基于护套电流和的110 kV GIS终端电缆行波故障定位研究

摘要

为了在不拆开GIS替换原有电磁型电流互感器的条件下仍能够采用行波法对电缆进行在线故障定位，以110 kV交联聚乙烯绝缘皱纹铝护套电力电缆为原型，研究故障暂态电流行波在护套交叉互联电缆中的传播特性。提出利用三相护套电流和作为行波测距信号，其在护套交叉互联点和护套接地点处大小不发生变化，且主要成分为传播特性稳定的模量。在PSCAD/EMTDC中建立电缆系统模型进行各种故障电阻和故障距离的仿真，采用小波变换模极大值进行波头识别，故障测距结果都表明该方法可行并具有较高的准确性。%In order to locate the fault online by traveling wave without replacing the original electromagnetic current transformer in the GIS, using the 110 kV XLPE power cable as the prototype, the transient current propagation characteristics in the sheath cross-bonded cable are analyzed. The method using the sum of three sheath currents as fault location signal is proposed. The signal doesn’t change in the sheath-crossing point and sheath grounding point, and the main component of the signal is a stable modulus. A model of 110 kV power cable system is built by PSCAD/EMTDC to simulate various fault resistance and fault location. Using the wavelet transform modulus maxima to locate the arrival time of traveling wave, the result shows that the method is feasible and has higher accuracy.