一起不同电压同杆双回线纵联零序保护动作分析

文中分析了一起500 kV和220 kV同杆并架线路,在500 kV线路末端发生故障时,220 kV线路纵联零序保护误动的原因,并从一般性原理上分析同杆架设双回路零序互感引起纵联零序保护误动的机理.分析表明在弱电耦合的情况下由于零序互感的存在,在相邻线路发生接地故障时,由于本线路两侧零序电压出现反相,使得纵联零序方向保护误判为线路内部故障,引起保护装置误动,为同类事故的分析提供了参考.

Analysis on Protection Actions of Zero-sequence Direction Relay for Double-parallel Lines with Different Voltage Level

This paper analyzes the process of zero-sequence direction relay mal-operation of a double parallel 500 kV and 220kV lines after a fault occurred at the end of the 500 kV line. The mechanism is studied, which shows that the mal-operation is caused by the zero-sequence mutual inductance between multi-transmission lines. In the case of grounding fault occurred at one of parallel line, the existence of zero-sequence mutual inductance would activate the zero-sequence direction relay of the other line. The conclusion of this paper will provide a valuable reference for similar faults analysis.