BUCHHOLZ RELAY TESTING KIT

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
p-ISSN: 2395-0072
Volume: 10 Issue: 03 | Mar 2023 www.irjet.net
BUCHHOLZ RELAY TESTING KIT
Mr. Rahul Ashok Bandekar1, Mr. Mihir Sandip Wadekar2, Mr. Cajetan David Dsouza3 ,Mr. Sayyan
Noormahammad Shaikh 4, Mr. Abdulgafur Mahammadjahur Shaikh5, Ms. T. R. Shenai. 6
12345 Student, Yashwantrao Bhonsale Polytechnic, Sawantwadi, Maharashtra, India
6 Faculty Yashwantrao Bhonsale Polytechnic, Sawantwadi, Maharashtra, India
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Abstract - Transformers are one of the most important
components of an electrical power system, and protecting
them is an essential requirement. The cost of the transformer
is very high, so we have to protect it carefully because a single
fault in the transformer can damage it. The first operation of
the transformer was discovered by Michael Faraday in 1831
and Joseph Henry in 1832. A transformer is a static electrical
device that transforms the electrical energy from one
electrical circuit to another without any change in frequency
through the process of electromagnetic induction. It is
interesting to note that mutual induction, which is flux-
induced in the circuits, is used to transmit energy from one
circuit to another. This flux-induced induction in the primary
winding gets linked with the secondary winding, which we
shall explain in a while. A Buchholz relay is used to monitor a
large transformer for oil loss or insulation breakdown. The
location of the Buchholz relay is in between the transformer
and conservation tank and connected through the pipe. The
Buchholz relay is a protective device. It is generally used only
in the protection of power transformers. A transformer's
Buchholz relay, an oil-activated relay, is used to detect
anomalies, including short circuits, overheating, and oil leaks.
The main advantage of this method is that the relay kits are
easy to manufacture. One of the most vital and expensive
electrical devices is the transformer. A Buchholz relay is used
to check for oil loss or insulation failure in big transformers is
used to check for oil loss or insulation failure in big
transformers. Betweenthe transformer and its oilstorage tank
is an inclined pipe where the relay is housed.
Key Words: Buchholz relay, Transformer, Conservator
tank, Transformer tank, Air compressor.
1. INTRODUCTION
Then Buchholz would relay the protection for the
transformer. The relay has two mercury switches: an
alarm and a trip switch, which are placed at the top and
bottom of the chamber with a hinged float and flap,
respectively. The relay operates when the transformeroil is
heated due to fault current and decomposes into gas
bubbles. The intensity of the fault produces a proportional
amount of gas, which accumulates in therelay chamber and
displaces oil equivalent to the volume of gas. Gas builds up
at the top of the chamberduring small failures, tilting the
float downward and turning on the warning switch. The
fault pushes the flap and engages the trip switch if the fault
intensity isstrong enough to generate a significant amount
of gas.The main advantage of this method is that the relay
kitsare easy to manufacture and understand. Short circuits,
overheating, and oil leaks are among the anomalies that a
transformer's Buchholz relay, an oil-activated relay, is
designed to find. It is a cylinder that is locatedin the line that
joins the conservator to the main tank of sizable, oil-
immersed transformers. Internal problems in an oil-filled
transformer may generate heat, which may lead to the
insulating oil dissolving into gases like methane, carbon
monoxide, and hydrogen.
Fig No. 1 Circuit diagram of Buchholz relay testingkit.
© 2023, IRJET | Impact Factor value: 8.226 | ISO 9001:2008 Certified Journal | Page 1102
Max Buchholz created the Buchholz relay in 1921. The
Buchholz relay is used for protection, which makes it
sensitive to the effects of dielectric failure inside the
equipment. That is a dome-shaped structure. Between the
main transformer tank and the conservator tank is a
Buchholz relay. When a transformer is heated or when a
fault occurs, like a short circuit fault, a core fault causes
core heating, an incipient fault causes inter-turn faults,
and bubbles are created in the oil.

