基于自适应阀值的小波全频降噪方法研究及实现  

Study and Realization of a Wavelet Full-Frequency Noise Reduction Method Based on Adaptive Threshold

作　　者：吕泽承 杨健 邬蓉蓉 蒋圣超 苏毅 LV Zecheng;YANG Jian;WU Rongrong;JIANG Shengchao;SU Yi(Electric Power Research Institute of Guangxi Power Grid Co.,Ltd.,Guangxi Nanning 530023,China)

机构地区：[1]广西电网有限责任公司电力科学研究院

出　　处：《广西电力》2019年第6期13-16,21,共5页Guangxi Electric Power

摘　　要：在含噪信号中提取有效的局部放电信号时,传统的小波阈值降噪方法只对小波分解的高频部分进行降噪处理,而忽略了低频部分噪声对局部放电信号的影响。针对该方法的缺陷,本文提出一种基于自适应阈值的小波全频降噪方法。该方法根据噪声的小波分解系数随尺度增大而减小的特点,采用随尺度变化的自适应阈值对高频部分噪声进行处理,采用传统的固定阈值对低频部分噪声进行处理,从而实现对局部放电信号的小波全频降噪处理。实验数据表明:与传统的小波阈值降噪方法相比,小波全频降噪方法的均方根误差降低了19.3%,噪声抑制比和噪声降低水平分别提高56.4%、10.8%。由此验证了自适应阈值的小波全频降噪方法的降噪效果优于传统小波阈值降噪方法。For the extraction of the effective partial discharge signal from noise signal, the traditional wavelet threshold noise reduction method only denoises the high frequency part of wavelet decomposition and ignores the influence of the low frequency part of noise in the partial discharge signal. Aimed at eliminating the defect of the method, a wavelet full-frequency noise reduction algorithm based on adaptive threshold is proposed. According to the feature that the wavelet decomposition coefficient of noise decreases with the increase of the scale, the adaptive threshold which varies with the scale is used to process the high frequency part of noise and the traditional fixed threshold is used to process the low frequency part of noise so that the wavelet full-frequency noise reduction for partial discharge signals is realized. Experimental data shows that compared with the traditional wavelet threshold noise reduction method, the root mean square error of the wavelet full-frequency noise reduction method is reduced by 19.3%, the noise suppression ratio and noise reduction level are respectively increased 56.4% and 10.8%, verifying that the noise reduction effect of the wavelet full-frequency noise reduction method based on adaptive threshold is better than that of the traditional wavelet threshold noise reduction method.

关 键 词：局部放电 小波变换 自适应阈值 全频段降噪 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]