用小波变换提取局部放电信号

为了提取局部放电信号，采用二进尺度小波变换的Ｍａｌａｔ算法，应用Ｄａｕｂｅｃｈｉｃｓ小波，设计了低通、带通滤波器。数值仿真研究中，用指数衰减或衰减振荡波来模拟放电信号，研究了小波变换提取信号的效果及有关影响因素。仿真和现场监测数据处理的结果表明，由于小波变换具有多分辨率特性，能快速而有效地从多种窄带干扰中提取出放电信号，适当条件下还可实现较完整波形的提取。由于处理速率较高，适合在线监测时实时使用。

Extraction of partial discharge signals using wavelet transform

Using Mallat's algorithm of dyadic wavelet transform and Daubechies wavelet, low pass and band pass filters were designed to suppress narrow band disturbance for extracting partial discharge signals. In numerical simulation experiments the exponential damping or oscillating damping functions were used to simulate discharge signals and the effect of extracting signal as well as some other influential factors was investigated. The processing results of numerical simulation and on site monitoring data show that based on the feature of multi scales the wavelet transform could extract discharge signals quickly and efficiently from up to 10 narrow band disturbances and under adequate circumstances complete wave form could be obtained. Because of the faster processing speed this method is more suitable for real time application during on-line monitoring.