Noise Analysis on Frequency Shifting and Filtering Algorithm-Based Phasor Estimator

The estimations of amplitude and phase are of great importance in the synchronous phasor measurement for power systems. In addition to the off-nominal frequency, the amplitude and phase estimations accuracy level of the power system signal is affected by the inevitable noise. In this article, the effect of white noise on amplitude and phase estimations provided by DFT-based frequency shifting and filtering algorithm (FSF) is analyzed. With the help of the equivalent weighting filter's merits, i.e., equivalent noise bandwidth and overlap correlation, the FSF-based amplitude and phase variance expressions are derived theoretically by considering the overlap of two processed samples. The effectiveness of the proposed amplitude and phase variance expressions are verified through computer simulations.