Test Requirements for Microprocessor Relays

Test Requirements for
Microprocessor Relays

Chris Werstiuk

Manta Test Systems

Why am I Performing This Test?
 Type Testing
• Evaluate relay for application
• Many complex tests
 Acceptance Testing
• Is relay damaged or malfunctioning?
• Simple tests of analog and digital I/O
• Self Check OK?

Why am I Performing This Test?
 Commissioning
• Perform acceptance tests
• Will relay work in this application as
programmed?
 Maintenance Testing
• Is the relay still working?
 Troubleshooting
• Why did that happen?

Evolution of Relay Testing

Electromechanical Relays
 Magnets and Mechanisms = dirt and

drift
 Installed in cases with fixed wiring

and features
 Very simple relay test sets

Electromechanical Relays (Cont.)
 Steady State Pickup Test

• Simple ramps
• Simple Jogs
5A ELEMENT PICK-UP 5A ELEMENT PICK-UP
4A 4A
3A PICK UP 3A PICK UP
2A 2A
1A 1A

STEADY-STATE PICK-UP TEST JOGGING PICK-UP TEST

 Dynamic On/Off Timing Test

 Simple Dynamic State Timing Test

• Pre-Fault, Fault 1,2,3.., Post-Fault

 Wiring Checks
A PHA SE CO RELA Y 50/51 C PHA SE CO RELA Y 50/51
B PHA SE CO RELA Y 50/51 GROUND CO RELA Y 50/51

10 10 10 10

IC S IC S IC S IC S
A PH A PH A PH B PH B PH B PH C PH C PH C PH GND GN D GND 43C S
51 IC S 50 51 IC S 50 51 IC S 50 51 IC S 50 LO C A L
CO IIT CO IIT CO IIT CO IIT T RI P

1 2 1 2 1 2 1 2

TC

52a


Solid State Relays
 Same Features and installation as

E/M
 Less adjustments but different kind

of failures
 Same test equipment = same test

procedures


Simple Microprocessor (Digital) Relays
• Same features with all-in-one for all
phases
• Less redundancy = riskier testing
• Different processor = different kind of
failures
• Test equipment essentially the same
with new flashy displays = same test
procedures


Complex Digital Relays
• All eggs in one basket
• More powerful = more complex and
confusing
• Self-tests = no need for testing?

Complex Digital Relays (Cont.)
• Different kind of failures
Percentage of Comments

3.57
7.79 5.84
Design/Wiring
4.62
Documentation
Installation
Relay
Settings
78.18

 Typical Test Procedure
 What’s enabled? (51PT + 50P
+ 51GT + 50G)
 Set OUT107 = 51P
 Pickup test 51P
 Set OUT107 = 51PT
 Timing Test 51PT
 Repeat for 50P, 51GT, 50G


• Automated Test Procedure
 What’s enabled? (51PT + 50P + 51GT + 50G)
 Set OUT107 = 51P
 Pickup Test 51P
 Set OUT107 = 51PT
 Timing Test 51PT
 Repeat for 50P, 51GT, 50G
• Sound Familiar?
• Computers checking computers?

• Problems not detected by previous procedures
 OUT1 = XFMR PCNT DIFF OP A not XFMR PCNT DIFF
OP
 50N vs 50G (SEL-321 and SEL-551)

• Problems not detected by previous procedures
 52a actually 52b H
CT'S 36-37-38

 Transformer W1 CTs
3-2000:5 MR
SET 1000:5 CT 57
C800 1-2000:5 MR

connected to Relay W2 GSU XFMR SET 1200:5
XFMR-1 C800
TS
115 - 13.2 kV

Garbage in = Garbage out
75 / 100 / 125 MVA
• ONAN / ONAN / ONAF
@ 65c Z = 8.26%
X
51
W2
50
52G W2
TS
67 51
G G

87

4160V Source 52S

50
CT'S 24-25-26 W1
3-8000:5
DIGITAL GENERATOR PROTECTION C800 51
TS W1
BECKWITH ELECTRIC M-3425
50 50
87 RLY-2
27 BF A CTG-1
114 MVA
C 13.8kV
XFMR O/C DIFF
BECKWITH ELECTRIC
81 27 59 24
B 0.85 PF LAG M-3310 TS

27 50
59N 21 78 32 51V 40 46
TN 27 TS CT'S 7-8-9
3-8000:5
RLY-1 0.3B-2.0
TS CT'S 1-2-3
3-8000:5
C800

0.4 OHMS NGR-1
400 A 12kV:240V
1 MIN 25kVA

 New test sets = new procedures?

