High-accuracy, wide-range frequency estimation methods for power system signals under nonsinusoidal conditions

Summary form only given. A numerical differentiation based algorithm(NDBA) for high-accuracy, wide-range frequency estimation of power systems is proposed in this paper. The signal includes up to 31-order harmonic components. Using the central numerical differentiation of multi-points on the basis of Lagrange interpolation, the estimated frequency of non-sinusoidal signals of power systems can be measured at an accuracy of 99.999% over a wide range of from 10 Hz to 100 Hz with fundamental amplitude varying from 100 V to 300 V and with fundamental phase angle varying from 0 to 360. The proposed algorithm needs at most 2 cycles or 40 ms for estimation of frequency over 40 Hz to 60 Hz, and needs at most 3 cycles or 60 ms over 10 Hz to 40 Hz or 60 Hz to 100 Hz. Using Matlab software, the simulation results of the test example are satisfactory.