220kV变电站二次设备PT断线事故分析与处理

Analysis and Treatment of PT Break Accident of Secondary Equipment in 220 kV Substation

针对某220 kV变电站近期发生的一起全站220 kV保护装置报PT断线信号的事故进行了分析,结果表明二次电压切换箱中母线刀闸辅助触点不能及时返回导致二次电压的反充电,环流使运行中的电压互感器二次空开跳闸,进而使全站220 kV设备失压报PT断线信号,最后就该事件进行了总结并提出了相应事件的改进措施,以避免类似事件的再此发生。

A recent accident occurred in 220 kV substation where the 220 kV protection device of the whole station reported the PT break signal was analyzed.The auxiliary contact of bus bar switch in the secondary voltage switch box cannot return in time,which leads to the reverse charging of the secondary voltage.The circulation makes the voltage transformer in operation open and trip for the second time.The whole station’s 220 kV equipment loses voltage and reports the PT break signal.The improvement measures are put forward to avoid the occurrence of similar events.