基于变分模态分解和凹凸型阈值小波的电缆局部放电信号降噪方法

针对中高压电缆局部放电信号测量中常见的周期性窄带干扰和随机白噪声干扰的问题，提出了一种基于变分模态分解(variational mode decomposition, VMD)和凹凸型阈值小波变换相结合的局部放电信号的降噪方法。先通过VMD对原始信号进行分解重构完成初步的降噪，再通过凹凸型阈值的小波变换进行进一步降噪。应用此方法分别对仿真信号和实测信号进行噪声抑制，并与传统降噪方法的降噪效果进行对比。对比结果证明所提方法相较于传统的软硬阈值的小波降噪等方法有更好的降噪效果，局放信号特征保留效果也更好。

Denoising Method of Cable Partial Discharge Signal Based on Variational Mode Decomposition and Concave-Convex Threshold Wavelet

In allusion to familiar periodic narrowband interference and random white noise interference during the measurement of partial discharge signals of medium and high voltage cables, based on variational mode decomposition (abbr. VMD) and concave-convex threshold wavelet a method to denoise cable partial discharge signal was proposed. Firstly, By means of VMD the original signal was decomposed and reconstructed to perform the preliminary noise reduction. Secondly, the wavelet transform of concave-convex threshold was utilized to conduct further noise reduction. Applying the proposed method the noise reduction for the simulation signal and the measured signal was carried out and the obtained results were compared with the effects by traditional noise reduction method. Comparison results show that the noise reduction effect of the proposed method is better than those of traditional noise reduction method such as soft and hard threshold wavelet noise reduction and so on, meanwhile, the reservation effect of the characteristic of local discharge signal is better.