttozero.SpecifywhereandhowtoconnecttheanalogVoltmeter.
b. With the transformer un-energised, and with the auxiliary voltage reduced to 85% of
itsratedvalue,onecompletecycleofoperation.
c. With the transformer energized at rated voltage and frequency at no load, one
completecycleofoperation.
The following additional check points/ guidelines for OLTC is recommended in consultation
withOLTCmanufacturertoensuretheabsenceofproblemsandproperoperation:
a) Functionofcontrolswitches
b) OLTCstoppingonposition
c) Fastenertightness
d) Signsofmoisturesuchasrusting,oxidationorfreestandingwaterandleakages
e) Mechanicalclearancesasspecifiedbymanufacturer'sinstructionbooklet
f) Operation and condition of tap selector, changeover selector and arcing transfer
switches
g) Drivemechanismoperation
h) Counter operation, Position indicator operation and its co-ordination with
mechanismandtapselectorpositions
i) Limitswitchoperation
j) Mechanicalblockintegrity
k) Properoperationofhand-crankanditsinterlockswitch
l) Physicalconditionoftapselector
m) Freedomofmovementofexternalshaftassembly
n) Extentofarcerosiononstationaryandmovablearcingcontacts
o) Inspectbarrierboardfortrackingandcracking
p) Afterfillingwithoil,manuallycrankthroughoutentirerange
q) Oil BDV and Moisture content (PPM) to be measured and recorded (Min BDV
shouldbe 60KVandMoisturecontentshouldbelessthan10PPM)
Continuity, Polarity and secondary winding resistance tests of individual cores of Bushing
Cts
(For detailed procedure, please refer to DOC NO: D-2-03-XX-01-01 Maintenance
ProceduresforSwitchyardEquipmentsPart1:EHVTransformers/Reactors)
1) Operational Checks on Breathers (Conventional Silcagel or Drycol as supplied with
thetransformers).
3.13 TESTS/CHECKSONBUSHINGCURRENTTRANSFORMERS (BCTS)
3.14 OPERATIONALCHECKSONPROTECTIONSYSTEM
Doc No. D-2-01-03-01-03

2) VisualcheckofMOGofMainConservator
3) MarshallingBox&KioskChecks
4) ValveOperationalChecks
5) ChecksonCoolingSystem
i. Checks on cooling fans-rotation, speed & Control (Manual /temp /load)
settingchecks
ii. ChecksonCoolingpumps-rotation,vibration/noise,oilflowdirection
6) Checks on temperature Gauges (OTI/WTI-Calibration and Cooler Control, alarm &
tripsettingtests
7) Checks on gas actuated (SPRs/ PRDs/ Buchholz) relays –Operational checks by
simulationaswellasshortingtherespectivecontactsasapplicable
8) Checks on tightness of Terminal connectors - micro-ohm measurement of each
connection
9) Checks on Transformer/ Reactor protection (differential, REF, Over-current &
stabilitytestsetc.)
This test is performed to check the correctness of CT polarity, CT secondary core
connections, connections at relay terminals and operation of relay under fault conditions.
Heretheentireelectricalprotectionschemeischecked.
3.15.1 REF STABILITY TEST FOR TRANSFORMER
1) After opening the Circuit Breaker and isolators at both side (H.V. and L.V. side) of
transformer, use “Primary Test Tap (M point or PI1/PI2)” provided in the BUSHING
TURRET CTs to bypass the Transformer with the help of Primary current injection
leads. Now, after ensuring completion of all CT wiring & normal polarity, inject
current with the help of Primary Injection kits in the relevant turret CTs of R phase &
Neutral,subjecttothe maximumratingofPrimaryTestTap.
2) MeasurethespillcurrentinREFrelaywhichshouldbenearlyzero.
3) SwitchoffCurrentInjection.
4) Reverse the polarity of R phase Bushing CT and again start Current Injection.
AppreciablespillcurrentwillappearinREFrelay.
5) Normalize the CT circuit which was reversed in step no. (4), after switching off
Currentinjection.
6) Repeat the same procedure for Y and B phases and note down the results in
formats.
7) Normalize the connections of CT.
8) This test has to be performed from both HV side & LV side w.r.t. Neutral.
3.15 STABILITYOFDIFFERENTIAL, REFOFTRANSFORMER/REACTOR
Doc No. D-2-01-03-01-03

However, if Primary Test Tap is not available in the Turret CTs, adopt following
procedure:
1) After opening the Circuit Breakers and Isolators at both side (H.V. and L.V. side) of
transformer apply 440V three phase voltage at three phase bushing of H.V. side with
thehelpofthreephasevariac.
2) EarththeRphaseoftheLVside(throughisolatorearthswitchordischargerod).
3) Measure the spill voltage (in mV)/ spill current (in mA) at REF relay which should be
nearlyzero.
4) Switchoff440Vsupply.
5) Reverse the polarity of R phase Bushing CT and again switch on 440V supply.
Appreciablespillvoltage/currentwillappearinREFrelay.
6) Normalize the CTcircuit which was reversed in step no. (5), after switching off 440V
supply.
7) RepeatthesameprocedureforYandBphasesandnotedowntheresultsinformats.
8) NormalizetheconnectionsofCTandremovefeedingofthreephasesupply.
3.15.2 REF STABILITY TEST FOR REACTOR
1) After opening the Circuit Breaker and Isolators of Reactor, use “PrimaryTestTap (M
point or PI1/PI2)” provided in the BUSHING TURRET CTs to bypass the Reactor
with the help of Primary current injection leads. Now, after ensuring completion of
all CTwiring & normal polarity, inject Current with the help of Primary Injection kits
in the relevant Turret CTs of R phase of Reactor & earth side CT of NGR, subject to
themaximumratingofPrimaryTestTap.
2) MeasurethespillcurrentinREFrelaywhichshouldbenearlyzero.
3) SwitchoffCurrentInjection.
4) Reverse the polarity of R phase Bushing CT and again start Current Injection.
AppreciablespillcurrentwillappearinREFrelay.
5) Normalize the CT circuit which was reversed in step no. (4), after switching off
Currentinjection.
6) RepeatthesameprocedureforYandBphasesandnotedowntheresultsinformats.
7) NormalizetheconnectionsofCT.
However, if Primary Test Tap is not available in the Turret CTs, adopt following
procedure:
1) After opening the C.B. and isolators of Reactor, remove the jumpers of three
phase bushings. Reactor Neutral will remain connected to NGR, however Earth
connection of NGR Bushing will be opened.
2) Apply 415 volts, phase to phase voltage across R phase bushing of Reactor & earth
sideBushingofNGR,afterensuringcompletionofallCTwiring&normalpolarity.
3) Measure the spill voltage (in mV)/ spill current (in mA) in REF relay which should
benearlyzero.
4) Switchoff415VsupplytoReactor/NGRBushing.
Doc No. D-2-01-03-01-03

5) ReversethepolarityofRphasebushingCT.
6) Switchon415VsupplytoReactor/NGRBushing.
7) Appreciablespillvoltage/currentwillappearinREFrelay.
8) NownormalizethepolarityoftheBushingCTwhichwasreversedinstep(5).
9) RepeatthesameprocedureforYandBphaseandnotedowntheresultsinformats.
10) After completing the test for all three phases normalize the reactor CT connection
andjumpers&EarthconnectionofNGRBushing.
Frequency Response Analysis (FRA) is conducted to assess the mechanical integrity of the
transformer which may get disturbed due to transportation shocks. FRA signatures will be
taken after assembly and oil filling and compared with factory testing to ensure the
healthiness of core /coil assembly during transportation. These signatures will be the
benchmark for future reference. The FRAsignatures should be analyzed in conjunction with
Impact Recorder readings. Report of Impact recorder readings is to be obtained from
manufacturer.
It is recommended to follow the standard procedure for the SFRA measurement as per the
Table-7.Itshouldbedoneonmaximum,normalandminimumtapofthetransformer.
3.16 FREQUENCYRESPONSEANALYSIS (FRA)MEASUREMENT
Combination of tests for Auto Transformer
Test Type Test 3 Ô 1 Ô
Test 1 H1-X1
Test 2 H2-X2Series Winding (OC)
All Other Terminals Floating
Test 3 H3-X3
H1-X1
Test 4 X1-H0X0
Test 5 X2-H0X0
Common Winding (OC)
Test 6 X3-H0X0
X1-H0X0
Test 7 Y1-Y3
Test 8 Y2-Y1
Tertiary Winding (OC)
Test 9 Y3-Y2
Y1-Y2
(Y1-Y0)
Test 10 H1-H0X0
Test 11 H2-H0X0
Short Circuit (SC)
High (H) to Low (L)
Short (X1-X2-X3) Test 12 H3-H0X0
H1-H0X0
Short (X1-H0X0)
Test 13 H1-H0X0
Test 14 H2-H0X0
Short Circuit (SC)
High (H) to Tertiary (Y)
Short (Y1-Y2-Y3) Test 15 H3-H0X0
H1-H0X0
Short (Y1-Y2)
Test 16 X1-H0X0
Test 17 X2-H0X0
Short Circuit (SC)
Low (L) to Tertiary (Y)
Short (Y1-Y2-Y3) Test 18 X3-H0X0
X1-H0X0
Short (Y1-Y2)
Table-7: Various combinations for FRA measurement in Auto Transformer
Doc No. D-2-01-03-01-03

CombinationoftestsforShunt Reactor
IncaseofShunt Reactor,FRAtobedoneinfollowingcombinations:
ØH1-H0
ØH2-H0
ØH3-H0
Preferably to be carried out usingAutomatic kit, in case of non availabilityV/I method can be
adopted.
To reduce the high inductive effect, it is advisable to use a sufficiently high current to saturate
the core. This will reduce the time required to get a stabilized reading. It is essential that
temperatures of the windings are accurately measured. Care shall be taken that self inductive
effects are minimized. Care also must be taken to ensure that direct current circulating in the
windings has settled down before the measurement is done. In some cases this may take
severalminutesdependinguponthewindinginductance.
The winding resistance shall be preferably done when the difference in the top and bottom
temperature of the winding (temperature of oil in steady-state condition) is equal to or less
than5C.
The winding resistance should preferably be carried out last after completion of all other LV
tests, as after this test core gets saturated and tests like magnetizing current, magnetic
balance etc. carried out after winding test may be affected and indicate a misleading results,
ifthecoreis notde-magnetizedbeforecarryingoutthesetests.
For star connected auto-transformers the resistance of the HV side is measured between HV
terminal and IV terminal, then between IV terminal and the neutral AT ALL TAPS. The tap
changer should be changed from contact to contact so that contact resistance can also be
checked. Measurement of winding resistance is to be carried out from tap position 1 to 17 and
againfrom17to9.Whiledoingmeasurementsinreverseorder,2to3stepsshallbeenough.
During tap changing operation, continuity checks between HV to neutral to be carried out by
analogmultimeterwhilechangingtap.
For delta connected windings, such as tertiary winding of auto-transformers, measurement
shall be done between pairs of line terminals and resistance per winding shall be calculated
asperthefollowingformula:
Resistanceperwinding=1.5xMeasuredvalue
Takethewindingtemperaturereadingwhiledoingtheresistancemeasurement.
Calculatetheresistanceat75°Casperthefollowingformula
R =R (235+75)/(235+t),WhereR =Resistancemeasuredatwindingtemperaturet75 t t
3.17 WINDING RESISTANCEMEASUREMENT
Doc No. D-2-01-03-01-03

Acceptable Limit: The resistance value obtained should be compared with the factory test
value. Results are compared to other phases in Star-connected transformers or between pairs
of terminals on a Delta–connected winding to determine if a resistance is too high or low.
Because field measurements make it unlikely that precise temperature measurements of the
winding can be made, the expected deviation for this test in the field is not more than 5.0% of
thefactorytestvalue.
Dissolved Gas Analysis (DGA) is a powerful diagnostic tool to detect any incipient fault
developing inside the oil-filled equipment. The oil sample is to be taken after oil filling
(before commissioning ) as a benchmark and there after 24hrs of charging, 7 days, 15 days,
one month and three months after charging to monitor the gas build up if any.The oil samples
are to be sent to the designated labs for DGA and first two samples for oil parameter testing
also.
For detailed procedure for each test, please refer Transformer and Reactor
Maintenancemanual(DocNo.D-2-03-XX-01-01)-FirstRevision,PartB,C&D.
3.18 DISSOLVEDGASANALYSIS (DGA)OFOILSAMPLE
Doc No. D-2-01-03-01-03

4.1 PRELIMINARYCHECKS
1. Release air at the high points, like oil communicating bushings, buchholz petcock,
tank cover and the cooling devices including headers, radiators, pumps, expansion
joints etc. of the transformer. Air release should be resorted from low points to high
points.
2. Checkthewholeassemblyfortightnessandrectifywherenecessary.
3. Checkthegeneralappearanceandretouchthepaintworkifneeded.
4. Checkthatthevalvesareinthecorrectposition:
ØTank: valvesclosedandblanked
ØCoolingcircuit: valvesopen
ØConservatorconnection:valvesopen
ØBy-pass: valvesopenorclosedasthecasemaybe.
ØOn-loadtapchanger:valvesopen
5. Check that the silica gel is completely filled in the breather and is blue and that there
isoilinthebreathercup(oilseal)
6. EnsurethatCC&CLareproperlygrounded.
7. Check the oil level in the main conservator and the conservator of on-load tap
changer,aspermanufacturersrecommendations
8. Checkthebushings:
ØOillevel(bushingsfittedwithsight-glasses)
ØAdjustmentofspark-gaps/arcinghorn–gaps,ifprovided
ØConformityofconnectiontothelines(notensilestressontheterminalheads)
ØBushingCTsecondaryterminalsmustbeshortedandearthed,ifnotinuse.
ØNeutralbushingeffectivelyearthed
ØTandeltacapshouldbetightandproperlyearthed.
9. Checktheon-loadtap changer:
ØConformity of the positions between the tap changer control cubicle and the
tapchanger head
CHECK LIST FOR ENERGISATION OF
TRANSFORMER/ REACTOR
Doc No. D-2-01-03-01-03

ØAdjustmentofthetap-changercontrolcubiclecoupling
ØElectricandmechanicallimitswitchesandprotective relays
ØStep by step operation- local and remote electrical operation as well as
manualoperationandparalleloperation,ifany
ØSignalingofpositions
10. Checkthequalityoftheoil:
ØDrawasamplefromthebottomofthetank.
ØCarryoutDGAandoilparameterstest
11. Prior to energization at site, oil shall be tested for following properties &
acceptancenormsasperbelowgenerallyinlinewithIS:1866/IEC60422:
1. Break Down voltage (BDV) : 70 kV (min.)
3. Tan-delta at 90 °C : 0.01 (max.)
4. Total Gas Content : < 1%
12
5. Resistivity at 90 °C : 6 X 10 ohm-cm (min.)
6. Interfacial tension : 0.035 N/m (min.)
7. *Oxidation Stability (Test method as per IEC 61125 method C, Test
duration: 500 hour for inhibited oil)
a) Acidity : 0.3 (mg KOH /g) (max.)
b) Sludge : 0.05 % (max.)
c) Tan delta at 90 °C : 0.05 (max.)
8. * Total PCB content : Not detectable (2 mg/kg total)
· *For Sr. No. 7 & 8 separate oil sample shall be taken and test results shall be
submittedwithin45daysaftercommissioningforapprovalofPowergrid
12 CheckthatequalizinglinkbetweenOLTCtankandMaintankisremoved
13 Extraneous materials like tools, earthing rods, pieces of clothes, waste etc. should be
removedbeforeenergizing.
1. Ensurethatthetemperatureindicatorsarecalibrated.
2. Check the setting and working of the mercury switches of winding and oil
temperatureindicators
3. Ensurepresenceofoilinthethermometerpockets.
ØFollowthesameprocedureforthethermalreplicas
4. Checkthedirectionofinstallationofbuchholzrelay.
4.2 CHECKINGOFAUXILIARYANDPROTECTIVECIRCUITS
Doc No. D-2-01-03-01-03

5. Check the operation of the buchholz relay and the surge protective relay of the tap-
changerfor:
ØAlarmandtripping
ØProtectionsandsignalsassociatedwiththeserelays
6. Check the insulation of the auxiliary circuits with respect to ground by 2 kV
insulationtesterfor1min.Itshouldwithstandthetest.
7. Checktheearthingof thetankandauxiliarieslikecoolerbanksattwoplaces.
8. Measurethesupplyvoltagesoftheauxiliarycircuits
9. Checkthecoolingsystemforthefollowing:
ØCheckthedirectionofinstallationofoilpumps
ØCheckthedirectionofrotationofthepumpsandfans
ØChecktheworkingoftheoilflowindicators
ØCheckthesettingofthe thermaloverloadrelays
ØGo through the starting up sequences, control and adjust, if necessary, the
relaytimedelays
10. Check that there is sufficient protection on the electric circuit supplying the
accessoriesandtightnessofallelectricalconnections
11. Checktheheatingandlightinginthecubicles
12. Check the schemes of differential protection, over-current protection, restricted
earth fault protection, over-fluxing protection etc. With implementation of settings
asrecommendedbyCC/Engg
After the inspection / tests are completed, the transformer may be energized from the
incoming side on NO LOAD, 400kV or 220kV. The initial magnetizing current at the time of
switching will be very high, depending upon the particular moment in the cycle. The
transformer should be kept energised for twelve hours before taking on load. During this
time,vibrations,abnormalcrackingnoise,etc.aretobeobserved.
After that it may be checked for gas collection. If the gas prove to be inflammable, try to
detect the cause which may probably be an internal fault. If the breaker trips on differential
/REF, buchholz or any other protective device, the cause must be investigated thoroughly
before re-energizing the transformer/ reactor. After successful charging, performance of
transformer / rector should be checked under loading; OTI/WTI readings should be
monitoredfor24hoursandensuredthattheyareasperloading.
DGAsamples may be sent as per Standard practice (after 24 hrs of energizing, one week, 15
days, one month and three months after charging, thereafter as per normal frequency of 6
months). Loading data may be forwarded to CC/OS and manufacturer (if requested by
them).
Doc No. D-2-01-03-01-03

5.1 THERMOVISIONSCANNING (IRTHERMOGRAPHY)
5.2 OnLinemoisturemeasurement
5.3 VIBRATIONMEASUREMENTOFOIL-IMMERSEDREACTOR
Once the transformer/ reactor is charged and loaded, Thermovision scanning is to be carried
out to see any hotspots.Thermovision scanning of transformer to be done at least after 24 hrs.
ofloadingandrepeatedafteroneweek.
Movement of the core-coil assembly and shielding structure caused by the time –varying
magnetic forces results in vibration of the tank and ancillary equipment. These vibrations
have detrimental effects such as excessive stress on the core-coil assembly.The shunt reactor
under test shall be completely assembled in normal operating condition with cooling
equipments, gauges and accessories. The shunt reactor shall be energized at rated voltage
and frequency. Three phase excitation for 3-ph units. The shunt reactor should be mounted
on a level surface that will provide proper bearing for the base, in order to eliminate the
generationofabnormaltankstresses.
The vibration of shunt reactor shall be measured by transducers, optical detectors or
equivalent measuring devices.The measuring equipment should be accurate within +/- 10 %
nd
at2 harmonicof theexcitingfrequency.Thepeak-to-peakamplitudeshallbedeterminedby
direct measurement or calculated from acceleration or velocity measurement. The average
amplitude of all local maximum points shall not exceed 60 µm (2.36 mils) peak to peak. The
maximum amplitude within any individual reading shall not exceed 200 µm (7.87 mils) peak
topeak.
Sr.
No.
Name of Test/
Check point
5.1 Thermovision Infra-
red scanning (IR
thermography)
A thermo vision Camera determines the temperature distribution
on the surface of the tank as well as in the vicinity of the Jumper
connection to the bushing. The information obtained is useful in
predicting the temperature profile within the inner surface of
tank and is likely to provide approximate details of heating
mechanism.
5.2 On Line moisture
measurement
To determine the moisture content in paper insulation by
measuring % Relative Saturation/ Active Water. This test to be
carried out once the Transformer/ Reactor is stabilized and
operating at higher temperature (>60 deg C).
5.3 Vibration
measurement of Oil-
immersed Reactor
To measure the vibrations of core /coil assembly in the tank of
the reactor. Movement of the core-coil assembly and shielding
structure caused by the time–varying magnetic forces results in
vibration of the tank and ancillary equipment. These vibrations
have detrimental effects such as excessive stress on the core-coil
assembly
Doc No. D-2-01-03-01-03
POST COMMISSIONING CHECKS/TESTS
FOR TRANSFORMERS AND REACTORS

Once erection is completed, various pre-commissioning checks/ tests are performed to ensure the
healthiness of the switchyard equipments prior to their energisation. Various major electrical tests to
beperformedandtheirsignificancearegivenbelow:
Sr.
No.
Name of Test / Check
point
6.1 Tan ä & Capacitance
measurement of CT,
each stack of CVT &
total capacitance, CB
voltage grading
capacitor & each stack
of Surge Arresters
The purpose of the dissipation factor measurement of high
voltage insulation is to detect incipient weaknesses in HV
insulation. The most important benefit to be gained from
this measurement is to obtain a “benchmark reference
reading” on costly and high voltage equipment when the
equipment is new and insulation is clean, dry and free from
impurities. Tan delta & Capacitance values shall be
comparable with factory test results and in no case shall be
more than 0.5 %.
6.2 Checks/ Tests applicable for CTs
6.2.1 Polarity test for CT To ascertain whether the polarity markings are correct or
not as per drawing.
6.2.2 Magnetization
characteristics of CT
To prove that the turns of CTs secondary windings are not
short circuited and to check healthiness of CT cores. The
magnetizing currents at KPV (Knee point voltage) shall be
less than the specified value. The ratio of secondary and
primary voltage shall also be measured.
6.2.3 Ratio test for CT The ratio errors of the primary to the secondary currents
should within specified ratio errors.
6.2.4 IR measurement of CT
(Primary & Secondary
windings)
Changes in the normal IR value of CT indicate abnormal
conditions such as presence of moisture, dirt, dust, crack in
insulator of CT and degradation of insulation.
6.2.5 DGA test of CT oil This test shall be conducted after 30 days of
commissioning. The purpose is to identify evolving faults
in the CT and DGA values shall be comparable with
factory values (if available)
6.3 Checks/ Tests applicable for Circuit Breakers
6.3.1 Dew point measurement
of SF6 gas
Dew point of SF6 gas is to measure moisture content in
SF6 gas which shall indicate whether CB evacuation is
done properly or not. This test shall be carried out
preferably at rated pressure of SF6 gas.
6.3.2 Measurement of Circuit To measure closing/ tripping/ CO timings. These timings
Doc No. D-2-01-03-01-03
PRE-COMMISSIONING CHECKS/TESTS
FOR OTHER SWITCHYARD EQUIPMENTS

Breaker Operating
Timings including PIR
Timings
should be within permissible limits and shall be comparable
with factory values. Pole discrepancies and Break to Break
discrepancies shall be less than specified values.
6.3.3 DCRM Contact Travel
Measurement / DC
injected currents and
trip/ close coil currents.
DCRM is the technique for measuring Contact Resistance
during operation (Close/ Trip) of a circuit breaker with a
delay Tco of 300ms. A DC current of at least 100 Amp is
injected through the circuit breaker. The current and
voltage drop are measured and resistance is calculated. The
resistance and travel versus time data provides useful
information on the condition of the circuit breaker contacts
and is used as a diagnostic tool. DCRM test signatures shall
be approved by Corporate OS.
6.3.4 Operational lockout
checking for EHV
Circuit Breakers
To ensure various lockout operation of CB by simulating
the actual conditions at the specified pressure of oil/ air/
operating medium.
6.3.5 Measurement of static
contact resistance
This test is conducted to evaluate healthiness of Main
contacts. 100 Amp DC is injected and voltage drop is
measured across each CB contact to compute contact
resistance.
6.3.6 Checking the Anti-
Pumping feature
By giving simultaneous close/ trip commands, CB hunting
shall not take place by operation of Mechanical/ Electrical
anti pumping feature.
6.3.7 Checking the Anti-
Condensation Heaters
To check correct operation of Thermostat provided for anti
condensation heaters.
6.3.8 Pole discrepancy relay
testing
To test tripping of CB in case of pole discrepancy more
than 2.5 seconds or specified value.
6.3.9 Checking the N2
priming pressure
This test is to check healthiness of N2 accumulators
provided in Hydraulic drive mechanisms. N2 priming
pressure shall be as per the rated pressure.
6.4 Checks/ Tests applicable for CVTs
6.4.1 CVT polarity, Ratio test This test is conducted in the same manner as for CT to
determine correct CVT polarity, ratio and phasor group.
6.4.2 Insulation resistance
measurement of Primary
& secondary winding
Changes in the normal IR value of CVT indicate abnormal
insulator of CVT and degradation of insulation.
6.5 Checks/ Tests applicable for Isolators
6.5.1 MILLIVOLT Drop test The voltage drop gives a measure of resistance of current
carrying part and contacts by injecting minimum 100 A DC
current.
6.5.2 50 operation tests To test operation of contacts etc with jumpers connected
and contact resistance to be measured after 50 operations.
There shall not be any change from the previous value.
Doc No. D-2-01-03-01-03

6.6 Checks/ Tests applicable for Surge Arrestors
6.6.1 Third Harmonic
Resistive Current
(THRC) for surge
arrestors
To monitor healthiness of Surge arrestors by monitoring
third harmonic resistive current from the leakage current.
This test is to be conducted after charging of Las. The value
of THRC shall be less than 30 µA.
6.6.2 IR measurement of each
stack of LA
Changes in the normal IR value of LA indicate abnormal
insulator of LA and degradation of insulation.
6.6.3 Checking of operation of
LA counter
This test is done to check the healthiness of LA counter.
6.7 Checks/ Tests for other areas/ equipments
6.7.1 Earth resistance
measurement
To ensure value of earth resistance is below 1 ohm.
6.7.2 Secondary current
injection test
Conducted for testing of protecting devices, circuit
breakers, trip coils, motor overloads etc.
6.7.3 Contact Tightness check
of Bay contacts by
Primary injection
method
Since complete bay contact resistance measurement is
practically not possible because DC current may not be
injected in CT primary, hence contact tightness check by
primary injection method has been introduced to check
overall contact tightness.
Doc No. D-2-01-03-01-03

6.1 TAN DELTA & CAPACITANCE MEASUREMENT OF CT, CVT, CB
VOLTAGEGRADINGCAPACITORSANDLASTACKS
To measure dissipation factor/loss factor (Tan delta) and Capacitance measurement of EHV
class CTs, CVTs, CB Voltage Grading Capacitors & LA stacks by applying test voltages up
to10kV.
A) CURRENTTRANSFORMERS
CTswithtesttaps
1. Tandeltataptobedisconnectedfromground.
2. High voltage lead from tan delta kit to be connected to primary(HV)Terminal and LV
leadtobeconnectedtotheTandeltatesttap.
3. P1andP2tobeshorted
4. Porcelainsurfacetobethoroughlycleaned.
5. MeasurementshavetobetakeninUSTmodewithfullyautomatictestkit.
6. Standard procedure(as specified by kit supplier) for measuring capacitance and tan
delta in charged switchyard/induced voltage conditions should be followed for
measurementofcapacitanceandtandeltavalues.
7. Itistobeensuredtoconnectthetesttaptogroundterminalaftercarryingoutthetest.
B) CBVOLTAGEGRADINGCAPACITOR
1. ConnectLVcabletothemiddleofthedoubleinterrupter.
2. ConnectHVcabletotheotherendoftheGradingcapacitortobetested.
3. Theoppositeendofthegradingcapacitorhastobegroundedusingearthswitch.
4. MeasurementshavetobetakeninUSTModewithfullyautomatictestkit.
5. Disconnect the HVcable and connect the same to the other grading capacitor and ground
thepreviousgradingcapacitor. Nowthesecondgradingcapacitorisreadyfortesting.
6. Standard procedure (as specified by kit supplier) for measuring capacitance and tan
deltainchargedswitchyard/inducedvoltageconditionsshouldbefollowed
7. Measurementsaretobecarriedoutat10kV/12KV.
C) CAPACITORVOLTAGETRANSFORMERS
1. TestingprocedureforTopandMiddleStacks:
(a) Apply 10 KV between flanges of Top/Middle stacks (whichever is being
tested)
(b) CarryoutmeasurementsinUSTmodeat10.0KV
(c) WhilemeasuringMiddle/Bottomstacks,Top/middlestackstobeshorted.
2. TestingprocedureforBottomStackconnectedtoEMUPT
(a) Connect HV of the test kit at the top flange of bottom stack. HF point to be
grounded. Earth connection of the neutral of the PT to be opened/ isolated
fromground.
(b) Top of CVT to be guarded. LV lead of the kit to be connected at the top of the
CVTforguarding.
Doc No. D-2-01-03-01-03

(c) CarryoutmeasurementsinGSTgmodeat10.0KV
(d) RepeattheTestwithneutralofPTconnectedtoground.
(e) In case Tan delta value is negative or erratic, only capacitance values are to be
monitored.
(f) Measurementtobecarriedoutusingfullyautomatickit.
deltainchargedswitchyard/inducedvoltageconditionsshouldbefollowed.
D) SURGEARRESTERS
1. TestingprocedureforTop,MiddleandBottomStacks:
(a) Apply 10 KV between flanges of Top/Middle/ Bottom stacks (whichever is
being tested)
(b) CarryoutmeasurementsinUSTmodeat10.0KVwithfullyautomatictestkit.
(c) While measuring Middle/ Bottom stacks, the stacks above the HV lead to be
shorted.
deltainchargedswitchyard/inducedvoltageconditionsshouldbefollowed.
3. Whiledoingmeasurementofbottomstacktheearthconnectiontoberemoved.
6.2.1 POLARITYTESTFORCT
A centre zero voltmeter is connected across CT secondary. A 1.5 Volt battery is touched to
primaryofCT.ThedeflectionofpointershouldbesimilarincaseofeachCTcore.
At any instant current entering the primary from P1 the current should leave secondary from
the terminal marked S1. A setup shown in the Figure 9 can show whether the polarity
markingsarecorrectornot.
When the key is pressed, current enters the primary through terminal P1, the voltmeter
connected as shown, should read positive. A general arrangement of polarity test setup is
indicatedinFig.10.
6.2 CHECKS/TESTSAPPLICABLEFORCTs
+
-
KEY
P2 S2
S1P1
-
+
V
1.5 V
Figure - 10Figure - 9
-
+
+
-
V
R Y B
S2
S1
P1 P1 P1
Doc No. D-2-01-03-01-03

6.2.2 MAGNETIZATIONCHARACTERISTICS OFCTs
PRECAUTIONS
a) There should be no joints in testing leads/cables.
b) It should be ensured that whole testing equipment along with testing procedures are
available at testing site. Testing must be carried out in presence of testing personnel
only.
Test Equipment: Voltage source of 5 kV, Voltmeter of range 0 to 5 kV, Ammeter, of range
0to500Amps,testingleads/cablesetc.
Test Procedure: Make connections as per diagram shown below (Fig- 11). After making
proper connections, applied voltage is increased from zero to rated Knee Point Voltage in
steps of 25%, 50%, 75% and 100%. Measure the current drawn by the CT secondary core at
respectiveappliedvoltagesandrecordthetestresults
Figure - 11
A
V 5 kV 0- 5 kV
0-500 mA
Doc No. D-2-01-03-01-03

