中性线断路造成母差保护误跳闸

110 kV母差保护误动作跳闸后，排查了相关电流互感器饱和、损坏、极性接线错误、二次回路短路及母差保护装置本身故障等原因，采用带负荷进行回路测试分析，发现2#主变电流互感器二次负载异常，进一步检查出中性线在母差保护屏电流端子排处断路，二次侧没有了零序回路，使区外故障造成了误动作跳闸。中性线断路隐蔽性极强、潜在危害性极大，对此提出了加强二次回路的细致检查、生产厂家研发检测技术等措施，以防范类似事故的发生。

Incorrect trip by bus difference protection due to broken neutral line

After one 110 kV bus difference protection tripped breakers incorrectly,the issues, such as saturation or broken down of current transformer, improper polarity, short-circuit of secondary loop, fault of bus protection relay were excluded one by one. Then, the abnormal secondary loop load of the current transformer of 2# power transformer was found by load test of the loop. Broken of the neutral line at terminal board in bus protection panel was found at last. The incorrect trip due to short circuit beyond p...