一起35kV不接地系统单相弧光接地事故分析

Single Phase Arc-Earthing Accident Analysis of a Case of 35kV Non-Effective Ground System

某220 kV变电站的35 kV不接地系统中,因单相接地故障引起的弧光接地过电压,导致滤波支路过流保护动作及多处设备损坏。阐述了事故的发生过程,分析了事故电压波形并找出现场故障原因。基于PSCAD/EMTDC软件建立了包含弧光接地故障的现场仿真模型,分析了间歇性弧光接地引起的过电压过程,仿真结果验证了该事故是由于间歇性弧光接地引起系统故障的分析,并提出了相应解决方案。

There was a single-phase ground fault of arc-earthing overvoltage causing filtering circuit over-current protective action which occurred in a 220 kV substation where the 35 kV system was non-effective grounded. Lots of equipments were damaged because of the non-continuous single-phase ground fault. This paper expounded the generating process of the accident, analyzed the accident voltage waveform and founded the field failure causes. The field simulation model including arc-earthing was established by using the common electromagnetic transient simulation software PSCAD/EMTDC. This paper analyzed the generating process of the overvoltage caused by the intermittent arc-earthing. The simulation results verify that this accident is caused by intermittent arc-earthing and the corresponding solution is proposed to avoid these incidents.