Knee Point Voltage is normally defined as the voltage at which 10% increase in the applied
voltage causes 30 to 50% increase in secondary current. The magnetization current at rated
Knee Point Voltage should not be more than the specified/designed value. A curve can be
drawn between applied voltage and magnetizing current. Typically, the curve drawn should
beliketheonegivenbelowinFig.-12.
100
200
300
400
500
600
MAGNETIZING
CURRENT
30 %
10 %
TYPICAL MAGNETIZATION CURVE
VOLTAGE
Figure - 12
From the curve it can be implied that up to rated KPV (Knee Point Voltage), the VI curve
should be almost a straight line. However, if this line is not linear, this indicates that the
magnetizing characteristics are not desirable. If the slop of the curve starts increasing, it
indicates that magnetizing induction becomes low and total primary current is utilized in
excitingthecorealone. Consequently,outputofCTsecondarydisappears.
6.2.3 RATIOTESTFORCURRENTTRANSFORMER
The ratio check has to be carried out as indicated in Fig-13 below.
PRIMARY
CURRENT
INJECTION
SET
A1
A2
A1 : PRIMARY CURRENT
A2 : SECONDARY CURRENT
Figure - 13
It is customary to conduct this in conjunction with the primary injection test. Current is
passed through the primary circuit with the secondary winding circuit to its normal circuit
load. The ratio of the primary to the secondary currents should approximate closely to that
stampedunderCTidentificationplate.
Doc No. D-2-01-03-01-03

Alternatively,ratiotestistobeconductedasperthefollowingmethod(Fig-14).
V1
V2
A
Figure - 14
Apply voltage from secondary of the CT and measure voltage in primary winding. Increase
voltage in secondary up to rated KPV/ ISF and by recording Primary Voltage, compute ratio
ofV1/V2.Theratioshouldmatchwiththespecifiedvalue.
6.2.4 INSULATIONRESISTANCEMEASUREMENTOFCURRENTTRANSFORMER
PRECAUTIONS
a) Thereshouldbenojointsintestingcables.
b) Testleadsshouldnottouchanylivepart.
c) Meggerbodyshouldbeearthed(ifseparateterminalisprovided).
d) Surface/terminalsshouldbecleaned.
e) IRmeasurementshouldbecarriedoutpreferablyindryandsunnyweather.
f) Neverconnectthetestsettoenergizedequipment.
g) Thegroundterminalmustbeconnectedfirstandremovedatlast.
h) Highvoltageplugsshouldbefreefrommoistureduringinstallationandoperation.
i) If oil traces are found on the surface of CT, the same should be cleaned by Methyl
Alcoholonly. Petrolordieselshouldneverbeused.
j) It should be ensured that whole testing equipment along with testing procedures are
available at testing site. Testing must be carried out in presence of testing engineer
only.
k) After testing with high voltage, test terminals must be grounded before being
touchedbyanypersonnel.
l) Testleadsshouldbeproperlyscreened/shielded.
Doc No. D-2-01-03-01-03

Connect the Megger as per figure-15 given below. Connect the HV terminal to the
Primary terminal of CT by using crocodile clip for firm grip
HV
LV
IR Test Kit
Figure-15 Typical Arrangement for IR measurement
Carryoutthemeasurementasperstandardproceduregivenbythekitsupplier.
A test voltage as specified is applied as per the above connections and successive readings
are taken. Values of IR should be recorded after 15 seconds, 60 seconds and 600 seconds.
Ambienttemperatureandweatherconditionsaretoberecorded.
6.2.5 DGATest of CT Oil: Oil samples to be collected in 300ml bottles and to be sent to CIOTL
Hyderabad for testing. Test results should be comparable to factory values. In case of any
deviation,testresultstobeforwardedtoCC-OSforapproval.
6.3.1 DEWPOINTMEASUREMENTOFSF6GASFORCIRCUITBREAKER
DewPointisthetemperatureatwhichmoisturecontentinSF6gasstartscondensing.
Dew Point at rated pressure of CB: Dew Point when measured keeping regulating valve in
service at the outlet of dew point kit to allow required flow rate of gas, is called at rated
pressureofCB.Inletvalveisopenedcompletely.
Dew Point at atmospheric pressure : Dew Point when measured by regulating the gas flow
at the inlet of dew point kit and keeping outlet regulating valve ( if provided) in fully open
conditionsothatflowrateofgasismaintainedasrequired,iscalledatatmosphericpressure.
TESTINGPROCEDURE
a) Make the connections to the kit from CB pole ensuring that regulating valve is fully
closedatthetimeofconnectionsoftheDewPointkit.
b) By regulating the flow rate of SF6 gas (0.2 liter/min to 0.5 liter/min - ref. IEC 60480),
thevalueofdewpointisobservedtillitbecomesstable.
6.3 CHECKS/TESTSAPPLICABLEFORCIRCUITBREAKERS
Doc No. D-2-01-03-01-03

c) If the regulating valve is provided at outlet of the dew point kit then values as given in
Doc.no.forratedpressuresaretobemonitored.
Dew Point of SF6 gas varies with pressure at which measurement is being carried out.This is
due to the fact that SaturationVapour Pressure decreases with increase in Pressure of the SF6
gas. Hence, dew point of SF6 gas at higher pressure is lower than dew point at atmospheric
pressure Therefore, it is to be ensured that if measurement has been done at a pressure other
than the atmospheric pressure, same is to be converted to the atmospheric pressure as given
in the table below used at the time of commissioning for various CB manufacturers: Method
forconvertingdewpointatdifferentgaspressures,isgiven/describedinIEC-60480.
6.3.2 MEASUREMENT OF CIRCUIT BREAKER OPERATING TIMINGS INCLUDING
PREINSERTIONRESISTORTIMINGS
PRECAUTIONS
a) Thereshouldnotbeanyjointintestingcables.
b) Testleadsshouldnottouchanylivepart.
c) Neverconnectthetestsettoenergisedequipment.
d) Thegroundcablemustbeconnectedfirstandremovedatlast.
e) Highvoltageplugsshouldbefreefrommoistureduringinstallationandoperation.
f) CircuitBreakerAnalyserbodyshouldbeearthed(ifseparateearthisprovided).
g) It should be ensured that whole testing equipment along with testing procedures are
availableattestingsite. Testingmustbecarriedoutinpresenceoftestingpersonnelonly.
h) Surface/terminalsshouldbecleanedwheretheconnectionsfortestingaretobemade.
i) Cleanearthpointwithsandpaper/wirebrushwhereearthterminalistobeprovided.
j) Ensurethatallthepolestripsimultaneouslythroughsingleclose/tripcommand.
TESTINGPROCEDURE
a) Make connections as shown in the figure-16 below. It is to be ensured that R, Y, B
phase marking cables are connected with the proper place in the CB analyser and
colourcodesaretobemaintainedforallthethreepolesofCB.
b) MakeconnectionsforrecordingoperatingtimingsofAuxiliarycontacts.
c) ExtendpowersupplytoCircuitBreakerAnalyzer.
d) Give closing command to closing coil of CB and note down the PIR and main contact
closing time.Taketheprintoutfromtheanalyzer.
Sl. No. Make of
CB
Dew point at
rated pressure
Dew point at
Atmospheric Pressure ( Limit )
1 BHEL (-) 15° C - 36° C
2 M & G - - 39° C
3 CGL (-) 15° C - 35° C
4 ABB (-) 15° C - 35° C
5 NGEF (-) 15° C - 36° C
Doc No. D-2-01-03-01-03

e) Give tripping command to trip coil-I of CB & note down the main contact tripping
time.
f) Give tripping command to trip coil-II of CB & note down the main contact closing
time.
g) Note down the timings for `CO', and `OCO' by giving respective commands. CO
command to be given without time delay but 300ms time delay to be given between
OandCOoperationintestingforOCO.
h) To find out opening time of PIR contacts, PIR assembly has to be electrically isolated
from Main contacts and then PIR contacts are to be connected to separate digital
channelsoftheAnalyzer.
EVALUATIONOFTESTRESULTS
A) CLOSING TIMINGS
Closing timings and Discrepancy in operating times of PIR and main contacts should not
exceed the permissible limits as specified in the DOC NO: D-5-02-XX-01-03. In any case,
main contacts should not close prior to closing of PIR contacts and PIR contacts should not
open prior to closing of main contacts. In case, contact bouncing is observed in operating
timings for PIR and main contacts, same should be rectified by tightening the cable
connections.
Main Contact
PIR
Green
Black
Red
CB
Analyser
Typical Arrangement for Operating Timings Measurement of CB
Figure - 16
B) TRIPPING TIMINGS
Trip time and pole discrepancy in operating timings should not exceed beyond permissible
value given in Doc. No. D-5-02-XX-01-03. In case of ABB, NGEF and CGL make CBs,
whiletripping,PIRcontactsshouldnotopenafteropeningofmaincontacts.
Doc No. D-2-01-03-01-03

C) 'CO'TIMINGS
COtimingsshouldbewithinpermissiblelimitsasspecifiedbydifferentmanufacturers.
IfoperatingtimingsofCBpolesarenotwithinlimits,samemaybecorrectedby:
1. EqualizingtheSF6gaspressureinallthepoles
2. Adjustingplungermovementoftrip/closecoils
3. Adjustmentinoperatingmechanism
4. Changingoftrip/closecoils(ifrequired)
It is also important to measure timings of auxiliary contacts from the point of view of
variationsw.r.t.themaincontacts.
6.3.3 DYNAMIC CONTACTRESISTANCE MEASUREMENT(DCRM)AND CONTACT
TRAVELMEASUREMENTOFEHVCIRCUITBREAKERS
Test Equipment: 100Amp. DCRM kit with CB operational analyzer with 10k Hz sampling
frequency.
IsolationRequired
a) CBshouldbeinopenposition.
b) IsolatorofbothsidesofCBshouldbeinopenposition.
c) EarthswitchofonesideofCBshouldbeinopenposition.
Precautions
a) Thereshouldbenojointsintestingleads/cables.
b) It should be ensured that whole testing equipment along with testing procedures are
available at testing site. Testing must be carried out in presence of testing personnel
only.
c) Current leads should be connected such that voltage leads are not outside area of
currentflow.
TestingProcedure
1. FollowthestandardprocedureasgivenininstructionmanualofDCRMkit.
2. The tightness of connections at CB flanges is most important to ensure error free
measurement. CB during CO operation generates lot of vibrations and failure of
connections during this period can dramatically change the dynamic signature of CB
resistance.
3. DCRM signatures should be recorded for CO operation. Open command should be
extendedafter300ms fromtheclosecommand.
4. Clean portions of incoming and outgoing flanges of CB with polish paper to remove
paint,oxidationetc,atpointswhereCurrentclampsaremounted.
5. Select this point of connection, as close as possible to the end of porcelain insulator to
ensurethatminimumresistanceisofferedbyflanges,bolts,terminalconnectorsetc.
6. ItshouldbeensuredthatTravelTransducersareproperlyfitted.
7. Samplingfrequencyduringmeasurementshouldbe10KHz.
8. Resistance,travel,injectedcurrentandTrip/Closecoilcurrentsaretoberecorded.
Doc No. D-2-01-03-01-03

The variations in the measured resistance versus time will be seen as a finger print for the
breaker contacts and can be used as a bench mark for comparing with future measurements
on the same breaker. This provides information on the condition of the breaker contacts,
drivingmechanism,operatingleversetc.
DynamicContactResistanceMeasurementforCBhealthiness
By application of Dynamic Contact Resistance Measurement, condition of arcing contact,
main contact, operating levers, driving mechanism can be predicted. If DCRM signature
shows vide variations and also there is change in arcing contact insertion time, it indicates
erosionofthearcingcontactstomaincontactsandsubsequentfailure.
ContactTravelMeasurement
Transducers are attached to the operating rod or interrupting chamber in order to record the
contact travel. When CB closes, contact travel is recorded. Contact bounces or any other
abnormalityisalsoclearlyindicatedbytheContactTravelMeasurement.
If contact travel, contact speed and contact acceleration signature are compared with the
original signatures, then it may indicate problems related with the operating mechanism,
operatinglevers,main/arcingcontacts,alignmentsetc.
DCRM along with Contact Travel measurement is useful in monitoring length of Arcing
contacts. Erosion of Arcing contacts may lead to commutation failures and current may get
transferredtoMaincontacts. Duetoheatofarc,maincontactsmaygetdamaged.
6.3.4 OPERATIONALLOCKOUTCHECKINGFOREHVCIRCUITBREAKERS
6.3.4.1 TESTINGPROCEDURE:
A. SF6 GASPRESSURELOCKOUT
a) LOWPRESSUREALARM
Close Isolation Valve between CB Pole(s) and density monitor. Start releasing SF6
gas from density monitor till the low pressure gas alarm contacts are actuated which
is detected by Multimeter. Note down the pressure and temperature at which the
contactsgetactuated.
b) OPERATIONALLOCKOUT:
Continue releasing SF gas from isolated zone till the operational lockout Alarm6
Contacts are actuated which are detected by Multimeter. Note down the pressure and
temperature at which the contacts get actuated. This is called operational lockout
pressure.
B. PNEUMATICOPERATINGSYSTEM LOCKOUT
a) COMPRESSOR START/STOPSWITCH
Close the isolating valve of CB. Release air into atmosphere from the compressor.
Note down the value of pressure at which Compressor starts building up air pressure
andpressureatwhich Compressorstops.
Doc No. D-2-01-03-01-03

b) CBAUTORECLOSELOCKOUT
Close isolation valve between pneumatic system and pressure switches. Release air
from the isolated zone to atmosphere. Note down pressure at whichA/R L/O contacts
of pressure switch get actuated which are detected by Multimeter. The leads of the
MultimetershouldbeconnectedtothecontactorwheretheARL/OofCBaremade.
c) CBCLOSINGLOCKOUT
Release air from the isolated zone to atmosphere. Note down pressure at which CB
Closing L/O contacts of pressure switch get actuated which are detected by
Multimeter.
d) CBOPERATIONALLOCKOUT
Release air from the isolated zone to atmosphere. Note down pressure at which CB
Operational L/O contacts of pressure switch get actuated which are detected by
Multimeter.
e) MECHANICALCLOSINGINTERLOCK (FORABB&BHELCBsONLY)
CB should be in closed position. Release air from pneumatic system of CB to
atmosphere and observe whether CB poles start opening, if so, note down the
pressure at which tie rod starts coming down. In such case the closing interlock is to
beopenedforinspectionandifrequired,replacetheclosinginterlock.
C. HYDRAULIC OPERATINGSYSTEMLOCKOUT
a) PumpSTART/STOP
By opening pressure release valve, note down the pressure at which Pump starts
buildingupoilpressureandpressureatwhichpumpstops.
b) CBAUTORECLOSELOCKOUT
Close Isolation valve between hydraulic system and pressure switches. Release oil
from the isolated zone to oil tank. Note down pressure at whichA/R L/O contacts of
pressureswitchgetactuatedwhicharedetectedbyMultimeter.
c) CBCLOSINGLOCKOUT
Release oil from the isolated zone to oil tank. Note down pressure at which CB
Closing L/O contacts of pressure switch get actuated which are detected by
Multimeter.
d) CBOPERATIONALLOCKOUT
Release oil from the isolated zone to container. Note down pressure at which CB Opera-
tionalL/OcontactsofpressureswitchgetactuatedwhicharedetectedbyMultimeter.
D. OPERATINGPRESSUREDROPTEST:
For Pneumatic/ Hydraulic operating system, operating pressure drop test to be performed
during OCO operation of CB, keeping AC supply of Hydraulic pump/ Compressor in off
condition. Hydraulic/ Pneumatic pressure drop should be within limits (as recommended by
Manufacturer)
Doc No. D-2-01-03-01-03

6.3.4.2 EVALUATIONOFTESTRESULTS
A. SF GASPRESSURELOCKOUT6
All the SF6 gas pressure switches settings should be checked and corrected with ambient
temperature. Settings of SF6 gas pressure switches should be within ± 0.1 bar/ Kg/cm2 of
thesetvalue(aftertakingintoaccountthetemperaturecorrectionfactor).
B. AIR PRESSURELOCKOUT
All the air pressure switches settings should be checked and corrected and should be within
±0.3bar/Kg/cm2ofthesetvalue.
C. OIL PRESSURELOCKOUT
All the oil pressure switches settings should be checked and corrected and should be within
±0.3bar/Kg/cm2ofthesetvalue.
6.3.5 MEASUREMENTOFSTATICCONTACTRESISTANCE
The Static contact resistance of main circuit of each pole of a circuit breaker is of the order of
a few tens of micro ohms. 100 A DC is injected and milli volt drop is measured across each
CB contact to compute contact resistance. The values should be within specified limits as
giveninDocNo.D-5-02-XX-01-01.
6.3.6 CHECKINGTHEANTI-PUMPINGFEATURE
When the breaker is in open position and closing and opening commands are given
simultaneously the breaker first closes and then opens, but does not reclose even though the
closingcommandismaintained.
6.3.7 CHECKINGTHEANTI-CONDENSATIONHEATERS
Check the supervisory circuit of the anti-condensation heaters for correct functioning. With
theheatersswitchedON,measuretheircurrentoutput.
6.3.8 POLEDISCREPANCYRELAYTESTING
Pole Discrepancy is defined as the difference in closing & opening timings of different poles
of CB.
A. WHENCBINOPENPOSITION
Closing Command is extended to close one pole, say R-Pole, of CB. After closing R-Pole of
CB, this Pole should automatically open after 2.5 seconds (as per pole discrepancy timer
settings). RepeatthetestforremainingtwopolesofCB.
Doc No. D-2-01-03-01-03

B. WHENCBINCLOSEDPOSITION
Tripping Command is extended to trip one pole, say R-Pole, of CB. Remaining Y and
B- Poles of CB should automatically open after 2.5 seconds. Repeat the same test for
remainingtwopolesofCB.
C. EVALUATION OF TEST RESULTS
Permissible value of pole discrepancy between two poles of CB is 3.33 msec. from
system point of view and it should not be confused with the setting of pole discrepancy
timer which is generally 1.0 or 2.5 sec. depending on Auto-reclose scheme.
6.3.9 CHECKINGTHENITROGENPRIMINGPRESSURE
Close the pressure release valve. Shortly after the oil pump starts, the priming pressure (200
bar at 20C) in the accumulator can be read. The relationship between the pressure and
temperatureisindicatedinFig.17.
150160170180190200210220230
Priming pressure as a function of the temperature
Nominal rating at 20 deg.C: 200.1 bar
bar
Figure - 17
6.4 CHECKS/TESTSAPPLICABLEFORCVTs
6.4.1 CVTPOLARITY,RATIOTEST
CVTpolarity is checked in the same manner as for CT, taking care to ensure that the battery is
connected to the primary winding. In case of star/star winding configuration care has to be
taken to ensure that the primary and secondary neutral points are not connected together. It is
necessary to verify that the phase rotation sequence of the 3 phase CVT is correct. The
secondary voltage between phases and neutral are measured and then phase rotation meter is
connectedacrossthethreephaseterminal.
6.4.2 INSULATION RESISTANCE MEASUREMENT OF PRIMARY & SECONDARY
WINDING
Doc No. D-2-01-03-01-03

6.5 CHECKS/TESTSAPPLICABLEFORISOLATORS
6.6 CHECKS/TESTSAPPLICABLEFORSURGEARRESTERS
6.5.1 MILLIVOLTDROPTESTS
The milli volt drop across the isolator is measured using DC current.The voltage drop gives a
measureofresistanceofcurrentcarryingpartandcontacts.
The DC current should be equal to or more than 100 A. The resistance of isolator should be
measured at ambient air temperature. The temperature of specimen/environmental
temperature should be recorded.The value of measured resistance should be converted to the
value of temperature at which factory test results are taken. Temperature corrected value of
resistanceshouldbecomparabletothefactoryvalue.
6.5.2 50OPERATIONTESTS
6.6.1 MEASUREMENT OF THIRD HARMONIC RESISTIVE CURRENT FOR SURGE
ARRESTERS
TestingProcedure
a. Maketheconnectionsasperthediagramgivenbelow(Fig.18)
b. Thekitshouldbeproperlyearthed.
c. Clamp On type CT should be placed above the surge monitor to pick up the total
leakagecurrent.
d. Carryout the measurements as per standard procedure supplied by the test kit
manufacturer.
e. Notedownthesystemvoltageandambienttemperaturealongwiththetestcurrentvalue.
f. Avoidmeasurementduringmonsoon.
Field probes for
harmonics in the system
Test
Kit
Adapter
Figure- 18 Typical arrangement for THRCM Test
Doc No. D-2-01-03-01-03

EVALUATIONOFTESTRESULTS
A. ZnO Surge Arrester continuously conducts a small leakage current (Fig.19). The
resistive component of this leakage current may increase with time due to different
stressescausingageingandfinallycausearresterfailure.
B. If Harmonics are present in the system voltage, it affects the value of measured third
harmonic current. Compensating device provided to be used to nullify the effect.The
valueofThirdHarmonicResistivecurrentshallbelessthan30µA
Capacitance
HV
side
Non-linear
resistor
Figure-19 Arrester equivalent circuit
6.7 CHECKS/TESTSFOROTHERAREAS/EQUIPMENTS
6.7.1 EARTHRESISTANCEMEASUREMENT
NormallyEarthtesterisusedformeasuring
(a) Soilresistivity
(b) Earthresistance
a. Prior to the testing of soil resistivity and earth resistance the operation manual of the
testing instrument available at site may be referred for procedures to be adopted for
measurementofsoilresistivityandearthresistance.
Atypical earth tester has 4 terminals. C1, P1, C2, P2 and 4 similar electrodes are driven
in the ground at equal distances and connected to the instruments in the order of C1, P1
and P2, C2. Then the handle is rotated or button is pressed and the reading of the
resistanceisreadonthescaleoftheinstrument.IfRistheresistancemeasuredthen
SpecificResistivity=2 aR
Where'a'isthedistancebetweentheelectrode
AndRistheresistanceinohmsmeasuredontheearthtester.
b. In order to measure earth resistance of the electrode of the substation, it could be
connected to C1 and the value of R could be read in the scale with the rotation of the
handle of the Insulation tester. This will give the earth resistance. The value as far as
possible should be around 1 ohm.To improve the value, water should be spread at the
earthpit.
Doc No. D-2-01-03-01-03

6.7.2 SECONDARYCURRENTINJECTIONTESTSETS
The primary test is essential when commissioning and new installation as a test the whole
protection system and will detect current transformers connected with incorrect polarity or
relays that have been set in the wrong sequence in differential system. Secondary current
injection sets are very useful for conducting these tests. The standard secondary current
injection test equipment consists of a 1/5 A current injection set, separate wave form filter
unit and a digital counter. The equipment is designed in a portable kit for on site testing of
protecting devices, circuit breakers, trip coils, motor overloads, and similar apparatus. The
filter unit should be used when testing saturating core type relays to ensure that the test
current has a substantially sinusoidal waveform. The typical test setup is shown in fig. 20.
Detailsofthetestingwillbeelaboratedintherelaytesting.
S2
S1
P1 P1 P1
LOAD
INSULATING TEST
PLUGS
INJECT
CURRENT
HERE
A1
A2
Figure - 20
Doc No. D-2-01-03-01-03

POINT 1 POINT 2
CB
CB
LINE
LINE
POINT 3POINT 4
Figure-21 : Primary injection test to check contact tightness of Bay/ feeders
6.7.3 CONTACTTIGHTNESSTESTOFBAYCONTACTS:
a. IsolatetheBayfromBus–SideandlinesideasshowninFig.-21.
b. Ensurethatallthesecondarycoresareconnectedorshortifnotinuse.
c. Inject the Current at Point 1 (200A) from primary injection kit (w r t earth) and return
currentviaearthpointat2asshowninFig.-21.
d. Checkthatweareabletoinjectcurrentatpoint1andmeasurethecurrentatpoint2.
e. Injectionofcurrentis theindicationofcontacttightness.
f. Repeattheprocedureforpoint1&3
g. Repeattheprocedureforpoint1&4
Note: Above tests can be aborted if individual contact resistances are within satisfactory
limit and physical phase checking is satisfactory.
Doc No. D-2-01-03-01-03

Typesof busbarprotection
a) Highimpedance
b) Lowimpedance
The High-impedance protection scheme, is a good solution for single busbar arrangements,
1 ½ breaker systems or ring Busbars, provided that appropriate dedicated CT cores are
availableforthisusealone.
Sensitive,stableandfastprotectionforsinglebusbararrangementsand1½breakersystems.
Eg:RADHA(ABB),FAC34(EE),PBDCB(EE),PBLSB(EE)
7.1.1 TypesofHighimpedanceprotectionschemes
TwomainprotectionswithCTsupervisionfeature
Main&checkzonescheme
a) Twomainprotections
GenerallyusedwheredirectmeasurementispossiblewithoutswitchingoftheCTcircuits
Tripcommandwillbeissuedonoperationofanyoneofthemainprotection.
b) Main&checkzonescheme
Have highest degree of security in the form of check zone, generally used where CT
switchingisrequiredthroughauxiliarycontactsofisolator(like220kVDMTscheme)
For a double busbar arrangement, two different high impedance units are required. In this
case, the current must be switched between the two different measuring units by connecting
auxiliaryswitchestothebusbarisolatorcontacts.
In some cases the auxiliary switches did not operate correctly. This caused the busbar
Protection to trip the busbar. For this reason, a safety precaution was introduced:An overall
Check-Zone unit, fed from individual CT cores. This overall scheme does not include any
switchingofCTandthereforeismoresecure.
The TRIP command is only issued when both a discriminating and check-zone system
Operates.
Therelaycoilwillbedesignedasvoltagemeasuringdeviceconsumingnegligiblecurrent.
Vf=If(Rct+2.Rl)
Vk=2Vf
ParallelingCTcurrentshouldbedoneatCTmarshallingboxes.
7.1 HighImpedanceprotection
Doc No. D-2-01-03-01-03
CHECKS/TESTS FOR
BUS BAR PROTECTION

7.1.2 CTrequirementsforHighimpedanceprotectionsystem
ØKneepointvoltagerequirementoftheCTwillbehigh
ØCT core shall be dedicated to the High-impedance Busbar Protection Scheme (i.e.
cannotbesharedwithotherprotectionrelays)
ØCT Must have identical turns-ratio (CT Ratio) (Aux.CT for ratio corrections not
acceptable)
ØShallhavealowresistanceofthesecondarywindings
ØShallhaveaminimumknee-pointvoltageofapprox.300-500V.
ØShouldhavealowmagnetisingcurrent(fewmilliamps)
7.1.3 SupervisionoftheCTcircuits
Any interruption of CT currents up to the point of parallel connection can cause instability
during external faults even though their degree of unbalance is with in the limits during
normaloperation.HencesupervisionschemeforCTwirearerequired.
Supervisionrelayshouldbeprovidedacrosseachphaseforeachzone.
ItwillblockthecurrentpassingthroughthedifferentialrelaybyshortingtheCTterminals
GeneralsettingoftheCTsupervisionrelayis10%ofthelowestcircuitrating.
Calculationoftypicalsettingsforbusbardifferentialprotection
CTratio: : 2000/1
CTresistance: : 10Ohms
Max.busfaultMVA : 10000MVA
6
Max.faultcurrent : 10000x10 /1.732*400000=14434A
Faultcurrentinsecondary : 7.217A
Voltagesettingoftherelay : V V = I (R +2R )for S f ct L
Leadresistanceof1000m,2.5sq.mmcopperwireis7.28ohms
Assume500mofleadlength
Vs=7.217*(10+2*7.28/2)=124.7V
Nearestavailablesettingcanbeadoptedfortherelay
The most suitable protection scheme for Double and multiple busbar Systems (with or
without transfer bus) with feeders being switched between sections of the busbar, which
operateswithfullselectivityforallpossiblebusbarconfigurations.
7.2 LowImpedancebusbarscheme
Doc No. D-2-01-03-01-03

FreeofanyneedformatchedCTcharacteristicorratios,lowleakagereactanceorresistance.
Otherprotectiverelayscanbeincludedinthesamecircuit.
Stableforinfinitefaultlevel.
InsensitivetoCTsaturation.
AlltheCTwiringwillberoutedtorelayeitherdirectlyorthroughaux.relay.
Eg:RADSS (ABB),MBCZ(EE)
7.3. Primaryinjectionandbusbardifferentialstabilitytest(NewSubstation)
Bus - I
Bus - III
Bay B
Bay A
T
T - Primary current injection text kit
1. Takeoneofthebays(A)asthereference
2. Select other bay (B) for testing the differential stability. Inhibit the tripping of the
breaker in bay B from control room due to operation of distance or over current
protection caused by primary current injection, if the earthing has been made after
thebreakerbyusingearthswitch.
3. Earth the bus bar after CTusing local earth or nearby earth switch on bay B to provide
returnpathforthecurrent.
4. EnsurebusbarisearthedonlyatbayB
5. Inject primary current using primary current injection test kit across one phase (e.g.R
Phase)andground;don'tuseotherphaseasreturnpathforthecurrent.
6. Measure the current at both CT marshalling boxes and voltage across differential
relayterminalsincase ofhighimpedancedifferentialprotection.
7. Measure currents before and after aux. CTs and at relay terminals, incase of low
impedancedifferentialprotectionisbeinginstalled.
Doc No. D-2-01-03-01-03

8. Themeasuredspillvoltage/currentatrelayterminalsshouldnotbemorethan2%.
9. If the spill voltage/current is more (almost twice the CT secondary current) at the
relay terminals, stop injecting the primary current and then reverse the secondary
terminalsofCTatbayB.
10. Start injecting primary current and measure the current at both CTmarshalling boxes
and at the relay terminals at control room and observe the spill current/ voltage
magnitudelessthan2%.
11. Stop injecting primary current and then create in-zone fault on primary side (by
providing earthing between the two CTs) and start injecting primary current and
Measures the current at both CT marshalling boxes and at the relay terminals at
control room and observe the spill current/ voltage of considerable magnitude
corresponding to the injected primary current. (a pictorial example is attached
herewithatAnnexure)
12. After ensuring the above stop injecting the current. The CT connection should be as
perpolaritythusproved.
13. Repeatthetestforothertwophases.
14. Repeat the same procedure for other bays of the same bus bar by taking adjacent bus
bar stability checked bay as the reference bay in order to inject max. possible current
intheprimaryusingprimaryinjectiontestkit.
15. Repeattheaboveprocedureforotherbusbarsalso.
16. Above said procedure shall be carried out between Phase-Phase (R-Y &Y-B) by
injecting in one phase and joining with other phase for using it as return path instead
ofearthreturnforonesetofCTs(Twobays).
7.4. Primary injection and bus bar differential stability test (Bay Extension in the old
substation):
Newly adding diameter
T- Primary current injection test kit
Bus - I
Bus - III
Bay A
T
Bay B
Doc No. D-2-01-03-01-03

