改进自适应无参经验小波变换在变压器高频局放电流噪声抑制中的应用  

Application of Improved Adaptive Parameterless Empirical Wavelet Transform in Transformer High Frequency Partial Discharge Current Noise Suppression

作　　者：唐志国[1] 李阳 TANG Zhiguo;LI Yang(Beijing Key Laboratory of High Voltage&EMC(North China Electric Power University),Changping District,Beijing 102206,China)

机构地区：[1]高电压与电磁兼容北京市重点实验室(华北电力大学),北京市昌平区102206

出　　处：《电网技术》2023年第8期3474-3482,共9页Power System Technology

摘　　要：变压器是电力系统中的关键设备,局部放电(partial discharge,PD)是致使变压器绝缘劣化的主要原因,也是绝缘劣化的重要表现形式。针对高频PD信号中窄带干扰和白噪声这些复杂的噪声信息,提出一种基于互信息和样条插值拟合优化频谱分割的改进自适应无参经验小波变换的降噪方法。该方法以无参经验小波变换为基础,计算经无参经验小波变换分解的各个时域分量的互信息值进行合并优化得到新的频谱分割点,然后在各个频段内提取峰值点,将这些峰值点进行三次样条插值拟合得到拟合曲线,将拟合曲线的极小值点作为最新频谱分割点进行划分得到各个时域分量,最后计算各个分量的峭度值,去除峭度值小于3的分量,将剩余分量进行通用阈值降噪重构达到PD信号降噪效果。仿真、实验室和现场测试表明,与现有小波变换降噪和基于经验模态分解降噪的方法进行对比,文中的方法能够更加有效抑制变压器高频PD信号中的噪声信息。Transformer is the key equipment in a power system.Partial discharge(Partial Discharge,PD)is the main cause of transformer insulation deterioration,and also an important manifestation of insulation deterioration.Aiming at the complex noise information such as the narrowband interference or the white noise in the PD signals,an improved adaptive parameterless empirical wavelet transform noise reduction based on the mutual information and the spline interpolation fitting to optimize the spectrum segmentation is proposed.The method combines and optimizes the mutual information values of each time domain component decomposed by the parameterless empirical wavelet transform to obtain new spectral division points.Then,by extracting the peak points in each frequency band,the cubic spline interpolation fitting is performed to obtain a fitting curve.The minimum value point of the fitted curve is used as the latest spectrum division point to obtain the component in each time domain.Finally,the kurtosis value of each component is calculated.By removing components with a kurtosis value less than 3,the remaining components are subjected to the general threshold noise reduction and reconstruction,which achieves the PD signal noise reduction.Simulation,laboratory and field tests show that,compared with the existing wavelet transform noise reduction and the empirical mode decomposition noise reduction methods,the method in this paper more effectively suppresses the noise information in the PD signals.

关 键 词：变压器局部放电 改进自适应无参经验小波变换 互信息 三次样条插值 峭度 降噪 

分 类 号：TM721[电气工程—电力系统及自动化]