基于并行隐马尔科夫模型的电能质量扰动事件分类

Parallel hidden Markov model based classification of power quality disturbance events

为满足电能质量扰动准确分类的需求,提出了一种基于极大重叠离散小波变换(MaximalOverlapDiscrete WaveletTransform, MODWT)和并行隐马尔科夫模型(ParallelHiddenMarkovModel, PHMM)的电能质量扰动分类方法。首先利用MODWT提出一种实用的电能质量扰动检测算法,该算法无需设定检测阈值,可准确获取扰动时段的起止时刻。接着提取扰动时段的电压谐波成分并组成特征向量。然后用PHMM分类器对扰动信号进行分类识别。PHMM方法克服了人工神经网络方法收敛性较差、训练时间较长的缺陷,使分类器性能大大提升。通过应用于现场实测扰动数据表明,所提出的方法适用于多种类型的电能质量扰动检测,分类正确率高,训练速度快,具有良好的应用价值。

In order to meet the requirements of accurately classifying power quality disturbances,a method for power quality disturbance classification is proposed based on Maximal Overlap Discrete Wavelet Transform(MODWT)and Parallel Hidden Markov Model(PHMM).Initially,a practical power quality disturbance detection algorithm is proposed by using MODWT.This algorithm can obtain the disturbance beginning and ending time accurately without setting detection threshold,from whose results the voltage harmonic components of power quality disturbance are extracted and used to form feature vector.Then,PHMM,as a classifier,is used to identify power quality disturbances.PHMM method solves the problem of poor convergence and longer training time for Artificial Neural Network(ANN)method,and thus the performance of the classifier is greatly improved.The test results based on power grid field data show that the proposed method is suitable for detecting various types of power quality disturbances,and it is characterized by high recognition correctness and less training time,and it will find extensive application.