利用小波包变换实现电力系统谐波分析

小波包变换(WPT)建立在小波变换的基础上,可以实现信号频带的均匀划分,能够更好地提取信号的时频特性,具有更好的谐波分析特性.但是现有的小波包变换算法实现的频带划分不是按频率大小顺序排列的,给系统和谐波分析带来混乱.根据采样定理和滤波器组实现电路分析了小波包变换实现频带划分的特点,并利用改进的小波包变换实现算法进行系统分析,实例验证这种新的小波包分解结构对谐波分析具有更好的特性.

POWER SYSTEM HARMONIC ANALYSIS USING WAVELET PACKET TRANSFORM

Using wavelet package transform (WPT) constructed on the basis of wavelet transform, the frequency band of signals can be uniformly divided and the signal features in time domain and frequency domain can be better extracted, so WPT possesses better performance for harmonic analysis. However, with the commonly used implementation method of WPT, the decomposed frequency sub bands of the signal are not arranged according to the frequency value of the sub bands, therefore, it brings disarray in signal processing. According to the sampling theorem and the implementation of filter bank, the character of frequency band division by WPT is analyzed and a new WPT algorithm for power system harmonic analysis is put forward. It is verified by practical examples that the new WPT decomposition structure possesses better performance.