基于小波尺度相关性的暂态数据降噪压缩方法  

Power Quality Disturbance Data Denoising and Compression Using Signal's Scale-dependencies of Wavelet Coefficients

作　　者：贾毅婷[1] 张东来[1] 张斌 

机构地区：[1]哈尔滨工业大学深圳研究生院,广东省深圳市518055 [2]深圳航天科技创新研究院,广东省深圳市518057

出　　处：《电力系统自动化》2013年第5期68-73,共6页Automation of Electric Power Systems

基　　金：国家自然科学基金资助项目(50977016);国家国际科技合作计划资助项目(2010DFB63050);深圳市风力发电新能源装备和智能电网重点实验室资助项目(CXB201005250025A)~~

摘　　要：电力系统本身噪声及录波装置采样引入的噪声对电力系统信号数据压缩及故障信息提取造成不利影响。传统软硬阈值降噪法未考虑噪声本身特性,一方面,其降噪处理后难以分辨故障发生的起始时刻及持续时间,不利于故障检测;另一方面,软硬阈值降噪后将保留过多冗余系数且一些有用信息被滤除,不利于数据压缩。文中给出基于尺度内和尺度间的暂态数据降噪方法,在一个确定方差的未知区间内,将小波系数建模为独立具有零均值高斯随机变量,其方差由相关区间来确定且缓慢变化,利用邻域尺度内和尺度间小波系数之间的相关性,估计噪声方差以求得无噪声系数,提取故障信息时刻并降低噪声对故障辨析带来的不利影响,得到数据量极少的高频系数,有利于故障数据压缩。The noise from electrical power system itself and introduced by the sampling of fault recorder （FR） have adverse effect on data compression of electrical power system signals and the extraction of fault information. The traditional approach such as wavelet soft/hard-threshold denoising method is not concerned with the nature of noise itself, because it is difficult to distinguish the outset time and the duration time for fault detection after denoising, and it will retain excessive redundant coefficients at the same time which is not conducive to data compression. This paper presents a denoising method for transient data based on intra and interscale dependencies of wavelet coefficients. In an unknown interval with definite variance, the wavelet coefficients are modeled as independent zero mean Gaussian random variables and the variance of them which is determined by related interval changes slowly. By using the intra and interscale dependencies of wavelet coefficients and estimating the noise variance, the noise-free coefficient used to extract the fault information time can be obtained. This method can reduce the noise effect of fault analysis, obtain high frequency coefficients with extremely few quantities and be advantageous to fault data comoression.

关 键 词：故障数据 小波降噪 故障信息提取 数据压缩 

分 类 号：TM76[电气工程—电力系统及自动化] TN911.7[电子电信—通信与信息系统]