The Detection And Application Research Of Power Quality Based On Wavelet Analysis

In recent years, with the rapid development of power electronic technology, large number of the nonlinear load and high-tech equipments, which have high efficiency and good performance but sensitive to changes in the power characteristics, begin geting wide application in power system, power quality is becoming increasingly serious. Perfect power quality monitoring and management system is a necessary and positive and effective measures to improve power quality, and it is the essential premise and basis for which to detect and locate the power quality disturbances.Firstly, this paper introduces the research background and significance of the project, and explains the concept of power quality, standards and classification of various power quality problems in detail. Then, describes and discusses the power quality analysis method and its application, and gets the basis of power quality analysis by wavelet transform.By using the nature of which wavelet analysis can detect mutations, this paper describes the detection methods and theories about transient power quality in detail, and makes detailed and careful description and simulation of five common phenomenon of transient power quality. It can be proved that the starting and clothing time of disturbances singals can be detected accurately and real-timely through the matlab simulation, as the basis of transient power quality disturbances evaluation and treatment. On the other hand, it is realized to achieve the separation of the envelope signal by the multiresolution analysis theorem of wavelet transform, and good at tracking the flicker trends preferably. The harmonic is one of the the most extensive research aspects in steady-state power quality, it overcomes the shortcoming that the traditional Fourier transform can't analyse time-frequency features simultaneously, in addition, it can detect the harmonic composition and properties in more detail. This paper proves the effectiveness of this method through the matlab simulation.Finally, this paper describes the wavelet analysis of power quality signals by using the method of combining digital filter and its PC software with wavelet toolbox in practical engineering applications, and discusses the practical value of wavelet analysis.