1. Arrangetheshutdownofthebusbarundertest
2. Consideroneoftheexistingbays(A)asthereference
3. Short the CTcores used for the other protections (like LBB, distance or differential or
O/Cormetering,etc),atCTMBitself,noCTcoreshallbeinopencondition.
4. Select one of new bays (B) for testing the differential stability and inhibit the tripping
of the breaker from control room due to operation of distance or over current caused
byprimarycurrentinjection.
5. EarththebusbarafterCTusinglocalearthornearbyearthswitchonbayB.
6. EnsurebusbarisearthedonlyatbayB
7. Inject primary current using primary current injection testing kit across one phase
(eg.RPhase)andground;don'tuseotherphaseasreturnpathforthecurrent.
8. Measure the current at both CT marshalling boxes and voltage across differential
relayterminalsincaseofhighimpedancedifferentialprotection.
9. Measure currents before and after aux. CTs and at relay terminals, incase of low
impedancedifferentialprotectionisbeinginstalled.
10. Themeasuredspillvoltage/currentatrelayterminalsshouldnotbemorethan2%.
11. If the spill voltage/current is more (almost twice the CT secondary current) at the
relay terminals, stop injecting the primary current and then reverse the secondary
terminals of CT at bay B.
12. Start injecting primary current and measure the current at both CTmarshalling boxes
and at the relay terminals at control room and observe the spill current/voltage
magnitudelessthan2%.
13. Stop injecting primary current and then create in-zone fault on primary side (by
providing earthing between the two CTs) and start injecting primary current and
measure the current at both CTmarshalling boxes and at the relay terminals at control
room and observe the spill current/voltageof considerablemagnitudecorresponding
to the injected primary current. (a pictorial example is attached herewith at
Annexure)
14. After ensuring the above stop injecting the current. The CT connection should be as
perpolaritythusproved.
16. Repeat the same procedure for other bays of the same bus bar by taking adjacent bay
(whose stability check completed) as the reference in order to inject max. possible
currentintheprimary usingprimaryinjectiontestkit.
17. Repeattheaboveprocedureforotherbusbarsalso.
18. Restorethesystemtonormalconditions.
Doc No. D-2-01-03-01-03

7.5 Scheme Checking of bus bar protection & DC trip logic. (New substation & Bay
extension)
7.5.1 TwoMainprotectionphilosophy
1. Testtherelaybysecondaryinjection.
2. Check the tripping of the corresponding breakers and non tripping of other bus
breakersandtiebreakers.
3. CheckinitiationofLBBrelaysofthebreakerscorrespondingtoparticularbus.
4. CheckblockingofthebusbarprotectiononoperationofCTsupervisionrelay.
5. EnsurethatoperationofCTsupervisionrelayshouldnotinitiatebusbartripping.
6. Check initiation of bus bar tripping by operation of corresponding breaker LBB
relays.(BackTripfeature)
7. a. Check the direct tripping scheme on operation of bus bar protection (only if
tiebreakerisinopencondition)
b. Direct trip signal should not go on operation of Bus bar protection if the Tie
CB isinclosecondition.
8. Test CT supervision relays and ensure for triggering control panel annunciation and
eventloggertriggeringasperapprovedscheme.
9. CheckbusbarIN/OUTswitchforcorrectnessofwiringasperthedrawing.
7.5.2 MainandCheckzonephilosophy
1. Testthebothmainandcheckzonerelaysbysecondaryinjection.
2. Ensure bus bar should not initiate tripping for operation of either main or check zone
alone.
3. Forcheckingthetrippingscheme,bypassthecheckzonecontact.
4. Check the tripping of the corresponding breakers and non tripping of other bus
breakersandtiebreakers.
7. EnsureoperationofCTsupervisionrelayshouldnotinitiatebusbartripping.
9. a. Check the direct tripping scheme on operation of bus bar protection (only if
tiebreakerisinopencondition)
b. Direct trip signal should not go on operation of Bus bar protection if the Tie
CB isinclosecondition.
12. RepeattheaboveforcheckzoneandCTsupervisionschemes.
Doc No. D-2-01-03-01-03

7.6 AMPTestingofbusbarprotectionandscheme
1. Arrange bus bar shutdown for off line testing. Preferably the bus bar isolation should
donethroughbusbarprotectiontriprelay.
2. Insertthetestblockaftershortingtheincomingcurrentterminalsforonlinetesting.
3. Testtherelays.
4. Forofflinetesting:
i. Check tripping scheme of bus bar (2 main/ main and check scheme), in case
of main and check scheme, operation of one relay should not initiate bus bar
trip.
ii. CheckinitiationfromLBBofcorrespondingbaysofbusbar
iii. CheckinitiationofLBBofcorrespondingbaysofbusbar
iv. CheckannunciationsandDRtriggeringasperthedrawings
5. After completion of the above checks, normalise the connections and take bus bar
intoservice.
Doc No. D-2-01-03-01-03

7.7 Doublemaintransferscheme(400kV/220kV):
For the double main transfer scheme, bus bar protection shall preferably be Main and check
zone scheme because of dependency on CT switching between BUS-I & II bus bar
protections.
7.7.1 Primaryinjectionandbusbardifferentialstabilitytest(NewSubstation):
BUS-I
TE – Testing Equipment
X – Temporary Earthing point
B3
X
X2 X1
TE
Bay BBay A
T3
T2T1
C2C1
B4
B2B1
A4
A3
A2A1
Bay C
Bay T
BUS-II
TRANSFER BUS
1. Takeoneofthebays(A)asthereference
2. Select other bay (B) for testing the differential stability. Inhibit the tripping of the
breakers in bay A and B from control room due to operation of distance or over
currentprotectioncausedbyprimarycurrentinjection.
3. EarththebusbarafterCTatXusingearthrodsonbayB.
4. Preferably connect the primary injection testing kit to the CT terminal pad of
referencebay(A)afteropeningthejumperfromlineside.
5. EnsurethatbusorlineconnectedtobayBshallnotbeearthedotherthanatX.
6. Close the isolators A1 in bay A, B1 in bay B and Ensure that corresponding CT
switchingrelaysoperatedforcheckingthebusbardifferentialstabilityofBUS-1.
7. CloseisolatorA3andbreakerinbayAandisolatorB3andbreakerinbayB.
8. Measure the resistance of the CTcores (used for main and check zone) towards CTin
the CT switching cubicle and it shall be equal to the sum of resistance of the CT core
and lead resistance. If the resistance towards CT core is more, then check the CT
circuitandcorrespondingCTswitchingrelay.
Doc No. D-2-01-03-01-03

9 InjectprimarycurrentusingprimaryinjectiontestingkitfrombayA.
10. Measure the current at both CT marshalling boxes (both cores used for main and
check zone) and relay terminals in the control room in case of low impedance
protection or measure voltage across cores in CT MB and differential relay terminals
incaseofhighimpedancedifferentialprotection.
11. The measured spill voltage/current at relay terminals shall be very less compared to
theprimarycurrent/correspondingvoltage(around2%).
12. If Spill current/voltage is more (almost twice the CT secondary current) at the relay
terminals.
a. Stop injecting the primary current and Check CT paralleling connections
after the CT switching relay. If every thing is correct then reverse the
secondaryterminalsofCTatbay'B'.
b. Start injecting primary current and Measures the current/voltage at both CT
marshalling boxes and relay terminals at control room and observe the spill
current/ voltage magnitude shall be very less compared to the set value
(around2%).
13. Stop injecting primary current and then create in-zone fault in primary side (by
providingearthingbetweentwoCTs).
14. Start injecting primary current and Measures the current at both CT marshalling
boxes (both cores used for main and check zone) and at the relay terminals at control
totheinjectedprimarycurrent.
15. Afterensuringtheabovestopinjectingthecurrentandnormalizethesystem.
16. Open isolatorsA1 on bayA& isolator B1 on bay B and ensure that corresponding CT
switchingrelaygotresetted.
17. Close isolatorsA2 in bayA, B2 in bay B for connecting the feeder to bus-2 and ensure
the operation of corresponding CT switching relay for checking the bus bar
differentialstabilityofBUS-2.
18. Repeattheabovesequencefrom9to16
19. Open isolatorsA2 on bayA& isolator B2 on bay B and ensure that corresponding CT
switchingrelaysgotresetted.
21. Above said procedure shall be carried out between Phase-Phase (R-Y &Y-B) by
injecting in one phase and joining with other phase for using it as return path instead
ofearthreturnforonesetofCTs(Twobays).
22. Repeat the same procedure for other bays including transfer bus coupler bay w.r.t
Bus-I&II.
Doc No. D-2-01-03-01-03

7.7.2 Checkingofdifferentialprotectionstabilityw.r.tbuscoupler:
1. TakeoneofthebayAasthereferencebay
2. CloseisolatorA1inbayAtocheckdifferentialstabilityofthebuscouplerw.r.tBus-1.
3. CloseisolatorC1andbreakerinbuscouplerbayCandearthatX1inbayC.
4. Adoptthesameprocedureasexplainedaboveforstabilitytestingofnormalbays.
5. Openbreaker&isolatorsA1inbayAandOpenbreaker&isolatorC1onbayC,
6. Close isolator A2 & breaker in bay A and isolator C2 & breaker on bay C to check
differentialstabilityofbuscouplerCTw.r.tBus-2.
7. EarthbayCatX2.
8. Adoptthesameprocedureasexplainedaboveforstabilitytestingofnormalbays.
9. Open the breaker and isolator in bay A & bay C and open earthing on bay C and
normalizethesystem.
7.7.3 Checkingofdifferentialprotectionstabilityw.r.tTransferbus:
TE
Bay BBay A
T3
T2T1
C2C1
B4
B2B1
A4
A3
A2A1
Bay C
Bay T
E
B3
BUS-I
BUS-II
TRANSFER BUS
1. Before carrying out this test, ensure that differential protection stability with respect
toBus–I&Bus-IIhasbeencarriedoutonallbaysincludingtransferbuscouplerbay.
2. For checking the differential protection stability w.r.t to transfer bus, take one of the
baysasreferencebayandinjectcurrentfromtransferbuscouplerbayCT.
3. CloseisolatorT3andbreakerintransferbuscouplerbayT.
4. Close isolator A4 to check stability w.r.t transfer bus and ensure the operation
correspondingCTswitchingrelay.
5. Keepthenormal/transferswitchofbayAintransfermode.
Doc No. D-2-01-03-01-03

6. Measure the resistance of the CTcores towards CTin the CTswitching cubicle and it
shall be equal to the resistance of the CT core and lead resistance. If the resistance
towards CT core is more, then check the CT circuit and corresponding CT switching
relay.
7. InjectprimarycurrentusingprimaryinjectiontestingkitfrombayT.
8. Measure the current at both CT marshalling boxes and relay terminals in the control
room in case of low impedance protection or measure voltage across cores in CT MB
anddifferentialrelayterminalsincaseofhighimpedancedifferentialprotection.
terminals.
after the CT switching relay. If every thing is correct then reverse the
secondaryterminalsofCTatbay'T'onlywhiletestingfirstbay.
(around2%).
providingearthingbetweentwoCTs)
boxes and at the relay terminals at control room and observe the spill current/ voltage
ofconsiderablemagnitudecorrespondingtotheinjectedprimarycurrent.
14. Open isolators and earthing which are closed for testing and keep N/T switches in
normalposition.
16. Repeat the above procedure for other bays to ensure the operation of CT switch relay
fortransferbus.
Doc No. D-2-01-03-01-03

7.7.4 Primary injection and bus bar differential stability test for Bus-I (Bay extension in
existingSubstation)
E
TE
Bay BBay A
T3
T2T1
C2C1
B4
B2B1
A4
A3
A2A1
Bay C
New bay
BUS-I
BUS- II
TRANSFER BUS
B3
1. Arrange the shutdown of the one of the existing feeder or take a bay which is already
inoutofserviceasreferencebay(A).
2. Arrangeshutdownofthebusbar(Bus-I).
3. Close the isolator of new bay B (B1) and ensure the operation of corresponding CT
switchingrelay.
relay.
5. Close the isolator B3 and breaker in bay B and isolatorsA1,A3 and breaker in bayA
forconnectingtheCTstoBus-I.
6. InjectprimarycurrentusingprimaryinjectiontestingkitfrombayA.
7. Measure the current at both CT marshalling boxes (both cores used for main and
check zone) and relay terminals in the control room in case of low impedance
protection or measure voltage across cores in CT MB and differential relay terminals
incaseofhighimpedancedifferentialprotection.
terminals:
Doc No. D-2-01-03-01-03

a. Stop injecting the primary current and check CTparalleling connections after
the CT switching relay. If every thing is correct then reverse the secondary
terminalsofCTatbay'B'.
current/ voltage magnitude shall be very less compared to the primary
current/correspondingvoltage(around2%).
providingearthingbetweentwoCts.
boxes (both cores used for main and check zone) and at the relay terminals at control
totheinjectedprimarycurrent.
13. OpenthebreakerandisolatorA1inbayAandbreakerandisolatorB1inbayB.
14. Repeattheaboveprocedureforotherphases.
15. Repeat the testing of the other newly adding bays (if any) taking this stability tested
new bay (B) as the reference bay to avoid outage of old reference bay A for longer
periods.
16. Repeat the above procedure of stability testing for new bay w.r.t. Bus-II by selecting
ofappropriatesection(i.e.isolatorsA2&B2)withBus-IIshutdown.
7.7.5 Primary injection and bus bar differential stability test w.r.t to transfer bus (Bay
extensioninexistingSubstation):
Bay
BUS-I
BUS- II
TRANSFER BUS
E
TEBay BBay A
T3
T2T1
C2C1
B4
B2B1
A4
A3
A2A1
C
New bay
B3
TE - Testing equipment
Doc No. D-2-01-03-01-03

1. Arrangeshutdownoftransferbus.
2. TaketransferbusTasreferencebus.
3. Close isolator B4 and keep N/T switch in transfer position and ensure the operation
ofcorrespondingCTswitchingrelay.
relay.
5. CloseisolatorT3andbreakerinbayT.
6. InjectprimarycurrentusingprimaryinjectiontestingkitfrombayT.
7. Measure the current at both CT marshalling boxes and relay terminals in the control
room in case of low impedance protection or measure voltage across cores in CT MB
anddifferentialrelayterminalsincaseofhighimpedancedifferentialprotection.
thesetvalue(around2%).
terminals.
aftertheCTswitchingrelay.
(around2%).
providingearthingbetweentwoCTs.
boxes and at the relay terminals at control room and observe the spill current/ voltage
ofconsiderablemagnitudecorrespondingtotheinjectedprimarycurrent.
13. Start injecting primary current and measure the current/voltage at relay terminals and
ensurethatitsmagnitudeisverylesscomparedtotheprimarycurrent.
14. Open isolators and earthing which are closed for testing and keep N/T switches in
normalposition.
15. Repeat the test for other two phases.
Doc No. D-2-01-03-01-03

7.8 Scheme checking of bus bar protection & DC trip logic. (New substation & Bay
extension)
7.8.1 TwoMainprotectionphilosophy
1. Testtherelaybysecondaryinjection.
2. Check the tripping of the corresponding selected breakers and bus coupler breaker
(incaseofBus-I&Bus-IIonly)andnontrippingofotherbreakers.
3. Check initiation of LBB relays of the selected breakers corresponding to particular
bus.
5. EnsurethatoperationofCTsupervisionrelayshouldnotinitiatebusbartripping.
7. Checkthedirecttrippingschemeonoperationofbusbarprotection.
7.8.2 MainandCheckzonephilosophy
1. Test the both main (i.e. Bus-I, Bus-II and Transfer Bus) and check zone relays by
secondaryinjection.
2. Ensure bus bar should not initiate tripping for operation of either main or check zone
alone.
3. Forcheckingthetrippingscheme,bypassthecheckzonecontact.
4. Check the tripping of the corresponding selected breakers and bus coupler breaker
(incaseofBus-I&Bus-IIonly)andnontrippingofotherbreakers.
6. Checkblockingofthe busbarprotectiononoperationofCTsupervisionrelay.
7. EnsureoperationofCTsupervisionrelayshouldnotinitiatebusbartripping.
9. Checkthedirecttrippingschemeonoperationofbusbarprotection.
12. RepeattheaboveforcheckzoneandCTsupervisionschemes.
Doc No. D-2-01-03-01-03

7.9 AMPtestingofbusbarprotectionandscheme
1. Arrangebusbarshutdownforofflinetestingandschemechecking.
2. While switching all the loads from one bus to other bus observe the operation and
resetting of corresponding CT switching relays in accordance to the operation of
isolators.
3. CTswitchingdiscrepancyalarmshallnotappearinthecontrolpanel.
4. Check tripping scheme of bus bar ( 2 Main/ Main and check scheme), in case of main
andcheckscheme,operationofonerelayshouldnotinitiatebusbartrip.
5. CheckannunciationsandDRtriggeringasperthedrawings
6. After completion of the above checks, normalise the connections and take bus bar
intoservice.
7. Insertthetestblockaftershortingtheincomingcurrentterminalsforonlinetesting.
8. Testtherelays.
Doc No. D-2-01-03-01-03

Doc No. D-2-01-03-01-03
No. CF/ICT/01/ R-3 DATED 01/04/2011 75
I. GENERAL DETAILS
DETAILS
Region: Sub-Station:
LOA No. : Make:
Sr. No.: Type:
Year of Manufacture: Rating:
Voltage Ratio : Cooling Type:
Type of Neutral Grounding: Oil Make:
Oil type: Oil quantity:
Date of Receipt at site: Date of Starting of Erection:
Date of Completion of Erection and
Oil filling:
Date of energisation( After
commissioning)
II. CHECK LIST OF ELECTRICAL TESTS CARRIED OUT FOR TRANSFORMER
SL.N
O
NAME OF TEST PERFORMED
(YES/NO)
TEST RESULTS
(OK/ NOT OK)
a Insulation Resistance Measurement
b Vector Group Test & Polarity Check
c Short Circuit Impedance Test
d Magnetic Balance Test
e Floating Neutral Voltage Measurement
f Magnetisation Current Test
g Voltage Ratio Test
h Insulation Resistance Measurements Of
Bushing CTs
i Continuity Test Of Bushing CTs
j Secondary Winding Resistance Of Bushing CTs
k Polarity Test Of Bushing CTs
l Current Ratio Test
m Magnetizing Curves Performance
n Contact Resistance Measurement
PRE-COMMISSIONING FORMATS
FOR TRANSFORMER
Transformer

No. CF/ICT/01/ R-3 DATED 01/04/2011Transformer
Doc No. D-2-01-03-01-03
76
SL.N
O
NAME OF TEST PERFORMED
(YES/NO)
TEST RESULTS
(OK/ NOT OK)
o Tan Delta & Capacitance Measurement Of
Bushing
p Tan Delta & Capacitance Measurement Of
Windings
q Protection And Alarm Tests
r Stability Test Of Differential And Ref Protection
s Frequency Response Analysis
t Measurement of Winding Resistance
Signature:
Name:
Desgn.:
Organization:
(Supplier
Representative)
(Wherever
Applicable)
Signature:
Name:
Desgn.:
(Erection Agency)
Signature:
Name:
Desgn.:
(POWERGRID Site
I/C)
Signature:
Name:
Desgn.:
(POWERGRID
Commg. Team)
Members:

No. CF/ICT/01/ R-3 DATED 01/04/2011 Transformer
Doc No. D-2-01-03-01-03
77
III. CHECKS AFTER RECEIPT OF TRANSFORMER AT SITE:
A) N2 PRESSURE & DEW POINT RECORD
N2 PRESSURE DEW POINT *REMARKS
During dispatch at factory
After receipt at site
Storage at site before commissioning
* Please write 'NIL' in case of No Remarks
NOTE: N2 pressure and dew point should be within permissible range as per graph provided by manufacturer
and also given in os doc no d-2-03-xx-01-01 rev-01. During storage at site, dew point has to be measured
whenever any drop in n2 pressure is observed. During storage at site before commissioning, n2 pressure has to
be measured daily and record to be maintained in a separate sheet.
Refer graph 2.1.3 fig.1
B) IMPACT RECORDER ANALYSIS
STATUS BRIEF ANALYSIS
Received in healthy condition at
site
Yes No
Analysis report received from
manufacturer before charging
Yes No
Note: Impact Recorder should be detached from the Transformer preferably when the main unit has been placed
on its foundation.
*Permissible limit for maximum shock is ±3G for any axis.
C) CORE INSULATION TEST
APPLY 1 kV DC BETWEEN CL & CC + G
INSULATION VALUE
Between CC-G
Between CL-G
Between CC-CL
Note: Shorting link between CC, CL & G to be removed and IR value to be taken between CC-G, CL-G & CC-
CL (Recommended value > 10 M? )
D) INTERNAL INSPECTION
INTERNAL INSPECTION
STATUS
YES NO
Details photographs of all visible parts /components are taken during internal
inspection and enclosed.(refer procedure2.1.6)
Any abnormality observed during internal inspection
Matter referred to manufacturer, CC-ENGG and CC-OS
Details of abnormalities notice if any:

IV. CHECKS /PRECAUTIONS DURING ERECTION :
a. Active part of transformer should be minimum exposed to atmosphere
b. Use of dry air generator / dry air cylinders, during
exposure of active part of transformer to atmosphere.
c. While entering in transformer tank, check availability
of proper Oxygen
d. Transformer kept sealed with N2 in between
different erection activities
V. PRE-COMMISSIONING CHECKS:
SL.
NO.
DESCRIPTION OF ACTIVITY
STATUS REMARK
DEFICIENCIE
S, IF ANYYES NO
1 ICT and its Auxiliaries are free from visible defects
on physical Inspection
2 All fittings as per out line General Arrangement
Drawing
3 Check Main Tank has been provided with double
earthing
4 Check neutral is grounded through separate
connections. Ensure metallic requirements as per
specification (e.g. Cu) in earthing strips used
5 Check that Marshalling Box, T/C Driving Gear,
Diverter, Radiator Bank Pump & Fan Motor etc. has
been earthed
6 All nuts and bolts are tightened correctly as per
specified torque (as per manufacturers
recommendation)
7 Check tightness of Terminal Connectors
8 Check leveling of Transformer and its accessories
9 Erection Completion Certificate along with list of
outstanding activities reviewed
10 Any Paint removed / scratched in transit has been
touched up
11 Bushings are clean and free from physical damages
12 Oil level is correct on all Bushings
13 Check Hermitically sealing is intact in all Bushings
14 Check oil leakage through any Joints / Valves etc.
15 Check oil drain valves are properly closed and locked
16 Check oil level in Main / OLTC Conservator tank
Yes No Remarks
Yes No Remarks
Yes No Remarks
Doc No. D-2-01-03-01-03
78

17 Check oil level at conservator matches with oil
temperature of transformer
18 Check Gear box oil level in OLTC
19 Check OTI and WTI pockets and replenish the oil, if
required
20 Check all valves for their opening & closing
sequence
21 Check the colour of the breather silica gel (blue when
dry)
22 Check availability of oil in the breather cup
23 Check all rollers are locked and tack welded with
rails (wherever applicable)
24 Check busing test tap is grounded
25 Check no debris, loose T & P and oil strains on and
around the Transformer
26 Check door seals of Marshalling Box is intact and all
cable gland plates unused holes are sealed
27 Check that pressure relief valve is correctly mounted
28 Ensure unused secondary cores of Bushing CT’s, if
any, has been shorted
29 Check CT star point has been formed properly and
grounded at one end only as per scheme
30 Check that permanent and adequate lighting
arrangements are ready
31 Check that labeling and identification is permanent
and satisfactory
32 Check that Buchholz Relay is correctly mounted with
arrow pointing towards conservator
33 Check cables are properly fixed and ensure cable
entry at the bottom
34 Ensure all Power and Control cable Terminals are
tightened
35 Check all cables and Ferrules are provided with
Number as per Cable Schedule (Cross Ferruling to be
checked)
36 Check that all cables are correctly glanded
37 Check external cabling from Junction Box to Relay /
Control Panel completed
38 Check that air has been released from the Radiators
and their headers/OLTC Buchholz relay/Main
tank/tank/Bushing turrets etc
39 Check Fire Protection System & Emulsifier systems
is adequate & ready
40 Check that CC-CL & G are shorted
41 Check that all radiator bank valves on top and bottom
headers are open
Doc No. D-2-01-03-01-03
79

42 Change over operation of ac supply from source- I to
source-II checked
43 Check the flanges of bushing & oltc for any crack
after fixing
44 Calibration of OTI & WTI performed as per
procedure
45 Check various interlocks provided with Fire Fighting
as per the schematic Ref. Drg.
No.___________________
Description
of Interlocks
Checked
VI. MEASUREMENT OF EARTH RESISTANCE OF ELECTRODE
LOCATION VALUE
With Grid (Earth Pit -1)
Without Grid (Earth Pit -1) (Neutral Earth )
Without Grid (Earth Pit -2) (Neutral Earth)
*Permissible limit with grid < 1 ohm
VII. DETAILS OF RELAYS/ CONTACTORS USED: SCHEMATIC DRAWING NO.
CIRCUIT REFERENCE MAKE SERIAL NO. TYPE NO+NC
VIII. EVACUATING AND OIL FILLING
a) Before filling oil, each drum has been physically
checked for free moisture and appearance
b) Details of oil filter machine
Make _____________________ Capacity________________________
SL.NO DESCRIPTION OF WORKS REMARKS / READING
1 Changing of Lubricating oil of vacuum pump
2 Cleaning of Filter packs
3 Flushing of whole filter machine with fresh oil
4 Vacuum obtained without load (milli bar)
c) Vacuum pump for evacuation of transformer
3 Diameter of vacuum hose (50 mm)
4 Employ of Dry ice chamber
Yes No
Doc No. D-2-01-03-01-03
80

7 Break of vacuum
* Vacuum to be kept for 12 hrs Up to 145 KV, 24 hrs
for 145 to 220kV and 36 hrs for 420 kV and above
d) Oil storage tank
Capacity_____________________ Quantity_________________________
1 Silica gel breather provided in the tank
2 Any opening left uncovered
3 Inside painted or not
4 Cleanliness of inside of pipes/ hoses to the storage tank
e) Exposure during erection
1 First day exposure ( in hrs)
2 Second day exposure ( in hrs)
3 Third Day exposure ( in hrs)
4 N2 pressure applied after each days erection work ( in PSI)
5 Ambient Temperature (in degC)
6 Average Relative Humidity
7 Weather Condition Rainy / Stormy /
Cloudy / Sunny
f) N2 sealing in case of delay in oil fillingi.
1 No. of Cylinders used for displacing the air inside the tank
2 N2 admitted from bottom valve
3 Valve at diametrically opposite end at top kept open
4 No. of Cylinders used for building up 2 PSI
ii. Schedule for Vacuum & Tightness Test
Sl.No INSPECTION ACTIONS DATE TIME REMARKS /
READING
1 Starting of evacuation on complete unit
2 Stopping of evacuation below the pressure of 0.3 kPa (3
mbar)
3 Pressure P1 in kPa after 1 hour of stopping evacuation
4 Pressure P2 in kPa after half an hour of reading pressure
P1
5 Leakage = (P2-P1) x V ,
V=Oil quantity in Cu mtr
*If leakage >3.6, continue evacuating
If leakage < 3.6Similar action may be carried out for
2 to3 times for confirmation.
6 Start of Vacuum after N2 pressure reaching below
0.13kPa(1 torr)
Doc No. D-2-01-03-01-03
81

iii. Schedule for Oil filling and Settling
Sl.N
o
INSPECTION ACTIONS DAT
E
TIM
E
REMARKS /
READING
1 Oil Filling in Main Tank
2 Oil filling in Conservator tank
3 Oil filling in diverter switch
4 Start of oil settling
5
End of oil settling
* Minimum settling time to be given 12 hrs for 145
KV ,48 hrs for 145 to 420kV and 120 hrs for above
420 kV .
iv. Record of drying out process (if carried out)
Drying out started on date: Time:
Ambient temp:
Hourly reading to be taken
DATE TIME
VACUUM
READING IN
FILTRATION
MACHINE
VACUUM
READING IN
TRANSFORMER
TANK
OTI
OF
TANK
CONDENSATE
COLLECTED
TOTAL / RATE
REMARKS & SIGN
OF MTC
ENGINEER
Record of filtration and Dry out shall be kept in a register and shall be made a part of the Pre-
commissioning document.
IX. INSULATION RESISTANCE MEASUREMENT
a) Insulation Resistance Measurement of Cable and others
(Using 500 Volt Megger)
Make & Sl. No of testing kit _____________________
Date of last calibration of kit _____________________
Ambient temp in º C _____________________
SL. NO. DESCRIPTION
STATUS
REMARKS, IF ANY
YES NO
A Control wiring
B Tap changer
a) Motor
b) Control
C Cooling System
a) Motor Fan
b) Motor Pump
c) Control wiring
* Permissible limit of IR value should be > 50 M ?
Doc No. D-2-01-03-01-03
82

b) Insulation Resistance Measurement in M? (Using 5000 V Megger)
Make & Sl. No of testing kit _______________________
Date of last calibration of kit_______________________
Ambient temp in º C _______________________
MAIN WINDING
IR VALUE
DIELECTRIC
ABSORPTION
COEFFICIENT
DAI= 60 Sec /
15 Sec
POLARISATION
INDEX
PI= 600 Sec / 60
Sec
REMARKS15
sec
60
sec
600
sec
Combination for Auto transformer
a) HV+IV / LV
b) HV+IV / E
c) LV / E
Combination for 3 winding transformer
a) HV+IV / LV
b) HV+IV / E
b) HV+IV+LV / E
*Permissible limit of IR value should be > 500 M ? at 30°C, DAI should be >1.3
and PI should be >1.25 To 2
X. VECTOR GROUP TEST & POLARITY CHECKING
Connect Neutral Point with earth, join 1 RI and 3 R1 Terminals and apply 415 V. 3-
phase supply to HV Terminals
TERMINALS
VOLTAGE MEASURED
(VOLTS)
REMARKS
1R1 – 1Y1
1Y1 – 1B1
1B1 – 1R1
3Y1 – 1B1
3Y1 – 1Y1
3R1- N
3Y1 – N
3B1 – N
2R1- N
2Y1 – N
2B1 – N
Ensure 2R1 – N = 2Y1 – N = 2B1 – N = constant
If 3R1 -N > 3Y1 - N > 3B1 - N, AND 3Y1 - 1B1 >
3Y1 - 1Y1
Vector group Ynaod11 is confirmed and polarity
verified
1R1
3R1
3B1
3Y1
2R1
2B1 2Y1
1B1 1Y1
1R1
3R1
3B1
3Y1
2R1
2B1 2Y1
1B1 1Y1
Doc No. D-2-01-03-01-03
83

