混压同塔四回线路跨电压故障选相元件动作分析与对策研究  

Analysis of the performance of a phase selector for a cross-voltage fault in mixed-voltage four-circuit transmission lines and countermeasures

作　　者：郑涛 吴琼 于溯 吴建云 王小立 罗美玲 赫嘉楠 ZHENG Tao;WU Qiong;YU Su;WU Jianyun;WANG Xiaoli;LUO Meiling;HE Jianan(State Key Laboratory of New Energy Power System(North China Electric Power University),Beijing 102206,China;State Grid Ningxia Electric Power Company,Yinchuan 750001,China)

机构地区：[1]新能源电力系统国家重点实验室(华北电力大学),北京102206 [2]国网宁夏电力公司,宁夏银川750001

出　　处：《电力系统保护与控制》2020年第8期44-51,共8页Power System Protection and Control

基　　金：国家重点研发计划智能电网技术与装备重点专项(2016YFB0900600);国家电网公司科技项目资助(52094017000W)。

摘　　要：混压同塔四回线发生跨电压故障时,零序互感的存在会对各相故障电流产生较大的影响。针对混压同塔四回线路中发生跨电压不接地故障的情况,主要分析了故障相电流的特征及电流选相元件的动作情况,采用改进复合序网的方法求解故障电流。利用相量图详细讨论了跨电压故障的电流特征及其对相电流差突变量选相元件的影响。针对混压同塔线路跨电压故障可能存在的误选相问题,提出一种基于相电流差突变量与相电流突变量相结合的综合选相方案,以实现正确选相。基于PSCAD/EMTDC对混压同塔四回线的各类跨电压故障进行大量仿真实验,验证了理论分析的准确性。When a cross-voltage fault occurs in the four-circuit lines of the same tower, the existence of zero-sequence mutual inductance will have a great influence on the fault current. When the cross-voltage unground-fault occurs in the mixed-voltage four-circuit lines of the same tower, the characteristics of current of the fault phase and the performance of the phase selector are analyzed, using the method of an improved composite sequence network to calculate the fault current. This paper uses a phasor diagram to examine the characteristics of the cross-voltage fault current and its effect on the phase selector based on the sudden-change of phase-to-phase current. Looking at the possible mis-selection of phase selector based on the sudden-change of phase-to-phase current, a comprehensive phase selection method based on the combination of sudden change of phase-to-phase current and sudden change of phase-current is proposed to achieve a correct selection. Based on PSCAD/EMTDC, a large number of simulation experiments are carried out in the mixed-voltage four-circuit lines of the same tower. The simulation results verify the accuracy of the theoretical analysis.

关 键 词：混压同塔四回线 跨电压故障 改进复合序网法 选相元件 相电流突变量 

分 类 号：TM75[电气工程—电力系统及自动化]