Transformer Buchholz Relay Working

Before learning the operating principle and design features it is necessary to understand why is a buchholz relay used in a transformer they are used to sense the faults occurring in the transformer winding and core such as inter turn faults short circuits earth faults overheating of the core oil leakage etc it senses these faults and interrupts the transformer s input supply so.

Transformer buchholz relay working. The classic buchholz relay has to comply with the requirements of the din en 50216 2 standard. Such type of relay is used in the transformer having the rating higher than 500kva. Sometimes due to oil outflow on the major tank air bubbles may build up in the upper part of the buchholz container which may also source a drop of oil level in it and alarm circuit will strengthen. The buchholz relay is placed between the main tank and the conservator.

Buchholz relay is located in the pipeline connecting the transformer main tank and the conservator. The relay was first developed by max buchholz 1875 1956 in 1921. Working principle of buchholz relay. Buchholz relay diagram working principle.

The upper element consists of a float. The float is attached to a hinge in such a way that it can move up and down depending upon the oil level in the buchholz relay container. It is used for the protection of a transformer from the faults occurring inside the transformer such as impulse breakdown of the insulating oil working principle of buchholz relay whenever a fault occurs inside the. Buchholz relay relies on the fact that an electrical fault inside the transformer tank is accompanied by the generation of gas and if the fault is high enough it will be accompanied by a surge of oil from the tank to the conservator.

The buchholz relay protects the transformer from internal faults. The transformer is filled with hydrocarbon oil for the insulation of. The switches of the contacts stopped and an alarm circuit strengthened. It is not used in small transformer because of economic consideration.

It is a mechanical device that accompanies two numbers of mercury electric switches for sending the electrical command to the relays. Check the following buchholz relay diagram to understand the working principle and construction. It is the gas actuated relay. Buchholz relay is a safety device which is generally used in large oil immersed transformers rated more than 500 kva.

As we proceed further we will learn the construction and working principle of the buchholz relay. This means lowering the location of the float and thus rolling the mercury switch. Depending on the requirements it is equipped with up to four 2 per float switches or change over switches which can either send a light signal or switch off the transformer. What is buchholz relay.