The function of buchholz relay in oil filled transformer is to give protection to the transformer from the any types of minor and major faults occurring in the transformer that causes heating of the transformer. They will sense the faults and send signal to the alarm and trip circuit.
When minor fault occurs, transformer oil displaced in buchholz relay activates alarm circuit through upper mercury switch whereas when major fault occurs, buchholz relay activates trip circuit through lower mercury switch. It improves reliability and ensures safety of the power system.
Conclusion
Hope, you have clearly understand about the function of the buchholz relay in the oil filled transformer. Make sure to leave your opinion and suggestion about this post in the comment section below.