p-ISSN: 2395-0072
1.1 OBJECTIVES
 To understand actual working of Buchholz relay afterfault
occurrence.
 To protect transformer against all internal faults in
transformer tank by using Buchholz relay.
 To analyze the performance of Buchholz relay.
 To detect defective conditions in order to provide
safety to transformer
2. METHODOLOGY
The transformer is the heart of the power system. A key
piece of equipment in a power system is the power
transformer. It required a highly reliable protective device.
The protective scheme depends on the size of the
transformer used for transmission and distributionsystems,
which range from a few KVA to several hundred MVA. For
small transformers, a simple fuse is sufficient for
protection. For medium-capacity transformers,
overcurrent relays are used. For large transformers, a
differential protection scheme is used. Transformers are
connected to a load 24 hours a day,seven days a week. If a
transformer gets damaged due to a fault, there will be a
large impact on industrial, commercial, and residential
areas. The cost of a transformer is very high, so we have to
protect them carefully because a single fault in a
transformer can damage it and reduce its life. It takes a
long time to repair, and the replacement of a transformer
makes things difficult. Hence, transformer protection is
necessary. The different types of relays are used for the
protection of transformers.
2.1 THERMAL RELAY
To safeguard the transformer windings from damage
brought on by heating, thermal relays are employed tostop
the transformer from overheating. Temperaturerelays will
compare the data from the temperature sensors to a pre-
set temperature value. An indication flags at the
annunciator panel along with an alarm when the winding
temperature reaches the present level for the alarm
warning. The relay circuit delivers the signal to trip the
transformer breaker if the temperature rises further and
reaches the predetermined temperature threshold.
2.2 RESTRICTED EARTH FAULT RELAY
2.3 OVER CURRENT RELAY
There would essentially be a current coil in an overcurrent
relay. Because the restraining force is greater than the
deflecting force when normal current is flowing through
this coil, the magnetic effect it produces is insufficient to
cause the moving element ofthe relay to move. But as the
current through the coil increases, the magnetic effect also
does. At some point, the deflecting force produced by the
coil's magnetic effect crosses the restraining force, which
causes the moving element to begin moving in order to
change the position of the contact in the relay. The
instantaneousover-current relay is fairly easy to build and
operate. In this case, a current coil typically winds a
magnetic core. When there is insufficient current flowing
through the coil, a piece of iron is placed into the relaywith
a restraining spring and hinge support to keep the NO
contacts open. The nodes close when the current inthe coil
reaches a predetermined amount, which causes the
attractive force to be strong enough to draw the iron piece
towards the magnetic core.
Restricted an earth fault relay that only works for faults
occurring in a specific, localized zone is known asearth fault
protection. The area between a transformer's earthed
neutral terminal and start side winding is designated as the
zone for protection. The system continues to operate
normally since REF relays do not detect any earth faults
outside of this zone. REF requires a current transformer
with identical ratios and loads. The neutral CT and phase CT
ratios will alter for larger electrical equipment,
necessitating the installation of an additional current
transformer to compensate for the ratio difference.
Interposing current transformer, or ICT, is what
that isthe output of a current transformer shouldn't be
shared. If a through fault occurs, the relay triggers thetrip
mechanism as a result of any CT core becoming saturated.
Relay stability deteriorates. By connecting a suitable
stabilizing resistor in series with the operational coil, we
may eliminate.
2.4 BUCHHOLZ RELAY
Every time a defect develops in the tank, the Buchholzrelay
activates because it is based on the gases produced in the
transformer tank during an internal failure. And
disconnects the transformer from supply or generates an
alarm in the case of an incipient fault. When an incipient
fault develops in the transformer, it produces heat.
Decomposition of solid and liquid insulating materials
begins as a result of heat generation, producing
combustible gases. When a certain number of gases build
up in the relay chamber, the Buchholz relay activates an
alert. By doing an analysis of gases, we can get an idea
about the type ofincipient fault.
Gas that is produced in the transformer tank due to a fault
rises towards the collector tank and gathers in the relay's
upper chamber. Hence, the oil level in the relaydrops, and
the top float triggers an alarm switch. Gas shall not freely

