从华能巢湖电厂220 kV 线路接地故障引起发变组高压侧断路器误跳闸现象入手，通过建立模型，分析探讨该事故发生的原因，为解决高频分量通过二次电缆分布电容侵入跳闸回路引起的断路器误跳闸问题提供一些对策。

The mistrip of high-voltage side circuit breaker of generator-transformer unit occurs and is induced by 220 kV line-to-ground fault in Huaneng Power Plant of Chaohu. In the paper, the causes of the accident are analyzed by constructing models, that the high frequency components invade into the trip circuit by the distributed capacitance of secondary cable, providing references for similar malfunction.