二起线路复杂故障引起越级跳闸事故分析

Analysis of Two Override Trip Accidents Caused by the Line Complex Fault

在10千伏小电阻接地的系统中,线路经常发生单相接地故障,引起线路开关跳闸。但是,偶尔也会发生主变开关越级跳闸的情况,造成事故范围扩大,停电影响增加,并且给分析故障带来了一定的困难,给电力系统的正常运行和正常供电都带来了较大的危害。该文通过对工作中分别出现的两次线路接地故障后引起主变越级跳闸的故障分析,还原了事故发生的过程,检验了保护配置情况,验证了保护动作的行为,分析了事故发生的原因,为今后完善微机保护装置系统,避免类似故障提供了参考,对实际运行工作具有较大的借鉴意义。

In the lOkV low resistance grounding system,lines switch tripped as the single phase grounding fault often occurred. It＇s difficult for fault analysis when main transformer switch override tripped.It will cause the accident enlargement and increase the impact of power outages.Through analysis of the twice line--to--ground faults which caused the main transformer switch override tripped,the process of the accident is restored,the protection configuration is tested,the correctness of the protection actions is verified,the cause of the accident is analyzed.Improvement of microcomputer protection system can be used as a reference for similar future faults.It has reference significance for the practical operation work.