分布电容对输电线路负序方向纵联保护的可靠性影响研究

Study on the Influence of Distributed Capacitance on the Reliability of the Negative Sequence Directional Protection of Transmission Line

特高压输电线路的分布电容较大,会产生一定的接地电流,影响输电线路的负序方向纵联保护的可靠性。文中从长距离输电线路外部不对称故障的负序网着手,分析了此种情况负序方向纵联保护的可靠性。通过仿真分析,得出了不同线路长度外部故障时两端负序方向元件的动作特性。最后综述了改进负序方向纵联保护可靠性的措施。

Since the distribution capacitance is large on the UHV transmission lines, and it will produce certain grounding current, influencing the reliability of the negative sequence directional protection of transmission line. This paper analyzes the negative sequence network of asymmetry fault of the long distance transmission lines, and analyzes the reliability of this kind of negative sequence directional protection. Through ATP simulation analysis, the action characteristic of negative sequence directional element in the outer fault of different line length is obtained. At last, the paper summarizes the measures to improve the reliability of the negative sequence direction.