基于改进Protrugram和小波变换的超高频局部放电信号去噪方法  

De-noising Method of Ultra-high Frequency Partial Discharge Signal Based on Improved Protrugram and Wavelet Transform

作　　者：代荡荡 王先培[1] 龙嘉川 田猛[1] 朱国威[1,2] 赵乐 DAI Dangdang;WANG Xianpei;LONG Jiachuanl;TIAN Meng;ZHU Guowei;ZHAO Le(Electronic Information School,Wuhan University,Wuhan 430072,China;Information ＆ Communication Branch,State Grid Hubei Electric Power Company,Wuhan 430077,China)

机构地区：[1]武汉大学电子信息学院,武汉430072 [2]国网湖北省电力有限公司信息通信公司,武汉430077

出　　处：《高电压技术》2018年第11期3577-3586,共10页High Voltage Engineering

基　　金：国家自然科学基金(50677047);湖北省科技支撑计划(2015BCE074)~~

摘　　要：为同时抑制超高频（UHF）局部放电（PD）信号中的周期性窄带噪声和随机白噪声,在分析UHF PD信号频谱特性的基础上,发现PD脉冲的频谱具有以某一频率为中心向左右两侧衰减的特征,中心频率处的谱线幅值要明显高于边带部分,且位于谱图上的局部极大值点处。为此,提出了一种基于改进Protrugram和小波变换的UHFPD信号去噪算法。该方法首先在频域上识别PD脉冲的中心频率,然后依据＂峭度值＂这一指标自适应获取中心频率所对应的频宽,实现脉冲的频谱定位。最后采用小波去噪法去除信号中的冗余白噪声,实现多类噪声的有效抑制。仿真和实测结果表明：同经典的小波去噪算法和集合经验模态分解（EEMD）自适应阈值算法相比,所提算法不仅具有更好的噪声抑制能力,且能更好地保留有效信号。论文研究可为超高频信号去噪提供参考。In order to simultaneously suppress the periodic narrow-band noise and random white noise in ultra-high frequency（UHF） partial discharge（PD） signal, by analyzing the spectrum characteristics of the UHF PD signal, we have found that the spectrum of PD pulse possesses the characteristics of reaching its maximum value at a certain frequency and decaying gradually toward the edge. The amplitude of the spectrum at its center frequency is significantly higher than that in the side-band section, and it is located at the local maximum point of the UHF signal spectrum. Thus, we proposed a novel method based on the improved Protrugram and wavelet transform to suppress the above noise in UHF PD signal. In the proposed method, firstly, the center frequency of the PD pulse is recognized in frequency domain; then, the corresponding bandwidth of the center frequency is obtained by self-adapting using kurtosis as an indicator, realizing the frequency spectrum locating of PD pulse; finally, the redundant white noise is eliminated using a wavelet de-noising method, realizing the effective suppression of multiple types of noise. The simulation and practical tests show that the proposed method has better performances not only in noise suppression but also in useful signal reserve compared with the traditional wavelet de-noising method and the ensemble empirical mode deposition（EEMD） adaptive threshold method. The research can provide reference for the de-noising of the UHF PD signal.

关 键 词：超高频局部放电 频谱特征 噪声抑制 Protrugram 峭度值 小波变换 

分 类 号：TM855[电气工程—高电压与绝缘技术]