p-ISSN: 2395-0072
tilts to close the mercury switch's contact as a result of
the turbulent oil flow. This completes the trippingcircuit to
open the circuit breaker, and transformers get
disconnected from the supply.
Different methods have been used to protect transformers,
like Buchholz relays, thermal relays, REF relays, and over-
current relays. However, Buchholz relay is good for
transformer protection because its operation time is
shorter than that of other relays. The Buchholz relay is a
very sensitive device compared to other relays. The
Buchholz relay is lightweight, andit’ssuitable for indoor and
outdoor substations. Normally,a protective relay does not
indicate the appearance ofthe fault. It operates when a fault
occurs. But Buchholz
Relay gives an indication of the fault at a very early stage
by anticipating the fault and operating the alarmcircuit. As
a result, accidents can be avoided, and the transformer can
be pulled out of service before suffering any major
damage.
2.5 There are two type of methods for creating
bubbles
2.5.1. By using heater
In this procedure, a heater will be connected to the
transformer oil tank. In this way, a fault can be created at
any time when heat is applied to transformer oil, where
bubbles will be created and gas will be formed.This gas will
then be passed to the Buchholz relay by pipe. The Buchholz
relay will sense the fault and give a signal to the circuit
breaker; the circuit breaker will trip, and the transformer
will stay protected. Thismethod takes longer to complete.
2.5.2. By using air compressor
The cost of an air compressor is less, and it’s easily
available for us. In comparison to a heater, the operation
of an air compressor is very simple and quick. The process
of heating a heater is more time- consuming as compared
to using an air compressor. The operation of an air
compressor is simple and safe because there are no live
parts on the outside.
That is why we decided to use an air compressor in our
project.
Fig.2. Block diagram of Buchholz relay testing kit.
pass from the relay body and escape into the pipework
before the alarm contact has operated. Large amounts of
gases are produced in the main tank due to a significant
failure. Which causes a violent flow of transformer oil. This
oil in the main tank rushes towards the conservator tank
through the Buchholz relay connected in the pipe, which
connectsthe transformer tank and conservator. The lower
float
Fig.3. Actual model of Buchholz relay testing kit.
3. ACKNOWLEDGEMENT
It is a great pleasure for me to express my mostsincere
heart felt gratitude to project guide Ms. T. R.Shenai. , for
this valuable technical guidance & efforts during the
completion of this synopsis. We areextremely thankful
to Mr. B. M. Patil, head of the department of electrical
engineering, for his everlastingmoral support as well as our
teacher & co-operation. We are very much thankful to
Principal Mr. G. A. Bhosale for his support &
encouragement. This workwe completed with the blessing
of our all family members. We express our sincere
gratitude towards them for their kind co-operation &
encouragement which helped us in completion of this
project. We would like to express our sincere thanks to all
teaching & non-teaching staff of department of electrical
engineering. YBP for their expert advanced & help. Itwas
indeed of fabulous experience & learning for us to this
synopsis. Last but not the least we would like tothank all

p-ISSN: 2395-0072
4. CONCLUSION
In this project, we will learn about the actual operationof a
Buchholz relay after a fault has occurred. The mainpurpose
is to observe and protect the transformer from all internal
faults in the oil tank by using a Buchholz relay.
5. FUTURE SCOPE
In the future, wireless Buchholz relays will be developed.
Relay connecting to the microcontroller andsensor. Sensor
will sense the fault and send a signal tothe microcontroller,
then the microcontroller will senda signal to the trip circuit
and the alarm circuit will start to beep, the circuit breaker
will trip, and the transformer will stay protected.
REFERENCES
[1] IEEE Standard association “C57.104-1991 - IEEE
GUIDE FOR THE INTERPRETATION OF GASES
GENERATED IN OIL-IMMERSED TRANSFORMERS” IEEE
Standard.
[2] Sitemason “TRANSFORMER OIL VOLUME
CONVERSION TABLE”.
[3] H. C. Hitchcock,” BUCHHOLZ RELAYS, SUPPLY WAS
RESTORED IN A MATTER OF MINUTES” THE 1968
INANGAHUA EARTHQUAKE AND ELECTRICTY SERVICES.
[4] E. Takahashi K. Tanaka K. Toda M. Ikeda, T. Teranishi,
M. Inaba T. Yanari, “DEVELOPMENT OF LARGECAPACITY
GAS-INSULATED TRANSFORMER” IEEE Transactions on
Power Delivery, Vol. 11, No. 2, April 1996.
[5] M. Duval, J. Aubin, Y. Giguere, G. Pare and Y.
Langhame, “OIL ADDITIVES FOR THE EVALUATION OFHOT
SPOT TEMPERATURE IN POWER TRANSFORMER DURING
OVERLOADING ” IEEE Transaction.
[6] ALTERNATIVES OF BUCHHOLZ RELAY AND MORE
ROBUST SCHEMES FOR TRANSFORMER INTERNAL
FAULT PROTECTION Dr. Nishant Kumar.
friends and well wishes that were involved directly and
indirectly successful completion of the synopsis.

BUCHHOLZ RELAY TESTING KIT

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