XI. MEASUREMENT OF WINDING RESISTANCE (IN OHM)
Make of testing kit________________________ Date of calibration____________________
Ambient temperature____________________ Temperature of oil_________________________
WTI reading _____________________________
A) HIGH VOLTAGE SIDE
TAP
POSITI
ON
WINDING
RESISTANCE(HV-N)
RESISTANCE AT 75º
C
FACTORY VALUE AT
75º C
% DEVIATION
1R1–
2R1
1Y1–
2Y1
1B1–
2B1
R Y B R Y B R Y B
1
2
3
4
5
6
7
8
9b
10
11
12
13
14
15
16
17
REVERSE ORDER
TAP
POSITI
ON
WINDING
RESISTANCE(HV-N)
RESISTANCE AT 75º
C
FACTORY VALUE AT
75º C
% DEVIATION
1R1–
2R1
1Y1–
2Y1
1B1–
2B1
R Y B R Y B R Y B
TAP..….
TAP……
TAP……
TAP……
* Formula for calculating the resistance at 75°C: R75 = RT (235+75)/ (235+T), where RT = Resistance
Measured At Winding Temperature T.
B) INTERMEDIATE VOLTAGE SIDE
BETWEEN
WINDING
RESISTANCE RESISTANCE AT 75 °C IN OHMS
% DEVIATION
SITE VALUE FACTORY SITE
2R1 – N
2Y1 – N
2B1 – N
Doc No. D-2-01-03-01-03
84

C) LOW VOLTAGE SIDE
BETWEEN
WINDINGS
RESISTANCE RESISTANCE AT 75 °C IN OHMS
% DEVIATION
SITE VALUE@ --ºC FACTORY SITE
3R1 – 3B1
3Y1 – 3R1
3B1 – 3Y1
NOTE: LV winding resistance at factory measured without formation of delta. However measurements carried
out at site are after formation of delta. Hence a correction factor of 1.5 times to be applied in site results
Permissible limit: ±5% variation between phases or from Factory test results
XII. MAGNETIC BALANCE TEST
Details of testing kit ________________________Date of calibration_________________
Apply single phase 230 V across one phase of HV winding terminal and neutral then
measure voltage in other two HV terminals across neutral. Repeat the test for each of the
three phases.
APPLY 1-PH 230V
AC ACROSS (1)
VOLTAGE MEASURED IN VOLTS REMARKS
BETWEEN (2) BETWEEN (3)
2R1 – N: 2Y1 – N: 2B1 – N:
2Y1 – N: 2R1 – N: 2B1 – N:
2B1 – N: 2Y1 – N: 2R1 – N:
Note: (1)=(2)+(3), Approx
When outer phase is excited, voltage induced in the center phase shall be 50 to 90% of the
applied voltage. However, when the center phase is excited then the voltage induced in the outer
phases shall be 30 to 70% of the applied voltage.
XIII. FLOATING NEUTRAL VOLTAGE MEASUREMENT
i. Disconnect the Transformer neutral from the ground and apply 3 phase 415 Volts
to the high voltage winding and make the measurement in the IV winding with
respect to neutral and neutral point to ground
TAP
POSITION
PRIMARY
WINDING
VOLTAGE
APPLIED
IV
WINDING
VOLTAGE
MEASURED
REMARKS, IF ANY
Normal (__) 1R – N 2R – N
Normal (__) 1Y – N 2Y – N
Normal (__) 1B – N 2B – N
N – Earth
ii. Apply 3 phase 415 Volts to the Intermediate voltage winding and make the
measurement in the Tertiary winding with respect to neutral and neutral point to
ground
IV WINDING
VOLTAGE
APPLIED
LV WINDING
VOLTAGE
MEASURED
REMARKS, IF ANY
2R – N 3R – N
2Y – N 3Y – N
2B – N 3B – N
N – Earth
Doc No. D-2-01-03-01-03
85

iii. Check after the test, neutral reconnected to the
ground
XIV. MAGNETIZATION CURRENT TEST
i. Apply 1 Phase, AC supply on HV Te rminals and keep IV and LV open
TAP
POSITION
VOLTAGE APPLIED
IN VOLTS
CURRENT MEASURED IN mAMPS
REMARK
LOWEST
R - N R - PH
Y - N Y - PH
B - N B - PH
NORMAL
R - N R - PH
Y - N Y - PH
B - N B - PH
HIGHEST
R - N R - PH
Y - N Y - PH
B - N B - PH
ii. Apply 1 phase, 415V AC supply on IV Terminal and keep HV & LV open
TAP POSITION VOLTAGE APPLIED IN VOLTS CURRENT MEASURED
(IN LV SIDE) IN M AMP
Normal
2R – 2Y R – PH
2Y – 2B Y – PH
2R – 2B B – PH
*If the excitation current is less than 50 milli-Amperes (mAmp), the difference between the two higher
currents should be less than 10%. If the excitation current is more than 50 mAmp, the difference should
be less than 5%. The value on the outside legs should be within 15% of each other and values for centre
leg should not be more than either outside for a three phase transformer. Results between similar single
phase units should not vary more than 10%.
XV. VOLTAGE RATIO TEST
Make of testing kit _______________________Date of calibration_____________________
Ambient temperature_________________ Temperature of oil________________________
Remarks: To be done by Automatic Turns ratio meter
i. RATIO : HV / IV
POS.
VOLTAGE APPLIED VOLTAGE MEASURED RATIO FACTORY RATIO % DEVIATION
1R-N 1Y-N 1B-N 2R-N 2Y-N 2B-N R Y B R Y B R Y B
1
2
3
4
5
6
Yes No
Doc No. D-2-01-03-01-03
86

7
8
9
10
11
12
13
14
15
16
17
REVERSE SIDE
TAP NO…….
TAP NO…….
TAP NO…….
TAP NO…….
ii. RATIO : HV / LV
POS.
1R-N 1Y-N 1B-N 3R-3Y 3Y-3B 3R-3B R Y B R Y B R Y B
Lowest
Normal
Highest
iii. RATIO : IV / LV
POS.
2R-N 2Y-N 2B-N 3R-3Y 3Y-3B 3R-3B R Y B R Y B R Y B
Lowest
Normal
Highest
Remarks (if any):
*The variation of result should be within ± 0.5 % from specified values or factory test result.
XVI. OIL CHARACTERISTICS
(Sample to be taken prior to charging to Transformer and it should fulfill the
recommendations as per IS 1865 /IEC 60422)
DATE OF OIL
SAMPLING
B.D.V.
MOISTURE TAN DELTA RESISTIVITY
INTERFACIAL
TENSION
Permissible
Limit
70KV(min) 5 PPM(Max) 0.01 at 90º C
(Max)
6x 10 ^12 ? -CM
at 90º C (Min)
0.0 35 N/m at
27ºC (Min)
Doc No. D-2-01-03-01-03
87

XVII. DISSOLVED GAS ANALYSIS
DISSOLVED GASES JUST BEFORE
CHARGING
JUST AFTER
CHARGING
24 HRS AFTER
CHARGING
7 DAYS AFTER
CHARGING
15 DAYS
AFTER
CHARGING
H2
CH4
CO
CO2
C2H4
C2H6
C2H2
O2
N2
TCG
* TCG should be below 1%
XVIII. TEST ON OLTC
SL.N
O
DESCRIPTION
STATUS
REMARKS
OK NOT OK
1 Visual inspection of equipment
2
Manual operation on all taps ( local ) with
confirmation of the no. Of revolutions and
locking at extreme taps
3 Over load device of driving motor
4 Local operation (electrical)
5 Remote operation (electrical)
6 Tap position indicator
7 Check operation with master follower
Scheme ( parallel operation )
8 Out of step relay
9 Step by step contactor
10 Limit switch
11 Winding resistance at all taps
12
Continuity test of winding during one complete
cycle of operation
XIX. OPERATIONAL TEST OF OTHER EQUIPMENTS
i. Checking of cooling Equipments
SL.NO DESCRIPTION
STATUS
OK NOT OK
1 Rotation direction of Pumps
2 Rotation direction of Fans
ii. Protection Check
EQUIPMENT FAN NO SETTING VALUE PICKUP VALUE
SINGLE PHASING
PREVENTION CHECK
1
2
3
Doc No. D-2-01-03-01-03
88

4
5
6
7
8
9
10
11
12
13
14
15
16
Pump No.
1
2
3
4
XX. INSULATION RESISTANCE MEASUREMENT OF BUSHING CT’S(USING 500V MEGGER)
MEASUREMENT
BETWEEN
UNIT
HV IV
R – Ø Y - Ø B - Ø R - Ø Y - Ø B - Ø
Earth - Core I M ?
Earth - Core II M ?
Earth - Core III M ?
Earth - Core IV M ?
MEASUREMENT
BETWEEN
UNIT
LV
NEUTRAL
R - Ø Y - Ø B - Ø
Earth - Core I M ?
Earth - Core II M ?
Earth - Core IV M ?
MEASUREMENT
BETWEEN
UNIT
HV IV
R – Ø Y - Ø B - Ø R - Ø Y - Ø B - Ø
Core I – Core II M ?
Core I – Core III M ?
Core I – Core IV M ?
Core II – Core III M ?
Core II – Core IV M ?
Core III – Core IV M ?
Doc No. D-2-01-03-01-03
89

MEASUREMENT BETWEEN UNIT
LV
R - Ø Y - Ø B - Ø
Core III– Core IV M ?
XXI. CONTINUITY TEST OF BUSHING CT’S (in ? )
Continuity, Check between Terminals : OK / NOT OK
CORE BETWEEN
TERMINAL
HV IV
R - Ø Y - Ø B - Ø R - Ø Y - Ø B - Ø
Core – I 1S1–1S2
Core – II 2S1–2S2
Core – III 3S1–3S2
Core – IV 4S1–4S2
CORE
BETWEEN
TERMINAL
LV
NEUTRAL
R – PHASE Y – PHASE B – PHASE
XXII. SECONDARY WINDING RESISTANCE OF BUSHING CT’S (IN OHM)
i. HV side
CORE
BETWEEN
TERMINAL
UNIT
R - Ø Y - Ø B - Ø
FACTORY SITE FACTORY SITE FACTORY SITE
Core I 1S1 – 1S2 ?
Core II 2S1 – 2S2 ?
Core III 3S1 – 3S2 ?
Core IV 4S1 – 4S2 ?
ii. IV side
CORE
BETWEEN
TERMINAL
UNIT
R - Ø Y - Ø B - Ø
Core I 1S1 – 1S2 ?
iii. LV side
CORE
BETWEEN
TERMINAL
UNIT
R - Ø Y - Ø B - Ø
Core I 1S1 – 1S2 ?
Doc No. D-2-01-03-01-03
90

iv. Neutral Side
CORE
BETWEEN
TERMINAL
UNIT FACTORY SITE
Core I 1S1 – 1S2 ?
Factory Type Test Report Ref. No._________________________________
XXIII. POLARITY TEST OF BUSHING CT’S
With 1.5 V DC supply (Connect +ve at P1 and –ve at P2)
i.
CORE BETWEEN
HV IV
R - Ø Y - Ø B - Ø R - Ø Y - Ø B - Ø
Core I 1S1 (+ve) 1S2 (-ve)
Core II 2S1 (+ve) 2S2 (-ve)
Core III 3S1 (+ve) 3S2 (-ve)
Core IV 4S1 (+ve) 4S2 (-ve)
ii.
CORE BETWEEN
LV
NEUTRAL
R - Ø Y - Ø B - Ø
XXIV. CURRENT RATIO TEST
Primary Injection through Primary Injection Kit at Primary Terminal P1 – P2
Measure current on the secondary Terminals
i. HV side R – Phase side
CORE
S1 - S2
PRIMARY
%
CURRENT
ACTUAL
SECONDARY
CURRENT
THEORETICAL
RATIO
ACTUAL
RATIO
% OF
ERROR
Core I
(1S1 – 1S2)
20%
40%
80%
Core II
(2S1 – 2S2)
20%
40%
80%
Core III
(3S1 – 3S2)
20%
40%
80%
Core IV
(4S1 – 4S2)
20%
40%
80%
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91

ii. HV side Y – Phase
CORE
S1 - S2
PRIMARY
%
CURRENT
ACTUAL
SECONDARY
CURRENT
THEORETICAL
RATIO
ACTUAL
RATIO
% OF
ERROR
Core I
(1S1 – 1S2)
20%
40%
80%
Core II
(2S1 – 2S2)
20%
40%
80%
Core III
(3S1 – 3S2)
20%
40%
80%
Core IV
(4S1 – 4S2)
20%
40%
80%
iii. HV side B – Phase
CORE
S1 - S2
PRIMARY
%
CURRENT
ACTUAL
SECONDARY
CURRENT
THEORETICAL
RATIO
ACTUAL
RATIO
% OF
ERROR
Core I
(1S1 – 1S2)
20%
40%
80%
Core II
(2S1 – 2S2)
20%
40%
80%
Core III
(3S1 – 3S2)
20%
40%
80%
Core IV
(4S1 – 4S2)
20%
40%
80%
iv. IV side R – Phase
CORE
S1 - S2
PRIMARY
%
CURRENT
ACTUAL
SECONDARY
CURRENT
THEORETICAL
RATIO
ACTUAL
RATIO
% OF
ERROR
Core I
(1S1 – 1S2)
20%
40%
80%
Core II
(2S1 – 2S2)
20%
40%
80%
Core III
(3S1 – 3S2)
20%
40%
80%
Core IV
(4S1 – 4S2)
20%
40%
80%
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92

v. IV side Y – Phase
CORE
S1 - S2
PRIMARY
%
CURRENT
ACTUAL
SECONDARY
CURRENT
THEORETICAL
RATIO
ACTUAL
RATIO
% OF
ERROR
Core I
(1S1 –
1S2)
20%
40%
80%
Core II
(2S1 –
2S2)
20%
40%
80%
Core III
(3S1 –
3S2)
20%
40%
80%
Core IV
(4S1 –
4S2)
20%
40%
80%
vi. IV side B – Phase
CORE
S1 - S2
PRIMARY
%
CURRENT
ACTUAL
SECONDARY
CURRENT
THEORETICAL
RATIO
ACTUAL
RATIO
% OF
ERROR
Core I
(1S1 –
1S2)
20%
40%
80%
Core II
(2S1 –
2S2)
20%
40%
80%
Core III
(3S1 –
3S2)
20%
40%
80%
Core IV
(4S1 –
4S2)
20%
40%
80%
Permissible limit ±3%
XXV. MAGNETISING CURVES PERFORMANCE
(Not to be done for metering Core)
Knee Point Voltage (KVp) = ………………..Volt
i. HV Side R – Phase
VOLTAGE
UNIT
CURRENT MEASUREMENT
TO BE APPLIED
ACTUAL
VALUE
CORE – I
1S1-1S2
CORE – II
2S1-2S2
CORE – III
3S1-3S2
CORE – IV
4S1-4S2
0.25 x KVp mA
0.50 x KVp mA
0.75 x KVp mA
1.00 x KVp mA
1.10 x KVp mA
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93

ii. HV Side Y – Phase
VOLTAGE
UNIT
CURRENT MEASUREMENT
TO BE APPLIED
ACTUAL
VALUE
CORE – I
1S1-1S2
CORE – II
2S1-2S2
CORE – III
3S1-3S2
CORE – IV
4S1-4S2
0.25 x KVp mA
0.50 x KVp mA
0.75 x KVp mA
1.00 x KVp mA
1.10 x KVp mA
iii. HV Side B – Phase
VOLTAGE
UNIT
CURRENT MEASUREMENT
TO BE APPLIED
ACTUAL
VALUE
CORE – I
1S1-1S2
CORE – II
2S1-2S2
CORE – III
3S1-3S2
CORE – IV
4S1-4S2
0.25 x KVp mA
0.50 x KVp mA
0.75 x KVp mA
1.00 x KVp mA
1.10 x KVp mA
iv. IV Side R – Phase
VOLTAGE
UNIT
CURRENT MEASUREMENT
TO BE APPLIED
ACTUAL
VALUE
CORE – I
1S1-1S2
CORE – II
2S1-2S2
CORE – III
3S1-3S2
CORE – IV
4S1-4S2
0.25 x KVp mA
0.50 x KVp mA
0.75 x KVp mA
1.00 x KVp mA
1.10 x KVp mA
v. IV Side Y – Phase
VOLTAGE
UNIT
CURRENT MEASUREMENT
TO BE APPLIED
ACTUAL
VALUE
CORE – I
1S1-1S2
CORE – II
2S1-2S2
CORE – III
3S1-3S2
CORE – IV
4S1-4S2
0.25 x KVp mA
0.50 x KVp mA
0.75 x KVp mA
1.00 x KVp mA
1.10 x KVp mA
vi. IV Side B – Phase
VOLTAGE
UNIT
CURRENT MEASUREMENT
TO BE APPLIED
ACTUAL
VALUE
CORE – I
1S1-1S2
CORE – II
2S1-2S2
CORE – III
3S1-3S2
CORE – IV
4S1-4S2
0.25 x KVp mA
0.50 x KVp mA
0.75 x KVp mA
1.00 x KVp mA
1.10 x KVp mA
Note: 1.0 CT should not saturate at 110% of Knee Point Voltage (KVp)
2.0 If Knee Point Voltage is not mentioned then Knee Point Current may be taken into
consideration.
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94

XXVI. CONTACT RESISTANCE MEASUREMENT at 100 Amps
CONTACT RESISTANCE UNITS R - Ø Y - Ø B - Ø
Across HV Bushing Terminal Joint µ ?
Across IV Bushing Terminal Joint µ ?
Across LV Bushing Terminal Joint µ ?
Across Neutral Connection Point µ ?
Across Surge Arrester Connection µ ?
The value of Contact Resistance should not be more than 10 Micro – ohms per Joint /
Connector
XXVII. BUSHING DETAILS
STYLE NO / DRAWING NO.
DETAILS
HIGH VOLTAGE SIDE INTERMEDIATE VOLTAGE SIDE
R - Ø Y - Ø B - Ø R - Ø Y - Ø B - Ø
Make
Type
Sl. No.
DETAILS LOW VOLTAGE SIDE
R - Ø Y - Ø B - Ø
Make
Type
Sl. No.
XXVIII. TAN DELTAAND CAPACITANCE MEASUREMENT OF BUSHING
Make of testing kit ____________________________
Date of calibration _____________________________
Ambient temperature _____________________________
i. HV side
VOLTAGE
CAPACITANCE (MEASURED VALUE)
REMARKSR - Ø Y – Ø B - Ø
SITE FACTORY SITE FACTORY SITE FACTORY
Measurement of C1
2 KV
KV 10
Measurement of C2
1 KV
VOLTAGE
TAN ä (MEASURED VALUE)
Measurement of C1
2 KV
10 KV
Measurement of C2 Tan ä
1 KV
Doc No. D-2-01-03-01-03
95

ii. IV side
VOLTAGE
Measurement of C1
2 KV
Measurement of C2
1 KV
VOLTAGE
Measurement of C1
2 KV
1 KV
iii. LV side
VOLTAGE
Measurement of C1
2 KV
Measurement of C2
1 KV
VOLTAGE
Measurement of C1
2 KV
1 KV
C2 values shall be only for record purpose.
Factory test report ref no:
*ACCEPTABLE LIMIT FOR Tan ä1:-0.004 & Tan ä2:-0.01
XXIX. TAN DELTAAND CAPACITANCE MEASUREMENT OF WINDING
Ambient temperature _ ____________________________
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96

VOLTAGE WINDING COMBINATION TEST MODE CAPACITANCE TAN DELTA * REMARK
SITE FACTORY SITE FACTORY
2 KV
HV-IV/ LV UST
10 KV
2 KV
HV-IV/ LV+G GST
10 KV
2 KV
HV-IV/ LV with Guard GSTg
10 KV
2 KV
HV-IV/LV UST
10 KV
2 KV
LV/ HV-IV+G GST
10 KV
2 KV
LV/ HV-IV with Guard GSTg
10 KV
Factory Test Report Ref. No.: ______________________________________
* Should be comparable (+/- 0.001) with factory value subjected to max of 0.005.
XXX. SHORT CIRCUIT IMPEDANCE TEST
Date of calibration __ ___________________________
Ambient temperature _ ____________________________
Temperature of Oil _____________________________
i. HV TO IV
TAP
NUMBER
1U1 ( R ) 1V1 (Y) 1W1 (B)
(IV OF R Ô AND N SHORTED, LV
OPEN)
(IV OF Y Ô AND N SHORTED, LV
OPEN)
(IV OF B Ô AND N SHORTED, LV
OPEN)
VOLTAGE in
Volt
CURRENT in
Amp
VOLTAGE in
Volt
CURRENT in
Amp
VOLTAGE in
Volt
CURRENT in
Amp
1
9b
17
ii. IV TO LV
Tap No 9b
SUPPLY
SHORT ALL 3 LV BUSHINGS, HV
OPEN
SHORT ALL 3 LV BUSHINGS,
HV OPEN
SHORT ALL 3 LV
BUSHINGS, HV OPEN
2U1-N, ……....V ………………………………A
2V1-N,……….V …………………………A
2W1-N, ……...V ………………………A
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97

iii. HV TO LV
Tap No 9b
SUPPLY
SHORT ALL 3 LV
OPEN
HV OPEN
SHORT ALL 3 LV
BUSHINGS, HV OPEN
1U1-N, ……....V ………………………………A
1V1-N,……….V …………………………A
1W1-N, ……...V ………………………A
Tap No 17
SUPPLY
OPEN
OPEN
HV OPEN
1U1-N, ……....V ………………………………A
1V1-N,……….V …………………………A
1W1-N, ……...V ………………………A
Tap No 1
SUPPLY
OPEN
OPEN
HV OPEN
1U1-N, ……....V ………………………………A
1V1-N,……….V …………………………A
1W1-N, ……...V ………………………A
XXXI. PROTECTION AND ALARMS
i.
SL.NO DEVICE
SET FOR PROVED
ALARM TRIP ALARM TRIP
1 Excessive winding temperature. 100 110
2 Excessive oil temperature. 90 100
3 Oil flow failure NA NA
4 Pressure relief valve NA NA
5 Main tank Buchholz relay
6 OLTC Buchholz relay NA NA
7 Fan failure NA NA
8 Low oil level (MOG) NA NA
9 Differential relay NA NA
10 Over load relay NA NA
11 Earth fault relay ( ref ) NA NA
12 Over current relay NA NA
13 Inter trip , if any NA NA
14 Trip free check NA NA
15 Backup over current NA NA
16 Over flux
ii. Protection setting applied as per engg.approved
settings
Yes No Remarks
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98

iii. Stability test of differential and REF protection
NOTE : Prove the tripping of associated brea kers by actual operation of the
various devices and relays as per the schemes.
XXXII. FREQUENCY RESPONSE ANALYSIS (FRA)
i. Carried out after completion of all commissioning
activities
ii. Interpretation of test results carried out
iii. Test results matching with the factory results
iv. Factory & site FRA test report available at site
XXXIII. ALL ELECTRICAL TEST RESULTS COMPARED WITH
FACTORY TEST RESULTS & FOUND TO BE IN ORDER
XXXIV. CHECKS AFTER CHARGING OF TRANSFORMER
Record the following after charging
i. Any abnormal sound emanating from the
transformer
ii. No load current at relay terminal
R - Ø A
Y - Ø A
B - Ø A
iii. Temperature at the time of charging
OTI º C
WTI º C
AMBIENT º C
iv. Maximum temperature after 24 hours____________º C
v. OLTC electrical operation checked in idle charged condition from minimum
position to maximum position & back to
normal position
Ok Not Ok Remarks
Yes No Remarks
Yes No Remarks
Yes No Remarks
Yes No Remarks
Yes No Remarks
Yes No Remarks
Yes No Remarks
Doc No. D-2-01-03-01-03
99

vi. Thermo vision scanning done at least after 24 hours of loading & repeated
after one week.
XXXV. FINAL DOCUMENTATION REVIEW
i.
ii.
iii.
iv.
Signature:
Name:
Designation:
Organization:
(Supplier
Representative)
(Wherever
Applicable)
Signature:
Name:
Designation:
(Erection Agency)
Signature:
Name:
Designation:
(POWERGRID Site
I/C)
Signature:
Name:
Designation:
(POWERGRID
Commissioning. Team)
Members:
Yes No Remarks
Yes No
Yes No
Yes No
Yes No
Factory test results are available
Final documents of Pre- Commissioning checks reviewed and
approved
Document regarding spares equipment, O&M manuals etc
available at site
After modification, if any, “As built Drawings” are available at site
Doc No. D-2-01-03-01-03
100

I. GENERAL DETAILS
DETAILS
Sub-Station:Region:
LOA No. : Make:
Sr. No.: Type:
Year of Manufacture: Rating:
Cooling Type:Voltage Class :
Type of Neutral Grounding: Oil Make:
Oil type: Oil quantity:
Quantity of Radiator Date of Receipt at site:
Date of Completion of Erection and OilDate of Starting of Erection: filling:
II. CHECK LIST OF ELECTRICAL TESTS CARRIED OUT FOR REACTOR
S.N NAME OF TEST PERFORMED
(YES/NO)
TEST RESULTS
(OK/ NOT OK)
a Insulation Resistance Measurement
b Tan Delta & Capacitance Measurement Of Bushing
c Tan Delta & Capacitance Measurement Of Windings
d Tan Delta & Capacitance Measurement Of NGR Windings
e Measurement of Winding Resistance
f Measurement of Winding Resistance of NGR
g Magnetisation Current Test
h Insulation Resistance Measurements Of Bushing Cts
i Continuity Test Of Bushing Cts
j Secondary Winding Resistance Of Bushing Cts
k Polarity Test Of Bushing Cts
l Current Ratio Test
m Magnetizing Curves Performance
n Contact Resistance Measurement
o Vibration Measurement
p Protection And Alarm Tests
q Stability Test Of Differe ntial And Ref Protection
r Frequency Response Analysis
Signature:
Name:
Desgn.:
Organization:
(Supplier
Representative)
(Wherever
Applicable)
Signature:
Name:
Desgn.:
(Erection Agency)
Signature:
Name:
Desgn.:
(POWERGRID Site
I/C)
Signature:
Name:
Desgn.:
(POWERGRID
Commg. Team)
Members:
FOR REACTOR
No. CF/SR/02/ R-3 DATED 01/04/2011 Reactor
Doc No. D-2-01-03-01-03
101

III. CHECKS AFTER RECEIPT OF REACTOR AT SITE:
A) N2 PRESSURE & DEW POINT RECORD
N2 PRESSURE DEW POINT REMARKS
During dispatch at factory
After receipt at site
Storage at site before commissioning
Please write 'NIL' in case of No Remarks
NOTE: N2 pressure and dew point should be within permissible range as per graph provided by manufacturer
and also given in os doc no d-2-03-xx-01-01 rev-01. During storage at site, dew point has to be measured
whenever any drop inN2 pressure is observed. During storage at site before commissioning, N2pressure has to
be measured daily and record to be maintained in a separate sheet.
Refer graph 2.1.3 fig.1
B) IMPACT RECORDER ANALYSIS
STATUS BRIEF ANALYSIS
Received in healthy condition at site Yes No
Analysis report received from
manufacturer before charging
Yes No
Note: Impact Recorder should be detached from the Reactor preferably when the main unit has been placed on
its foundation.
Permissible limit for maximum shock is ±3G for any axis.
C) CORE INSULATION TEST
APPLY 1 kV DC BETWEEN CL & CC + G
INSULATION VALUE
BETWEEN CC-G
BETWEEN CL-G
BETWEEN CC-CL
Note: Shorting link between CC, CL & G to be removed and IR value to be taken between CC-G, CL-G & CC-CL
(Recommended value > 10 M? )
D) INTERNAL INSPECTION
INTERNAL INSPECTION
STATUS
YES NO
Details photographs of all visible parts /components are taken during internal
inspection.(refer procedure2.1.6)
Any abnormality observed during internal inspection
Matter referred to manufacturer, CC-ENGG and CC-OS
Details of abnormalities notice if any:
No. CF/SR/02/ R-3 DATED 01/04/2011Reactor
Doc No. D-2-01-03-01-03
102

IV. CHECKS /PRECAUTIONS DURING ERECTION :
a. Active part of Reactor should be minimum exposed to atmosphere
b. Use of dry air generator / dry air cylinders, during
exposure of active part of Reactor to atmosphere.
c. While entering in Reactor tank, availability of proper
Oxygen is checked
d. Reactor kept sealed with N2 in between
different erection activities
V. PRE-COMMISSIONING CHECKS:
SL.
NO.
STATUS REMARK
DEFICIENCIES,
IF ANYYES NO
1 Reactors and its Auxiliaries are free from visible
defects on physical Inspection
2 All fittings as per out line General Arrangement
Drawing
3 Check Main Tank has been provided with double
earthing
4 Check neutral is grounded through separate
connections. Ensure metallic requirements as per
specification (e.g. Cu) in earthing strips used
5 Check that Marshalling Box, Radiator Bank Pump &
Fan Motor etc. has been earthed
6 All nuts and bolts are tightened correctly as per
specified torque (as per manufacturers
recommendation)
7 Check tightness of Terminal Connectors
8 Check leveling of Reactor and its accessories
9 Erection Completion Certificate along with list of
10 Any Paint removed / scratched in transit has been
touched up
11 Bushings are clean and free from physical damages
12 Oil level is correct on all Bushings
13 Check Hermitically sealing is intact in all Bushings
14 Check oil leakage through any Joints / Valves etc.
15 Check oil drain valves are properly closed and locked
16 Check oil level in Main and Conservator tank
17 Check OTI and WTI pockets and replenish the oil, if
Yes No Remarks
Yes No Remarks
Yes No Remarks
required
Doc No. D-2-01-03-01-03
103

18 Check all valves for their opening & closing
sequence
19 Check the colour of the breather silica gel (blue when
dry)
20 Check availability of oil in the breather cup
21 Check all rollers are locked and tack welded with
rails (wherever applicable)
22 Check busing test tap is grounded
23 Check no debris, loose T & P and oil strains on and
around the Reactor
24 Check door seals of Marshalling Box is intact and all
cable gland plates unused holes are sealed
25 Check that pressure relief valve is correctly mounted
26 Ensure unused secondary cores of Bushing CT’s, if
any, has been shorted
27 Check CT star point has been formed properly and
grounded at one end only as per scheme
28 Check that permanent and adequate lighting
arrangements are ready
29 Check that labeling and identification is permanent
and satisfactory
30 Check that Buchholz Relay is correctly mounted with
arrow pointing towards conservator
31 Check cables are properly fixed and ensure cable
entry at the bottom
32 Ensure all Power and Control cable Terminals are
tightened
33 Check all cables and Ferrules are provided with
Number as per Cable Schedule (Cross Ferruling to be
checked)
34 Check that all cables are correctly glanded
35 Check external cabling from Junction Box to Relay /
Control Panel completed
36 Check that air has been released from the Radiators
and their headers/OLTC Buchholz relay/Main
tank/tank/Bushing turrets etc
37 Check Fire Protection System & Emulsifier systems
is adequate & ready
38 Check that CC-CL & G are shorted
39 Check that all radiator bank valves on top and bottom
headers are open
40 Change over operation of ac supply from source- I to
source-II checked
41 Check the flanges of bushing for any crack after
fixing
Doc No. D-2-01-03-01-03
104

