谐振接地系统选线瓶颈及动态电阻选线方式

Bottleneck of line selection in resonant grounding system and dynamic resistance line selection method

研究发现谐振接地系统在发生永久性单相接地故障时,受故障合闸角、过渡电阻以及各馈线零序电流无规律性影响,基于故障稳态和暂态信号的选线方法在实际应用中效果不佳。为突破谐振接地系统选线瓶颈,提出一种动态电阻选线方式,运用理论分析和ATP-EMTP仿真,确定了选线程序启动方式与动态电阻阻值选取办法。通过现场实验验证该方式在谐振接地系统发生永久性单相接地故障时,能准确识别故障发生,并通过阻性电流注入准确选出故障线路,且过渡电阻识别能力达3 500Ω,为谐振接地系统单相接地选线难题提供了一种有效可行的解决办法。

It is found that due to the fault closure angle, the transition resistance and the irregularity of the zerosequence current of each feeder, the line selection method based on fault steady state signal and transient signal of resonant grounding system is not effective in practical applications. In order to break through the bottleneck of line selection in resonant grounding system, a dynamic resistance line selection method is proposed. Through theoretical analysis and ATP-EMTP simulation, the startup mode of line selection program and the selection method of dynamic resistance value are determined. Through field test, it is verified that the method can accurately identify the occurrence of permanent single-phase ground fault in the resonant grounding system, and select the fault line through resistive current injection. The transition resistance recognition capability reaches 3 500 Ω. It provides an effective and feasible solution for the line selection problem of single-phase ground fault in resonant grounding system.