谐振接地系统单相接地故障仿真分析

摘要

针对谐振接地系统发生单相接地故障时因故障线路电流很小且方向不确定而导致选线难度大的问题,从理论上分析了谐振接地系统发生单相接地故障时的零序电压、零序电流变化规律；在Matlab软件中建立了小电流接地系统仿真模型,并分别对中性点不接地系统、全补偿谐振接地系统、过补偿谐振接地系统、欠补偿谐振接地系统进行了仿真分析,仿真结果与理论分析结果一致,进而得出结论:发生单相接地故障时,中性点不接地系统可选用基于幅值和方向等稳态分量的选线方法,谐振接地系统不可选用该种选线方法,但两种系统可选用同一种基于暂态分量的选线方法.%For problem of difficult line selection caused by small current of fault line with uncertain direction when single-phase grounding fault happens in resonant grounding system, the paper theoretically analyzed change law of zero-sequence voltage and zero-sequence current at the time of single-phase grounding fault. It built simulation model of small current grounding system in Matlab and did simulation analysis of isolated neutral system and resonant grounding systems under conditions of full compensation, over compensation and under compensation separately. The simulation analysis result was the same as the theoretical one. Finally it got conclusions, namely when single-phase grounding fault happens, isolated neutral system can use line selection methods based on steady state component of amplitude and direction while resonant grounding system cannot, and the both systems can use the same line selection method based on transient state component.