基于自定义阈值函数的小波去噪算法

基于硬阈函数和软阈函数的小波去噪算法处理的信号分别存在偏差和方差过大的缺点,为有效解决这一问题,提出基于自定义阈值函数的小波去噪算法。研究给出了一种改进型的自定义阈值函数,建立了该函数的数学模型,对基于该函数的小波去噪算法的去噪效果进行了仿真,并将该算法应用于实际的电能质量暂态信号检测之中。仿真和实验结果进一步表明了自定义阈值函数的优越性和基于自定义阈值函数小波去噪算法的有效性。

Wavelet-based power quality disturbances de-noising by customized thresholding

Much of the wavelet-based denoising algorithms are based on hard or soft shrinkage function. It is showed that hard shrink tends to have bigger variance and the soft shrink tends to have bigger bias. To remedy these drawbacks, in this paper, a new denoising algorithm based on customized thresholding function is proposed. The proposed denoising algorithm has two thresholds, the lower threshold and the upper threshold. The upper threshold is fixed to the universal threshold proposed by Donoho, and the lower one can vary its value with the processed signal adaptively. The effectiveness of the proposed algorithm is ascertained using various PQ events, including simulated events and those recorded events at industrial sites.