| Recently, with the widespread application of various kinds of electrical and electronic devices (mainly some non-linear equipment), harmonics pollution is becoming more and more serious, which contain harmonics and massive inter-harmonics. Inter-harmonic is a kind of the harmonics which are not an integer of the fundamental frequency component. Harmonics and inter-harmonics cause power quality to come down and different kinds of faults and accidents to happen often. So, harmonic for the detection and analysis is very necessary.Harmonic Wavelet is newly proposed and becomes a new signal-processing tool. With the launching on the spectrum of wavelet, the harmonic wavelet is structured, which has strict box-like spectrum and simple function expression. Wavelet divided into dyadic harmonic wavelet and generalized harmonic wavelet. It has a fast algorithm based on the Fast Fourier Transform (FFT) and its inverse transform (IFFT), which can be realized in the numerical. The algorithm has characteristics of faster speed and higher precision and better practical value.The harmonic wavelet widely applied in mechanical vibration area, is adopted in this paper to deal with the harmonic and inter-harmonic problem in power system., in view of its ability of detail frequency section. Firstly, in order to reduce the impact of Gibbs phenomenon in spectrum, a step of adding window process is employed. And then, the harmonic signal is decomposed by harmonic wavelet transform (HWT) and the instantaneous amplitude and phase of harmonic components are identified; furthermore, in order to increase accurate, the amplitude and phase of each harmonic components are calculated by least squares fitting method.Numerical results show that the presented approach is an effective one with high accuracy.
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