一起线路故障导致母差保护误动事故分析

Analysis of a Bus Differential Protection Malfunction Caused by a Line Fault

针对一起线路故障造成母差保护误动作的事故,通过现场情况检查,确定了CT绕组短接片未拆除导致的CT变比变化是造成母差保护误动作的主因。利用一次通流试验获得CT实际变比后,通过带入实际运行数据,给出了CT变比变化对各保护动作的影响,最后针对本次事故提出了相应的改进措施。

Through the on-site inspection of a bus differential protection malfunction due to a line fault,it is determined that the main cause was failure to remove the CT winding shorting piece,which led to change of the CT transformation ratio.After obtaining the actual CT transformation ratio with a flow test,the influence of CT transformation ratio change on each protection action is given by bringing in the actual operation data.Finally,the corresponding improvement measures are proposed for this accident.