PT二次回路多点接地引起线路过电压保护事故分析  

Analysis of Line Over-Voltage Protection Accident Caused by Multi-Point Grounding of PT Secondary Circuit

作　　者：夏玉裕 宛杨 奚汉江 XIA Yuyu;WAN Yang;XI Hanjiang(Nanjing SAC Power Grid Automation Co.,Ltd.,Nanjing 211153,China)

机构地区：[1]南京国电南自电网自动化有限公司,江苏南京211153

出　　处：《电工技术》2021年第9期94-96,98,共4页Electric Engineering

摘　　要：从一起某500 kV变电站线路过电压保护装置误动事故出发,首先介绍了这次过压保护误动事故概况及事故排查过程,然后分析了过电压保护装置采集的三相电压向量,计算出电压中性点偏移电压,得出了该偏移电压造成线路B相电压过电压误动的结论,最后从原理上定性分析了PT二次回路多点接地导致保护装置误动的原因,并结合事故数据验证了理论分析的正确性。Starting from a misoperation accident of line overvoltage protection device in a 500 kV substation,the general situation and troubleshooting process of the accident are introduced.Then the three-phase voltage vector collected by the overvoltage protection device is analyzed,and the offset voltage of the neutral point of the voltage is calculated.The conclusion that the offset voltage causes the overvoltage of phase B of the line to move incorrectly is obtained.Finally,the reason of protection device malfunction caused by PT secondary circuit multi-point grounding is qualitatively analyzed,and the correctness of theoretical analysis is verified by accident data.

关 键 词：电压互感器 PT二次回路 多点接地 保护误动 

分 类 号：TM77[电气工程—电力系统及自动化]