Complex Harmonic Detection Based on MSLD Self-multiplication-convolution Window

High precision detection of complex harmonics is a very challenging task in smart grid signal processing. The interpolated discrete Fourier transform (DFT) method is widely used to accurately detect the harmonics in the power grid. However, due to the influence of spectrum leakage and fence effect, the detection accuracy of these algorithms in complex applications such as complex mulifrequency harmonics and sub/super-synchronous harmonics still needs to be improved. In this paper, a self-multiplication-convolution window function based on the maximum sidelobe decay (MSLD) window is proposed, which has more excellent sidelobe performance than the original MSLD window. In addition, to further reduce the complexity, a simple formula for four-spectral-line interpolation based on the proposed window is derived for the high accuracy estimation of harmonic parameters. Simulation experiments are carried out in different complex signals, and the results show that our method has higher detection accuracy compared with other window function interpolation algorithms.