一起电流二次绕组分流引起的主变差动保护误动作原因分析  

Analysis of the Main Transformer Differential Protection False Operation Caused by a Current Secondary Winding Shunt

作　　者：李世伟 李齐全 张元龙 刘红梅 LI Shiwei;LI Qiquan;ZHANG Yuanlong;LIU Hongmei(Honghe Power Supply Bureau,Yunnan Power Grid Co.,Ltd.,Mengzi 661100,China)

机构地区：[1]云南电网有限责任公司红河供电局,云南蒙自661100

出　　处：《电工技术》2023年第13期184-187,共4页Electric Engineering

摘　　要：某110 kV变电站主变差动保护装置发出“差流越限告警启动”“低压侧CT断线启动”告警信号,随后110 kV#2主变差动保护动作。由于10 kV线路发生了AB相间故障到ABC三相故障的发展性故障,而主变差动保护的C相二次绕组引出线绝缘胶套绝缘受损,导致C相绕组S1端和S2端短路引起分流,造成主变差动保护误动作。依据国电南瑞变压器差动保护原理,通过变压器差动保护录波图、采样值及电流互感器饱和校验等来判断保护是否正确动作,同时对变压器保护“差流越限”的原因进行分析,并提出改进意见。The differential protection device of the main transformer of a 110 kV substation sent the alarm signals of"differential current overlimit alarm start"and"TA line break start at the low voltage side",and then the differential protection of 110 kV#2 took effect.The development fault from phase AB fault to three-phase ABC fault occurs on the 10 kV line,and the main transformer differential protection of C-phase secondary winding lead wire insulation sleeve insulation damaged,resulting in C-phase winding S1 end and S2 end short circuit caused by shunt,then,the main transformer differential protection malfunction.According to the principle of differential protection of Guodian Nari transformer,the transformer differential protection recording map,sampling value and current transformer saturation check are used to judge whether the protection is correct.At the same time,the reasons for the"differential current overreach"of transformer protection are analyzed,and suggestions for improvement are proposed.

关 键 词：电流互感器 差动保护 分流 差流越限 

分 类 号：TM77[电气工程—电力系统及自动化]