局部同塔输电线路的接地距离保护影响及对策

摘要

There is zero-sequence mutual inductance between two lines partially on the same tower,which may lead to mal-operation or refusal of ground distance protection when a ground fault occurs on the transmission lines.In this pa-per,several typical tower structures are introduced,and the zero-sequence mutual inductances between two double-cir-cuit lines on the same tower are analyzed.A simulation model of double-circuit transmission lines partially on the same tower is founded based on the tower structure that has a larger zero-sequence mutual inductance.Specifically,the ef-fects of different fault positions on the ground distance protection for the transmission lines partially on the same tower are analyzed,and the corresponding improvement measures are proposed.The correctness and accuracy of the proposed method are verified by PSCAD.The research in this paper has practical significance and values for the improvement of ground distance protection of the double-circuit transmission lines partially on the same tower.%局部同塔输电线路两回线之间存在零序互感,当输电线路发生接地故障时,可能导致接地距离保护的误动或拒动.本文阐述了同塔双回输电线路的几种典型杆塔结构,计算了同塔双回输电线路线间零序互感大小,基于线间零序互感较严重的杆塔结构搭建了局部同塔双回输电线路的仿真模型,重点研究了局部同塔输电线路不同故障位置对接地距离保护的影响,并提出了相应的改进措施.通过PSCAD仿真软件验证了该方法的正确性与准确性.本文研究对局部同塔双回线路接地距离保护的改进,具有很重要的现实意义和实用价值.