真空断路器关合速度与预击穿对同步关合的影响研究

通过对真空灭弧室击穿电压的测量及电场强度的计算,拟合出了真空灭弧室在小间隙下的击穿电压与间隙的关系式.并结合配永磁机构的真空断路器关合时的动特性,对10kV系统与35kV系统的电容器组进行关合时,考虑到断路器合闸时间的分散性,在一定合闸速度下,确定了关合涌流为最小的最佳预期关合点.

Study of the Influence of the Closing Velocity and the Pre-strike on Synchronous Closing in a Vacuum Circuit Breaker

This paper describes the closing velocity and the pre-strike of vacuum circuit breaker in the synchronous closing. The expression of the gap withstand voltage vs. the gap separation between the two contacts of vacuum circuit breaker was derived from the experiments and the calculations. A critical velocity was proposed by calculation respectively for 10kV and 35kV. If the velocity were lower than the critical one, the pre-strike would happen when synchronous closing. The real closing point will be shifted from voltage zero due to pre-strike. If the velocity is higher than it, the circuit will be closed at zero voltage with no pre-strike. Taking into account the variation of the closing time, the prospective closing time is distinct with different closing velocity. Moreover, the optimal closing point will vary form system voltage and parameters, and closing velocity.