The Study On Wavelet Transform In The Use Of Harmonics Detection Of Dissymmetrical System

Electricity is one of the most important energy sources, and the quality of electricity is nearly correlative with our lives. However, as the fast development of power electron technology, and the diversified equipment of power electron, home electrical instruments and other no-linear charges greatly increase, harmonics contamination of power system increases severity, and badly affects the quality of electricity and the safe run of power system. To insure the safe run of power system, and limit the harm of harmonics into a safe range, the harmonics of power system must be mearsured then according to its result to take necessary protection action to control its harm. Harmonics detection is the basis of harmonics problem, and is also the foundation to deal with the harm of harmonics. The harmonics detection methods based on wavelet transform are discussed in this paper. The main contents are as follows:Harmonics detection methods based on Fourier transform, instantaneous reactive power theory, artificial neural network and wavelet transform are shortly introduced and discussed, and the advantages and the disadvantages of the whole bag of tricks are compared. The main production of the whole bag of tricks are listed. The basic principium of wavelet transform based on MALLAT Arithmetic and the way to process harmonics detection by wavelet transform are introduced and discussed detailedly, the disadvantage of wavelet transform in the use of harmonics detection of dissymmetrical system is analyzed, too. The simulation system is founded by Matlab6.5, and the harmonics detection based on wavelet transform is simulated. Aimming at the disadvantage of wavelet transform in the use of harmonics detection of dissymmetrical system, a new detection method based on wavelet transform in dissymmetrical system is brought forward and simulated by Matlab, and the corresponding simulated waveforms are given.According to the new harmonic detection methods of this paper, and the signal processing power of TMS320LF2407 DSP(Digital Signal Processing), as well as the ISR(interrupt service routine), the assembler of harmonics detection based on wavelet transform is compiled. The practical detection system is founded to validate the new detection method of this paper, and the experiment waveforms are given by the waveformic function of DSP.According to the simulated and experimental results, the wavelet transform is...