直流线路故障再启动功能与换流变中性点偏移保护配合策略分析  

Coordination Strategy Analysis Between the DC Line Failure Recovery Function and Neutral Shifting Protection of Converter Transformer

作　　者：孔祥平 李鹏 徐凯 阮思烨 KONG Xiangping;LI Peng;XU Kai;RUAN Siye(State Grid Jiangsu Electric Power Co.,Ltd.Research Institute,Nanjing 211103,China;National Electric Power Dispatching and Control Center,Beijing 100031,China)

机构地区：[1]国网江苏省电力有限公司电力科学研究院,南京211103 [2]国家电力调度控制中心,北京100031

出　　处：《高压电器》2022年第3期155-162,共8页High Voltage Apparatus

基　　金：国家自然科学基金资助项目(51807027)。

摘　　要：文中对一起现场故障案例中直流线路故障再启动失败后逆变站换流变中性点偏移保护动作的机理进行了分析,指出保护动作的原因是由于直流线路故障点与整流站Z闭锁投入的旁通对形成了对健全极直流电流的分流回路,导致故障点无法熄弧、整流站旁通对无法关断;然后,逆变站Y闭锁投入的旁通对与整流站旁通对再次形成了分流回路,导致逆变站换流变单相接地,换流变中性点偏移保护动作。进一步地,结合直流输电工程运行情况,提出了可有效避免逆变站旁通对与线路故障点、整流站旁通对形成分流回路,换流变中性点偏移保护动作的改进措施。The mechanism of neutral shifting protection action of converter transformer in the inverter station after the failure of DC line failure recovery sequence in one site fault case is analyzed in this paper.It is pointed out that the reason of the protection action is that bypass pair of the DC line fault point and the locking operation of rectifier station Z forms a branch loop for the DC current of the healthy pole,causing the arc of the fault point not be interrupt⁃ed and the bypass pair not be turned off.Then,the bypass pair of inverter station caused by the Y locking operation and the bypass pair of rectifier station form current branch loop again,causing the single phase of the converter trans⁃former to ground and the neutral shifting protection to trip.Furthermore,the improvement measures which can pre⁃vent the development of the current branch loop and the trip of converter transformer neutral shifting protection are proposed by taking the operating condition of the DC transmission project into consideration.

关 键 词：直流线路故障再启动 单相接地 分流回路 中性点偏移保护 改进措施 

分 类 号：TM721.1[电气工程—电力系统及自动化]