一起110 kV GIS开关合闸瞬间交直流窜电故障分析

Analysis of AC-DC Transient Overvoltage Fault During 110 kV GIS Switching Operation

交直流窜电是变电站直流系统中较为严重的接地故障,极有可能造成保护误动或拒动,严重影响供电可靠性。针对某实际运行的110 kV变电站交直流窜电故障,首先结合保护动作、故障录波情况给出了事故原因分析与故障排查过程;然后进一步结合二次原理图与现场接线情况提出了整改方案,并验证了整改后回路的安全性;最后给出了此类故障的预防措施与建议,可为防范交直流窜电引起保护误动、拒动提供参考。

AC-DC transient overvoltage is a severe grounding fault in the DC systems of substations,which can potentially lead to incorrect operation or failure of protection devices,seriously affecting power supply reliability.This paper analyzes a case of AC-DC transient overvoltage fault occurring during the switching operation of a 110 kV substation.Initially,the analysis of the accident cause and fault investigation process is presented based on protection actions and fault waveform records.Subsequently,a rectification plan is proposed combining secondary schematic diagrams and on-site wiring conditions to validate the safety of the revised circuit.Finally,preventive measures and recommendations for avoiding protection misoperation and failure due to AC-DC transient overvoltage are provided.