电压互感器二次短路引起发电机定子接地保护动作分析

Analysis on Stator Ground Fault Protection Trip Caused by Ground Fault in Voltage Transformer Circuit

介绍了一起因电压互感器二次回路短路导致的发电机定子接地保护跳机事件。单台发电机电压回路故障同时影响到同厂升压站和相邻发电机的电压采样,存在导致多台发电机跳闸的安全隐患。文中对故障录波数据和二次回路进行深入分析,并对分析结果进行仿真验证,最终查明了导致跳机的原因,提出了有效的防范措施。最后对电压互感器二次回路接地方式存在的问题进行了探讨,并提出了改进方案。

This paper introduces the stator ground fault protection trip caused by a typical ground fault in the voltage transformer circuit,resulting in secondary voltage fluctuation of the units in the same power plant.By analyzing the data of fault recorder and inspecting the secondary loops of the voltage transformer,the cause of protection trip is found out,which is proofed by PSCAD simulation,and the effective measures are presented as well.In addition,the problems of current grounding strategy for secondary circuit of voltage transformer are also discussed.