配电网接地故障检测和定位技术研究

Research on Detection and Location Technology of Ground Fault in Distribution Net work

油田配电网线路普遍距离长、分支多、设备繁杂、地理情况变化多样,一旦发生接地故障,故障点查找时间长并存在一定的误报,针对此问题,提出需要综合单相接地多种故障特性来判断发生故障的原因及位置。对单相接地后稳态、暂态的故障特性和不同的检测方法进行了分析,对近期新兴的检测方法,即比较零序电流波形法、零序电压传导时域法和广域同步暂态录波法进行了比较,结果表明暂态特征法能够检测各种不同性质的接地故障,准确度相对较高,且实施方便。暂态特征法在大庆油田的应用效果比较理想,短路、过流故障定位准确率达到95%以上,永久性接地故障检测准确率达到75%以上,大大提高了接地故障检测的准确性,增强了电网的可靠性。

Oilfield distribution network lines generally have long distances,many branches,complicated equipment,and diverse geographical conditions.Once a ground fault occurs,the fault point search time is long and there are certain false positives.In order to solve this problem,it is necessary to judge the cause and location of faults by synthesizing the fault characteristics of single phase grounding.The steady-state and transient fault characteristics after single phase grounding and different detection methods are analyzed.Newly developed detection methods are compared,such as the zero-sequence current waveform comparison method,zero-sequence voltage conduction time-domain method and wide-area synchronous transient recording method.The results show that the transient feature method can detect various ground faults with different nature,its accuracy is relatively high,and it is easy to implement.The application effect of the transient feature method in Daqing Oilfield is relatively ideal,the short-circuit and over-current fault locating accuracy reaches more than 95%,and the permanent ground fault detecting accuracy reaches more than 75%,greatly improving the accuracy of ground fault detecting and enhancing the reliability of power grid.