尺度空间滤波在局部放电脉冲提取中的应用

在提出脉冲提取思想的基础上，利用局部放电信号所固有的奇异性特征，将小波变换的奇异性检测原理应用于提取局部放电脉冲。为了满足局部放电在线监测的在线准实时要求，提出了改进的尺度空间滤波算法，并将其应用于局部放电脉冲的提取。通过相邻尺度的小波系数直接相乘，可以突出奇异点的信号，并获得基于尺度的屏蔽滤波器，将阈值方法和尺度空间滤波相结合，最终得到基于时域的屏蔽滤波器，将时域滤波器和原信号相乘，就可以提取出局部放电脉冲。仿真试验和发电机实测信号的算例表明，相对于模极大值算法，该方法在提高运算速度的基础上，不但能准确检测出局部放电脉冲，而且能很好地保持局部放电脉冲的幅度和位置。

APPLICATION OF SCALE SPACE FILTERING TECHNIQUE IN PARTIAL DISCHARGE PULSE EXTRACTION

A wavelet domain singularity detection algorithm, based on the theory of pulse extraction, is applied in partial discharge (PD) pulse extraction utilizing the singularity of PD signal. In order to satisfy the quasi real-time requirement of generator PD online monitoring, an improved scale space filtering technique is proposed and applied in PD pulse extraction. Scale based spatial filters are obtained by the multiplication of wavelet coefficients at adjacent scales. Shrinkage method is also used to get the time domain spatial filters. Meanwhile, PD pulse is obtained through the multiplication of the original signal and the time domain filters. Simulation tests and generator online monitoring signal tests show that this method can shorten the calculation time comparing with modulus maximum method. In conclusion, the method can not only detect PD pulse correctly, but retain the amplitude and position of PD pulse.