一起高阻接地故障时线路差动保护拒动的分析及其改进研究

通过对一起线路高阻接地故障时电流差动保护拒动的分析,得出是由于弱故障侧电流启动元件灵敏度不足使得线路两侧差动保护启动元件没有同时动作的原因。因此提出了一种改进的电流差动保护双端零序电流电压辅助启动方法。改进后的辅助启动元件借助线路两侧电流或电压中的故障分量信息,提高了弱故障侧电流差动保护启动性能。现场故障录波数据回放以及RTDS仿真结果显示,改进后的电流差动保护在高阻接地故障,尤其是对于在靠近线路一侧故障而远故障侧仅感受到很小的故障量时,动作性能有明显提升。

An analysis and improvement of refusal-operation of line differential protection in high resistance grounding fault

This paper analyzes a refusal-operation of line differential protection in high resistance grounding fault, and works out the reason of no simultaneous operation of differential protection starting element in both sides of line is lack of sensitivity of current starting element in weak fault side. Therefore, an improved auxiliary start-up method of differential protection double-ends zero sequence current and voltage is presented. This new method improves the starting sensitivity of current differential protection in weak fault side through fault component information of current or voltage in both sides of line. Fault recording data replaying and RTDS simulation results show that the protection performance of improved current differential protection is apparently enhanced in high resistance fault, especially in the one-side fault and the side far from the fault only feels the tiny fault component.