What Is Buchholz Relay? Which Equipment Is Protected By It?
A Buchholz relay is a protective device installed on some oil transformers and power reactors equipped with an external overhead oil tank called a “conservator”.
Used to detect the effects of dielectric faults in the device, such as B.Gas buildup, oil leaks, or overheating.
¹²The Buchholz relay has two floats with mercury switches in a metal chamber connected to the pipeline between the expansion tank and the main tank.
When a fault occurs in the transformer, the oil temperature rises and the oil evaporates into gas. The gas rises and shifts the oil level in the chamber, causing the floats to tip and trip the switches.
Depending on the severity of the fault, the switches may trigger an alarm or disconnect power from the transformer. ¹²³The Buchholz relay owes its name to its inventor Max Buchholz, who patented it in 1921.
¹ It is a protective device commonly used for oil transformers with a capacity of more than 500kVA.This can prevent further damage to the transformer and avoid the risk of fire.