电流二次回路两点接地引起母差保护误动事故分析及预防措施

Fault Analysis and Prevention Measures of Busbar Differential Protection Malfunction Caused by Two Grounding Points on Secondary Circuit of Current Transformer

电力系统中,为了防止电流互感器二次回路过电压,二次回路必须一点接地,但是由于二次回路绝缘破坏、安装工艺存在缺陷或者其他人为原因造成互感器二次回路多点接地,引起继电保护装置误报警甚至误动作造成停电事故,本文结合一例电流互感器二次回路两点接地引起的母线差动保护误动的事故,分析事故原因,提出了针对电流互感器两点接地的防范措施。

In the power system,in order to prevent the secondary circuit of the current transformer from over-voltage,the secondary circuit must be grounded at one point.However,due to the secondary circuit insulation failure,the installation process is defective or other man-made causes the secondary circuit multi-point grounding,will cause relay protection Device false alarm or even relay protection malfunction accident.In this paper,a case of busbar differential protection malfunction caused by two grounding points on secondary circuit of Current transformer,analysis of the cause of the accident,put forward two-point grounding for the current transformer preventive measures.