What is the purpose of a Buchholz relay in transformer protection?
Answer & step-by-step solution
Correct answer: A. To detect internal faults such as short circuits and arcing in oil
Quick explanation
A Buchholz relay is a gas- and oil-surge-operated relay on oil-immersed transformers with a conservator. It alarms on slow internal faults and trips on severe internal faults.
Where it sits
In the pipe between the main tank and the conservator of an oil-immersed transformer.
Incipient faults
Local overheating or minor arcing decomposes oil; the gas collects in the relay chamber and operates the alarm contact.
Severe faults
A major internal short circuit produces a sudden oil surge toward the conservator, operating the trip element and opening the breaker.
Not for
Measuring core flux, temperature rise or system overvoltage.
Verified · SRO Electrical desk Report
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