Harmonic detection and de-noising based on Db37 wavelet

Abstract. The existence of the harmonic seriously influences the quality of the power grid electricity.In order to guarantee the safe operation of power system, it must be accurately detect harmonic and analysis harmonic components in the grid.Usually harmonic signal consists of fundamental wave, every harmonic and noise component. The noise will seriously affect the processing precision of the harmonics in power system. In this paper, the harmonic signal’s detection is based on Mallat algorithm of multi-resolution analysis and the de-noising method is select wavelet threshold.Through Matlab simulation, using Db37 wavelet transform is realized on the system harmonic signal detection and separation of the signal frequency components in the system. The simulation results show that wavelet transform has good time-frequency features so it can effectively restrain and eliminate noise