基于小波包变换的电压骤降信号分析

电压骤降是暂态电能质量问题中最常见的现象,对其进行准确的检测是控制和治理的前提。小波包变换是小波变换的进一步完善和发展,其均等划分频带特性使之具有比小波更好的时频分辨率。利用此特性,信号被分解到小波包平面,根据有用频带信息,提取电压骤降信号的特征分量;对信号中混有噪声和数据量过大的情况,利用软阈值法同时进行去噪和压缩处理,并对调节系数对软阈值法处理的影响进行了分析。仿真结果表明,小波包变换也是分析电压骤降信号的一种有效方法。

Voltage sag analysis based on wavelet package transform

Voltage sag is the most familiar problem in power quality transient, and its detection is the precondition of monitoring and restraining.Wavelet package transform with better time-frequency resolution is developed on the wavelet transform. The signal is decomposed on the wavelet package plane and the characteristic weights of voltage sag can be achieved using available information. As for the voltage sag interfered with noise and overmuch data, this paper presents the soft-thresholding method for the de-noising and compression, and analyzes the effect of adjustable coefficients to this method. The simulation results show that wavelet package transform is also useful in analyzing the voltage sag.