针对电能质量信号的去噪,提出了一种基于MAP估计的双树复小波电能质量扰动信号的去噪方法.首先对带噪信号进行相关性预处理,然后通过MAP方法对双树复小波分解不同层次的细节系数估计噪声方差和信号方差,并计算各层阀值从而得到去噪方案,针对带噪的电压跌落等扰动信号进行仿真,并与传统实小波去噪进行了信噪比和突变点信息保留能力的比较.仿真结果表明,所提算法速度快,去噪效果理想,且易于实现,实用性强,有良好的发展前景.%Aiming at power quality signal denoising, we proposed, in this paper, a dual-tree complex wavelet denoising method for power quality disturbance signal based on MAP estimation. Firstly, performing the correlativing pretreatment to the noising signal, then using MAP method to estimate noise variance and signal variance from the detail coefficients after dual tree complex wavelet analysis at different level and calculate each layers of threshold to get the denoising scheme. To make the research more accurate and comprehensive, we also simulate the noisy voltage sag as well as other disturbed signals of power and compare the simulation results with the traditional real wavelet denoising method at SNR as well as information retention capacity of break point. Simulation statistics show that the proposed algorithm turns out to be a fast, satisfactory, realizable and practical method with a cheerful prospect.
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