基于小波包能量谱的电网故障行波定位方法

为减少电网故障行波传播色散特性对行波波头检测和波速测量的影响,提高电网故障行波定位的准确度,提出了基于小波包能量谱的电网故障行波定位方法。该法结合小波包技术与傅立叶变换的谱分析,对行波信号进行分析,提取能量相对集中的故障频带信号进行故障行波定位计算;行波到达时间由该频带相应尺度下的小波包能量时谱提取的行波特征点位置计算;该频带行波传播速度由输电线路两端对外部扰动的实测行波数据计算。大量的电网故障行波定位ATP仿真分析结果和现场实验测试分析表明,该电网故障行波定位方法能有效提取电网行波特征信号,减少行波传播色散特性和线路长度变化的影响,定位误差<200m。

Traveling Wave Fault Location Method for Power Grids Based on Wavelet Packet Energy Spectra

In order to reduce the influence of the transmission dispersion characteristics of power grid faults generated traveling wave on the wave head detection and the wave transmission velocity measurement,and to improve the faults location precision,a fault location method based on wavelet packet energy spectra is presented. The wavelet packet technology and spectrum analysis of the Fourier transformation is adopted to analyze the traveling wave signals and extract the frequency band signal with energy concentrated for fault location. The traveling wave arrival time is calculated by the frequency band signal's characteristic points which are extracted by wavelet packet energy spectra in time domain. The frequency band signal transmission velocity is calculated by the transmission line two-end-measured traveling waves generated by an external disturbance. Many fault location cases are simulated with an ATP software and some field tests are carried out in a power grid. The results show that the fault location method can extract the faults characteristic signals effectively and reduce the influence of traveling wave dispersion characteristics and line length change,and the fault location error is no more than 200 meter.