小波包提取算法和相关分析用于电缆双端行波测距

Wavelet Packet Extraction Algorithm and Correlation Analysis for Double Terminal Traveling Wave Fault Location of Cable

由于故障行波传播色散的影响,确定行波到达时刻和选择行波波速一直是电缆行波测距的难题。针对以上两个问题,提出了基于小波包提取算法和相关分析的电缆双端行波故障测距方法。该方法将暂态行波信号通过小波包分解为不同的频带,然后提取能量相对集中的频带进行小波包重构。在该频带,线路的衰减系数和波速都可近似为常数,因此电缆两端的重构波形相似。用相关分析方法确定两端波形时间差,再结合该频带的波速,即能精确确定故障位置。通过对实验结果的分析表明,提出的方法提高了测距精度,是有效的。

Because of the influence of the transmission dispersion characteristics of faults generated traveling wave, the detection of traveling wave arriving time and the selection of traveling wave velocity are two difficulties in traveling wave fault location of cable. We put forward a new fault location method on the basis of the wavelet packets extraction algorithm and correlation analysis algorithm. By utilizing the theory of wavelet packet decomposition, transient traveling wave is decomposed into different frequency sections, and the frequency band signal with concentrated energy is extracted for wavelet packet reconstruction. The attenuation coefficient and wave velocity of this frequency band are regarded as constants, so the reconstructed waveforms at both terminals are similar. The correlation is analyzed to calculate the time difference, and the accurate fault location can be figured out combined with the constant velocity of this frequency band. The experimental results verify both the validity and the high precision of this algorithm.