Buchholz Relay

 
 
Buchholz Relay

This is installed at a small angle (sloping from conservator to cover) between the conservator and the cover plate. Generally, isolating valves are provided on either side of the relay. A separate gas relay is provided for the conservator or partition for the on-load tap changer. The isolating valves help in opening or removal of the gas relay for inspection or maintenance purposes, without having to drain the oil from the conservator. The gas relay has alarm and trip contacts. The relay can be provided with a gas-sampling valve, which can be located at a convenient height for ease of use.