单相接地故障时零序电流增益分析

Analysis on Zero-sequence Current Gain Due to the Single Phase Grounding Fault

输电线路发生单相故障时,两侧断路器断开时间不完全一致,这将直接导致后跳开侧零序电流的变化。本文依据零序电流增益和线路参数的定量关系,推导了后跳开侧零序电流增益最大值出现的条件,并将分析拓展到不同故障发生点的情形;进一步分析了线路零序阻抗的校核方法及故障测距的测定方法;结合所绘制的零序电流增益曲面,得出了故障点发生于不同位置时零序电流增量的变化规律。

When single phase grounding fault of transmission line occurs,the operation time of the breakers at the two ends of fault line is usually different,which will directly result in the change of the zero-sequence current at the later trip-out side.In this paper,the relationship between line parameters and the zero-sequence current gain is analyzed quantitatively according to line parameters,and the condition for obtaining maximum zeros-sequence current gain at the later trip-out side is derived.In addition,the analysis is further expanded to take into account the impacts of different fault points.Furthermore,the examination method of zero-sequence impedance and the measurement method of fault point locating are analyzed.By zero-sequence current gain surface,the changing rule of the zero-sequence current is obtained,when the faults occur at different points.