改进LMD在高压输电线路行波故障定位中的应用

鉴于传统局域均值分解(LMD)对行波信号进行分解时,由于过平滑处理导致获取局域均值函数和包络函数的误差较大,最终影响暂态故障信号的提取。采用波形匹配方法对测量点电流线模分量进行端点延拓,并利用线性插值求取局域均值函数与包络函数,然后根据首个PF分量的频谱图标定行波波头到达测点的时刻,最后根据双端行波故障测距原理计算出故障距离。仿真结果表明,提出的定位方法与传统LMD方法相比具有较高的定位精度。

Application of Improved LMD in Traveling Wave Fault Location of High-voltage Transmission Lines

In the decomposition of traveling wave signal through traditional local mean decomposition (LMD),big errors in the local mean function and envelope function caused by over-smoothing finally affect extraction of transit fault signal.Firstly,waveform matching is used to extend the endpoint of the aerial mode component of the current at the measuring points,and local mean function and envelope function are obtained through linear interpolation.Then,the time of arrival of traveling wave range at the measuring point is demarcated according to the spectrogram of the first PF component.Finally,fault distance is calculated in the principle of double-end traveling wave fault location.Simulating results show that the presented location method has a higher location accuracy than the traditional LMD method.