基于CEEMDAN与改进小波阈值的电缆局部放电信号降噪方法

Noise Reduction Method of Cable Partial Discharge Signal Based on CEEMDAN and Improved Wavelet Threshold

对检测到的电缆局部放电信号降噪是实现电缆绝缘诊断与评估的前提,为此提出一种基于自适应噪声的完备集合经验模态分解(CEEMDAN)与改进小波阈值的电缆局部放电信号降噪方法。首先,采用CEEMDAN算法将染噪局部放电信号进行分解,得到数个模态分量;然后,计算模态分量的峭度值,筛选出有效特征分量并重构;最后,将重构信号通过改进小波阈值法再次降噪去除冗余噪声,得到降噪后的局部放电信号。将该方法、传统小波阈值法及集合经验模态分解与改进小波阈值法分别用于不同噪声强度下局部放电仿真信号的降噪处理,结果表明该方法具有更高的信噪比与波形相似系数,能有效抑制周期性窄带干扰与白噪声。

Noise reduction of detected cable partial discharge signal is the premise of cable insulation diagnosis and evaluation,so a complete set empirical mode decomposition(CEEMDAN)based on adaptive noise and improved wavelet threshold noise reduction method of cable partial discharge signal is proposed.Firstly,the CEEMDAN algorithm is used to decompose the noise partial discharge signal to obtain several modal components.Then,the steepness value of the modal component is calculated,and the effective feature component is filtered out and reconstructed.Finally,the reconstructed signal is reduced again by improving the wavelet threshold method to remove the redundant noise,and the partial discharge signal after noise reduction is obtained.This method,the traditional wavelet threshold method and the ensemble empirical mode decomposition and improved wavelet threshold method are used for the noise reduction processing of partial discharge simulation signals under different noise intensities.The results show that the proposed method has a higher signal-to-noise ratio and waveform similarity coefficient,and can effectively suppress periodic narrowband interference and white noise.