Earth leakage breaker

一种防止不必要地切断闪电电涌产生的脉动接地电流的接地漏电断路器包括第一比较器(7)；第三比较器(12)，区分来自接地电流的漏电流是由闪电电涌还是由严重接地故障产生的；被第三比较器(12)的输出触发的单稳态多谐振荡器(13)，形成预定周期的时间门；三脉冲计数器(14)，检测第一比较器(7)输出的三个脉冲，以区分接地电流是由闪电电涌还是由严重接地故障产生的；断路信号发生器电路(10)，在漏电和严重接地故障情况下输出断路信号γ。 The earth leakage breaker of the invention includes a first comparator; a second comparator connected to the first comparator; a third comparator having a threshold higher than the threshold of the first comparator for distinguishing a leakage current from the grounding current caused by a lightning surge or by the heavy ground fault; a monostable multivibrator triggered by the output of the third comparator for forming a time gate of a predetermined period; a counter for detecting a pulse outputted from the first comparator to distinguish whether the grounding current is caused by the lightning surge or by the heavy ground fault; and a trip signal generator circuit for outputting a trip signal in the case of leakage and heavy ground fault. The earth leakage breaker facilitates avoiding unnecessary breaking of the impulsive grounding current caused by the lightning surge.