矿井多级供电网络漏电故障的分析与检测

Analysis of Electric Leakage Fault of Mine Multi-level Power Supply Network and Its Detection

对中性点不接地系统和中性点经消弧线圈接地系统发生单相漏电故障时的故障分量进行了分析,明确了漏电故障点的电气量特征,并进一步分析了矿井多级供电网络中零序电流的分布情况,得出结论:(1)中性点不接地系统发生漏电故障时,接地线路的漏电流为整个供电系统所有线路漏电流的最大值,接地线路上级线路的零序电流均比接地线路的零序电流小;(2)中性点经消弧线圈接地系统发生漏电故障时,接地线路的零序电流大小和非接地线路及接地线路的上级线路不一定有明显的区别,但接地线路零序电流的有功分量远远大于非接地线路及接地线路上级线路的零序电流有功分量。最后介绍了几种中性点不接地系统漏电保护检测原理,重点分析了一种易于在微机保护中实现的中性点经消弧线圈接地系统的漏电保护方案,即基于线路零序有功功率大小的选线方法。

The paper analyzed fault components at the electric leakage moment of isolated neutral power supply system and power supply network connected to earth through an arc suppression coil,and got electrical characteristics of fault point.It also analyzed distribution of zero-sequence current of mine multi-level power supply network and got following collusions：（1） When electric leakage fault happens in isolated neutral power supply system,leakage current of the grounding line is the maximum in the whole power supply system,and zero-sequence current of the grounding line is bigger than the ones of the superior lines.（2） When electric leakage fault happens in power supply system connected to earth through an arc suppression coil,zero-sequence current value of the grounding line may be similar to the ones of other lines in the whole power supply system,but active component of the zero-sequence current of the grounding line is far more than the ones of non-grounding lines and the superior lines.Finally,it introduced several detecting principle of electric leakage protection of isolated neutral power supply system,and emphatically analyzed an electric leakage protection scheme of power supply system connected to earth through an arc suppression coil which is easily implemented in microcomputer protection,namely line selection method based on zero-sequence active power of lines.