基于小波包变换的电力系统谐波电流检测

A novel measuring approach of power harmonics based on wavelet transform

针对常规快速傅立叶变换无法检测非整数次谐波,以及改进的加窗插值快速傅立叶变换运用困难,采用小波、小波包变换对电网信号中的谐波进行检测分析。小波包变换建立在二进小波变换基础上,可以实现对信号的均匀划分,能够更好地提取信号的时频特性。仿真结果证明,较之傅立叶变换和小波变换,小波包变换对电网信号中谐波的幅度、频率的估计具有更高的精度。

This paper introduces two methods for detecting harmonics in power network signals by means of wavelet transform (WT) and wavelet packet transform (WPT). Because the wavelet packet transform is based on binary discrete wavelet transform, it can decompose the spectrum of a signal into uniform subbands, and then improve the accuracy of detecting harmonic time frequency. The simulating result shows that the estimation of the harmonics' frequency and amplitude based on WPT reached a more reasonable accuracy than FFT and WT.