配电网单相接地故障的负序电流纵联差动选线方法

Fault line selection of single-phase to ground based on negative sequence current pilot differential in distribution network

单相接地是配电网发生几率最高的故障,但单相接地故障选线一直是困扰人们的技术难题。本文首先分析了配电网单相接地故障负序电流的分布规律。在此基础上,提出了一种用于配电网单相接地故障的负序电流纵联差动选线方法,该方法通过比较线路两端的负序电流选出故障线路,具有较强的实用价值。利用35k V配电网的PSCAD模型进行仿真,并且进行了相关的动模实验。仿真结果和实验结果表明,该方法能够正确、可靠地选出故障线路,并能摒弃系统正常运行时固有负序电流的影响,该原理不因接地方式改变而失效,且适用于包括消弧线圈接地在内的所有接地类型配电网。本文最后提出了该方法的优缺点以及今后可在配电网单相接地故障选线方面开展的进一步研究工作。

Single-phase to ground short is most liable to fault, but how to detect fault section is the largest technical problem in distribution network. At first, the general changes of negative sequence current distributing is discussed and theoretical basis is provided for single-phase to ground fault detection in distribution network in this paper. And then a new fault selection method is proposed base on negative sequence current pilot differential in distribution net- work. The method detects fault section through comparing the negative sequence current of line＇ s both ends, and the method has great value of practical application. The principle is verified by PSCAD simulator, which has been tested in dynamic power system model, and the results show that the method proposed in this paper is reliable and accurate. The principle can neglect negative sequence current during system normal operation and is effective for all types of neutral grounding mode in distribution network. Finally, the advantages and disadvantages of this method are discussed, and the technology that need further studied is also proposed.