中文摘要：

城市配电网同母多回线相继故障频繁发生,此问题在中性点经消弧线圈接地系统中尤为严重,为了分析此类事故原因,首先针对单相接地引起的稳态过电压进行了理论研究,具体分析了过渡电阻、无功补偿对健全相稳态过电压的影响;随后对间歇性弧光暂态过电压及其分布特点进行了定量分析,结果表明非故障线路末端的过电压水平高于故障线路,因而率先发生相间短路故障的几率高;在此基础上,以实际事故为例,基于PSCAD/EMTDC建立仿真模型对事故发生过程进行详细分析,并结合故障信息揭示事故发生的原因;最后,针对性地提出了解决方案。

英文摘要：

Successive faults occur frequently at multi-feeder connected to the same bus in urban distribution networks, which is particularly severe in resonant grounding systems. To find out the cause of such accidents, we firstly studied steady-state overvoltage caused by single-phase-to-ground fault, and analyzed the influences of fault resistor and reactive power compensation on the steady-state overvoltage of healthy phases. Then, we analyzed the distribution characteristics of transient overvoltage caused by intermittent earth fault. The results show that the intermittent arc overvoltage at the end of a non-fault line is much higher than that of the faulty line. Thereby, phase-to-phase fault may occur first in a non-fault line. Therefore, taking an actual accident as an example, we used a simulation case in PSCAD/EMTDC to study the pro- cess of the accident. Combined with the fault information, the cause of the accident was revealed. At last, corresponding solutions were put forward.