High Precise Harmonic Analysis Based on Auto-increase Frequency and Zeroing Spectral-Line Amplitudes

This paper describes two high precise harmonic analysis methods to find and analyze the harmonics of complex power network signals accurately and completely, the first one analyzes the harmonics by setting appropriate loop variant to make the frequency increase automatically, the second one zeroes spectral-line amplitude to analyze the harmonics. Four-item Nuttall window and triple-spectrum-line interpolation algorithm are chosen to improve the precision of two methods in this paper. The precision of the two methods under the stable fundamental frequency are studied, and the precision of the two methods under fluctuant fundamental frequency is also researched.