What is buccholz relay, how does it work?

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Accepted Answer

Buccholz relay is a protective device used in oil-filled transformers to detect faults such as internal arcing or overheating.

Buccholz relay is installed in the oil pipe connecting the transformer tank and conservator tank.
It works based on the principle that gas is generated when a fault occurs in the transformer, causing oil level to drop and gas to accumulate in the relay.
The relay consists of two float switches - one for oil level and one for gas accumulation, which trigger alarms or trip the transformer if abnormal conditions are detected.
It provides early warning of developing faults, preventing major damage to the transformer.
For example, if a fault like internal arcing occurs, gas is generated which rises to the top of the relay and triggers the alarm or trip signal.

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