基于EWT的高压电缆局部放电信号降噪研究

在测量高压电缆的局放信号时会混入以周期性窄带干扰和随机白噪声为主的噪声成分。为抑制噪声成分对局放信号测量精确度的影响，提出一种基于经验小波变换(Empirical Wavelet Transform, EWT )的高压电缆局放信号降噪方法。利用自适应经验小波变换对含噪信号进行分解，通过计算模态分量的峭度值，实现对脉冲信号的定位，将筛选出的有效特征分量进行重构。最后利用改进阈值函数去除重构信号中的冗余噪声，实现对多噪声的有效抑制。经仿真对比及现场试验测试，该方法能有效抑制窄带干扰和白噪声，较大程度地保留高压电缆局放中的有效信息，且在不同噪声环境下的降噪表现较为稳定。

Research on noise reduction of a partial discharge signal of a high voltage cable based on EWT

When measuring partial discharge signals of high-voltage cables, noise components dominated by periodic narrowband interference and random white noise are mixed. In order to suppress the influence of noise components on the accuracy of partial discharge signal measurement, a partial discharge signal noise reduction method for high-voltage cable based on Empirical Wavelet Transform (EWT) is proposed. The noisy signal is decomposed using adaptive EWT. By calculating the kurtosis value of the modal component, the pulse signal can be located, and the effective feature components screened are reconstructed. Finally, the redundant noise of a reconstructed signal is removed using an improved threshold function to effectively suppress multiple noise. By conducting simulation comparison and field test, it is shown that the method in this paper can effectively suppress narrow-band interference and white noise, retain the effective information in partial discharge of high-voltage cable to a large extent, and perform stable noise reduction in different noise environments.This work is supported by Natural Science Foundation of Henan Province (No. 182300410280) and Science and Technology Research Project of Henan Province (No. 182102310936).