The Harmonic Analysis Based On Wavelet Transform And Add Window Fourier

With the rapid development of economy and the wide application of the new power electronic equipment, power quality problems become the important problem of power supply system and common user attentioned. People is not only to concern the traditional sense of the power supply reliability, stability and various parameters deviation from nominal value problems, such as oscillation and pulse on today, paying attention to the phenomenon of the dynamic disturbance up. To improve power quality, we must establish the power quality monitoring and analysis system, according to various disturbance on proper inspection, identification and classification. This thesis mainly discussed the power quality analysis, especially for harmonic analysis of the common problems, and in the light of these problems, this paper puts forward a method:First of all, This thesis briefly introduces the power quality analysis in the domestic and foreign development situation, and i n the study status of the stage.Secondly, this paper introduces the analysis of power quality, especially for harmonic analysis, the basic theoretical knowledge and common analysis method, and the method of theoretical basis briefly. Then, based on some analysis and research of conventional methods, this paper puts forward a comprehensive and based on Hanning window Fourier transforms and wavelets transform analysis method in solving the problem of harmonic analysis. In this scheme, using a combination of window function-cosine—hanning window function. For the steady state electric power signal harmonic, the window function with fast Fourier transform is united in wedlock; for unsteady harmonic, the wavelet analysis based on the maximum detection method is used. In the last, this paper give an example to simul a, and the result show that this method in time domain and frequency domain possess good detection performance, and it can accurate get steady state of frequency and phase harmonic, portray the signal singularity change characteristics, know the short time of since interference and disturbance of degree. The practicality of this algorithm is proved by PV11.0of power quality analyzer.Finally, this paper simply conclud the research prospect of the power quality analysis and harmonic analysis, and the place still need to perfect, and to prospect the subsequent research work.