双断口真空开关的动态介质恢复特性分析

从双断口真空开关的等值模型出发,分析了双断口真空开关的动态介质恢复过程,说明只要恢复电压的峰值和上升速度低于某一极限值,整个双断口真空开关并不会因为一个灭弧室发生重击穿而导致开断失败。这是因为另一个真空灭弧室的介质强度仍可能高于此时的恢复电压,它还可以承受整个恢复电压一个比较短的时间,当重击穿的真空灭弧室的介质恢复以后,共同完成分断过程。仿真计算和试验结果表明,由于各真空灭弧室断口的恢复电压分布不均匀,使得各灭弧室弧后电荷鞘层的发展不同,进而影响了各自的实际介质恢复特性。这可以解释双断口及多断口真空开关与单断口真空开关相比开断能力有显著提高的机理。

Dynamic Dielectric Recovery Characteristics of Vacuum Circuit-Breakers with Double-Break

Dynamic dielectric recovery characteristics of the vacuum circuit-breaker with double-break in high power system were analytically and experimentally studied.The simulated and measured results show that the sheath-growing in the doublebreak strongly affects the dynamic dielectric recovery characteristics.Since different voltage distributions in the double break in post arc insulation state lead to different sheath growing,and the difference determines the dielectric recovery characteristics of the individual break.We conclude that as long as the peak of the transient recovery voltage(TRV) and its rising rate are below the critical values,breakdown of one of the double break does not necessarily lead to the failure of the vacuum circuit breaker(VCB).The mechanism was also discussed.