Analysis of Harmonic and Inter-Harmonic Based on Hilbert-Huang Transform

To analyze harmonic and inter-harmonic accurately is significant to the stability of power system. The Hilbert-Huang transform (HHT) is adopted to analyze harmonic and interharmonic in order to overcome the shortcoming of FFT method and wavelet analysis method. The power quality signals are decomposed by empirical mode decomposition (EMD) method, and then a series of intrinsic mode function (IMF) are obtained. Owing to different IMFs correspond to different harmonics and inter-harmonics, all harmonics´ amplitudes, frequencies and phases can be achieved via Hilbert transform plus Least Square fitting, to realize accurate analysis of power system harmonic and inter-harmonic. The method has high precise and is satisfied to analysis power system harmonic and inter-harmonic.