 What’s enabled? (51PT + 50P + 51GT +

50G)

 New test sets = new procedures?

 How do I test 51P when 51G turns on first?

A-N = 51A + 51G A-B = 51A + 51B

51A 51A

51B 51G 51B 51G

51C 51C

 @#$% LOP setting won’t let me test 21

elements!
 Relays constantly evaluate input signals

looking for errors
 Apply simple dynamic tests with realistic

quantities to solve problem


• Logic Testing
 Collect all documentation
 Compare documentation to ensure

everything matches
 Note everything assigned an output

(Output, LED Communication)


Complex Digital Relays – Logic Testing
• Breakdown logic to base “OR” statements
• OUT101 = 51PT + 50P + 51GT + 50G
• OUT101 Test Plan
 A-B, B-C, C-A 51PT (PU, Time @ 2x, 4x, 5x)
 A-B, B-C, C-A 50P (PU, Time Test 1.1x PU)

 A-N, B-N, C-N 51GT (PU, Time @ 2x, 4x, 5)

 A-N, B-N, C-N 50G (PU, Time Test 1.1x PU)

Complex Digital Relays – Logic
Testing
• Breakdown logic to base “OR” 50P2 50N2

statements
• OUT102 = SV1T = (50P2 + 50N2) *
(SV1T + TRIP) * 15 cycles
TRIP SV1T

50P2 TD=15 cy
OR
50N2 SV1 T=TIMER 15 cy
SV1T
TRIP
OR

Complex Digital Relays – Logic Testing
• Breakdown logic to base “OR” statements
• OUT102 = SV1T = (50P2 + 50N2) * (SV1T +
TRIP) * 15 cycles
• OUT102 Test Plan
 50P2 * TRIP = Do not stop 51PT test and time
between OUT101 and OUT102
 50P2 * SV1T = Lower current and OUT101 should
drop out followed by OUT102 after current < 50P2
 50N2 * TRIP = Do not stop 51NT test and time
between OUT101 and OUT102
 50N2 * SV1T = Lower current and OUT101 should
drop out followed by OUT102 after current < 50N2

• Don’t forget Garbage in = Garbage out!
• Test this logic
• Opening the Capacitor Bank
 SV8 =(RB15 * ! (PB10 * !LT6 * (!LT5 * PB5)) +
PB7 * (!LT5 * PB5)) * (!LT10 * (PB6 * LT5 + RB12
* !LT6)) + RB13 * ! (!LT10 * (PB6 * LT5 + RB12 * !
LT6)) + /3P27 * !50L * 52A
• Closing the Capacitor Bank Switches
 SV9 =(RB16 * ! (PB10 * !LT6 * (!LT5 * PB5)) +
PB8 * (!LT5 * PB5)) * (!LT10 * (PB6 * LT5 + RB12
* !LT6)) * SV10T + RB14 * ! (!LT10 * (PB6 * LT5 +
RB12 * !LT6)) * IN104

 It’s better to get engineer’s intent!
 Closing the Capacitor Bank Switches
• If the capacitor switches are open and the capacitor control is in
“Manual”, close the capacitor switches when the “Close Capacitor”
button is pushed.
• If the capacitor switches are open and the capacitor control is in
“Auto”, the capacitor switches will close if:
 If the phase to phase voltage is below 6.84 kV.
 If there is a lagging power factor and the load is above 10 MW.
 If there is a leading power factor between 0.99 and 1.00 and the load is
above 15 MW.
 Opening the Capacitor Bank
• If the capacitor switches are closed and the capacitor control is in
“Manual”, open the capacitor switches when the “Open Capacitor”
button is pushed.
• If the capacitor switches are closed and the circuit breaker opens,
open the capacitor switches.
• If the capacitor switches are closed and the capacitor control is in
“Auto”, the capacitor will close if:
 If the phase to phase voltage is above 7.74 kV.
 If there is a leading power factor of 0.96 or less.


• Save more time and be more effective
by combining all tests in one step
 Pickup
 Timing

 Logic

• Digital relays work or not. There is no
drift


• Combined PU/Timing/Logic
 Apply pre-fault to “Prime the Relay”
 Apply fault 1 below pickup

 Apply fault 2 above pickup

 Measure the time in fault 2 to input operate

 Check for correct output operation

• Combined PU/Timing/Logic - Ideal Test
Pre-Fault Fault 1 Fault 2

Nominal Current 24.99 A for 1 second 25.00 A
(4.0 A) Start timer
for 2 seconds Stop timer when relay output operates.
Time should be instantaneous.