42 Calibration of OTI & WTI performed as per
procedure
43 Check various interlocks provided with Fire Fighting
as per the schematic Ref. Drg.
No._____________________
Description
of Interlocks
Checked
VI. MEASUREMENT OF EARTH RESISTANCE OF ELECTRODE
LOCATION VALUE
Without Grid (Earth Pit -1) (Neutral Earth )
Without Grid (Earth Pit -2) (Neutral Earth)
Permissible limit with grid < 1 ohm
VII. DETAILS OF RELAYS/ CONTACTORS USED: SCHEMATIC DRAWING NO.
VIII. EVACUATING AND OIL FILLING
a) Before filling oil, each drum has been
physically checked for free moisture and
appearance
b) Details of oil filter machine
Make _____________________ Capacity________________________
2 Cleaning of Filter packs
3 Flushing of whole filter machine with fresh oil
c) Vacuum pump for evacuation of Reactor
3 Diameter of vacuum hose (50 mm)
4 Employ of Dry ice chamber
Yes No
Doc No. D-2-01-03-01-03
105

d) Oil storage tank
Capacity_____________________ Quantity_________________________
1 Silica gel breather provided in the tank
2 Any opening left uncovered
3 Inside painted or not
4 Cleanliness of inside of pipes/ hoses to the storage tank
e) Exposure during erection
1 First day exposure ( in hrs)
2 Second day exposure ( in hrs)
3 Third Day exposure ( in hrs)
4 N2 pressure applied after each days erection work (
in PSI)
5 Ambient Temperature (in degC)
6 Average Relative Humidity
7 Weather Condition Rainy / Stormy / Cloudy /
Sunny
f) N2 sealing in case of delay in oil filling
i.
1
No. of Cylinders used for displacing the air inside the
tank
2 N2 admitted from bottom valve
3 Valve at diametrically opposite end at top kept open
4 No. of Cylinders used for building up 2 PSI
ii. Schedule for Vacuum & Tightness Test
READING
1 Starting of evacuation on complete unit
2 Stopping of evacuation below the pressure of 0.3 kPa (3
mbar)
3 Pressure P1 in kPa after 1 hour of stopping evacuation
4 Pressure P2 in kPa after half an hour of reading pressure
P1
5 Leakage = (P2-P1) x V ,
V=Oil quantity in Cu mtr
*If leakage >3.6, continue evacuating
If leakage < 3.6Similar action may be carried out for
2 to3 times for confirmation.
6 Start of Vacuum after N2 pressure reaching below
0.13kPa(1 torr)
Doc No. D-2-01-03-01-03
106

* Permissible limit of IR value should be > 50 M ?
7 Break of vacuum
* Vacuum to be kept for 12 hrs Up to 145 KV, 24 hrs
for 145 to 220kV and 36 hrs for 420 kV and above
iii. Schedule for Oil filling and Settling
READING
1 Oil Filling in Main Tank
2 Oil filling in Conservator tank
3 Start of oil settling
4
End of oil settling
* Minimum settling time to be given 12 hrs for 145
KV ,48 hrs for 145 to 420kV and 120 hrs for above
420 kV .
iv. Record of drying out process (if carried out)
Drying out started on date: Time:
Ambient temp:
Hourly reading to be taken
DATE TIME
VACUUM READING
IN FILTRATION
MACHINE
VACUUM READING
IN TRANSFORMER
TANK
OTI OF
TANK
CONDENSATE
COLLECTED TOTAL /
RATE
REMARKS & SIGN OF
MTC ENGINEER
Record of filtration and Dry out shall be kept in a register and shall be made a part of the Pre-
commissioning document.
IX. INSULATION RESISTANCE MEASUREMENT
a) Insulation Resistance Measurement of Cable and others
(Using 500 Volt Megger)
Date of last calibration _____________________
of the kit
SL. NO. DESCRIPTION
STATUS
REMARKS, IF ANY
YES NO
A Control wiring
B Cooling System
a) Motor Fan
b) Motor Pump
c) Control wiring
Doc No. D-2-01-03-01-03
107

b) Insulation Resistance Measurement in M?
(Using 5000 V Megger)
Make & Sl. No of testing kit _______________________
Date of last calibration _______________________
of the kit
Ambient temp in º C _______________________
MAIN WINDING
IR VALUE
DIELECTRIC
ABSORPTION
COEFFICIENT
DAI= 60 Sec / 15
Sec
POLARISATION
INDEX
PI= 600 Sec / 60
Sec
REMARKS
15 sec 60 sec 600 sec
a) HV / E
b)NGR WINDING
*Permissible limit of IR value should be >500 M ? at 30°C, DAI should be >1.3
and PI should be >1.25 To 2
X. MEASUREMENT OF WINDING RESISTANCE (IN OHM)
Make of testing kit ____________________Date of calibration____________________
Ambient temperature ___________________ Temperatureof oil___________________
WTI reading _____________________________
i. WINDING RESISTANCE OF REACTOR WINDING
WINDING RESISTANCE
WINDING RESISTANCE
(HV-N)
(HV-N)
*RESISTANCE AT 75º C
*RESISTANCE AT 75º C
FACTORY VALUE AT 75º C
FACTORY VALUE AT 75º C
% DEVIATION
% DEVIATION
R Ø
R Ø
Y Ø
Y Ø
B Ø
B Ø
R Ø
R Ø
Y
Y
B Ø
B Ø
R Ø
R Ø
Y Ø
Y Ø
B Ø
B Ø
R Ø
R Ø
Y Ø
Y Ø
B Ø
B Ø
ii. WINDING RESISTANCE OF NGR WINDING
* Formula for calculating the resistance at 75°C: R75 = RT (235+75)/ (235+T), where
RT = Resistance Measured At Winding Temperature T.
Permissible limit: ±5% variation between phases or from Factory test results
Doc No. D-2-01-03-01-03
108

XI. MAGNETIZATION CURRENT TEST
Make of testing kit______________________ Date of calibration___________________
Ambient temperature ______________________ Temperature of oil_______________
VOLTAGE APPLIED
IN VOLTS
CURRENT MEASURED IN mAMPS
REMARK
R - N R - PH
Y - N Y - PH
B - N B - PH
NGR
If the excitation current is le ss than 50 milli-Amperes (mAmp), the difference between the two
higher currents should be less than 10%. If the excitation current is more than 50 mAmp, the
difference should be less than 5%. The value on the outside legs should be within 15% of each
other and values for centre leg should not be more than either outside for a three phase reactor.
Results between similar single phase units should not vary more than 10%.
XII. OIL CHARACTERISTICS
(Sample to be taken prior to charging to Reactor and it should fulfill the recommendations as
per IS 1865 /IEC 60422 )
DATE OF OIL
SAMPLING
B.D.V.
MOISTURE TAN DELTA RESISTIVITY
INTERFACIAL
TENSION
Permissible
Limit
70KV(min) 5
PPM(Max)
0.01 at 90º C
(Max)
6x 10 ^12 ? -
CM at 90º C
(Min)
0.0 35 N/m at
27ºC (Min)
XIII. DISSOLVE GAS ANALYSIS
DISSOLVE GASES JUST BEFORE
CHARGING
JUST AFTER
CHARGING
24 HRS AFTER
CHARGING
7 DAYS AFTER
CHARGING
15 DAYS
AFTER
CHARGING
H2
CH4
CO
CO2
C2H4
C2H6
C2H2
O2
N2
*TCG
* TCG should be below 1%
XIV. OPERATIONAL TEST OF OTHER EQUIPMENTS
i. Checking of cooling Equipments
SL.NO DESCRIPTION
STATUS
OK NOT OK
1 Rotation direction of Fans
REMARK
Doc No. D-2-01-03-01-03
109

XV. INSULATION RESISTANCE MEASUREMENT OF BUSHING CT’S(USING 500V MEGGER)
i.
MEASUREMENT
BETWEEN
UNIT
HV
R – Ø Y - Ø B - Ø
Earth - Core I M ?
Earth - Core II M ?
Earth - Core IV M ?
ii.
MEASUREMENT BETWEEN UNIT
HV
R – Ø Y - Ø B - Ø
Core III – Core IV M ?
XVI. CONTINUITY TEST OF BUSHING CT’S (in ? )
Continuity, Check between Terminals OK / NOT OK
CORE BETWEEN
TERMINAL
HV
R - Ø Y - Ø B - Ø
XVII. SECONDARY WINDING RESISTANCE OF BUSHING CT’S (IN OHM)
i. HV side
CORE
BETWEEN
TERMINAL
UNIT
R - Ø Y - Ø B - Ø
Core I 1S1 – 1S2 ?
ii. Neutral Side
CORE
BETWEEN
TERMINAL
UNIT FACTORY SITE
Core I 1S1 – 1S2 ?
Factory Type Test Report Ref. No._________________________________
XVIII. POLARITY TEST OF BUSHING CT’S
With 1.5 V DC supply (Connect +ve at P1 and –ve at P2)
CORE BETWEEN
HV
R - Ø Y - Ø B - Ø
Doc No. D-2-01-03-01-03
110

XIX. CURRENT RATIO TEST
Primary Injection through Primary Injection Kit at Primary Terminal P1 – P2
Measure current on the secondary Terminals
i. HV side R – Phase side
CORE
S1 - S2
PRIMARY
%
CURRENT
ACTUAL
SECONDARY
CURRENT
THEORETICAL
RATIO
ACTUAL
RATIO
% OF
ERROR
Core I
(1S1 – 1S2)
20%
40%
80%
Core II
(2S1 – 2S2)
20%
40%
80%
Core III
(3S1 – 3S2)
20%
40%
80%
Core IV
(4S1 – 4S2)
20%
40%
80%
ii. HV side Y – Phase
CORE
S1 - S2
PRIMARY
%
CURRENT
ACTUAL
SECONDARY
CURRENT
THEORETICAL
RATIO
ACTUAL
RATIO
% OF
ERROR
Core I
(1S1 – 1S2)
20%
40%
80%
Core II
(2S1 – 2S2)
20%
40%
80%
Core III
(3S1 – 3S2)
20%
40%
80%
Core IV
(4S1 – 4S2)
20%
40%
80%
iii. HV side B – Phase
CORE
S1 - S2
PRIMARY
%
CURRENT
ACTUAL
SECONDARY
CURRENT
THEORETICAL
RATIO
ACTUAL
RATIO
% OF
ERROR
Core I
(1S1 – 1S2)
20%
40%
80%
Core II
(2S1 – 2S2)
20%
40%
80%
Doc No. D-2-01-03-01-03
111

Core III
(3S1 – 3S2)
20%
40%
80%
Core IV
(4S1 – 4S2)
20%
40%
80%
Permissible limit of error ± 3%
XX. MAGNETISING CURVES PERFORMANCE
(Not to be done for metering Core)
i. HV Side R – Phase
VOLTAGE
UNIT
CURRENT MEASUREMENT
TO BE APPLIED
ACTUAL
VALUE
CORE – I
1S1-1S2
CORE – II
2S1-2S2
CORE – III
3S1-3S2
CORE – IV
4S1-4S2
0.25 x KVp mA
0.50 x KVp mA
0.75 x KVp mA
1.00 x KVp mA
1.10 x KVp mA
ii. HV Side Y – Phase
VOLTAGE
UNIT
CURRENT MEASUREMENT
TO BE APPLIED
ACTUAL
VALUE
CORE – I
1S1-1S2
CORE – II
2S1-2S2
CORE – III
3S1-3S2
CORE – IV
4S1-4S2
0.25 x KVp mA
0.50 x KVp mA
0.75 x KVp mA
1.00 x KVp mA
1.10 x KVp mA
iii. HV Side B – Phase
VOLTAGE
UNIT
CURRENT MEASUREMENT
TO BE APPLIED
ACTUAL
VALUE
CORE – I
1S1-1S2
CORE – II
2S1-2S2
CORE – III
3S1-3S2
CORE – IV
4S1-4S2
0.25 x KVp mA
0.50 x KVp mA
0.75 x KVp mA
1.00 x KVp mA
1.10 x KVp mA
Note: 1.0 CT should not saturate at 110% of Knee Point Voltage (KVp)
2.0 If Knee Point Voltage is not mentioned then Knee Point Current may be taken into
consideration.
XXI. CONTACT RESISTANCE MEASUREMENT at 100 Amps
Across HV Bushing Terminal Joint µ ?
Across Neutral Bushing terminal joint µ ?
NGR terminal connector µ ?
The value of Contact Resistance should not be more than 10 Micro – ohms per Joint /Connector
Doc No. D-2-01-03-01-03
112

XXII. BUSHING DETAILS
STYLE NO / DRAWING NO.
R - Ø Y - Ø B - Ø NEUTRAL NGR
Make
Type
Sl. No.
XXIII. TAN DELTAAND CAPACITANCE MEASUREMENT OF BUSHING
i. Capacitance of bushing
VOLTAGE
APPLIED
R - Ø Y - Ø B - Ø
REMARKS
Measurement of C1
2 KV
Measurement of C2
1 KV
ii. Tan ä of bushings
VOLTAGE
APPLIED
R - Ø Y - Ø B - Ø
REMARKS
Measurement of C1
2 KV
1 KV
iii. Capacitance of NGR bushing
VOLTAGE
APPLIED
SITE FACTORY
2 KV
10 KV
iv. Tan ä of NGR bushings
VOLTAGE
APPLIED
SITE FACTORY
2 KV
10 KV
C2 values shall be only for record purpose.
Factory test report ref no:
*ACCEPTABLE LIMIT FOR Tan ä1:-0.004 & Tan ä2:-0.01
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113

XXIV. TAN DELTAAND CAPACITANCE MEASUREMENT OF WINDING
VOLTAGE
WINDING
COMBINATION
TEST MODE CAPACITANCE TAN DELTA * REMARK
SITE FACTORY SITE FACTORY
2 KV
HV/Tank+Earh UST
10 KV
Factory Test Report Ref. No.: ______________________________________
* Should be comparable (+/- 0.001) with factory value subjected to max of 0.005.
XXV. VIBRATION MEASUREMENT TEST
i. Vibration measurements are to be carried out
after energization of the reactor. This will be a
reference data for future Measurements.
ii. Various locations are to be shown in the
diagram with x,y co-ordinates for easy
identification.
SL.
NO
DATE OF
MEASUREMENT
LOCATION VALUE REMARKS
XXVI. PROTECTION AND ALARMS
i.
SL
NO
DEVICE
SET FOR PROVED
ALARM TRIP ALARM TRIP
1 EXCESSIVE WINDING TEMPERATURE. 100 110
2 EXCESSIVE OIL TEMPERATUR E. 90 100
Doc No. D-2-01-03-01-03
114

3 PRESSURE RELIEF VALVE (MAIN TANK ) NA NA
4 PRESSURE RELIEF VALVE ( NGR ) NA NA
5 MAIN TANK BUCHHOLZ RELAY
6 NGR BUCHHOLZ RELAY
7 FAN FAILURE NA NA
8 LOW OIL LEVEL ( MAIN TANK ) NA NA
9 LOW OIL LEVEL ( NGR ) NA NA
10 HIGH OIL LEVEL ( MAIN TANK ) NA NA
11 OTI ( MAIN TANK ) 90 100
12 OTI ( NGR )
13 WTI ( MAIN TANK ) 100 110
14 DIFFERENTIAL NA NA
15 BACKUP IMPEDENCE RELAY NA NA
16 EARTH FAULT RELAY ( REF ) NA NA
17 INTER TRIP , IF ANY NA NA
18 TRIP FREE CHECK NA NA
19 TEED PROTECTION
ii. Protection setting applied as per engg.approved
settings
iii. Stability test of differential and REF protection
NOTE : Prove the tripping of associ ated breakers by actual operation of the various
devices and relays as per the schemes.
XXVII. FREQUENCY RESPONSE ANALYSIS (FRA)
i. Carried out after completion of all commissioning
activities
ii. Interpretation of test results carried out
iii. Test results matching with the factory results
iv. Factory & site FRA test report available at site
Yes No Remarks
Ok Not Ok Remarks
Yes No Remarks
Yes No Remarks
Yes No Remarks
Yes No Remarks
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115

XXVIII. ALL ELECTRICAL TEST RESULTS COMPARED WITH
FACTORY TEST RESULTS & FOUND TO BE IN ORDER
XXIX. CHECKS AFTER CHARGING OF REACTOR
Record the following after charging
i. Any abnormal sound emanating from the
reactor
ii. No load current at relay terminal
R - Ø A
Y - Ø A
B - Ø A
iii. Temperature at the time of charging
OTI º C
WTI º C
AMBIENT º C
iv. Maximum temperature after 24 hours____________º C
v. Thermo vision scanning done at least after
24 hours of loading & repeated one week.
XXX. FINAL DOCUMENTATION REVIEW
i. Factory test results are available
ii. Final documents of Pre- Commissioning checks reviewed and
approved
iii. Document regarding spares equipment, O&M manuals etc
available at site for O&M purpose
iv. After modification, if any, “As built Drawings” are available at site
Signature:
Name:
Desgn.:
Organization:
(Supplier
Representative)
(Wherever
Applicable)
Signature:
Name:
Desgn.:
(Erection Agency)
Signature:
Name:
Desgn.:
(POWERGRID Site
I/C)
Signature:
Name:
Desgn.:
(POWERGRID
Commg. Team)
Members:
Yes No Remarks
Yes No Remarks
Yes No Remarks
Yes No
Yes No
Yes No
Yes No
Doc No. D-2-01-03-01-03
116

I. GENERAL DETAILS
DETAILS
Feeder Name: LOA No. :
Make: Year of Manufacture:
Sr. No.: Type:
Rating: Rated Breaking Capacity(kA):
Operating Voltage: Control Voltage (DC) :
Date of Receipt at site: Date of Erection:
Date of energisation:
II. PRE-COMMISSIONING CHECKS:
SL
.NO
DESCRIPTION
STATUS
REMARKS
YES NO
1 Equipment is free from dirt/dust foreign materials etc.
2 Equipment is free from all visible defects on physical inspection
3
Support structures, marshalling box has been provided with double
earth
4 All nuts and bolts are tightened correctly as per specified torque
5
Equipment erection is complete in all respect & erection completion
certificate along with list of outstanding activities reviewed
(attach remaining activities, if any)
6 Permanent pole leveling and identification is done
7 Leveling and alignment of structure and base frame is checked
8 Control box / marshalling kiosk is free from any physical defects
9 Tightness of nuts bolts of terminal connectors are checked
10
Auxiliary contacts and relays have been cleaned and free
from rust / damage
11
All spare wires to be kept with ferrules but not terminated
at the terminal blocks
12
Check all the valves in the sf6 pipe line are tightened,
DILO coupling are tightened.
13
Slow and power closing operation and opening done (wherever
applicable)
FOR CIRCUIT BREAKER
No. CF/CB/03/ R-3 DATED 01/04/2011 Circuit Breaker
Doc No. D-2-01-03-01-03
117

III. OPERATING SYSTEM
Closing Opening
Hydraulic Hydraulic
Pneumatic Pneumatic
Spring Spring
Others Others
i. Hydraulic system
a) Accumulator
b) Pump details
c) Details of relays/contactors used
Schematic drawing no______________________
Oil Pressure Monitor
Closing Lockout
Auto Reclosing Lockout
General Lockout
Anti Pumping Contactor
Pole Discrepancy Timer
Auxiliary
Power Contactor
Others
d) Operation checks
Date of Hydraulic Oil filling_____________________
Type of Hydraulic Oil _____________________
R Ø Y Ø B Ø
Make
Serial number
Type
Year of manufacture
Make Volt
Serial number Amperes
Type Hp/ kW
Year of manufacturer
O/L setting
(Thermal Over load)
No. CF/CB/03/ R-3 DATED 01/04/2011Circuit Breaker
Doc No. D-2-01-03-01-03
118

1. Venting of Hydraulic system
SL .NO ITEM DESCRIPTION
STATUS
REMARKS
YES NO
Pump
Pilot Valve
Accumulator
Hydraulic Mechanism
2. Pressurising hydraulic system
SL.NO DESCRIPTION
FACTORY
TEST VALUE
SITE TEST
VALUE
REMARK RECORD
DEFICIENCIES,IF
ANY
1 Pre-filling pressure of N2 in accumulator ( bar /
deg. C)
2 Pump running time for charging hydraulic
system from initial pressure to working pressure
3 Checking safety valve (open/close)
4 Hydraulic pressure drop for 1 hr
Breaker on position
Breaker off position
5 Oil pressure monitor
Pump on / off bar
Pump running time
6 Auto reclosing lockout (oil) Pressure contact
_____________ make/break
7 Closing lockout (oil) pressure Contact
__________make/break
8 General lockout (oil) Pressure contact
__________ make/break
9 Checking anti pumping contactor Pressure
contact __________make/break
10 Checking loss of nitrogen Pressure contact
__________make/break
Factory test report ref no: ________________________________
3. Oil pressure drop during operations and pump running time in seconds
SL.NO DESCRIPTION
FACTORY TEST
VALUE
SITE TEST VALUE
(i) Pressure before operation(Bar)
Pressure after closing operation(Bar)
Pump running time(Sec)
(ii) Pressure before operation(Bar)
Pressure after opening operation(Bar)
(iii) Pressure before operation(Bar)
Pressure after close/open operation (Bar)
Pump running time in sec
(iv) Pressure before operation(Bar)
Pressure after open-close-open operation(Bar)
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119

ii.Pneumatic System
a) Operating system details
R - Ø Y - Ø B - Ø Remarks
Air receiver no
Control block no
Pneumatic drive no
Magnetic ventil no
b) Motor details
c) ICU Details
d) Details of Relays / Contactors used
Schematic drawing no__ ____________________
Air Pressure Monitor
Closing Lockout
Auto Reclosing Lockout
General Lockout
Pole Discrepancy Timer
Auxiliary
Power Contactor in ICU
Others
e) Pressure Switch setting
CIRCUIT REFERENCE
FACTORY SETTING
VALUE
SITE SETTING VALUE
MAKE
REMARKS
BLOCK DEBLOCK BLOCK DEBLOCK
Operation lockout -1
Operation lockout -2
Closing lockout
Auto reclosing ckt
Low/high pressure
Alarm circuit
ICU auto setting
ICU safety valve
Operations
Make Volt
Serial number Amperes
Type Hp/ kW
Year of manufacturer O/L setting (Thermal Over load)
Make
Serial number
Type
Discharge
Capacity
Doc No. D-2-01-03-01-03
120

f) Pressure drop during operati on : ( in kg/ sq.cm -bar )
SL NO DESCRIPTION
FACTORY SETTING
VALUE
SITE SETTING
VALUE
A Tripping through TC-I
B Tripping through TC- II
C
Closing circuit
D Close-open operation
E
Open - close - open
g) Number of operation from local
Tank pressure ___________ kg/sq.cm or bar
BREAKER INITIALLY CLOSE :
FACTORY TEST : O-C- PLEASE KEEP INLET PNEUMATIC VALVE
CLOSED IN THESE OPERATION
SITE TEST : O-C-
BREAKER INITIALLY OPEN :
FACTORY TEST : C-O- PLEASE KEEP INLET PNEUMATIC VALVE
CLOSED IN THESE OPERATION
SITE TEST : C-O-
h) Air pressure drop in 24 hrs
DROP IN PRESSURE IN
KG/SQ.CM OR BAR
BREAKER ON
BREAKER OFF
iii.SPRING OPERATING SYSTEM
a) Motor details
Make Volt
Sl no Amperes
Type Hp/kw
Year of Manufacture Setting (thermal overload)
Dc current taken by motor for
charging the spring ( amp)
Doc No. D-2-01-03-01-03
121

b) Details of relays/contactors used : schematic drawing no
c) Spring operating time
DETAILS R-PHASE Y-PHASE B-PHASE
CHARGING TIME
Factory test report ref no
IV. SF6 DENSITY MONITOR DETAILS
i.
R-
PHASE Y-PHASE
B-
PHASE
Make
Model
Sl.no
Year of manufacture
Quantity of SF6 gas filled actual B:
As per Specification
ii. SF6 density monitor settings
SF6 gas filled at ________ bar at _____ deg. C on ___/___/___
PHASE
DETAILS
BLOCKING DEBLOCKING
FACTORY SITE FACTORY SITE
R - PHASE REFILL ALARM OPERATION BLOCK
Y - PHASE REFILL ALARM OPERATION BLOCK
B - PHASE REFILL ALARM OPERATION BLOCK
Factory test report ref no :
Closing lockout
Auto reclosing lockout
General lockout
Pole descrepancy timer
Auxillary
Power contactor
Others
Doc No. D-2-01-03-01-03
122

iii. Measurement of dew point of sf6 gas
SL. NO
MEASURED
VALUE PERMISSIBLE LIMITS TO BE DECIDED AS PER GRAPH
NOTE: Dew point measurement of SF6 gas needs to be done pole wise in close loop method without any wastage
of SF6 gas
iv. Leakage check
SL.NO INTERVALS UNIT
A
Initial filling of sf6 gas at ____deg c
(As per temp. Correction chart ) BAR
B Drop in sf6 gas pressure in 24 hrs : BAR
C
Final sf6 pressure at ________deg. C
After all testing BAR
D
Additional leakage test by covering
individual joint with polythene
YES NO
Doc No. D-2-01-03-01-03
123

V. COIL RESISTANCE MEASUREMENT
SL NO PHASE COIL
UNIT
MEASURED
VALUE
SERIES
RESISTOR TOTAL
A R
TRIP COIL - I ?
TRIP COIL - II ?
CLOSE COIL ?
B
Y
TRIP COIL - I ?
TRIP COIL - II ?
CLOSE COIL ?
C
B
TRIP COIL - I ?
TRIP COIL - II ?
CLOSE COIL ?
VI. CIRCUITRY / OPERATIONAL CHECKS
SL NO CIRCUIT REFERENCE
CIRCUITARY CHECK OPERATIONAL CHECK
LOCAL REMOTE LOCAL REMOTE
A TRIPPING THROUGH TC-I
B TRIPPING THROUGH TC-II
C CLOSING CIRCUIT
D ANTI-HUNTING FEATURE
(CLOSE OPEN OPERATION )
E POLE DISCREPANCY FEATURE
F BREAKER POSITION INDICATION ;
G HEATER IN SWITCH CUBICLE
H HEATER IN CONTROL CUBICLE
I ILLUM. IN SWITCH CUBICLE
J ILLUM. IN CONTROL CUBICLE
Note: In case wiring for remote operation is not ready, please indicate terminal number along with wire ferrule
number in switch cubicle where remote cables shall be terminated. Remote operation can be checked from these
terminals
VII. OPERATING TIME ( IN MILLI-SECONDS )
PHASE BREAK
CLOSE
(Max 150
ms)
T R I P (Max 25
ms 400kV,35 ms
220kV, 40 ms 132
kV)
CLOSE TRIP (Min. 35 ms)
TRIP - I TRIP - II TRIP - I TRIP - II
R - ph main contact
BREAK 1
R - PH PIR ( 12 ± 4 ms)
Auxiliary contact
R - ph main contact
BREAK 2
R - PH PIR ( 12 ± 4 ms)
Auxiliary contact
Y - ph main contact
BREAK 1
Y - PH PIR ( 12 ± 4 ms)
Auxiliary contact
Doc No. D-2-01-03-01-03
124

Y - ph main contact
BREAK 2
Y - PH PIR ( 12 ± 4 ms)
Auxiliary contact
B - ph main contact
BREAK 1
B - PH PIR ( 12 ± 4 ms)
Auxiliary contact
B - ph main contact BREAK 2
B - PH PIR ( 12 ± 4 ms)
Auxiliary contact
NOTE: for 765 kV, take measurements for four breaks
VIII. IR VALUE OF CONTROL CIRCUIT(USING 500 VOLT MEGGER)
COIL DETAILS
UNIT MEASUREMENT VALUE
R – PHASE TRIP COIL - I M?
R – PHASE TRIP COIL - II
M?
R – PHASE CLOSE COIL
M?
Y – PHASE TRIP COIL - I
M?
Y – PHASE TRIP COIL - II
M?
Y – PHASE CLOSE COIL
M?
B – PHASE TRIP COIL - I
M?
B – PHASE TRIP COIL - II
M?
B – PHASE CLOSE COIL
M?
CAUTION: Isolate necessary dc for trip coil i and trip coil ii ,closing coil before meggaring.
MINIMUM VALUE 2 MOHM
IX. IR VALUE WITH BREAKER OP EN(USING 5000 VOLT MEGGER)
ACROSS OPEN CONTACT UNIT MEASUREMENT VALUE
R - PHASE BREAK 1
M?
R - PHASE BREAK-2
M?
Y - PHASE BREAK 1
M?
Y - PHASE BREAK-2
M?
B - PHASE BREAK 1
M?
B - PHASE BREAK-2
M?
MINIMUM VALUE 2 MOHM
X. IR VALUE WITH RESPECT TO EARTH WITH BREAKER CLOSED, EARTH SWITCH
AND ISOLATOR OPEN
BETWEEN UNIT MEASUREMENT VALUE
R – PHASE AND EARTH
M?
Y – PHASE AND EARTH
M?
B – PHASE AND EARTH
M?
Doc No. D-2-01-03-01-03
125

XI. MINIMUM PICKUP VOLTAGE OF COILS
COIL DETAILS UNIT MEASUREMENT VALUE
R – PHASE TRIP COIL - I M?
R – PHASE TRIP COIL - II
M?
R – PHASE CLOSE COIL
M?
Y – PHASE TRIP COIL - I
M?
Y – PHASE TRIP COIL - II
M?
Y – PHASE CLOSE COIL
M?
B – PHASE TRIP COIL - I
M?
B – PHASE TRIP COIL - II
M?
B – PHASE CLOSE COIL
M?
XII. GRADING CAPACITOR
i. DETAILS
DETAILS
INTERRUPTER 1 INTERRUPTER 2
R Y B R Y B
MAKE
SERIAL NO.
CAPACITANCE VALUE
FACTORY VALUE
YEAR OF MANUFAC.
ii. CAPACITANCE AND TAN DELTA MEASUREM ENT (TO BE DONE IN UST MODE)
CAPACITANCE
INTERRUPTER 1 INTERRUPTER 2
R Y B R Y B
SITE
-FACTORY
% DEVIATION
TAN DELTA
SITE
-FACTORY
% DEVIATION
Permissible Limits
a) Tan delta of grading capacitors 0.007 (max.)
b) Rate of rise in Tan Delta 0.001 per year (max)
c) Capacitance of grading capacitors within ±5% of the rated value
Note:
a) Since temperature correction factor for Tan-Delta depends on make, type and also aging conditions, the correction
factors for different types / makes are different. Hence, no standard temperature correction factors can be applied.
b) In case of violation of Tan-Delta the test results with temperature are to be referred to CC/OS
Doc No. D-2-01-03-01-03
126

