An accurate harmonic parameter estimation method based on Slepian and Nuttall mutual convolution window

Abstract Harmonic is one of the most prominent power quality problems in the power system. Accurate estimation of harmonic parameters is an important reference for electric utilities and users to evaluate power quality. In this paper, a new window named Slepian and Nuttall mutual convolution window (SNMCW) is proposed. The SNMCW is constructed through the mutual convolution between the Slepian window and the Nuttall window to realize excellent sidelobe behaviors for accurate harmonic estimation. By making use of the smaller sidelobe level and faster sidelobe decaying rate of SNMCW and combining double spectral lines interpolation correction, parameters of each harmonic can be accurately obtained with fitted polynomials derived previously. Compared with the algorithms based on some other windows, the proposed algorithm has a higher estimation accuracy without additional computation and can be easily implemented in embedded systems. Moreover, because the spectrum leakage is more effectively suppressed, the proposed method is very suitable for the estimation of the parameters of weak harmonic components. The effectiveness and feasibility of our method are verified by computer simulations and practical experiments.