小电流接地系统选线与区段定位原理综述

Review of Line Selection and Section Location Principles in Small Current Grounding Systems

在我国,配电网中性点大多采用小电流接地方式,发生单相接地故障时,虽然允许带故障运行一段时间,但由于非故障相电压升高,使故障有发展扩大风险,因此仍需尽快选线、定位并隔离故障。由于诸多原因,单相接地故障快速准确选线问题尚未得到有效解决,区段定位难度更大。而如上述问题能成功解决,则可极大提高配网自动化水平,降低人力成本,提高供电可靠性。分析当前小电流接地选线及区段定位的研究现状,将现有的选线定位原理归纳分类为外加信号法和故障信号法两大类,并对各方法加以分析,提出了小电流接地未来的研究和建设重点。

In China,small current grounding mode is usually adopted for the neutral points of distribution networks.When a single-phase earth fault occurs ,it is allowed to keep on operating for some time with the fault ,but the fault may expands because of the increaseing of the non-fault phase voltage.Therefore ,the fault still needs to be selected,located and isolated.Due to many reasons, the problem of fast and accurate line selection for single-phase earth fault has not been solved effectively, and section location is more difficuh.However,if the problems above could be solved successfully,distribution network automation level will be greatly raised,labor costs will be reduced, and power supply reliability will be improved.In this paper,by analyzing the current research status of line selection and section location,we classifie the line selection and section location principles into external signal methods and fault signal methods,analyze every method,and propose the key points of research and structure for small grounding systems in the future.