断路器处于合闸位置时其对地绝缘由支持绝缘子承受，一旦真空断路器所连接的线路发生永久接地故障，断路器动作跳闸后，接地故点又未被清除，则有电母线的对地绝缘亦要由该断路器断口的真空间隙承受；各种故障开断时，一对触子间的真空绝缘问隙要耐受各种恢复电压的作用而不发生击穿。真空断路器是可以替代有油断路器的新型设备，对消除火灾事故具有重大意义。

The circuit breaker is closed when the insulation on the ground borne by the support insulator, once connected to the vacuum circuit breaker line permanent grounding fault circuit breaker tripping, grounding point and it is not clear, there are buses to the insulation should also bear the gap by the vacuum breaker; all kinds of fault breaking, one of the vacuum insulation between the gap to tolerate a variety of recovery voltage without breakdown. Vacuum circuit breaker is a new type of equipment that can replace the oil circuit breaker. It is of great significance to eliminate fire accidents.