基于小波去噪的加窗FFT电网谐波检测

摘要

This paper presents a Harmonic detection method based on combining An improved compromise for soft/hardrnthresholds in wavelet denoising and fast Fourier transform based on Blackman window. First, an Improved compromise for soft/hard thresholds in wavelet method is used to reduce the noises in the noised power harmonic signals.. Then by using fast Fourier transform based on Blackman window to analyze the signal of which has been reduced noises to extract the harmonic amplitude and frequency, Testing results show that the harmonic wave being detected after wavelet denoising is closer to purernharmonic wave, The denoising method increases the signal-to-noise ratio by 8, 3226dB. So the method base on FFT and wavelet denoising for harmonic detection is suitable for the application of harmonic detection systems and devices.%提出一种基于小波去噪的软硬阈值改良折衷法与加布莱克曼窗的傅里叶变换算法相结合的谐波检测方法.该方法采用小波软硬阈值改良折衷法对含噪的电力谐波信号进行降噪处理,利用加布莱克曼窗的傅里叶变换算法对去噪后的信号进行分析,提取各次谐波的幅值和频率.仿真检测结果表明小波去噪后的谐波波形接近于原始信号谐波波形,信噪比提高了8.3226dB,小波去噪与FFT结合的方法适合在谐波检测系统或装置中应用.