The multi-weighted interpolation FFT is a commonly algorithm of harmonic analysis for power systems. However, there are deficiencies in suppressing inter-spectral interference and broadband noise. This paper proposes a novel two-weighted interpolation DFT harmonic algorithm based on spectrally-resolution adaptive. Based on the influence mechanism of window function and interpolation method on inter-spectral interference error and wide-band noise error of the algorithm, the spectral interference of the fundamental wave to the harmonic calculation is adaptively suppressed by the spectral resolution, and the whole harmonic is obtained by the multiplication of the frequency, so as to avoid the error caused by the interpolation calculation of the harmonic. The simulation results verify that the algorithm has a better precision compared with two-weighted interpolation FFT and three-weighted interpolation FFT algorithm.
Keywords：Multi-weighted interpolation DFT, Interspectral interference, Broadband noise, spectrally-resolution adaptive, Frequency multiplication