基于谱序列变换的高精度谐波参数估计算法

High-precision harmonic analysis is the premise of harmonic pollution control in the power system. Due to the influence of spectrum leakage, the classical harmonic parameter estimation algorithms have some disadvantages, such as low accuracy of parameter estimation and high computational complexity.Based on the analysis of spectral line attenuation characteristics, a high-precision harmonic analysis algorithm based on spectral sequence transformation was proposed. The algorithm performed a specific weighted transformation on the spectral sequence obtained via fast Fourier transform(FFT), which accelerated the attenuation rate of spectral lines at the unreal frequencies, and thus effectively suppressed the spectrum leakage. Based on this, an effective estimation method of harmonic amplitude and phase was proposed. The results show that, compared with the classical windowed interpolation algorithm and the improved FFT algorithm, the proposed algorithm in the paper improves the accuracy of parameter estimation significantly, and shows excellent performance when the fundamental frequency changes or inter-harmonics exists. In addition, compared with the classical windowed interpolation algorithms, the proposed algorithm only needs simple processing of spectral sequence, and has the advantage of low computational complexity.