Principle and function of high-voltage vacuum circuit breaker

Working principle of high-voltage vacuum circuit breaker The application of light-controlled vacuum circuit breaker module in multi-break vacuum circuit breaker puts forward higher requirements on power supply reliability and low power consumption. For this reason, the low-power self-contained power supply module of light-controlled vacuum circuit breaker module is designed. The working principle of the self-contained power supply is analyzed, and the structure of its power electromagnetic induction coil (power CT) is optimized. The capacitor charging module reduces its working loss from the circuit structure, device selection, and working mode change. The charging and discharging characteristic model of the permanent magnet mechanism operating capacitor is established, and the optimal intermittent control strategy with low loss is analyzed. The low-power design of the intelligent controller is carried out, and the online low-power control strategy and offline dormant working mode are realized. Afterwards, it was verified by experiments that the optimized power CT has a working range of 200 A~3 000 A, which meets the working conditions of the online self-contained power supply module. The overall self-contained power supply has a normal working loss of 300 mW, which meets the power outage of the power grid for 3 weeks. The self-contained power supply system can still drive the light-controlled vacuum circuit breaker to operate. The designed self-contained power supply meets the system's requirements for the reliability and intelligence of the circuit breaker.

Vacuum circuit breakers use vacuum as arc extinguishing and insulating medium. They have strong arc extinguishing ability, small size, light weight, long service life, no fire and explosion hazards, and no environmental pollution. Therefore, they are widely used in the medium voltage field. However, due to the saturation effect between the vacuum breakdown voltage and the gap length, single-break vacuum switches cannot be used for higher voltage levels. Multi-break vacuum switches can make up for this shortcoming.

The dynamic and static insulation characteristics and dynamic voltage balancing problems of multi-break vacuum circuit breakers have been studied for many years at home and abroad. The static breakdown statistical distribution model of double-break and multi-break vacuum switches is established by introducing the concept of "breakdown weakness" and probability statistics method. It is concluded that the breakdown probability of the three-break vacuum interrupter is lower than that of the single-break vacuum interrupter, and it is verified by experiments. The article analyzes and verifies the static and dynamic voltage balancing effect of voltage balancing capacitors on multi-break vacuum circuit breakers. The article analyzes the breaking mechanism and key factors of double-break vacuum switches.