TRIP
25 A PICK UP
20 A PRE-FAULT
15 A FAULT 1
10 A
FAULT 2
5A

1 2 3 4 5 6 7
TIME IN SECONDS

• Realistic Test = 5% over – 5% Under

Nominal Current 23.75 A for 1 second 26.25 A
(4.0 A) (25 A - 5% = (25 A + 5% = 25 + (25 x 0.05) =
for 2 seconds 25 - (25 x 0.05) = 25 + 1.25 = 26.25 A)
25 - 1.25 = 23.75 A) Start timer
Stop timer when relay output operates.
TRIP
5% ERROR
Time should be less than 5 cycles
25 A PICK UP
20 A PRE-FAULT
15 A FAULT 1
10 A
FAULT 2
5A

1 2 3 4 5 6 7
TIME IN SECONDS

Voltage (69.28V) Voltage (30.0V) Voltage (30.0V)
Current (3.0 A @ -30º) Current (8.40 A) @ -87º Current (9.29 A) @ -87º
(23.09 Ω @ 30 º) (3.57 Ω @ 87 º) (3.23 Ω @ -87 º)
for 2 seconds for 1 seconds Start timer
X
Stop timer relay output operates.
FAULT 1 - NO TRIP
Time should be 20 cycles +/- 5%

FAULT 2 - TRIP

ZONE 2
21 ELEMENT

PRE-FAULT ---->
R

Voltage (69.28V) Voltage (20.0V) Voltage (30.0V)
Current (3.0 A) @ -30º Current (12.73 A) @ -87º Current (14.08 A) @ -87º
(23.09 Ω @ 30 º) (1.57 Ω @ 87 º) (1.42 Ω @ -87 º)
for 2 seconds for 10 cycles Start timer
Stop timer relay output operates.
Time should be less than 5 cycles
X

ZONE 2
21 ELEMENT

FAULT 1 = 10 cy = NO TRIP

FAULT 2 - TRIP

ZONE 1
21 ELEMENT
PRE-FAULT ---->
R

 Dynamic System-Model Testing

• Model of electrical system +
• Comtrade or conversion program or hand typed
values =
• Most realistic test with realism including:
 DC offset
 Transients
 CCVT distortions


PRE FAULT FAULT 1 FAULT 2 Post Fault
VA 66.40 0.00 67.26 0.00 67.31 0.00 66.40 0.00
VB 66.40 -120.00 33.65 180.00 52.50 -130.00 66.40 -120.00
VC 66.40 120.00 33.65 180.00 52.30 129.00 66.40 120.00
IA 0.50 -10.00 0.06 -85.00 0.06 -85.00 0.50 -10.00
IB 0.50 -130.00 4.65 9.00 3.66 -171.00 0.50 -130.00
IC 0.50 110.00 4.65 -172.00 3.66 10.00 0.50 110.00

 End to End Testing

• Two or more relays communicating to protect
transmission line +
• Two or more test sets synchronized via GPS
time signal +
• Dynamic System-Model tests for each side +
• Synchronized test simulations +
• Perfectly set relays, communication devices,
test plans =
• Successful End-End test

Conclusion
 Why am I testing this relay?
• Acceptance Testing
1. Meter test
2. Digital I/O test
3. Relay self check

Conclusion
• Commissioning
1. Meter test
2. Digital I/O test
3. Relay self check
4. Steady state pickup test for each element
5. Timing test for each element
6. Logic test for each output

OR…

Conclusion
• Commissioning
1. Meter test
2. Digital I/O test
3. Relay self check
4. Steady state pickup test for each element
5. Combine timing and logic tests

OR…

Conclusion
• Commissioning
1. Meter test
2. Digital I/O test
3. Relay self check
4. Combine pickup, timing, and logic tests

OR…

1. Meter test
2. Digital I/O test
3. Relay self check
4. Dynamic System-Model Testing or System Testing

Conclusion
• Maintenance
1. Meter test
2. Digital I/O test
3. Relay self check
4. Pickup Test for each element
5. Timing Test for each element
6. Logic tests for each element
OR…
1. Meter test
2. Digital I/O test
3. Relay self check
4. Compare Relay Settings
5. Combine pickup, timing, and logic tests for each output

Conclusion
• Maintenance
1. Meter test
2. Digital I/O test
3. Relay self check
4. Dynamic System-Model Testing for each element

OR…
1. Meter test
2. Digital I/O test
3. Relay self check
4. Compare Relay Settings
5. System Testing

Test Requirements for Microprocessor Relays

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