基于改进阈值函数的分数阶小波电能信号去噪

摘要

为了消除电力系统中噪声对电能质量扰动信号的影响,且能保留突变点信息,提出了一种基于改进阈值函数的分数阶小波电能质量扰动信号去噪方法.该方法采用离散分数阶小波变换对含噪信号进行多尺度分解,并根据信号和噪声在不同尺度上的分数阶小波域系数的分布特点,通过改进阈值函数对各层系数进行处理,将处理后的系数进行重构得到去噪后的信号.仿真结果表明,该方法弥补了软、硬阈值函数的缺点,能较好地去除噪声并保留突变点信息,且提高了输出信噪比.%In order to eliminate the influence of noise on power quality disturbance signal for power system,and retain more mutation points information,a power quality disturbance signals de-noising method for discrete fractional wavelet transform is proposed based on improved threshold function.The noise signal is decomposed in multi-scale by the discrete fractional orthogonal wavelet transform,furthermore according to the distribution characteristics of fractional wavelet domain coefficients at different scales of signal and noise,the coefficients in each layer are processed by the improved threshold function,and the processed coefficients are reconstructed to get the de-noised signal.Finally,the simulation results show that this method not only overcomes the disadvantages of soft and hard threshold functions,but also removes the noise and preserve the mutation point information more effectively,and improves the output signal to noise ratio.