考虑护套交叉互联的GIS终端电缆在线测距方法研究

Study on On-line Ranging Method for GIS Terminal Cable Considering Cross-connection of Protecting Bush

以110 kV护套交叉互联电缆为研究对象,应用小波变换和多尺度分析技术解决电缆故障电流行波色散问题,同时采用一种简单易行的数学处理方法对故障行波进行识别,在确定故障初始行波和故障点反射波到达电缆两个检测端的时刻后,提出一种不依赖于全球定位系统(global positioning system,GPS)的双端行波测距方法。采用电力系统计算机辅助设计-电磁暂态模拟程序软件(power system computer aided design and electir-mignatictrevnslent in DC system,PSCAD/EMTDC)中与频率相关的电缆建立仿真模型,故障仿真结果表明,该方法能避免波速度和波阻抗不确定性的影响,同时免除了由GPS时钟精度引入的测距误差,使得故障定位具有较高的可靠性和准确度,且不受故障距离、过渡电阻等因素的影响。

This paper takes 110 kV cable with cross-connected protecting bush as study object and applies wavelet transform and multi dimension analysis technology to solve problem of travelling wave dispersion of fault current. It adopts a simple mathematics processing method to recognize fault travelling wave and proposes double-end travelling wave ranging method which is independent of global positioning system after ensuring initial fault travelling wave and fault point reflected wave. It establishes simulation model by using cable related to frequency in PSCAD/EMTDC. The fault simulation result shows that this method can avoid affect of wave speed and uncertainty of wave impedance, meanwhile it can remove ranging error caused by GPS clock precision. This method can make fault positioning provided with higher reliability and accuracy while may not be affected by fault distance and transition resistance.