A smart method makes DFT more precise for power system frequency estimation

A precise digital algorithm based on discrete Fourier transforms (DFT) to estimate the frequency of a sinusoid with harmonics in real-time is proposed. This algorithm that we called the smart discrete Fourier transform (SDFT) smartly avoids the errors that arise when frequency deviates from the fundamental frequency, and keeps all the advantages of the DFT, e.g., immune to harmonics of fundamental frequency, easily obtaining the parameters of amplitude and phase, and even the recursive computing can be used in SDFT. These make the SDFT more accurate than conventional DFT based techniques. In addition, this method is recursive and very easy to implement, so it is very suitable for use in real-time. We offer the simulation results compared with conventional DFT method and second-order Prony method to validate the claimed benefits of SDFT.