XIII.XIII. CONTACT RESISTANCE MEASUREMENTCONTACT RESISTANCE MEASUREMENT
SL.NO PHASE
ACROSS EACH POLE ACROSS INTERRUPTR 1 ACROSS INTERRUPTER 2
AA RR--PHASE
B Y-PHASE
C BB--PHASE
a) Contact Resistance of CB (in Micro-Ohm)
* 75 ì? (Micro-Ohm) per break
b) Contact Resistance of CB terminal connector 10 Micro-Ohm per connector
Factory test report ref no :______________________
XIV. BREAKER OPERATION COUNTER READING
XV. CHECK FOR ANNUNCIATION IN CONTROL ROOM AS PER THE FOLLOWING
FORMATS AND RECORD THE READING
SL
NO
DESCRIPTION
OF TEST
SOURCE OF
INITIATION
WINDOW
DESCRIPTION
RESULT
REMARK
OK NOT OK
A Switch off the dc switch in Control
cubicle
Control cubicle
dc
Switch on/off
Source I/II dc
fail / ac fail
B Switch off the ac Switch in control
Cubicle
Control cubicle
ac
Switch on/off
Source I/II dc
fail / ac fail
C Short the alarm contacts of sf6 Gas
density monitor (R-phase) Density monitor
Sf6 gas density
lowlow
D
Short the alarm contacts of sf6 Gas
density monitor (Y-phase) Density monitor
Sf6 gas density
low
E Short the alarm contacts of sf6 Gas
density monitor (B-phase) Density monitor
Sf6 gas density
low
F
Remove the cable connected to
density monitor (R-phase)
Density monitorDensity monitor
Operation/closi
ng lockout
G
Remove the cable connected toRemove the cable connected to
density monitor (Y-phase)density monitor (Y-phase)
Density monitorDensity monitor
Operation/closi
ng lockout
H
Remove the cable connected to
density monitor (B-phase)
Density monitor
Operation/closi
ng lock out
400kV 220kV 132kV
150 ì? * 100* 100 ì? 100 ì?
COUNTER TYPECOUNTER TYPE
ELECTRICALELECTRICAL
MECHANICALMECHANICAL
SL.NO PHASE READING DATE
A RR--PHASE
B Y-PHASE
C B--PHASEPHASE
Doc No. D-2-01-03-01-03
127

I
Give tripping command to R-ph only
and check the operation of pole
discrepancy relay
Pole discrepancy
relay at breaker
Cubicle Breaker pole
discrepancy
J
Give tripping command to Y-ph
Only and check the operation of pole
discrepancy relay
Pole discrepancy
relay at breaker
Cubicle
Breaker pole
discrepancy
K Give tripping Command to B-ph only
and check the
operation of pole
discrepancy relay
pole
discrepancy
relay at breaker
cubicle
Breaker pole
discrepancy
L
Check other alarms as per plant
Circuit diagram
M Close the breaker and trip through
Protection which are applicable
protection relay
as per scheme
Breaker auto
trip
NOTE : The tripping details are to be checked as per the Scheme approved by
engineering.
XVI. DYNAMIC CONTACT RESISTANC E & TRAVEL MEASUREMENT
PHASE FACTORY SITE REMARKS
APPROVAL FROM
CC/OS OBTAINED
R
Y
B
XVII. OPERATION TIME MEASUREMENT OF POLE DISCREPANCY RELAY
Close/Trip time pole discrepancy at rated
operating pressure Permissible Limits
a) Phase to Phase (Max) - close operation
5.0ms
b) Phase to Phase (Max) - open operation 3.33ms
c) Break to Break (Max) of same pole 2.5 ms
Note- 2.5 Sec for CBs with Auto Reclose Function & 0.5 Sec for CBs without Auto Reclose Function.
XVIII. MECHANICAL CLOSE INTERLOCK CHECKED
(WHEREVER APPLICABLE)
XIX. FINAL DOCUMENTATION REVIEW
i. Factory test results are available
ii. Final documents of Pre- Commissioning checks reviewed and approved
iii. Document regarding spares equipment, O&M manuals etc available at sit
for O&M purpose
Yes No
Yes No
Yes No
Yes No
Doc No. D-2-01-03-01-03
128

iv. After modification, if any, “As built Drawings” are available at site
v. CC-OS approved dcrm signatures available
Signature:
Name:
Designation:
Organization:
(Supplier
Representative)
(Wherever
Applicable)
Signature:
Name:
Designation:
(Erection Agency)
Signature:
Name:
Designation:
(POWERGRID Site
I/C)
Signature:
Name:
Designation:
(POWERGRID
Members:
Yes No
Yes No
Doc No. D-2-01-03-01-03
129

I. GENERAL DETAILS
DETAILS
LOA No. : Make:
Sr. No.:
RØ:-
YØ:-
BØ:-
Type:
Year of Manufacture:
R Ø:-
YØ:-
BØ:-
Rating:
Date of Receipt at site:
RØ:-
YØ:-
BØ:-
Date of Erection:
RØ:-
YØ:-
BØ:-
Date of energisation (To be written
after commissioning)
II. RATED DATAAND DUTY
CORE RATIO CLASS BURDEN Kvp PROTECTION / METERING
Winding I
Winding II
Winding III
Winding IV
Winding V
KVp : Knee Point Voltage In Volts
III. PRE-COMMISSIONING CHECKS:
SL.
NO
DESCRIPTION
STATUS REMARKS
YES NO
RECORD
DEFICIENCIES, IF
ANY
1
Equipment is cleaned and free from dust / dirt foreign
materials etc.
2
Equipment is free from all visible defects on physical
inspection
FOR CURRENT TRANSFORMER
No. CF/CT/04/ R-3 DATED 01/04/2011Current Transformer
Doc No. D-2-01-03-01-03
130

SL.
NO
DESCRIPTION
STATUS
REMARKS
YES NO
RECORD
DEFICIENCIES, IF
ANY
3
Check CT tank has been provided with double earthing
(dead tank CT's)
4 Check that CT junction box is earthed.
5
All nuts and bolts are tightened correctly as per specified
torque
6 Check tightness of terminal connector
7 All fittings as per out line general arrangement drawing.
8
Leveling and alignment of structure and base frame is
checked
9
Erection completion certificate along with list of
10
Any paint removed / scratched in transit has been
touched up
11
Check primary polarity of CTs erected as per relevant
drawing.
12 Check hermetically sealing is intact
13
Check the oil level and leakage through any joints / sec.
Terminals
14 Check oil drain valve is properly closed and locked.
15 N2 pressure checked (wherever applicable)
16 Oil level on top chamber gauge glass
17
Oil sample taken for BDV and PPM measurement from
tank bottom drain valve ( only if Nitrogen pressure is
measured zero )
18
All the cable identification tags provided and all cores are
provided with identification ferrules at MB.
19
Check secondary cable end box is properly fixed and ensure
cable entry at the bottom and unused holes sealed
20
Ensure interpole cabling is completed and check the
continuity.
21 Check the ir value of secondary cable
22
Check external cabling from junction- box to relay / control
panel completed
23 Ensure unused secondary cores, if any, has been shorted
24
Check star point has been formed properly and
grounded at one end only
25
Check spark gap setting in P1 terminal (wherever
provided/ possible) permanent Pole leveling and
identification markings made
26 Check tan delta test tap is properly earthed
27 Check that lugs used in secondary circuit are of ring type
28
Check direction of primary (P1/ P2) w.r.t. Bus/ line on
erection
29
Provision of bimetallic strips (Cu+Al) ensured wherever
applicable
No. CF/CT/04/ R-3 DATED 01/04/2011 Current Transformer
Doc No. D-2-01-03-01-03
131

IV. INSULATION RESISTANCE MEASUREMENT
a) Insulation Resistance Measurement
(Using 5000Volt Megger)
Remove the connected earthing to system involving CT under test and disconnect the
connected terminals of ct marshalling box
CORE UNIT
PHASE
RØ YØ BØ
PRIMARY - CORE I
PRIMARY - CORE II
PRIMARY - CORE III
PRIMARY - CORE IV
PRIMARY - CORE V
PRIMARY - EARTH
M ?
M ?
M ?
M ?
M ?
M ?
* Permissible limit of IR value should be > 1000 M?
b) Insulation Resistance Measurement in M?
(Using 500 V Megger)
BETWEEN
UNIT
PHASE
RØ YØ BØ
SECONDARY CORE I - EARTH M ?
SECONDARY CORE II - EARTH M ?
SECONDARY CORE III - EARTH M ?
SECONDARY CORE IV - EARTH M ?
SECONDARY CORE V - EARTH M ?
BETWEEN
UNIT PHASE
RØ YØ BØ
CORE I - CORE II M ?
CORE I - CORE III M ?
Doc No. D-2-01-03-01-03
132

CORE I - CORE IV M ?
CORE I - CORE V M ?
CORE II - CORE III M ?
CORE II - CORE IV M ?
CORE II - CORE V M ?
CORE III - CORE IV M ?
CORE III- CORE V M ?
CORE IV - CORE V M ?
*Permissible limit of IR value should be > 50 M ?
c) Check IR value between tan delta point and
earth at 1 kV in secondary box
V. MEASUREMENT OF SECONDARY WINDING RESISTANCE (IN OHM)
Make of testing kit ___________________ Date of calibration______________
Ambient temperature __________________
CORE TERMINAL
UNIT
RØ Y Ø BØ
CORE I 1S1 - 1S2 ?
1S1 - 1S3 ?
1S1 - 1S4 ?
CORE II 2S1 - 2S2 ?
2S1 - 2S3 ?
2S1 - 2S4 ?
CORE III 3S1 - 3S2 ?
3S1 - 3S3 ?
3S1 - 3S4 ?
CORE IV 4S1 - 4S2 ?
4S1 - 4S3 ?
4S1 - 4S4 ?
CORE V 5S1 - 5S2 ?
5S1 - 5S3 ?
5S1 - 5S4 ?
Factory test report ref.no:________________________________
VI. POLARITY TEST (WITH 1.5 VOLT DC SUPPLY)
Connect +ve at P1 and –ve at P2
CORE BETWEEN
PHASE
R -PHASE Y -PHASE B -PHASE
CORE I 1S1 (+VE) 1S2 (-VE)
RØ YØ BØ
Doc No. D-2-01-03-01-03
133

1S1 (+VE) 1S3 (-VE)
1S1 (+VE) 1S4 (-VE)
CORE II
2S1 (+VE) 2S2 (-VE)
2S1 (+VE) 2S3(-VE)
2S1 (+VE) 2S4 (-VE)
CORE III
3S1 (+VE) 3S2(-VE)
3S1 (+VE) 3S3(-VE)
3S1 (+VE) 3S4(-VE)
CORE IV
4S1 (+VE) 4S2(-VE)
4S1 (+VE) 4S3(-VE)
4S1 (+VE) 4S4(-VE)
CORE V
5S1 (+VE) 5S2(-VE)
5S1 (+VE) 5S3(-VE)
5S1 (+VE) 5S4(-VE)
VII. TAN DELTAAND CAPACITANCE MEASUREMENT
Make of testing kit ______________________________
Ambient temperature __ ___________________________
CAPACITANCE
ACROSS STACK
PRE COMMISSIONING VALUES FACTORY VALUES
% DEVIATION FROM
FACTORY VALUES
R Ø Y Ø B Ø R Ø Y Ø B Ø R Ø Y Ø B Ø
2kV
10 kV
TAN DELTA
ACROSS STACK
PRE COMMISSIONING VALUES FACTORY VALUES
% DEVIATION FROM
FACTORY VALUES
R Ø Y Ø B Ø R Ø Y Ø B Ø R Ø Y Ø B Ø
2kV
10 kV
Permissible Limits Tan ä 0.007 (max.) and Rate of rise in Tan Delta 0.001 per year (max)
Deviation of Capacitance value from factory value should be within ± 5% of the rated value
1-Since temperature correction factor for Tan-Delta depe nds on make, type and also aging conditions, the
correction factors for different types / makes are different. Hence, no standard temperature correction
factors can be applied.
2- In case of violation of Tan-Delta the test results with temperature are to be referred to CC/OS
FACTORY TEST REPORT REF. NO:____________________________________________
VIII. CURRENT RATIO TEST
Make of testing kit ________________________________________
Date of calibration _______________________________________
Doc No. D-2-01-03-01-03
134

R PHASE-
CORE
S1 - S2
PRIMARY
CURRENT SECONDARY
CURRENT
THEORET-
ICAL RATIO
ACTUAL
RATIO
% OF
ERROR
% ACTUAL
CORE I
(1S1 - 1S2)
20 %
40 %
80 %
CORE II
(2S1 - 2S2)
20 %
40 %
80 %
CORE III
(3S1 - 3S2)
20 %
40 %
80 %
CORE IV
(4S1 - 4S2)
20 %
40 %
80 %
CORE V
(5S1 - 5S2)
20 %
40 %
80 %
CORE I
(1S1 - 1S3)
20 %
40 %
80 %
CORE II
(2S1 - 2S3)
20 %
40 %
80 %
CORE III
(3S1 - 3S3)
20 %
40 %
80 %
CORE IV
(4S1 - 4S3)
20 %
40 %
80 %
CORE V
(5S1 - 5S3)
20 %
40 %
80 %
CORE I
(1S1 - 1S4)
20 %
40 %
80 %
CORE II
(2S1 - 2S4)
20 %
40 %
80 %
CORE III
(3S1 - 3S4)
20 %
40 %
80 %
CORE IV
(4S1 - 4S4)
20 %
40 %
Primary Injection through Primary Injection Kit at Primary Terminal P1 – P2. Measure the current
on the secondary Terminals
Doc No. D-2-01-03-01-03
135

80 %
CORE V
(5S1 - 5S4)
20 %
40 %
80 %
Y PHASE-
CORE
S1 - S2
PRIMARY
CURRENT SECONDARY
CURRENT
THEORET-
ICAL RATIO
ACTUAL
RATIO
% OF
ERROR
% ACTUAL
CORE I
(1S1 - 1S2)
20 %
40 %
80 %
CORE II
(2S1 - 2S2)
20 %
40 %
80 %
CORE III
(3S1 - 3S2)
20 %
40 %
80 %
CORE IV
(4S1 - 4S2)
20 %
40 %
80 %
CORE V
(5S1 - 5S2)
20 %
40 %
80 %
CORE I
(1S1 - 1S3)
20 %
40 %
80 %
CORE II
(2S1 - 2S3)
20 %
40 %
80 %
CORE III
(3S1 - 3S3)
20 %
40 %
80 %
CORE IV
(4S1 - 4S3)
20 %
40 %
80 %
CORE V
(5S1 - 5S3)
20 %
40 %
80 %
CORE I
(1S1 - 1S4)
20 %
40 %
80 %
CORE II
(2S1 - 2S4)
20 %
40 %
80 %
CORE III
(3S1 - 3S4)
20 %
40 %
Doc No. D-2-01-03-01-03
136

80 %
CORE IV
(4S1 - 4S4)
20 %
40 %
80 %
CORE V
(5S1 - 5S4)
20 %
40 %
80 %
B PHASE:-
CORE
S1 - S2
PRIMARY
CURRENT SECONDARY
CURRENT
THEORET-
ICAL RATIO
ACTUAL
RATIO
% OF
ERROR
% ACTUAL
CORE I
(1S1 - 1S2)
20 %
40 %
80 %
CORE II
(2S1 - 2S2)
20 %
40 %
80 %
CORE III
(3S1 - 3S2)
20 %
40 %
80 %
CORE IV
(4S1 - 4S2)
20 %
40 %
80 %
CORE V
(5S1 - 5S2)
20 %
40 %
80 %
CORE I
(1S1 - 1S3)
20 %
40 %
80 %
CORE II
(2S1 - 2S3)
20 %
40 %
80 %
CORE III
(3S1 - 3S3)
20 %
40 %
80 %
CORE IV
(4S1 - 4S3)
20 %
40 %
80 %
CORE V
(5S1 - 5S3)
20 %
40 %
80 %
CORE I
(1S1 - 1S4)
20 %
40 %
80 %
CORE II
(2S1 - 2S4)
20 %
40 %
Doc No. D-2-01-03-01-03
137

80 %
CORE III
(3S1 - 3S4)
20 %
40 %
80 %
CORE IV
(4S1 - 4S4)
20 %
40 %
80 %
CORE V
(5S1 - 5S4)
20 %
40 %
80 %
Note:During ratio test of CT,the current level attained should not be less than 500A)
Permissible Limit for protection core ± 3% and for metering core ± 1%
IX. MAGNETISING CURVE PERFORMANCE
R – Phase
VOLTAGE
UNIT
CURRENT MEASUREMENT
TO BE APPLIED
ACTUAL
VALUE
CORE – I
1S1-1S2
CORE – II
2S1-2S2
CORE – III
4S1-4S2
CORE – IV
5S1-5S2
0.25 x KVp mA
0.50 x KVp mA
0.75 x KVp mA
1.00 x KVp mA
1.10 x KVp mA
Y-Phase
VOLTAGE
UNIT
CURRENT MEASUREMENT
TO BE APPLIED
ACTUAL
VALUE
CORE – I
1S1-1S2
CORE – II
2S1-2S2
CORE – III
4S1-4S2
CORE – IV
5S1-5S2
0.25 x KVp mA
0.50 x KVp mA
0.75 x KVp mA
1.00 x KVp mA
1.10 x KVp mA
B-Phase
VOLTAGE
UNIT
CURRENT MEASUREMENT
TO BE APPLIED
ACTUAL
VALUE
CORE – I
1S1-1S2
CORE – II
2S1-2S2
CORE – III
4S1-4S2
CORE – IV
5S1-5S2
0.25 x KVp mA
0.50 x KVp mA
0.75 x KVp mA
1.00 x KVp mA
1.10 x KVp mA
Doc No. D-2-01-03-01-03
138

X. CONTACT RESISTANCE MEASUREMENT
Across Terminal P1 µ ?
The value of Contact Resistance should not be more than 10 Micro – ohms per Joint / Connector
XI. DISSOLVED GAS ANALYSIS
DISSOLVED GASES
H2
CH4
CO
CO2
C2H4
C2H6
C2H2
O2
N2
TCG
XII. FINAL DOCUMENTATION REVIEW
i. Final documents of Pre- Commissioning checks reviewed and
approved
ii. Document regarding spares equipment, O&M manuals etc
iii. After modification, if any, “As built Drawings” are available at site
Signature:
Name:
Designation:
Organization:
(Supplier
Representative)
(Wherever
Applicable)
Signature:
Name:
Designation:
Signature:
Name:
Designation:
(POWERGRID Site
I/C)
Signature:
Name:
Designation:
(POWERGRID
Members:
Yes No
Yes No
Yes No
Doc No. D-2-01-03-01-03
139

FOR CAPACITIVE VOLTAGE TRANSFORMER
I. GENERAL DETAILS
DETAILS
Feeder name LOA No. :
Make: Type:
Sr. No.:
RØ:-
YØ:-
BØ:-
Primary Voltage rating
Secondary Voltage rating:
Winding-I
Winding-II
Winding III
Secondary Voltage Burden:
Winding-I
Winding-II
Winding III
Voltage Class:
Winding-I
Winding-II
Winding III
Purpose of
Winding-I
Winding-II
Winding III
Rating: Feeder name:
RØ:-
YØ:-
BØ:-
R Ø:-
YØ:-
BØ:-
Date of Erection:
RØ:-
YØ:-
BØ:-
Date of energisation
SL.
NO
DESCRIPTION
STATUS REMARKS
(RECORD
DEFICIENCIES,
IF ANY)
YES NO
1
Equipment is cleaned and free from dust / dirt foreign
materials etc.
2
inspection
3 Check CVT tank has been provided with double earthing
4 Check that CVT marshalling box is earthed
5
torque
No. CF/CVT/05/ R-3 DATED 01/04/2011Capacitive Voltage Transformer
Doc No. D-2-01-03-01-03
140

6 Check tightness of terminal connector
7 All fittings as per outline general arrangement drawing.
8 Leveling and identification marking is carried out
9
Leveling and alignment of structure and base frame is
checked
10
Erection completion certificate along with list of
11
Any paint removed / scratched in transit has been
touched up
12
Sl. No of HV capacitor identical to the sl.no mentioned on
rating & dig. Plate
13
Ensure brass vent plug between stacks of CVT's is
removed
14
Check the oil level and leakage through any joints / sec.
Terminals
15 Check oil drain valve is properly closed and locked.
16 Oil level on tank gauge glass
17 BDV of oil sample taken from tank bottom drain valve
18
Check secondary cable end box is properly fixed and ensure
cable entry at the bottom.
19
Ensure HF terminal of unused phases has been earthed
and no load on HF terminal bushing
20
Check rating / healthiness of fuses at CVT
marshaling.box and CVT terminal box.
21 Check that the neutral point is earthed
22
Ensure interpole cabling is completed and check the
continuity.
23
Check the ir value of secondary cable ( > 50 m ohms for
control cables)
24
Check external cabling from m.b to relay / control panel
completed
25
All the cable identification tags provided and all cores are
provided with identification ferrules at m.b.
III. CONTINUITY OF WINDING
(After removing Earth Link 1,2 & 3)
i. Between terminals 1a - 1n
ii. Between terminals 2a - 1n
iii. Between terminals 3a - 1n
OK NOT OK
OK NOT OK
OK NOT OK
No. CF/CVT/05/ R-3 DATED 01/04/2011 Capacitive Voltage Transformer
Doc No. D-2-01-03-01-03
141

Using a megger Of 5kV/ 10 kV
BETWEEN
UNIT
MEASURED VALUE
R Ø Y Ø B Ø
Primary - secondary core 1 M?
Primary - earth M?
Permissible Limit should be min 1000 M?
V. SECONDARY WINDING RESISTANCE
PHASE
CORE 1 CORE 2 CORE 3
REMARKS
R Ø
Y Ø
B Ø
Factory test report ref. No: _______________________________________________
VI. INSULATION RESISTANCE MEASUREMENT
(Using a megger of 500 volt)
BETWEEN
UNIT
MEASURED VALUE
R Ø Y Ø B Ø
Secondary core 1 - earth M?
Core 1 - core 2 M?
Core 1 - core 3 M?
Core 2 - core 3 M?
Permissible Limit should be MIN 50 M?
VII. VOLTAGE RATIO TEST
PHASE PRIMARY
VOLTAGE
SECONDARY VOLTAGE THEORETICAL
RATIO
ACTUAL RATIO %
BETWEEN VALUE FACTORY SITE ERROR
R
1a – 1 n
2a – 2 n
3a – 3 n
Doc No. D-2-01-03-01-03
142

Y
1a – 1 n
2a – 2 n
3a – 3 n
B
1a – 1 n
2a – 2 n
3a – 3 n
Permissible Limit should be min ± 5 % for protection cores and ± 0.5 % for metering cores
Note:-
a) Apply voltage of the order of 500v or more across line capacitor ( top flange ) to
earth link
b) Ensure all earth links connected
VIII.
i. All terminal blocks closed in the secondary
after all testing
ii. Phasing ( phase relationship ) of CVT by measuring voltage between R-phase, Y-
phase and B-phase at incoming terminal in control cubicle, for one circuit of the
checked CVT and output terninals R-phase, Y- phase and B-ph of a reference circuit
(existing CVT) with known phasing
REFERENCE
CIRCUIT
MEASURED VALUE
RØ YØ BØ
R-PHASE
Y-PHASE
B-PHASE
Note: Permissible Limits for CVTs used for purposes other than metering. For CVTs used for
commercial metering accuracy class limits to be followed.
IX. TAN DELTAAND CAPACITANCE MEASUREMENT
Make of testing kit _______________________________
Date of calibration ______________________________
Yes No
DRIFT IN SECONDARY VOLTAGE (TO
BE MEASURED BY 0.2 / 0.5 CLASS
MULTIMETER)
CONDITION
MEASUREMENT
FREQUENCY
a) Upto ± 0.5 volts Healthy 6 monthly
b) + 0.5 to +0.8 volts
To be
monitored
3 monthly
c) +0.8 to +1.2 volts
Close
monitoring
monthly
d) +1.2 to +2.0 volts
Close
monitoring
15 days
e) Above +2.0 volts Alarming replacement
f) -0.8 to -4.0 volts
Close
monitoring
15 days
g) Less than -4.0 volts Alarming replacement
No. CF/CVT/05/ R-3 DATED 01/04/2011 Capacitive Voltage Transformer
Doc No. D-2-01-03-01-03
143

CAPACITANCE
ACROSS STACK
PRE COMMISSIONING VALUES FACTORY VALUES % DEVIATION
R Ø YØ B Ø R Ø YØ B Ø R Ø Y Ø B Ø
TOP
MIDDLE
BOTTOM
TOTAL
TAN DELTA
ACROSS STACK
PRE COMMISSIONING VALUES FACTORY VALUES % DEVIATION
RØ YØ BØ RØ YØ B Ø R Ø YØ B Ø
TOP
MIDDLE
BOTTOM
TOTAL
1-Since temperature correction factor for Tan-Delta depe nds on make, type and also aging conditions, the
2- In case of violation of Tan-Delta the test results with temperature are to be referred to CC/OS
FACTORY TEST REPORT REF. NO:______________________________
X. FINAL DOCUMENTATION REVIEW
i. Final documents of Pre- Commissioning checks reviewed and
approved
ii. Document regarding spares equipment, O&M manuals etc
Signature:
Name:
Designation:
Organization:
(Supplier
Representative)
(Wherever
Applicable)
Signature:
Name:
Designation:
(Erection Agency)
Signature:
Name:
Designation:
(POWERGRID Site
I/C)
Signature:
Name:
Designation:
(POWERGRID
Members:
Yes No
Yes No
Yes No
Doc No. D-2-01-03-01-03
144

I. GENERAL DETAILS
DETAILS
Region Sub-Station
Feeder Name Voltage Level
Date of Starting of Erection Date of Completion of Erection and Oil filling
II. DETAILS OF EQUIPMENT INVOLVED
EQUIPMENT
R - PHASE Y - PHASE B - PHASE
MAKE
ID NO SL NO ID NO SL NO ID NO SL NO
CT
CVT
LA
BREAKER
TRANSFORMER
REACTOR
ISOLATOR
EARTH
SWITCH
LINE TRAP
No. CF/BAY/06/ R-3 DATED 01/04/2011 Bay/Feeder
Doc No. D-2-01-03-01-03
145
FOR BAY/FEEDER

III. DETAILS OF CR PANELAND PLCC
PANEL
DETAILS
IDENTIFICATION IDENTIFICATION IDENTIFICATION
MAKE
NAME NUMBER NAME NUMBER NAME NUMBER
Control
Panel
Relay
Panel
PLCC Panel
RTU Panel
RECORDING
INSTRUMENTS
IDENTIFICATION
NAME NUMBER
Fault Locator
Event Logger
Disturbance Recorder
Time Syncronisation
Strip Chart Recorder
IV. PROTOCOL DOCUMENTATION
EQUIPMENT
IDENTIFI
CATION
NO
ALL PRE-
COMM TESTS
CARRIED OUT
AS PER FQP
YES/ NO
ALL TEST RESULTS
ARE WITHIN THE
LIMIT OF
TOLERANCE
YES/ NO
JOINT PROTOCOLS
OF THE EQUIPMENT
INVOLVED IN
CHARGING ARE
DOCUMENTED AND
SIGNED BY ALL
CONCERNED YES/NO
REMARKS
CT
CVT
LA
BREAKER
TRANSFORMER
REACTOR
ISOLATOR
No. CF/BAY/06/ R-3 DATED 01/04/2011Bay/Feeder
Doc No. D-2-01-03-01-03
146

EQUIPMENT
IDENTIFI
CATION
NO
ALL PRE-
COMM TESTS
CARRIED OUT
AS PER FQP
YES/ NO
ALL TEST RESULTS
ARE WITHIN THE
LIMIT OF
TOLERANCE
YES/ NO
JOINT PROTOCOLS
OF THE EQUIPMENT
INVOLVED IN
CHARGING ARE
DOCUMENTED AND
SIGNED BY ALL
CONCERNED YES/NO
REMARKS
EARTH
SWITCH
LINE TRAP
CONTROL
PANEL
RELAY
PANEL
PLCC
RTU
PANEL
Doc No. D-2-01-03-01-03
147

V. CHECK OF BAY MARSHALLING KIOSK
Identification No_____________
DETAILS
STATUS REMARKS, IF ANY
OK/NOT OK OK/NOT OK OK/NOT OK
ILLUMINATION AND HEATER
5 /15 AMP SOCKET
ALL SPECIFIED FUSES IN POSITION
EARTHING AT 2 LOCATI ON
ALL CABLES TIGHTNESS
ALL CABLES ARE PROPER LY GLANDED
ALL CABLES HAVE IDENTIFICATION NO
ALL CORES HAVE IDENTIFICATION NO
SHIELDING WIRES ARE EARTHED
FREE FROM DUST AND DAMAGE
DOOR HINGES AND LOCKING
PAINTS
UNUSED HOLES ARE SEALED
VI. AVAILABILITY OF THE FOLLOWING
SL.
NO.
STATUS
REMARKS
DEFICIENCIES/TEM
PORARY
ARRANAGEMENT IF
ANY
YES NO
1 Fire fighting system commissioned
2 Fire protection including alarms
3 Fire hydrant system
4 Fire deluge (spinkler) system
5 Portable fire extinguishers are in position
6 Fire tenders can be made available for any
eventuality
7 All equipment erection as per general arrangement
drawing issued by engg.
8 Equipment identification name plate are properly
fixed
9 All bus post insulators are cleaned and free from
dust / dirt foreign materials etc.
10 All earthing points have been earthed
11 All nuts and bolts of bus bar are tightened correctly
as per specified torque
12 All clamps and connectors are as per the drawings
issues by Engineering. department and correctly
tightened as per specified torque
13 Any paint removed / scratched in yard
equipments have been touched up
Doc No. D-2-01-03-01-03
148

14 Bay identification and designation plate are on
position with R,Y,B phase marking
15 Gravel filling in the yard (if designed) has been
done
16 The ladders / tools / vehicles / work bench/
temporary earthing etc. Removed from the area
which is to be energized
17 DC emergency light in operation and in auto
18 DG set is available and in operation
19 Switching sequences with procedures are
documented and available in the control room
20 Regular operation in the control room is manned
round the clock with regular operation staff
21 All PTW issued earlier are cancelled and nothing
are pending
22 Operation data log sheets, PTW and other standard
formats of Powergrid are available for regular
operation
23 Confirm color coding of all equipments and phase
marking
24 Check star points of CT & CVT secondary and
associated links if any
25 Check that treated earth pits are covered and
numbered
26 Check the tightness of the connecting links of
treated earth pits
27 Core wise secondary injection test for both CTs and
PTs inputs from secondary terminal box of CT/PT
done to detect any mixing/ interchanging of cores/
phases
28 Fuse fail protection checked for m1, m2, backup
impedance etc
29 Necessary clearances as applicable have been
obtained
30 Charging clearance is received from grid
operation CPCC / IOCC / REB vide msg no
:________ Time__________Dated__________
VII. MEASUREMENT OF EARTH RESISTANCE
SL.NO
LOCATION
DESCRIPTION
DISTANCE BETWEEN
ELECTRODE
RESISTANCE
LOCATION – 1
LOCATION - 2
LOCATION - 3
LOCATION - 4
LOCATION - 5
LOCATION - 6
Permissible limit = 1.0 ? (MAX)
Doc No. D-2-01-03-01-03
149

