基于经验小波与小波变换的GIS局部放电信号去噪方法研究

为解决气体绝缘组合电器(gas insulated switchgear,GIS)内部缺陷局部放电(partial discharge,PD)信号含有噪声的问题,搭建了模拟局部放电环境,采用超高频法(ultra-high frequency,UHF)采集缺陷PD信号。针对UHF PD信号具有周期性窄带噪声与白噪声的特点,提出了基于改进的经验小波(experience wavelet,EWT)与小波变换结合进行UHF PD信号的去噪研究。首先,含噪信号通过EWT预处理分解为多频率的模态函数,然后对模态函数进行小波去噪处理,将去噪后的模态函数按照峭度值进行划分,根据合适的阈值选取UHF PD信号的有效成分并重构信号,最后,通过构建UHF PD仿真信号并采用实测数据验证所提算法的有效性。仿真实验与实测去噪结果表明:文中所提改进去噪算法具有良好的噪声抑制能力,为GIS设备内部UHF PD信号去噪提供参考。

Research on Denoising Method of GIS Partial Discharge Signal Based on Improved Empirical Wavelet and Wavelet Transform

In order to solve the problem that the internal discharge(PD)signal of gas insulated switchgear(GIS)contains noise,this paper builds a simulated partial discharge environment,and using ultra-high frequency(UHF)to acquire the defective PD signal.In view of the characteristics of periodic narrow-band noise and white noise for UHF PD signals,a denoising study of UHF PD signals based on improved experience wavelet(EWT)and wavelet transform is proposed.Firstly,the EWT transform can be used to decompose the signal into multi-frequency modal functions,then the modal function is wavelet denoised,divide the denoised modal function according to the kurtosis value,and select UHF PD according to the appropriate threshold.The active component of the signal and reconstructs the signal.Finally,the UHF PD simulation signal is constructed and the measured data is used to verify the effectiveness of the proposed algorithm.The simulation experiment and the measured denoising results show that the improved denoising algorithm proposed in this paper has good noise suppression ability.This paper provides a reference for the denoising of UHF PD signals inside GIS equipment.