Algorithm of DFT Phasor Measurement based on Frequency Tracking

In the case of power signal frequency deviation, traditional discrete Fourier transform (discrete Fourier transformation, DFT) is used to realize synchronous phasor measurement, which will cause fence effect and spectrum leakage, and seriously reduce the accuracy of the calculation. For this reason, an improved modified DFT algorithm for phasor measurement is proposed in this paper. Firstly, the frequency tracking algorithm is introduced, which is used to calculate fundamental frequency. Then the DFT error mechanism in the non-synchronous sampling is analyzed. The functional relation between the amplitude and phase errors and frequency deviation is obtained. A method of reducing spectrum leakage is proposed and the amplitude and phase errors expressions are improved. Finally the performance of the algorithm is tested by different signal models and actual data. The simulation results show that the proposed algorithm meets the accuracy requirements of synchronized phasor measurement.