Why Buchholz Relay Should Only be Installed in Oil Immersed Transformers

Question: Why Buchholz relay should only be used with oil immersed transformers?

Answer: The actuation of Buchholz relay relies on the gas generated from transformer oil due to which it should be used only with oil immersed transformers.

Working of Relay

The Relay is installed in the pipe joining conservator tank to the main body of the transformer. The fault in transformer main tank decomposes some portion of oil to hydrogen gas. The lightweight of hydrogen causes it to rise towards the conservator tank.

While passing through the relay, it entraps in the relay and stays there. The sufficient accumulation of gas inside the relay operates the circuit so as to operate the CB.

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