The application of optical vacuum circuit breaker module to multi-break vacuum circuit breaker puts forward higher requirements for power reliability and low power consumption, so the design of optical vacuum circuit breaker module with low power consumption is carried out. The working principle of the self-powered power supply is analyzed, and the structure of the electromagnetic induction coil (CT) is optimized. Capacitor charging module from the circuit structure, device selection, change of working mode and so on to reduce its working loss. The charge-discharge characteristic model of the operating capacitor of the permanent magnet mechanism is established, and the optimal intermittent control strategy with low loss is obtained. The low power design of the intelligent controller is carried out, and the online low power control strategy and off-line hibernation working mode are realized. After the test verification, the optimized power taking CT operating range of 200 A~3 000 A, meet the online self-powered power module work, the overall self-powered power loss of 300 mW during normal operation, meet the power grid power failure for 3 weeks, the self-powered power system can still drive the optical control vacuum circuit breaker action. The designed power supply meets the requirements of reliability and intelligence of circuit breaker.
Vacuum circuit breaker uses vacuum as arc extinguishing and insulating medium, strong arc extinguishing ability, small size, light weight, long service life, no fire and explosion risk, no pollution to the environment, so it is widely used in the field of medium voltage. However, due to the saturation effect between the vacuum breakdown voltage and the gap length, the single-break vacuum switch cannot be applied to higher voltage levels, and the multi-break vacuum switch can make up for this shortcoming.
The dynamic and static insulation characteristics and dynamic voltage equalizing 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 statistical method. It is concluded that the breakdown probability of three-break vacuum interrupter is lower than that of single-break vacuum interrupter. This paper analyzes and verifies the static and dynamic voltage equalizing effect of voltage equalizing capacitor on vacuum circuit breaker with multiple breaks. The breaking mechanism and key factors of double-break vacuum switch are analyzed in this paper.
