基于小波变换的电能质量信号谐波分析

快速傅里叶变换(FFT)可实现整数次谐波的精确检测;但对非整数次谐波的检测误差较大,加窗插值算法可提高非整数次谐波的检测精度,但会导致谐波分辨率降低,如果信号中存在频率相近的整数次和非整数次谐波,利用FFT和加窗插值算法都无法实现谐波的准确检测.为了弥补这种不足,本文采用基于小波变换和FFT相结合的方法来分析电能质量信号.用小波变换检测电能质量信号的间断点,对由间断点分段得到的低频信号用FFT进行分析,并进行了计算机仿真,取得了较满意的结果.

Signal Analysis of Power Quality Harmonic Based on Wavelet Transform

Fast Fourier transform can measure integer harmonics precisely.but with great error for non-integer harmonics.The interpolating windowed FFT can improve measurement precision of non-integer,while resulting in low resolution for a signal containing several integer and non-integer harmonics with near frequency.Both the existing FFT methods and interpolating algorithms cannot solve it with satisfaction.in order to make up shortcoming, This paper presents an approach to analyze the signal of power quality on the basis of wavelet transform and FFT.We get a satisfactory result by computer simulation through detecting breakpoints of the signal of power quality by wavelet transform and analyzing the low frequency spectrum of segment signal by breakpoint with FFT