基于煤矿供电系统接地故障的中电阻选线算法研究

Research on the algorithm of middle resistance line selection based on ground fault of coal mine power supply system

我国煤矿配电网多为中性点非有效接地系统,且分支较多,负荷多变,井下环境极为恶劣,由于受到砸压、受潮等多方面的影响,极易导致电缆线路绝缘层老化、绝缘电阻下降等问题,从而诱发井下接地故障。如果接地故障没有得到及时有效的处理,极有可能进一步发展为相间短路,甚至引起瓦斯爆炸等严重的安全事故,严重威胁井下工作人员的安全。为了能及时切除接地故障,该文提出了一种中性点并联中电阻的小电流接地选线算法,该算法通过分析中电阻投入前后线路零序电流阻性分量的变化量来定位故障线路,不受消弧线圈和高阻接地的影响,选线准确率高,能够有效防止电网事故进一步恶化,保障煤矿安全稳定的生产运行。目前,使用该算法开发的装置已经在晋能煤矿变电站进行了试点应用,并取得了良好的效果。

China's coal mine distribution network is mostly neutral point non effective grounding system,with many branches,variable load and extremely bad underground environment.Due to the impact of smashing pressure and moisture,it is very easy to lead to the aging of cable insulation layer and the decline of insulation resistance,so as to induce underground grounding fault.If the grounding fault is not handled timely and effectively,it is very likely to further develop into phase to phase short circuit,and even cause serious safety accidents such as gas explosion,which seriously threatens the safety of underground workers.In order to remove the grounding fault in time,this paper proposes a small current grounding line selection algorithm with neutral parallel medium resistance.The algorithm locates the fault line by analyzing the change of the resistive component of the line zero sequence current before and after the medium resistance is put into operation.It is not affected by arc suppression coil and high resistance grounding,has high line selection accuracy,and can effectively prevent the further deterioration of power grid accidents.Ensure the safe and stable production and operation of coal mines.At present,the device developed by using the algorithm has been applied in Datong coal mine substation,and achieved good results.