VIII. CONTACT TIGHTNESS CHECK BY PRIMARY CURRENT INJECTION
CURRENT
INJECTION AT
CURRENT
MEASURED AT
CURRENT
INJECTED
CURRENT
MEASURED
REMARKS ON CONTACT
HEALTHINESS
IX. MEASUREMENT OF SOIL RESISTIVITY DO NE EARLIER PRIOR TO COMMISSIONING
DATE DISTANCE BETWEEN
ELECTRODE
SOIL
RESISTIVITY
REMARKS
X. CHECK THE MINIMUM CLEARANCE BETWEEN LIVE PARTS W.R.T GROUND
AND BETWEEN LIVE PARTS
VOLTAGE PHASE TO GROUND PHASE TO PHASE REMARKS, IF ANY
132 kV 1270 mm 1473 mm
220 kV 2082 mm 2368 mm
400 kV 3065 mm 5750 mm
765 KV 6400 mm 9400 mm
Note : All the clearance between phases & phase to ground are to be checked as per the
drgs. issued by Engg. Dept.
XI. CHECKING OF INTERLOCKS
i. Please refer the relevant plant circuit diagram for checking the interlocks of
various equipments to be energized.
ii. All isolators and ground switches Inter locking
checked as per the Document no CF/ISO/08
XII. TRIP TEST
All breakers are tested and all the trip test as per the
required plant circuit diagrams are carried out as per
the document No CF/CB/05
Yes No Remarks
Yes No Remarks
Doc No. D-2-01-03-01-03
150

XIII. STABILITY TEST FOR BUSBAR
Details of kit used :
To be done in line with approved scheme
i. Bus earth switch open
PHASE PRIMARY INJECTION BETWEEN CTs CURRENT VALUE SPILL CURRENT VALUE REMARKS
R
Y
B
R
Y
B
R
Y
B
ii. Bus earth switch closed
PHASE PRIMARY INJECTION BETWEEN CTs CURRENT VALUE SPILL CURRENT VALUE REMARKS
R
Y
B
R
Y
B
R
Y
B
XIV. FINAL TRIP TEST
The trip test must be repeated prior to energization as per approved scheme.
Tripping operation to be checked for both the trip coils from local/ remote/ protection
i. DC source 1 off
SL.
NO
PROTECTION
TYPE
SIMULATION
METHOD
CB TRIP RESPONSE
REMARKS
MAIN TIE
I Main - I
II Main – II
III Over voltage
IV Carrier inter tripping
V LBB
VI Bus bar
VII Tee differential
VIII Differential
Doc No. D-2-01-03-01-03
151

IX Restricted earth fault
X Back up o/c & e/f
XI Over fluxing
XII OTI trip
XIII WTI trip
XIV Buchholz trip (main )
XV Buchholz trip (OLTC)
XVI PRD
XVII Auto-reclose - R ø
XVIII Auto-reclose - Y ø
XIX Auto-reclose - B ø
ii. DC source 2 off
SL.
NO
PROTECTION
TYPE
SIMULATION
METHOD
CB TRIP RESPONSE
REMARKS
MAIN TIE
I Main - I
II Main – II
III Over voltage
IV Carrier inter tripping
V LBB
VI Bus bar
VII Tee differential
VIII Differential
IX Restricted earth fault
X Back up o/c & e/f
XI Over fluxing
XII OTI trip
XIII WTI trip
XIV Buchholz trip (main )
XV Buchholz trip (OLTC)
XVI PRD
XVII Auto-reclose - R ø
XVIII Auto-reclose - Y ø
XIX Auto-reclose - B ø
Operational Constraints if any
Doc No. D-2-01-03-01-03
152

XV. FINAL DOCUMENTATION REVIEW
i. Final documents of Pre- Commissioning checks reviewed and approved
ii. Document regarding spares equipment, O&M manuals etc available at sit
for O&M purpose
iv. The above Bay/Feeder is cleared for high voltage energisation
Signature:
Name:
Designation:
Organization:
(Supplier
Representative)
(Wherever
Applicable)
Signature:
Name:
Designation:
(Erection Agency)
Signature:
Name:
Designation:
(POWERGRID Site
I/C)
Signature:
Name:
Designation:
(POWERGRID
Commissioning Team)
Members:
Yes No
Yes No
Yes No
Yes No
Doc No. D-2-01-03-01-03
153

I. GENERAL DETAILS
DETAILS
Make: Type:
Sr. No.:
RØ:-
YØ:-
BØ:-
Operating Voltage rating
Control Volatge: Current Carrying capacity:
RØ:-
YØ:-
BØ:-
R Ø:-
YØ:-
BØ:-
Date of Erection:
RØ:-
YØ:-
BØ:-
II. PRE-COMMISSIONING CHECKS
SL.NO DESCRIPTION
STATUS
REMARKS / RECORD
DEFICIENCIES, IF ANY
YES NO
1 Equipment is free from dirt/dust foreign materials etc.
2
inspection
3
Support structures, marshalling box has been provided
with two earthing pads / points
4
torque
5
Equipment erection is complete in all respect as per
instruction Manual (attach remaining activities, if any)
6 Permanent isolator lavelling and identification is done
7
Leveling and alignment of structure and base
frame is checked
8
Control box / marshalling kiosk is free from any
physical defects
9
Tightness of nuts bolts of terminal connectors
are checked
10
Auxiliary contacts and relays have been cleaned
and free from rust / damage
11 Corona rings are provided and properly fixed
12
Cable termination and tightness checked and unused
holes sealed
13 External cabling is completed in all respect
14
All the cable identification tags provided and all
cores are provided with Identification ferrules at m.b.
FOR ISOLATOR AND GROUNDING SWITCH
No. CF/ISO/07/ R-3 DATED 01/04/2011Isolator
Doc No. D-2-01-03-01-03
154

15 All moving parts are lubricated
16
Alignment of isolator already made to be checked
and locking bolt provided, if any
17 Freeness of manual operation is ok
18
Greasing has been made on the main contacts
according to the manufacturers instruction
19 Functional checking of auxiliary contacts for
indications and interlocks
20 Erection completion certificate along with list of
21 All spare wires to be kept with ferrules but not
terminated at the terminal blocks
22 Earth switch connected to earth through braided wires
23 Interlocks checked as per approved scheme
with all combinations
24 Check that earth switch blade alignment in condition
is at sufficient distant from isolator
25 Check that operation and positioning of the limit
switch & the auxiliary contacts assembly are ok
26 Check that all three phase isolators are closing &
opening at a time
27 Check all 3 earth switches close at the same time
28 Provision of bimetallic strips ensured wherever
applicable
III. MOTOR DETAILS
Make of testing kit
Date of calibration
Ambient temperature
Using 500 volt megger measure resistance between the winding of motor and earth
SL. NO BETWEEN PHASE
R Ø Y Ø B Ø
1 Winding to Earth
PERMISSIVE VALUE > 1000 M.OHM
R - Ø Y - Ø B - Ø
Make
Serial number
Type
Volt
Amperes
Hp/ kW
O/L setting (Thermal Over load)
No. CF/ISO/07/ R-3 DATED 01/04/2011 Isolator
Doc No. D-2-01-03-01-03
155

V. OPERATIONAL CHECKS
i. Operate the isolator and record the motor current
ISOLATOR
OPERATION
MOTOR CURRENT
R - Ø Y - Ø B - Ø
CLOSE
OPEN
ii. Operation of isolator from local / remote Ok/Not Ok
ISOLATOR
OPERATION
CONTROL PANEL
LOCAL REMOTE
CLOSE
OPEN
iii. Measurement of operating time
OPERATION
UNIT
PHASE
R - Ø Y - Ø B - Ø
OPENING TIME
CLOSING TIME
iv. Auxiliary contacts checking
ISOLATOR
OPERATION
AUXILLARY
RELAY TYPE
OPERATION TIME
R - Ø Y – Ø B - Ø
NO NC NO NC NO NC
CLOSE
OPEN
Reference drawing no:
Doc No. D-2-01-03-01-03
156

v. OPERATION ON UNDER VOLTAGE CONDITION
CONDITION COIL
UNIT
PHASE
R - Ø Y - Ø B - Ø
PICK UP
VOLTAGE
CLOSING VOLT DC
OPENING VOLT DC
INTERLOCK VOLT DC
DROP
VOLTAGE
CLOSING VOLT DC
OPENING VOLT DC
VOLT DCINTERLOCK
VI. INSULATION RESISTANCE MEASUREMENT (By 5kV Megger)
Make of testing kit
Date of calibration
Ambient temperature
Isolator open condition
BETWEEN PHASE
R Ø Y Ø B Ø
MALE SIDE TO GROUND
FEMALE SIDE TO GROUND
MALE SIDE TO FEMALE SIDE
PERMISSIVE VALUE > 1000 M.OHM
VII. CONTACT RESISTANCE MEASUREMENT
(To be measured after 50 operation)
Date of calibration __ ___________________________
i. Isolator Close condition
Connector(Male Side) µ ?
Connector(Female Side) µ ?
Main Contact(Male & Female) µ ?
The value of Contact Resistance should not be more than 10 Micro – ohms per / Connector
ii. Isolator Open condition and grounding switch close condition
Main Contact(Male & Female) Ground
Switch
µ ?
The value of Contact Resistance should not be more than 150 Micro – ohms per / Connector
No. CF/ISO/07/ R-3 DATED 01/04/2011 Isolator
Doc No. D-2-01-03-01-03
157

VIII.
i. Resistance of operating coil _______________________________
ii. Resistance of interlocking coil________________________________
IX. FINAL DOCUMENTATION REVIEW
for O&M purpose
Signature:
Name:
Designation:
Organization:
(Supplier
Representative)
(Wherever
Applicable)
Signature:
Name:
Designation:
(Erection Agency)
Signature:
Name:
Designation:
(POWERGRID Site
I/C)
Signature:
Name:
Designation:
(POWERGRID
Commissioning Team)
Members:
Yes No
Yes No
Yes No
Doc No. D-2-01-03-01-03
158

I. GENERAL DETAILS
DETAILS
Make: Type:
Sr. No.:
RØ:-
YØ:-
BØ:-
Voltage rating
Rating: Feeder name:
R Ø:-
YØ:-
BØ:-
RØ:-
YØ:-
BØ:-
Date of Erection:
R Ø:-
YØ:-
BØ:-
SL.
NO.
DESCRIPTION
STATUS REMARK RECORD
DEFICIENCIES, IF ANYYES NO
1 Equipment is free from dirt / dust foreign materials etc.
3 Support structures have been provided with double earth
5
Equipment erection is complete in all respect (attach remaining
activities, if any)
6 Permanent LA leveling andidentification is done
8
All insulators & surge counter are free from any physical
defects
9 Tightness of nuts bolts of terminal connectors are checked
10
Erection completion certificate along with list of outstanding
activities reviewed
11
Check one end of surge counter is connected to the bottom of
LA stack and one end of surge counter has been earthed
12
The direction of the exhaust vent ports away from the protected
equipment and other arrester poles
13
Clearance from the arrester to earthed objects and from the
arrester pole to another arrester pole maintained as per outline
drawing and all erection has been done as per drawing issued by
engg. Dept.
14 Operation of LA counter checkedby applying appropriate voltage
15
Check the serial no. and sequence of LA parts for erection in multi
stack LA
16 Check the alignment of corona ring
17 Check on charging, the surge counter pointer is in green zone
FOR SURGE ARRESTER
No. CF/SA/08/ R-3 DATED 01/04/2011 Surge Arrester
Doc No. D-2-01-03-01-03
159

III. INSULATION RESISTANCE MEASUREMENT : ( USING 5kV MEGGER)
SL. NO BETWEEN
UNIT
PHASE
R Ø Y Ø B Ø
1 1st stack & earth M?
2 2nd stack & earth M?
3 3rd stack & earth M?
4 4th stack & earth M?
MIN VALUE > 1000 M OHMS
IV. SURGE COUNTER READING
SL.NO READING R Ø YØ BØ
1 Counter sr. No.
2 Counter make
3
V. CAPACITANCE & TAN DELTA MEASUREMENT
STACK CAPACITANCE TAN DELTA
REMARKS
SITE FACTORY %DEVIATION SITE FACTORY %DEVIATION
Top
Middle 1
Middle 2
Bottom
Since temperature correction factor for Tan-Delta depe nds on make, type and also aging conditions, the
In case of violation of Tan-Delta the test results with temperature are to be referred to CC/OS
VI. CHECKING OF HEALTHINESS OF SURGE MONITOR
Refer manufacturer’s catalogue for detail checking of surge
monitor
VII. THIRD HARMONIC RESISTIVE CURRENT MEASUREMENT
AMBIENT TEMPERATURE __________ ___________________ SYSTEM VOLTAGE____________________________
PH
TOTAL
CURRENT
3RD
HARMONIC RESISTIVE
CURRENT (I3 R) in A
REMARKS
R
Y
B
Yes No
1
2
Counter reading
No. CF/SA/08/ R-3 DATED 01/04/2011Surge Arrester
Doc No. D-2-01-03-01-03
160

The value of third harmonic current after compensation shall be less than 30 µa. In case of
discrepancy, test results to be forwarded to CC/OS.
I. FINAL DOCUMENTATION REVIEW
ii. Document regarding spares equipment, O&M manuals etc available at site
for O&M purpose
Signature:
Name:
Designation:
Organization:
(Supplier
Representative)
(Wherever
Applicable)
Signature:
Name:
Designation:
(Erection Agency)
Signature:
Name:
Designation:
(POWERGRID Site
I/C)
Signature:
Name:
Designation:
(POWERGRID
Commissioning Team)
Members:
Yes No
Yes No
Yes No
No. CF/SA/08/ R-3 DATED 01/04/2011 Surge Arrester
Doc No. D-2-01-03-01-03
161

I. GENERAL DETAILS
DETAILS
Make: Type:
Sr. No.:
RØ:-
YØ:-
BØ:-
Voltage rating
mH Rating: Current Rating:
Band Width:
RØ:-
YØ:-
BØ:-
RØ:-
YØ:-
BØ:-
Date of Erection:
R Ø:-
YØ:-
BØ:-
II. PRE-COMMISSIONING CHECKS
SL
NO
DESCRIPTION
STATUS
RECORD
DEFICIENCIES, IF
ANYYES NO
1 Equipment is free from dirt / dust foreign materials etc.
3 Support structures has been provided with double earth
5 Permanent lavelling and identification is done
7
All insulators & line matching unit are free from any physical
defects
8 Tightness of nuts / bolts of terminal connectors are checked
9
Erection completion certificate along with list of outstanding
activities reviewed
10
Check that the tuning unit and arrestor are properly tightened
and free from any damage
FOR WAVE TRAP
No. CF/WT/09/ R-3 DATED 01/04/2011Wave Trap
Doc No. D-2-01-03-01-03
162

III. INSULATION RESISTANCE MEASUREMENT
Make of testing kit _______________________________
Ambient temperature _______________________________
SL. NO BETWEEN MEGGER PHASE PERMISSIVE
VALUE
RØ YØ BØ
1
UPPER TEMINAL AND EARTH 5000 V
> 1000 M.OHM
2
LA OF THE WAVE TRAP
500 V
> 1 M.OHM
IV. CONTACT RESISTANCE MEASUREMENT
The value of Contact Resistance should not be more than 10 Micro – ohms per Joint /
Connector
V. FINAL DOCUMENTATION REVIEW
for O&M purpose
Signature:
Name:
Designation:
Organization:
(Supplier
Representative)
(Wherever
Applicable)
Signature:
Name:
Designation:
(Erection Agency)
Signature:
Name:
Designation:
(POWERGRID Site
I/C)
Signature:
Name:
Designation:
(POWERGRID
Commissioning Team)
Members:
Yes No
Yes No
Yes No
No. CF/WT/09/ R-3 DATED 01/04/2011 Wave Trap
Doc No. D-2-01-03-01-03
163

LINE PROTECTION
General Details
Date of testing: Date of Energisation:
Main-I/II Protection Panel
1. Main-I /II Distance relay: (separate for Main-I & II Relays)
i
Check for proper programming of Input / Output contacts of the
relay as per approved schematics
OK/ NOT OK
ii
a Check for proper programming of LED’s(if applicable) of the
relay and check that stickers are provided as per the
configuration.
OK/ NOT OK
b Check Configuration / Programmable Scheme Logic of relay
according to scheme (applicable for numerical relays)
OK/ NOT OK
c Get the print out of Configuration / PSL OK/ NOT OK
iii Get a print of relay settings OK/ NOT OK
iv Compare with the recommended setting OK/ NOT OK
v Check for Reach Setting : Zone- I, II, III,IV OK/ NOT OK
vi Check time of operation : Zone- I, II, III,IV OK/ NOT OK
vii Test results of (iii) & (iv) enclosed YES/ NO
viii
Check polarity of send & receive for PLCC command (If Digital
Channel/ Under FET operation)
OK/ NOT OK
ix
Check Permissive tripping by Carrier command receive and
measure & record relay operation time for carrier aided trip.
Also check Carrier Send command on relay tripping
OK/ NOT OK
Verify respective counter advancement in each channel
Send Recv
Main-I
CH….. Code……… CH….. Code……… OK/ NOT OK
Main-II
x
Check Blocking scheme (if applicable) along with carrier
command for both send & receive.
OK/ NOT OK
Verify respective counter advancement in each channel
Send Recv
Main-I
PRE-COMMISSIONING CHECK LIST
FOR CONTROL & PROTECTION INCLUDING PLCC
No. CF/C&P/10/ R-3 DATED 01/04/2011Control & Protection
Doc No. D-2-01-03-01-03
164

Main-II
xi Check SOTF Logic. Check Control switch( TCS) & wirings on
Control panel to Relay Input for SOTF( if provided)
OK/ NOT OK
xii Check Weak-end in-feed logic OK/ NOT OK
xiii Check Selective Phase tripping( R Ph fault to R-Ph Trip etc) for
each phase separately
OK/ NOT OK
xiv Check Power swing blocking feature (if available) OK/ NOT OK
xv Check trip Block in case of CVT Fuse Failure OK/ NOT OK
xvi
Check Auto Reclose Initiation Contacts for
a Transient Single Phase Earth fault(Zone-1&Zone-2+CR) OK/ NOT OK
b Non initiation for 1 phase fault in Zone II OK/ NOT OK
c Transient Ph-Ph Fault OK/ NOT OK
d Transient 3 Phase Faults OK/ NOT OK
e Permanent Faults(Prepare 3Ph Trip) OK/ NOT OK
f Check for dead time and reclaim time setting OK/ NOT OK
g Check single phase auto reclosure for all three phases one by
one.
OK/ NOT OK
xvii
Check for tripping command directly to CB & correct operation
of tripping relays and auxiliary relays
OK/ NOT OK
xviii
Check Communication to PC keeping adjacent relay IN&OUT
of service (If available)
OK/ NOT OK
xix Check PLCC carrier Switch Operation( In/Out). OK/ NOT OK
xx
Check Time synchronizing by altering Time Zone. Restore on
confirmation
OK/ NOT OK
xxi Check Self-diagnostic feature of the relay (if provided) OK/ NOT OK
xxii Check metering function of the relay (if provided) OK/ NOT OK
xxiii Verify automatic downloading feature as per Tech spec. OK/ NOT OK
xxiv Verify open delta voltage in DR channel OK/ NOT OK
xxv Verify availability of configuration tool at site. OK/ NOT OK
xxvi Verify Main & Tie CT circuits by primary injection OK/ NOT OK
xxvii
Check directionality of the relay after synchronization of the
line
OK/ NOT OK
xxviii Check for DEF protection and its contacts (if applicable) OK/ NOT OK
xxix Check all the contacts of relay for proper operation & rating OK/ NOT OK
2. Overvoltage Stage-I/II
i Check Operate Value/Reset Value/Operate timing for all phases. OK/ NOT OK
ii
Check whether it trips Main/Tie CB & sends Direct trip to
remote end
YES/ NO
3. Stub protection (4 CT scheme)
i Check scheme logic OK/ NOT OK
ii Check operation at set value OK/ NOT OK
iii
Check Direct Trip send & receive circuit with carrier command.
Verify counter advancement in each channel
OK/ NOT OK
No. CF/C&P/10/ R-3 DATED 01/04/2011 Control & Protection
Doc No. D-2-01-03-01-03
165

4. TEE Differential-I/II (5 CT scheme)
i Check Operate Value/Reset Value/Oper ate Timing for all phases OK/ NOT OK
ii Check tripping of Main/Tie CB & send Direct trip to remote end OK/ NOT OK
iii Check stability for out zone fault OK/ NOT OK
iv. If Biased differential, check Biasing percentage for all phases OK/ NOT OK
5. Fault Locator
Feed FL & Distance relay with same Voltage & Current from test Kit. Simulate Zone-I/II,
Single Ph/Ph-Ph/3Ph Fault to Main-I/II Distance relay.
i Check initiation by Distance relay OK/ NOT OK
ii Compare Fault location by calculating the Set Vale on test Kit OK/ NOT OK
iii Repeat the above up to 99% in steps OK/ NOT OK
iv. Check healthiness of mutual compensation circuit OK/ NOT OK
6. Disturbance Recorder
i
Check analog & digital channels are connected as per approved
nomenclature
OK/ NOT OK
ii
Check threshold value of analog triggering (including open delta
voltage).
OK/ NOT OK
iii Check triggering on digital inputs OK/ NOT OK
iv Check automatic downloading feature OK/ NOT OK
v Check time synchronizing feature OK/ NOT OK
vi Verify open delta voltage in DR channel OK/ NOT OK
vii Check diagnostic feature(if provided) OK/ NOT OK
7. Final Documentation Review
S.No. Description Status
(Yes/
No)
Remarks(Record
deficiencies, if
any)
1. Final document of Pre-commissioning checks reviewed and
approved
2. Documents regarding spares, equipment, factory reports,
O&M manuals etc. available at site for O&M purpose
3. After modification, if any, “As built drawing are available at
site
Signature:
Name:
Desgn.:
Organization:
(Supplier
Representative)
(Wherever
Applicable)
Signature:
Name:
Desgn.:
(Erection Agency)
Signature:
Name:
Desgn.:
(POWERGRID Site
I/C)
Signature:
Name:
Desgn.:
(POWERGRID
Commg. Team)
Members:
Doc No. D-2-01-03-01-03
166

Circuit-Breaker Panel
General Details
1. Auto-reclose Scheme: (Checks applicable for distance protection scheme with auto
re-closure function as well)
i
Check auto reclose initiation/Block contacts for
a Transient Single Phase Earth fault OK/ NOT OK
b Non initiation for 1 phase fault in Zone II OK/ NOT OK
c Transient Ph-Ph Fault OK/ NOT OK
d Transient 3 Phase Faults OK/ NOT OK
e Permanent Faults OK/ NOT OK
ii
Simulate Zone-I ,Single Ph Transient E/F to Main-I/II Distance
relay Check AR for all 3 Phases,one by One
OK/ NOT OK
iii
Loop CS & CR, Simulate Zone-II ,Single Ph Transient E/F to
Main-I/II Distance relay Check AR for all 3 Phases, one by One
OK/ NOT OK
iv Check settings & operation of Synchronizing/DLC relays OK/ NOT OK
v Measure Dead Time setting ………………ms
vi Measure Reclaim Timer setting OK/ NOT OK
vii Check AR does not take place within reclaim time OK/ NOT OK
viii Check AR does not take place in case of fault on Line Charging. OK/ NOT OK
ix
Check AR does not take place in case of Failure of PLCC
Carriers
OK/ NOT OK
x
Further, check AR Interlocking in case of
a Pole discrepancy OK/ NOT OK
b Direct trip received OK/ NOT OK
c Over-voltage stage-I/II trips OK/ NOT OK
d Reactor protection trips OK/ NOT OK
e CB Troubles OK/ NOT OK
f Zone-2 & 3 time delayed faults OK/ NOT OK
xi In a one & half / Two CB scheme, Check AR does not take place
for any one of the CBs under S/D. Check Memory Circuit
Contact status( CB Closed/Opened conditions). Check Memory
Circuit Timer setting.
OK/ NOT OK
xii Check Logics of AR switch Operation ( NA/1Ph/2Ph/3Ph). OK/ NOT OK
xiii Check priority circuitry. Priority circuit of Tie CB should be
bypassed is any of the main CB is kept in Non Auto mode due to
shutdown or outages
OK/ NOT OK
xiv A/R should not take place in NON AUTO mode OK/ NOT OK
Doc No. D-2-01-03-01-03
167

2. Local Breaker Back Up Protection:
ii
Check adjacent CB’s as well as concerned Bus-Bar Trip relays
operate during operation of LBB relay
OK/ NOT OK
iii
Check Direct trip Transfer takes place only for feeder under
testing during LBB operation
OK/ NOT OK
3. Under-voltage Relay
i Check Operate Value/Reset Value/Operate Timing for all phases OK/ NOT OK
ii
Check E/S interlock operation under relay energized condition
& vice versa
OK/ NOT OK
4. Direct Trip Transfer
a. Check Direct trip transfer in case of:
i Over-voltage relay operations OK/ NOT OK
ii Reactor trip operations. OK/ NOT OK
iii
Manual trip to One CB(Main/Tie) when another CB(Tie/Main)
in same dia is under open condition
OK/ NOT OK
iv LBB relay Trip: for both the main & tie CB’s OK/ NOT OK
v
Busbar Trip to One CB(Main/Tie) when another CB(Tie/Main)
in same dia is under open condition
OK/ NOT OK
vi TEE Diff/ STUB Protection trip OK/ NOT OK
vii Direct trip Transfer thr’ 1st
Chanel OK/ NOT OK
viii Direct trip Transfer thr’ 2nd Chanel OK/ NOT OK
ix Check DT is not resulted by 1st
Chanel permissive trip OK/ NOT OK
x Check DT is not resulted by 2nd Chanel permissive trip OK/ NOT OK
b. Summary of Code Transfer for PLCC
Ch-1 Code-I……… Ch-1 Code-2……… Ch-2 Code-I ……… Ch-2 Code-2 ………
i Check individual Code Transfer to be as per scheme OK/ NOT OK
ii Ch-1 Code-I OK/ NOT OK
iii Ch-1 Code-2 OK/ NOT OK
iv Ch-1 Code-3 OK/ NOT OK
v Ch-2 Code-I OK/ NOT OK
vi Ch-2 Code-2 OK/ NOT OK
vii Ch-2 Code-3 OK/ NOT OK
viii
Check if signal through One code is not transferred to another at
Remote end
OK/ NOT OK
Doc No. D-2-01-03-01-03
168

5. CB Troubles
i
Check whether All relays are given elaborative nomenclatures. If
not, Paste descriptions (CB LOW Air/Oil pressure, Pole
discrepancy etc.)
OK/ NOT OK
ii
Check Operations of individual Relays by actuating initiating
Contacts from field
OK/ NOT OK
iii Check facia/Event Logger Input Contacts for the same OK/ NOT OK
(Yes/
No)
Remarks(Record
deficiencies, if
any)
approved
site
Signature:
Name:
Desgn.:
Organization:
(Supplier
Representative)
(Wherever
Applicable)
Signature:
Name:
Desgn.:
(Erection Agency)
Signature:
Name:
Desgn.:
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I/C)
Signature:
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Desgn.:
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Members:
Doc No. D-2-01-03-01-03
169

Line Reactor Protection
General Details
1. Differential Protection
i
CT secondary Circuitry Checked & Diff current is Nil by
Primary Injection for all Phases
OK/ Value….
ii
Check connection of stabilizing resistance & metrosil (wherever
applicable)
OK/ NOT OK
iii
If fed from Turret CT’s from both sides of Phase Windings.
Check Operate Value/Reset Value/Operate Timing for all phases
OK/ NOT OK
iv Measure differential pick up current OK/ NOT OK
v
Carry out stability test by simulating external and internal faults
and measure spill currents in Differential circuit
OK/ NOT OK
vi
Check Biasing percentage, Operate Value/Reset Value/Operate
including High set feature if applicable
OK/ NOT OK
vii Timing for all phases(if biased / percentage differential) OK/ NOT OK
viii
Check Blocking of tripping on Harmonic Restraints Feature ( 2nd
& 5th
harmonics)
OK/ NOT OK
ix Check DR feature (if available) OK/ NOT OK
2. Restricted Earth-Fault Protection:
ii
OK/ Value….
iii
applicable)
OK/ NOT OK
iv
Check CT Circuits so that summation of same phases(R-R, Y-Y,
B-B) is taking place (Sometimes R-B & B-R summations are
observed due to wrong Wirings).
OK/ NOT OK
v
OK/ NOT OK
vi Measure differential pick up current OK/ NOT OK
vii
by primary injection and measure spill currents in REF relay
OK/ NOT OK
Doc No. D-2-01-03-01-03
170

3. Back-Up Impedance Relay Type :…………
i Get a print of relay settings(wherever applicable) OK/ NOT OK
ii Compare with recommended setting OK/ NOT OK
iii Check for Reach Setting OK/ NOT OK
iv Check time of operation OK/ NOT OK
v Test results of (iii) & (iv) enclosed YES/NO
vi Check Selective Phase tripping( R Ph fault to R-Ph Trip etc) OK/ NOT OK
vii Check trip Block in case of CVT Fuse Failure. OK/ NOT OK
viii Check Communication to PC(If available) OK/ NOT OK
ix
confirmation
OK/ NOT OK
x Check Self-diagnostic feature of the relay (if provided) OK/ NOT OK
xi Check metering function of the relay (if provided) OK/ NOT OK
xii Verification of Directionality OK/ NOT OK
4. Electromechanical Relays : Check operation of:
i Buchholz Alarm & trip OK/ NOT OK
ii WTI Alarm & trip Alarm………Trip………..
iii OTI Alarm & trip Alarm………Trip………..
iv PRD Trip OK/ NOT OK
v MOG(LOL/Low Oil Level) Alarm OK/ NOT OK
i
In all cases of above trippings, Direct trip to remote end is sent
along with tripping of Main/Tie CB’s
OK/ NOT OK
ii Direct trip: From line Reactor LBB in case of switchable reactor OK/ NOT OK
6. Voltage selection for Protection & Metering
i
Ensure Voltage inputs at specific terminals from
a Line CVT OK/ NOT OK
b Bus-I CVT( say connected to CB-1) OK/ NOT OK
c Bus-II CVT( say connected to CB-2) OK/ NOT OK
ii
Check NO/NC Contacts from CB-1 & CB-2 for voltage selection OK/ NOT OK
Open Line Isolator: Close CB-1 : Bus-I CVT supply will be
selected. Check CVT Supply at selected CVT Terminals for
Metering & Protection. Trip CB-1
OK/ NOT OK
Close CB-2 : Bus-II CVT supply will be selected. Check CVT
Supply at selected CVT Terminals for Metering & Protection.
Trip CB-2.
OK/ NOT OK
Close Line Isolator: Line CVT supply will be selected. Close
CB-1 & 2, No change in status of Selection relays.
OK/ NOT OK
Doc No. D-2-01-03-01-03
171

7. Check RWTI on Control panel
i RWTI checked on control panel OK/ NOT OK
(Yes/
No)
Remarks(Record
deficiencies, if
any)
approved
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Signature:
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Doc No. D-2-01-03-01-03
172

Bus Reactor Protection
General Details
i
OK/ Value….
ii
applicable)
OK/ NOT OK
iii
observed due to wrong Wirings)
iv
OK/ NOT OK
v Measure differential pick up current OK/ NOT OK
vi
OK/ NOT OK
vii
OK/ NOT OK
2. Restricted Earth-Fault Protection:
ii
OK/ Value….
iii
applicable)
OK/ NOT OK
iv
OK/ NOT OK
v
OK/ NOT OK
vii
OK/ NOT OK
Doc No. D-2-01-03-01-03
173

