)是指当输电线路上发生单相、两相或三相短路故障时,线路保护动作使线路的三相断路一起跳闸,而后重合闸启动,经预定时间将断路器三相一起合上
A campus emergency ______ occur at any time of the day or night, weekend, or holiday, with little or no warning.
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