A spectral correction approach for harmonic/inter-harmonic analysis based on the odd points´ interpolation

Discrete Fourier Transform (DFT) is one of the most commonly used techniques for harmonic and inter-harmonic analysis in electric power system. However, the asynchronous sampling will cause spectral leakage and fence effect on each component of the signal in the frequency domain. Traditional interpolation approaches commonly use specific window with better spectrum characteristics to restrain the leakage interferences among all the components and use spectral lines´ interpolation to conquer the fence effect. Different from the traditional approaches, a new spectral correction approach for harmonic and inter-harmonic analysis is presented in this paper. It solves the two drawbacks of the DFT by simply odd points´ interpolation without applying any windows, and can locate all the components accurately. The simulation results indicate that the proposed approach is not only adapted for leakage elimination, but also adapted for the extraction of weak components.