煤矿供电系统单相接地故障区域确定

Fault Section Location of Single- phase Grounding in Coal Mine Power Supply System

根据煤矿供电系统过补偿运行时的特点,提出了一种根据上下级变电所进线的衰减直流分量判断单相接地故障线路所在变电所的方法。煤矿6 kV电网在单相接地故障的初期,故障线路直流分量最大,之后各线路直流分量开始波动,到1周波后,非故障线路直流分量衰减至几乎为0,而非故障线路依然存在很大的直流分量。依此方法在故障选线时可以确定出故障线路所在的变电所,缩小需要确定的故障发生的范围,进而减少了运算量、提高常见选线判据的准确性。

According to the operation character of the coal mine power supply system in overcompensation state, this article introduces the method to locate the substation with single - phase grounding fault circuit by analyzing the decaying DC component of upper substa- tion and lower substation. When single - phase grounding fault happens in coal mine 6 kV grid, the DC component of fault circuit is the largest at the beginning and the DC component of each circuit begins to fluctuate after one wave cycle, Non - fault circuit DC component decays to almost zero, but Non - fault line still exists a large DC component. This method can be used to locate the substation with fault circuit, narrow the area of the fault circuit that need to locate, which reduces the calculation and improves the accuracy of common line selection criterion.