Dynamic Estimation Algorithm for Modulation Frequency under Off-nominal Frequency and Oscillations

Due to the wide use of power electronic devices in power systems, low-frequency oscillations and disturbances lead to a rapid decline in the accuracy of phasor measurement units (PMUs). As a result, it takes obstacles to identify and suppress oscillations effectively. In this paper, a Taylor series-based dynamic phasor measurement model is proposed for estimating the modulation frequency directly. Firstly, Taylor series is employed to characterize the supplied signal. Secondly, the least square method (LSM) is applied to estimate the various parameters of the signal, especially to estimate the modulation frequencies. Finally, the simulation results are presented to verify the advantages of the proposed algorithm in providing accurate measurement results under the conditions with off-nominal frequency and oscillations.