Detail Buchholz Relay COMEM Type NF 80
The following protective devices are used so that, upon a fault development inside a Transformer, an alarm is set off or the Transformer is disconnected from the circuit. In the event of a fault, oil or insulations decomposes by heat, producing gas or developing an impulse oil flow.
To detect these phenomena, a Buchholz relay is installed.
Buchholz Relay
The Buchholz relay is installed at the middle of the connection pipe between the Transformer tank and the conservator.
There are a 1st stage contact and a 2nd stage contact as shown in Fig. ( 28) . the 1st stage contact is used to detect minor faults.
When gas produced in the tank due to a minor fault surfaces to accumulate in the relay chamber within a certain amount ( 0.3Q-0.35Q) or above, the float lowers and closes the contact, thereby actuating the alarm device.
