Current situation analysis of high voltage vacuum circuit breaker

The application of high-voltage vacuum circuit breaker in China's power supply system began in 1978, and its advantages such as light weight, simple structure and long service life were quickly recognized by the operation, maintenance and technical personnel of the power sector. Early domestic production of high voltage vacuum circuit breaker quality is not stable, the on-flow voltage in the operation process is high, individual vacuum interrupter there are still gas leakage phenomenon.

1, China's high voltage vacuum circuit breaker status

The application of high-voltage vacuum circuit breaker in China's power supply system began in 1978, and its advantages such as light weight, simple structure and long service life were quickly recognized by the operation, maintenance and technical personnel of the power sector. Early domestic production of high voltage vacuum circuit breaker quality is not stable, the on-flow voltage in the operation process is high, individual vacuum interrupter there are still gas leakage phenomenon. By the time of Tianjin vacuum Switch Application Promotion Conference in 1992, China's vacuum circuit breaker manufacturing technology has entered the forefront of the same type of products in the international industry, and has become a new historical turning point in China's high-voltage vacuum circuit breaker application and manufacturing technology.

2, the leakage problem of vacuum arc extinguishing chamber

The new generation of high voltage vacuum circuit breakers generally use the principle of longitudinal magnetic field arc extinguishing and copper-chromium contact material, the purpose of which is to reduce the contact burn loss and improve the electrical service life. Improper adjustment of the concentricity of the conductor rod will make the longitudinal gas line, ceramic, fusible metal sealing strength is not stable enough, resulting in gas leakage in the vacuum interrupter.

The vast majority of the bellows of the vacuum interrupt chamber are made of 0.15mm thick stainless steel oil pressing. The selection of pollution level, humidity, and salt spray in the application environment of the high-pressure vacuum circuit breaker is not appropriate. Harmful gases and condensation cause spot-like corrosion of the bellows, resulting in air leakage of the bellows, cover plates, and sealing surfaces.

It is an important measure to adjust the concentricity of the high voltage vacuum circuit breaker and choose the use and storage environment reasonably to solve the gas leakage problem of the vacuum interrupter.

3, reasonable selection of high voltage vacuum circuit breaker electrical life

The electrical life of the high-voltage vacuum circuit breaker refers to the number of full-capacity breaking times specified in the technical conditions of the equipment and actually carried out in the type test. In the application of high voltage vacuum circuit breaker contacts can not be repaired and replaced, it is necessary to require high voltage vacuum circuit breaker to have a high enough electrical life.

The new generation vacuum interrupter adopts longitudinal magnetic field electrode and copper-chromium contact material. The longitudinal magnetic field electrode multiplies the arc voltage (arc energy) under the action of the short-circuit breaking current, and makes the arc evenly distributed on the surface of the contact. The copper-chromium contact material reduces the amount of contact burn per unit arc energy. The organic combination of the two makes the electrical life of the high voltage vacuum circuit breaker have a breakthrough. At present, China's high voltage vacuum circuit breaker re-opening, closing capacity and other aspects of the performance is relatively high, but also relatively stable.