What is an Oil Circuit Breaker?

What is an Oil Circuit Breaker?

Oil circuit breaker definition

The oil circuit breaker is an early type of high voltage circuit breaker that uses insulating oil as an arc extinguishing medium and an insulating medium.

Structure

• Underframe

• Insulator

• Transmission system

• Conducting system

• Contact

• Arc suppressing chamber

Working principle

The working principle of the oil circuit breaker is based on the insulation characteristics and arc extinguishing ability of the oil. When the circuit breaker needs to disconnect the circuit, the moving contacts and the static contacts are separated, and the arc between the contacts is generated in the insulating oil. Because the oil has good insulation properties and arc extinguishing ability, the arc will be extinguished in a short time, thus cutting off the current. When the circuit needs to be closed again, the contacts re-contact and the circuit recovers.

Sort

Multi-oil circuit breaker: The contact and arc extinguishing device of the multi-oil circuit breaker are immersed in insulating oil. Its volume is large, the amount of oil is large, the maintenance workload is large, and it has been gradually eliminated.

Low-oil circuit breaker: The contacts and arc-extinguishing devices of the low-oil circuit breaker are partially immersed in insulating oil. Its small size, less oil, maintenance workload is small, and it is still used in some medium and high pressure systems.

Advantage

• Strong arc extinguishing ability, large breaking capacity.

• Good insulation performance, can adapt to higher voltage levels.

• Simple structure and high reliability.

• The price is relatively low.

Shortcoming

• The presence of oil increases the size and weight of the equipment.

• The maintenance workload is large, and the insulation oil needs to be checked and replaced regularly.

• The oil may leak and pollute the environment.

• At low temperatures, the fluidity of the oil will become worse, affecting the performance of the circuit breaker.

Apply

• Substation

• Industrial facility

• Special environment

Sum up

Although oil circuit breakers have certain advantages, due to their environmental protection and maintenance costs, they are gradually being replaced by more advanced circuit breaker technologies (such as vacuum circuit breakers and SF6 circuit breakers). However, for specific application scenarios, the oil circuit breaker still has an irreplaceable role.