Used in transformers with conservator, it is placed in a main pipe between conservator and main tank. Buchholz relay is a gas trap, with floats that detects bubbles from a transformer failure.
The purpose of this device is to protect the oil-immersed transformer when the following types of failures are originated:
- Slow generation of gas in the transformer due to the low energy failures.
- High generation of gas due to the high energy failures.
- Oil loss through leakage.
- Sudden pressure changes by high energy failures.