The multi-weighted interpolation FFT is a commonly algorithm of harmonic analysis for power systems. But, there are deficiencies in suppressing inter-spectral interference and broadband noise. This paper proposes a new harmonic analysis which is a two-weighted interpolation DFT algorithm based on spectrally-resolution adaptive. This paper analysis the relationship between the window function, the weighted interpolation method and the error of MWIpDFT algorithm. This paper suppress spectral interference of fundamental waves in harmonic calculation based on spectrally-resolution adaptive, and avoid the increase of error caused by interpolation and harmonics based on multiplier inverse estimation of the entire harmonic. The simulationresults have verified that the algorithm has a better precision than both two-weighted interpolation FFT and three-weighted interpolation FFT algorithm.
Keywords：Multi-weighted interpolation DFT, Interspectral interference, Broadband noise, spectrally-resolution adaptive, Frequency multiplication