High-voltage circuit breakers can be divided into four major components: conductive part, arc extinguishing part, insulating part, and operating part.

The main structure and function of each component:

(1) Conductive part. It mainly includes dynamic and static arc contacts, main contacts or intermediate contacts, and various forms of transition connections. Its role is to pass operating current and short-circuit current.

(2) Insulation part. Mainly include insulating medium such as oil, vacuum or SF6 gas, porcelain sleeve, insulating rod, etc. Its function is to ensure a good insulation state between the conductive part and the ground, between different phases, and between the same phase fractures.

(3) Arc extinguishing part. It mainly includes dynamic and static arc contacts, nozzles and pressure cylinders. Its function is to improve the arc extinguishing ability and shorten the arcing time. It is necessary to ensure reliable breaking of large short-circuit currents, and to ensure that the breaking of small inductive currents does not cut off, or the overvoltage generated does not exceed the allowable value; breaking small capacitive currents does not reignite.

(4) The operating part. Mainly refers to various types of operating mechanisms and transmission mechanisms. Its function is to realize the prescribed operating procedures for the circuit breaker and keep the circuit breaker in the corresponding opening and closing positions.