摘要
采用基于S变换下的模时频矩阵局部相似度对短时电能质量扰动进行分类。首先,由时频尺度缩放将各类持续时间不同的扰动特征标准化,按照各扰动特征选取其模时频矩阵特定部分,以此建立矩阵大小不一且特征明显的各类扰动标准化模板;然后计算未知扰动各局部模时频矩阵与各类扰动标准化模板之间的相似度,按照相似度最大原则将扰动进行分类。由于各类扰动在不同的时频区域高度聚合了自身特征,采用局部时频区域相似度原理大大提高了同类扰动的相似度,建立的各类扰动标准化模板之间差异明显,不使用辅助性分类器而直接实现扰动分类,且分类过程简单明确,可用于不同时间长度的扰动分类。该方法有效利用局部区域明确的时频相关性,抗干扰能力比采用全局相似度强。仿真结果表明了很好的短时电能质量扰动分类效果。
A classification method for short duration power quality disturbance based on S-transform with module timefrequency matrixes partial similarity is proposed. At first, all types of the disturbance characteristics with different duration are standardized by time-frequency scale zooming. The standard templates of various disturbances with difference size matrixes and obvious characteristics are built according to the special part of module time-frequency matrixes of disturbance characteristics. Then, comparing disturbance signal with standard template, the similarity can be calculated, and disturbances are classified according to maximum similarity principle. Due to various disturbances in different time-frequency area have a high polymerization degree in their characteristics, application of partial similarity theory in time-frequency area has greatly enhanced the similarity of same type disturbances, obvious difference among the standardized templates of different disturbances is built. So it can achieve the disturbance classification directly without using auxiliary classifier. Besides, it＇ s clear and simple, suitable for disturbances with different duration. Because the clear time-frequency relation in local area is effectively used, the method has stronger anti-jamming capability than that of overall similarity. The simulation results show that it has a good effect for classification of short duration power quality disturbance.
出处
《电力系统自动化》
EI
CSCD
北大核心
2009年第8期62-67,共6页
Automation of Electric Power Systems
基金
国家自然科学基金资助项目(50677041)~~
关键词
时频尺度缩放
S变换
局部相似度
扰动分类
time-frequency scale zooming
S-transform
partial similarity
disturbances classification
