Buchholz relay

Buchholz relays have been applied to large power transformers at least since the 1940s.

The Buchholz Relay is used as a protective device sensitive to the effects of dielectric failure inside the equipment.

Transformers without conservators are usually equipped with sudden pressure relays, which perform a similar function as the Buchholz relay.

Oil filled transformers with a conservator (an oil tank above the transformer) may have a gas detector relay (Buchholz relay).

The transformer was also protected by a Buchholz relay which monitored any gas build-up within the cooling/insulating oil, as the acetylene (ethyne) gas generated is highly explosive.

An oil-immersed transformer may be equipped with a Buchholz relay, which, depending on severity of gas accumulation due to internal arcing, is used to either alarm or de-energize the transformer.

In the field of electric power distribution and transmission, a Buchholz relay is a safety device mounted on some oil-filled power transformers and reactors, equipped with an external overhead oil reservoir called a conservator.

A Buchholz relay is a safety device sensing the accumulation of gas in large oil-filled transformers, which will alarm on slow accumulation of gas or shut down the transformer if gas is produced rapidly in the transformer oil.