基于小波分析的输电线路多端电压行波故障定位

Transmission line multi⁃terminal traveling wave fault location based on wavelet analysis

为了解决线路电气参数缺失或变化对双端输电线路行波故障定位造成的误差影响,提出一种在线路中再次提取故障信息的方法。首先对各检测端的故障电压行波信号进行相模变换得出线模分量,然后利用小波模极大值分析对线模分量处理得出故障电压初始行波到各端测点的传播时间,最后基于传统双端法测距推导出一种不含线路参数的故障定位新算法。改进后的定位方法只与初始行波波头到达各检测端的时刻有关,因此,该方法在实际中具有更好的适应性。使用PSCAD软件对这种多端结构的输电线路进行了仿真实验,结果表明多端检测的方法具有较好的适应性,在实际测距中对线路电气参数依赖性低,不受故障类型、故障位置和过渡电阻等因素的影响,定位误差较小、原理简单,具有较高的准确性和良好的适用性。

In order to eliminate the influence of deficiency or change of line electrical parameters on location of the end⁃to⁃end transmission line traveling wave fault,a method of extracting the fault information of the line is put forward.In the method,the phase mode transformation is performed for the fault voltage traveling wave signal in each detecting end to get the mode component,and then the wavelet modulus maxima analysis is used to process the component to obtain the transmission time from fault voltage initial travelling wave to the detection points at each side.A new fault location algorithm without any line parameter is deduced on the basis of the traditional method of double end ranging.The improved method relates only with the moment that the initial travelling wave head arrives to the detection end.Therefore,this method has better adaptability.The PSCAD software is used in the simulation experiment for this kind of transmission line with multi⁃end structure.The simulation experiment results show that the multi⁃terminal detection method has good adaptability,high accuracy,small positioning error,simple principle and low dependence to electrical parameters of the line in the actual range finding,and it is not affected by fault type,fault location and transition resistance.