Robust Frequency, Phase, and Amplitude Estimation in Power Systems Considering Harmonics

Efficient and accurate estimation of voltages and currents is essential for the control of electrical grids, particularly microgrids. In this paper, we present a novel two-step framework to estimate these parameters for both single-phase and three-phase power systems including harmonics and interharmonics. After employing a harmonic version of the Aboutanios and Mulgrew (HAM) estimator, the fundamental frequency and phase estimates are further refined by a weighted least squares (WLS) estimator. The WLS refinement step takes advantage of the harmonic and interharmonic relationships to further improve the parameter estimation from the HAM step. Consequently, the proposed HAM-WLS method maintains accuracy even in electrically-noisy environments that are also contaminated with both harmonics and interharmonics. Results from both simulated and real data under various power system conditions verify that the HAM-WLS estimator outperforms state-of-the-art estimation methods in terms of accuracy, complexity and convergence.