CT中性线二次电缆断线引起母差保护动作分析

Analysis of bus differential protection movement caused by CT neutral conductor secondary cable disconnection

详细分析了贵州一发电厂220kV出线发生C相故障，因该出线开关接入母差的CT中性线二次电缆断裂，故障时进入母差保护的开关电流异常，母差保护没有正确感受一次设备的电流，导致母差保护动作跳闸。

This paper analyzes a power plant in Guizhou,which 220kV line C phase fault occurs. Because CT neutral conductor second- ary cable with access to bus differential protection cracks. When failure occurs,bus differential protection, which does not correctly measure primary equipment current, switch currents break into abnormalities. And that causes bus differential protection trips.