一种基于参数识别的配电网单相接地故障区段定位方法

A Single-phase Grounding Fault Section Location Method for Power Distribution Network Based on Parameter Identification

针对中性点接地方式、配电网规模、过渡电阻等因素导致配电网单相接地故障选线和故障区段定位一直没有得到圆满解决的问题,提出了一种基于参数识别的配电网单相接地故障区段定位新方法。在零序网络中,对于特定的频带,正常线路与故障线上故障点之后的线路可以等效为正电容,而故障线上故障点之前的线路可以等效为负电容,在配电网各线路出口及分支处安装保护装置,利用保护装置测量得到的零序电压和零序电流识别各区段电容值,根据识别得到电容值的正负即可判别故障区段,进而结合网络拓扑即可实现故障区段定位。PSCAD仿真结果和动模实验表明,该方法耐过渡电阻能力强,在各种工况下均能可靠地选出故障区段,计算简单,易于实现,具有一定的实用价值。

Aiming at dissatisfactory solution to single-phase grounding fault line selection and fault section location of the power distribution network caused by the influence of neutral point grounding mode, power distribution network scale, the transition resistance, and so on, this paper presents a kind of new method for single-phase grounding fault section location based on parameter identification. In the zero sequence network for those specific frequency bands, normal lines and lines at back of the fault point can be equalized to positive capacitance, while lines in front of the fault point can be equalized to negative capacitance. By using the protection device installed at the export and the branch of every line, it can obtain zero sequence voltage and zero sequence current from measurement, and then identify capacitance values of sections. Then it can distinguish fault sections according to capacitance values and realize fault section location combining network topology. PSCAD simulation results and dynamic model experiments indicate that this method is resistant to high transition resistance and is able to pick out fault sections under various working conditions. In addition, the method is simple in calculation and easy to be realized, which means it has a certainly practical value.