3. Back-Up Impedance Relay Type :…………
i Get a print of relay settings(wherever applicable) OK/ NOT OK
ii Compare with recommended setting OK/ NOT OK
iii Check for Reach Setting OK/ NOT OK
iv Check time of operation OK/ NOT OK
v Test results of (iii) & (iv) enclosed YES/NO
vi Check trip Block in case of CVT Fuse Failure. OK/ NOT OK
vii Check Communication to PC(If available) OK/ NOT OK
viii
confirmation
OK/ NOT OK
ix Check Self-diagnostic feature of the relay (if provided) OK/ NOT OK
x Check metering function of the relay (if provided) OK/ NOT OK
xi Verification of Directionality OK/ NOT OK
4. Electromechanical Relays
i
OK/ NOT OK
ii Direct trip: From line Reactor LBB in case of switchable reactor OK/ NOT OK
i
ii
OK/ NOT OK
Trip CB-2.
OK/ NOT OK
OK/ NOT OK
Doc No. D-2-01-03-01-03
174

(Yes/
No)
Remarks(Record
deficiencies, if
any)
approved
site
Signature:
Name:
Desgn.:
Organization:
(Supplier
Representative)
(Wherever
Signature:
Name:
Desgn.:
(Erection Agency)
Signature:
Name:
Desgn.:
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I/C)
Signature:
Name:
Desgn.:
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Doc No. D-2-01-03-01-03
175

Auto-Transformer Protection
General Details
i
OK/ Value….
ii
applicable)
OK/ NOT OK
iii
observed due to wrong Wirings)
OK/ NOT OK
iv
OK/ NOT OK
v Measure differential pick up current OK/ NOT OK
vi
OK/ NOT OK
vii
OK/ NOT OK
2. Restricted Earth-Fault Protection
ii
OK/ Value….
iii
applicable)
OK/ NOT OK
iv
OK/ NOT OK
v
OK/ NOT OK
vii
OK/ NOT OK
Doc No. D-2-01-03-01-03
176

3. Electromechanical Relays: Check Operations of :
vi Oil surge relay OK/ NOT OK
vii OLTC Protections OK/ NOT OK
i
OK/ NOT OK
i
ii
OK/ NOT OK
Trip CB-2.
OK/ NOT OK
OK/ NOT OK
7. Over Flux Relay
i Checking of Pick up drop off value(Alarm ) OK/ NOT OK
ii Checking of Pick up drop off value(Trip ) OK/ NOT OK
8. Transformer Overload Relay
i Check Operation of alarm Function OK/ NOT OK
ii Operate Value of Current in secondary Terms …………….
iii Check time of operations OK/ NOT OK
iv Check if trip is provided on O/L Provided/ Not provided
Doc No. D-2-01-03-01-03
177

9. Directional Back-Up O/C & E/F Relay
i
Check Voltage-Current Circuit
(Ir –V……., Iy - V……., Ib - V………)
ii Check Voltage/Current summa tion for E/F relay OK/ NOT OK
iii Check Directional element Operation OK/ NOT OK
iv Check time of operation with different operating current OK/ NOT OK
v Attach Graph for IDMT operation for future ref. OK/ NOT OK
(Yes/
No)
Remarks(Record
deficiencies, if
any)
approved
site
Signature:
Name:
Desgn.:
Organization:
(Supplier
Representative)
(Wherever
Applicable)
Signature:
Name:
Desgn.:
(Erection Agency)
Signature:
Name:
Desgn.:
(POWERGRID Site
Signature:
Name:
Desgn.:
(POWERGRID
Commg. Team)
Members:
Doc No. D-2-01-03-01-03
178

Control Panel
General Details
1. Check metering circuit along with transducers first by secondary injection and
there by Primary injection with Standard Voltage & Currents(as per scheme)
i
With Voltmeter Selector switch at various positions
R-Y Y-B B-R RN YN BN
OK/ NOT OK
ii
With Ammeter selector switch at various positions
R Y B
OK/ NOT OK
iii MW /MVAR Meters OK/ NOT OK
iv
Check metering circuits with Primary injection for each phase
separately
OK/ NOT OK
v Check for frequency Meters OK/ NOT OK
2. Check Isolator Interlocks
i Isolator Operation when Adjacent CB Open OK/ NOT OK
ii Isolator Operation when Adjacent CB Close Locked/ Unlocked
iii
Check for all Bay/Line/Transformer/reactor isolators
with reference to interlock scheme
OK/ NOT OK
3. Check for Bus isolator Interlock
i Check Status of E/S interlock of Bus-I/II OK/ NOT OK
ii Isolator Operation when Bus is earthed OK/ NOT OK
iii
Isolator Operation when Bus is Not earthed (Checking
can be done with engaging/Disengaging Contact
Multiplication relay.)
Locked/ Unlocked
4. Check for E/S Interlock(Line)
i
Check E/S Mech. interlock in case Line isolator is
closed
OK/ NOT OK
ii U/V relay Operate/Reset Voltage ……………………
iii E/S Operation when U/V relay de-energized OK/ NOT OK
Doc No. D-2-01-03-01-03
179

5. Check for E/S Interlock(Bay)
i Check E/S Mech. interlock in case isolator is closed OK/ NOT OK
ii Check E/S interlock in case isolator in same bay is closed ………………
iii Check E/S Aux. Contact for Local CB Close I/P OK/ NOT OK
6. Synchronization Check
i Check DC supply at Specific Points on Synchro-Check Plug/Socket OK/ NOT OK
ii
Check CVT supply at incoming running & earth Points on Syncro-
Check Plug/Socket
OK/ NOT OK
iii DC(+ve) to be extended to Closing Coil of CB by Synchro-Trolley OK/ NOT OK
iv
No close Operation of CB W/O connecting & putting on Synchro-
Trolley
OK/ NOT OK
v Trip Operation is unbound OK/ NOT OK
vi
Check Incoming/running voltage selection and same phase must be
selected for a particular sub-station
OK/ NOT OK
vii
Synchronizing socket pin configuration must be same for trolly and
control panel for all bays
OK/ NOT OK
viii
Voltage selection: Verify operating as well as resetting logic ( both
logic should be mutually inverted)
OK/ NOT OK
7. Checking of Isolator Indications
Isolator No…………..
i Checking of Isolator Close Indication OK/ NOT OK
ii Checking of Isolator Open Indication OK/ NOT OK
iii Check Semaphore for E/S Close for Isolator OK/ NOT OK
iv Check Semaphore for E/S Open for Isolator OK/ NOT OK
v Check Operation if adjacent CB closed OK/ NOT OK
vi Check Operation if adjacent CB Opened OK/ NOT OK
vii Check all NO/NC status as per scheme OK/ NOT OK
viii Check all interlock status as per scheme OK/ NOT OK
8. Checking of CB Indications
CB No…………..
i Checking of CB Close Indication OK/ NOT OK
ii Checking of CB Open Indication OK/ NOT OK
iii Check DC healthy indication OK/ NOT OK
iv Check Local Closing I/L as per scheme OK/ NOT OK
v Check Aux. Contact for CVT selection OK/ NOT OK
vi
Check Aux. Contact for Direct trip (In series with TCS of adjacent
CB)
OK/ NOT OK
vii Check Aux. Contact for Sync circuit OK/ NOT OK
viii Check all Annunciations Points for CB Troubles OK/ NOT OK
ix Pole Discrepancy Timing set & Checked OK/ NOT OK
x Pole Discrepancy Operation Checked OK/ NOT OK
xi All Pressure switch settings/contacts checked OK/ NOT OK
xii Check Anti-Hunting Operation OK/ NOT OK
Doc No. D-2-01-03-01-03
180

9. Checking of Isolator Control Switch
Isolator No…………..
i Wiring & Status of Contacts as per Scheme OK/ NOT OK
10. Checking of CB Control Switch
CB No…………..
i Wiring & Status of Contacts as per Scheme OK/ NOT OK
ii Annunciation & Facia All Wo rking properly OK/ NOT OK
11. Control Panel
i Check for control fuse failure OK/ NOT OK
ii
Check that the control fuse failure alarm is reported to station ser by
removing one of the +ve/-ve fuse in control ckt.
OK/ NOT OK
iii Check that control DC is free from earthing OK/ NOT OK
iv Check there is no mixing of source I & II OK/ NOT OK
12. Facia Checking
i
Checking for proper functioning of Annunciation Facia with
individual elements of scheme
OK/ NOT OK
ii Indication for AC supply failure OK/ NOT OK
(Yes/
No)
Remarks(Record
deficiencies, if
any)
approved
site
Signature:
Name:
Desgn.:
Organization:
(Supplier
Representative)
(Wherever
Applicable)
Signature:
Name:
Desgn.:
(Erection Agency)
Signature:
Name:
Desgn.:
(POWERGRID Site
I/C)
Signature:
Name:
Desgn.:
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Commg. Team)
Members:
Doc No. D-2-01-03-01-03
181

Busbar Protection
General Details
Relay Name Zone-I……… Zone-II………… Check Zone…………..
i
Check Operate Value/Reset Value/Oper ate Timing for all phases OK/ NOT OK
Zone-I OK/ NOT OK
Zone-II OK/ NOT OK
Check Zone OK/ NOT OK
Block Auto-reclose for all CB’s Connected Zone-I OK/ NOT OK
Zone-II OK/ NOT OK
ii If directional Element provided ,Relay tested & Direction found O.K OK/ NOT OK
iii Test results enclosed & accepted
iv
Zone-I Tripping extended to :
Trip relay Location ………… for CB No………. LBB Initiated Yes/ No
PLCC/D.T. Yes/ No
PLCC/D.T. Yes/ No
v
Zone-II Tripping extended to :
PLCC/D.T. Yes/ No
PLCC/D.T. Yes/ No
vi
LBB/BFR trip checked & extended to Zone-I
From CB No……………. OK/ NOT OK
vii
LBB/BFR trip checked & extended to Zone-II
viii Transfer Bus Trip Checked OK/ NOT OK
ix Close Interlock in case of BB Trip Checked for all applicable CB’s
x RESET Working properly Yes/ No
xi DC selection working properly for DC-I & II Yes/ No
xii
Carry out stability test by simulating external and internal faults by
primary injection and measure spill currents in Bus bar diff. relay
OK/ NOT OK
xiii
Verify stabilizing resistor & Metrosil connection(wherever
applicable)
OK/ NOT OK
xiv
Check for CT switching relay operation, in case of DMT scheme by
closing respective isolators. Also inject current at the relay panel
entry point and measure current at Bus Bar protection relay
terminals after operating respective CT switching relay
OK/ NOT OK
Doc No. D-2-01-03-01-03
182

Others
Relay Name Zone-I……… Zone-II………… Check Zone…………..
1. Disturbance recorder
i Check communication to PC/Terminals/Printers OK/ NOT OK
ii
Check All Analog Inputs (R-Y-B-residual Voltages & R-Y-B-
Neutral currents)
OK/ NOT OK
iii
Check Conversion( Primary to secondary ratio) settings are
programmed as per scheme
OK/ NOT OK
iv Check contacts status of all digital inputs OK/ NOT OK
v
Normally six I/P’s are from Tw o CB’s. check Selective phase
operation for RYB Poles for both the CB’s. Ensure proper show of
Phase/Pole
OK/ NOT OK
vi Check Analog threshold setting OK/ NOT OK
vii
Check whether all digital Inputs are programmed for initiation of
recording Disturbance as well as right status( NO/NC). Also check
the sequence of digital channels as per Technical specifications
OK/ NOT OK
viii
Run self-diagnostic program & get a print for future reference.
Otherwise, note down various Voltages at Monitoring points
OK/ NOT OK
ix
Simulate a disturbance by shorting contacts of a Digital I/P.Check
recording in progress. Print the same
OK/ NOT OK
x Repeat the above for all digital I/P Contacts OK/ NOT OK
xi
For analog threshold values (if provided), connect to Standard test
kit to DR & test Threshold Value initiation of recording by Varying
Voltages & Frequencies( Voltage Th reshold, Frequency thresholds
& DF/DT thresholds)
OK/ NOT OK
xii
Check Time synchronizing by altering Time Zone in TSE. Restore
on confirmation. Also check time stamping in the relays by
externally triggering DR and record the error w.r.t. GPS time
OK/ NOT OK
xiii
Check all analogue & digital inputs are configured as per power grid
standard list
OK/ NOT OK
xiv
Compare/Check analog value displayed on PC with the injected
input analog value
OK/ NOT OK
xv Take a print out of DR settings & keep for future reference OK/ NOT OK
xvi Check for availability of proper software OK/ NOT OK
2. Sequential Event Recorder
i Check communication to PC/Terminals/Printers OK/ NOT OK
ii Check contacts status of all digital inputs OK/ NOT OK
iii Check whether all digital Inputs are programmed with right status( OK/ NOT OK
Doc No. D-2-01-03-01-03
183

NO/NC)
iv
Selective checking of each & every contacts is to be done in
sequences. Print-Out/Display is to be compared
OK/ NOT OK
v
Normally six I/P’s are from Tw o CB’s. check Selective Phase
operation for RYB Poles for both the CB’s. Ensure proper show of
Phase/Pole.
OK/ NOT OK
vi
confirmation
OK/ NOT OK
vii
Take a print out of plant status (if available) and compare with the
actual status
OK/ NOT OK
viii
Check for availability of proper software & site programmability
of event text
OK/ NOT OK
3. OLTC/RTCC for Transformer
i
OLTC Operation checked from
Local Panel OK/ NOT OK
Remote Panel OK/ NOT OK
Super/Control Panel OK/ NOT OK
ii Tap Position Display OK/ NOT OK
iii
Correct Tap position display at local panel & at remote display with
respective OLTC indicator.
OK/ NOT OK
iv All Indicating lamps checked OK/ NOT OK
v Tap Position Discrepancy Trip OK/ NOT OK
vi
Master/Follower scheme Checked for Master :Xformer-1 OK/ NOT OK
Master :Xformer-2 OK/ NOT OK
Master :Xformer-3 OK/ NOT OK
vii
Check auto supply changeover feature for OTLC/Transformer (If
available)
OK/ NOT OK
4. General
i
Many a time, different Auxiliary voltages are used for drive power
of DR & EL.For example, relay DC is 220 V, DR has it’s isolated
optical I/P , EL has 50 V drive DC. Conscious effort is to be put to
keep all voltage contacts of relay, DR & EL isolated from each other
OK/ NOT OK
ii
In case any changes are to be made in terminal designation,
corresponding change in ferruling
Done/ Not done
iii
In each & every panel & Marshalling Boxes/Kiosks, CT & CVT
Circuits must be provided with Disconnecting stud type terminals
OK/ NOT OK
iv 20% spare TB’s provided in all types OK/ NOT OK
v
Close Interlock of CB: In case trip relay is energized, Close
command not forwarded. Normally, Manual Close command from
CP must be in series with One set of NC contact of the Trip relay
OK/ NOT OK
vi
CB in OFF Condition Selective checking of Trip-CKT Supervision
relay of all CB’s.by Opening wire from TC, one by One.Repeat the
same with CB in On Condition
vii
Permissive Tripping command thr’ PLCC Main-I Main-II
1st
CH. Return Time ………. mS ………. mS
Doc No. D-2-01-03-01-03
184

2nd
CH. Return Time ………. mS ………. mS
viii If substantial difference noted in above, reason for the difference ……………….
ix Any Prospect for reduction of Diff. in Time Yes/ No
x Hanging of RTU reported in Event logger Yes/ No
xi Reporting of communication failure of each channel in SER Yes/ No
xii Any data error encountered during isolator operation Yes/ No
xiii Suggestion for improvement………………………………………..
5. General
i Single point earthing must be ensured for CT&PT circuit Yes/ No
ii
In case of four CT scheme ensure summation of Main/Tie/ Reactor
CTs secondary to input of relay/ meters
Yes/ No
(Yes/
No)
Remarks (Record
deficiencies, if
any)
approved
site
Signature:
Name:
Desgn.:
Organization:
(Supplier
Representative)
(Wherever
Applicable)
Signature:
Name:
Desgn.:
(Erection Agency)
Signature:
Name:
Desgn.:
(POWERGRID Site
I/C)
Signature:
Name:
Desgn.:
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Commg. Team)
Members:
Doc No. D-2-01-03-01-03
185

Checks for PLCC
Date of testing: Make:
Direction: Frequency:
Cabinet No. Eqpt Sr. No.
1. General test
i End to end Return Loss Measured (Attach separate sheet of results) Yes/ No
ii End to end attenuation Tests done (Attach separate sheet of results) Yes/ No
iii Composite loss (attenuation) measured for HF cable coupling device Yes/ No
iv Composite loss and return loss on coupling device using dummy load Yes/ No
v
Measurement of AF frequency response (end to end) for the entire
4Khz bandwidth for speech and tele-protection channels
Yes/ No
vi Measurement of Signal to Noise ratio with line energized condition. Yes/ No
vii Transmission time for tele-protection and other data channels Yes/ No
viii
Observation of Tx/Rx levels (test tone) for each channel at both ends
by sequential switching on/off parallel channels using dummy load
and also with transmission line
Yes/ No
ix Observation of end to end and trunk dialing performance Yes/ No
x
Observation of unwarranted commands sent & received during
switchyard operations
Yes/ No
2. Carrier SET Check List
a. Power Supply (Voltage as applicable)
i 48 v POWER SUPPLY OK/ NOT OK
ii 60V POWER SUPPLY OK/ NOT OK
iii +12 v POWER SUPPLY OK/ NOT OK
iv (-)12V POWER SUPPLY OK/ NOT OK
v +5V POWER SUPPLY OK/ NOT OK
b. Ripple test
i +12 V Ripple test OK/ NOT OK
ii (-) 12 V Ripple test OK/ NOT OK
iii +5V Ripple test OK/ NOT OK
c. Freq generation check
i System clock checked OK/ NOT OK
ii Tx carrier Hz checked OK/ NOT OK
iii Rx carrier Hz checked OK/ NOT OK
iv Pilot freq. checked OK/ NOT OK
Doc No. D-2-01-03-01-03
186

3. Transmitter
a.
AF signal level
i Pilot OK/ NOT OK
ii Check Pressing test button OK/ NOT OK
iii Test tone checked OK/ NOT OK
b. Tx RF setting done Yes/ No
c. Output Power/ Boosting checked OK/ NOT OK
d. Tx alarm threshold checked OK/ NOT OK
e. Tx alarm indication checked OK/ NOT OK
4. Receiver
i Standard AGC setting done OK/ NOT OK
ii Af rx level setting done OK/ NOT OK
iii AGC test done OK/ NOT OK
iv Remote Loop check done OK/ NOT OK
v Rx alarm indication( interrupting RF Line) OK/ NOT OK
5. Telephony
i. TX Level Check OK/ NOT OK
a. 4 wire IN Checked OK/ NOT OK
b. 2Wire in Checked OK/ NOT OK
ii. RX Level Check Feeding from Opposite Station OK/ NOT OK
a. 4 wire Out Checked at 600Ohm OK/ NOT OK
b. 4 wire Out Checked at 600Ohm OK/ NOT OK
iii Dialing Chanel Checked OK/ NOT OK
iv Service Telephone checked OK/ NOT OK
v
Frequency Response across 600 Ohm (Attach separate sheet of
results)
OK/ NOT OK
vi Tele-operation:
a. TX Level Check Done OK/ NOT OK
b. Rx Level check done OK/ NOT OK
6. Protection Coupler Check
a. Measurements
i All LED Indicators Checked OK/ NOT OK
ii Transmit Level checked OK/ NOT OK
iii Boost ratio Measured Boost ratio……………………… OK/ NOT OK
iv Muting of Speech Checked OK/ NOT OK
Doc No. D-2-01-03-01-03
187

b. Command Transmission checking
i RX Trip A
Command Transmission Time ………..ms
Command Prolongation Time ………..ms
ii Aux A Command Transmission Time ………..ms
iii RX Trip B
Command Transmission Time ………..ms
Command Prolongation Time ………..ms
iv Aux B Command Transmission Time ………..ms
Same for Trip C & D
v Trip Counters checked OK/ NOT OK
vi All Alarms Checked OK/ NOT OK
vii Loop test Done OK/ NOT OK
viii End to End test Done OK/ NOT OK
(Yes/
No)
Remarks(Record
deficiencies, if
any)
approved
site
Signature:
Name:
Desgn.:
Organization:
(Supplier
Representative)
(Wherever
Applicable)
Signature:
Name:
Desgn.:
(Erection Agency)
Signature:
Name:
Desgn.:
(POWERGRID Site
I/C)
Signature:
Name:
Desgn.:
(POWERGRID
Commg. Team)
Members:
Doc No. D-2-01-03-01-03
188

Sub-Station Automation System (SAS)
Date of testing: Make:
Direction: Frequency:
Cabinet No. Eqpt Sr. No.
1. Availability of Items
i. Check availability of all the IEDs, GPS Clock, Gateway, Computers
& Servers, Periferals, Network Switches, Modems and various
communication hardware etc. as per Scheme
OK/ NOT OK
ii. Check avaiability of all the orignal softwares for PC/ Servers (OS +
Application Softwares), IEDs, Switches, Gateway etc. as per the
scheme
OK/ NOT OK
iii. Check the originality/ authenticity of all the hardware & software
items for POWERGRID approval.
OK/ NOT OK
iv. Check the validity of license of softwares/ hardware keys. OK/ NOT OK
2. Communication Setup
i Check laying & termination of optical fiber as per approved scheme. OK/ NOT OK
ii
Check the proper tagging of optical fiber cable for identifying the
origin and termination.
OK/ NOT OK
iii
Check the LAN switches for proper installation & configuration as
per scheme e.g. IP address is entered correctly, ports of Network
switches are correctly configured as per requirement, satisfactory
working of all the ports etc. Keep the records of all IP addresses.
OK/ NOT OK
iv Check dual DC power supply to all Network switches. OK/ NOT OK
v
Check all the PCs & printers are connected over Ethernet LAN and
functioning properly.
OK/ NOT OK
vi Check the satisfactory working of dual LAN as per scheme OK/ NOT OK
vii Check for the alarm if any link failure(fiber cut) OK/ NOT OK
viii
Check communication of all IEDs through Network switches as per
the allocated IP address.
OK/ NOT OK
ix Check the functionality & running of original NMS software. OK/ NOT OK
x
Check the NMS software is monitoring the healthiness of Network
switches/ IEDs.
OK/ NOT OK
xi Check communication between GATEWAY & SAS PC. OK/ NOT OK
xii
Check the communication between GATEWAY and PLCC data
channel.
OK/ NOT OK
xiii
Check the communication of each IED with Both SAS PCs
individually.
OK/ NOT OK
xiv Check communication of each IED with DR PC. OK/ NOT OK
xv
Check the availability of spare cores in the armoured fiber optic
cable as per specifications.
OK/ NOT OK
Doc No. D-2-01-03-01-03
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3. Time Synchronization
i Check proper installation and configuration of GPS and associated
hardware like antenna etc
OK/ NOT OK
ii Check the availability of Time Synchronization Signal in the LAN
through SNTP
OK/ NOT OK
iii Check the synchronizing of each IED /Server with GPS. OK/ NOT OK
iv Check for alarm in case of failure of time synchronizing OK/ NOT OK
4. IED Setup
i Check the availability of list of names of IEDs and their front/rear
port address
OK/ NOT OK
ii Check IP address of all IEDs correctly entered. OK/ NOT OK
iii Check the proper installation and configuration of all IEDs (as per
their proprietary softwares) and Preparation of their ICD files for
integration in the S/S SCD file.
OK/ NOT OK
iv Check the GOOSE function(Analog/Binary) for each IEDs and
correctness of the same.
OK/ NOT OK
v Check SLD in IED HMI for correctness of same as per approved
drawing.
OK/ NOT OK
vi Check each IED(for line/transformer/reactor/Bus-Bar/BCU) are
correctly tested for every protection requirement of scheme.
OK/ NOT OK
vii Check loading of setting through local as well as remote. OK/ NOT OK
viii Check availability of all setting address as per the relay setting
received from CC-engg.
OK/ NOT OK
ix Check the operation of protection system and subsequent alarm at
remote Local/HMI.
OK/ NOT OK
x Check the availabilty of alarms/events as per the POWERGRID
requirement.
OK/ NOT OK
xi Check the Auto-downloading of DR Fault file in case of
disturbance.
OK/ NOT OK
5. Interlocking & Logic Setup (Through concerned BCUs)
i Check configuration & working of all soft interlocks for CBs,
Isolators, Earth Switches including Bus Isolators as per protection
schemes.
OK/ NOT OK
ii Check configuration & working of all soft logics for
Synchronization (DLDB, LLDB, LLLB, DLLB), Voltage Selection,
Protection Transfer for DMT, Auto-s equencing etc. as per protection
schemes.
OK/ NOT OK
Doc No. D-2-01-03-01-03
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6. SCADA Setup
xxx
Check the proper integration of all IEDs and their ICD files in the
S/S SCD file.
OK/ NOT OK
xxxi Check the building up of database as per approved point list OK/ NOT OK
xxxii
Check the correctness of HMI SLD for all bays/ feeders in both
SAS PCs.
OK/ NOT OK
xxxiii
Check the correctness of operation of CB,Isolators &Tap changing
operation through HMI SLD of both SAS PCs.
OK/ NOT OK
xxxiv
Check that the status of CB,Isolators should change immediately in
HMI after performing operation.
OK/ NOT OK
xxxv
Check raising of audio alarm with SCADA alarm state for each
breaker opening operation at HMI.
OK/ NOT OK
xxxvi
Check the PLCC,CB operation counters are correctly changing
with operation.
OK/ NOT OK
xxxvii
Check the blocking of operation of bay equipments in case of issue
of PTW through both SAS HMIs.
OK/ NOT OK
xxxviii
Check the availability of SLD of LT switchgear and operation of
the same through local/remote.
OK/ NOT OK
xxxix
Check all measurement functions (Current,Voltage,MW,MVA)
and their correctness in local/remote HMI.
OK/ NOT OK
xl
Check the availability of OTI, WTI readings of ICTs on HMI &
correctness of same.
OK/ NOT OK
xli
Check the availability of voltage & current of both auxiliary DC
systems sources .
OK/ NOT OK
xlii
Check the DG alarm/trip & fire fightning signals are coming in
SAS HMI.
OK/ NOT OK
xliii
Check the monitoring of Kiosk AC/ kiosk temperature through
both SAS HMI.
OK/ NOT OK
xliv
Check the colour coding of measurement parameters
(Voltage,current,MW,MVAr,f etc.) if the values increases above a
pre-set value with generation of audio/visual alarm.
OK/ NOT OK
xlv
Check colour coding of SLD i.e. energized section will be in one
colour and un-energized section will be in different colour.
OK/ NOT OK
xlvi Check supervision of each IED on HMI of SAS PCs. OK/ NOT OK
xlvii Check Hot-stand by function availability between the SAS PCs. OK/ NOT OK
xlviii
Check after restoring of Master server, all the data must be
transferred to Master server from slave server in a quick time as
per HOT STAND By feature.
OK/ NOT OK
xlix
Check there should not be missing of any events during transfer
from both Main to STANDBY and STANDBY to Main.
OK/ NOT OK
l
Check provision of auto data backup & storage of monthly data
backup.
OK/ NOT OK
li
Check the correctness of alarm list and event list and proper
sequencing of alarms/events.
OK/ NOT OK
lii
Check weather all the events in event list are timely punched with
milli second data.
OK/ NOT OK
liii
Check the alarm/events of Auxiliary system are included in
alarm/event list.
OK/ NOT OK
Doc No. D-2-01-03-01-03
191

liv
Check that the SAS configuration tool should be password
protected.
OK/ NOT OK
lv
Check for any error signal while operating/running any software or
performing any operation on SAS PC.
OK/ NOT OK
lvi
Check that basic training has been given to local operation staff so
that in case of emergency they will be able to start the SAS PC in
case of shut-down.
OK/ NOT OK
lvii Check there should be no interruption in availability test. OK/ NOT OK
lviii
Check the Acknowledged alarms should shift to acknowledge
window & persisting alarms should be in red colour with blinking
of the same.
OK/ NOT OK
lix Check the colour code of the acknowledged but persisting alarm. OK/ NOT OK
lx Check the nomenclature of events and alarms for user friendliness. OK/ NOT OK
lxi
Check the availability of backup of latest version configuration for
ICD, SCD files, IED basic configuration, HMI server database etc.
OK/ NOT OK
lxii
Ensure creation of appropriate restore points for each workstation
in the substation after completion of commissioning.
OK/ NOT OK
7. Trends & Reports Setup
i Check all the operation formats are as per POWERGRID formats. OK/ NOT OK
ii Check the reports generated by SAS PC are as per the requirement
like max. & min. readings of voltage, MW, MVAR, MVA,
Frequency, current etc. for a 24 hour period.
OK/ NOT OK
iii Check the reports/trends can be selected/filtered for any time
period (datewise) specified by user.
OK/ NOT OK
iv Check the availability of measurements reports at desired interval
of (15, 30,45 & 60 minutes) & correctness of the same.
OK/ NOT OK
v Check the trend display for each parameter(MW,MVA,MVAr,f,V,I
etc.) at any time and at a interval selected by user.
OK/ NOT OK
8. Remote Operation & RLDC reporting
i Check that Gateway has been installed and configured properly and
is working satisfactorily.
OK/ NOT OK
ii Check the Gateway Configuration as per approved interoperability
profile of RLDC.
OK/ NOT OK
iii Check the healthiness of communication between Gateway and
RLDC for both channels
OK/ NOT OK
iv Verify the data transfer to RLDC by point to point checking as well
as at local level through Protocol Analyser
OK/ NOT OK
v Check that the online perameters on local/remote SLD like
current,voltage,MW,MVAr,frequency etc are getting updated.
OK/ NOT OK
vi Check the operation of equipments/alarms/events for remote
controlled ss.
OK/ NOT OK
vii Check the satus of CBs & Isolators should be available at RLDC
and if any link fails then alarm should be generated.
OK/ NOT OK
Doc No. D-2-01-03-01-03
192

viii If SAS S/S has to be remote controlled then check authenticity of
operation from Local & remote end(i.e When control is in hand of
RCC, all local operation should be blocked and vice versa)
OK/ NOT OK
ix Check that in case of failure of one channel, changeover at remote
end happens automatically and no interruption in data flow to
Remote end occurs.
OK/ NOT OK
x Check for availability of final approved signal list for 101
communication with all details.
OK/ NOT OK
(Yes/
No)
Remarks(Record
deficiencies, if
any)
approved
site
Signature:
Name:
Desgn.:
Organization:
(Supplier
Representative)
(Wherever
Applicable)
Signature:
Name:
Desgn.:
(Erection Agency)
Signature:
Name:
Desgn.:
(POWERGRID Site
I/C)
Signature:
Name:
Desgn.:
(POWERGRID
Commg. Team)
Members:
Doc No. D-2-01-03-01-03
193

testing formats

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