小电流接地电网复杂接地故障保护动作特性分析  

Characteristic Analysis on Grounding Fault Protection in Small Current Grounding Power Systems

作　　者：鲍有理 季东方 

机构地区：[1]无锡供电公司,江苏无锡214061 [2]国电南自股份有限公司,江苏南京211100

出　　处：《江苏电机工程》2015年第4期17-20,共4页Jiangsu Electrical Engineering

摘　　要：小电流接地系统单相接地故障引发不同线路异名相两点接地故障问题大量存在。经消弧线圈接地系统异名相两点接地故障时,由于中性点电流不平衡注入的影响,两故障线路异名故障相电流存在偏差,保护无法准确跳开2条故障线。文章基于电路叠加定理,从理论上推导了偏差计算公式及产生原因,结合现场录波波形,从理论上分析验证了35kV线路保护的正确动作行为。进一步扩展分析了其他中性点接地方式,发生异地异名相接地故障时,故障定位及保护动作行为判别时应注意的问题,为异名相异地两点接地故障的保护动作行为分析提供经验参考。Two-point grouding faults in different phases and lines can be frequently caused by single-phase grouding fault in small current grouding power systems. When two-point grouding fault occurs in different phases in arc suppression coil grouding system, due to the influence of neutral point current injection, a difference occurs between the two fault lines, which can cause protection refusing to trip. Based on the circuit superposition theorem, this paper derives the deviation calculation formula. By using fault current＇s waveform, the protection action is analyzed. Moreover, other kinds of grounding problems are analyzed when two-point grouding faults occur in different phases and lines, which provides references for future studies.

关 键 词：小电流接地系统 消弧线圈 线路保护 

分 类 号：TM77[电气工程—电力系统及自动化]