This paper deals with the problem of the Instantaneous Frequency (IF) estimation of power systems, to be adopted for example in Phasor Measurement Units (PMUs) used for monitoring, control, and protection.
The main target is to provide an accurate estimation of power system frequency in real time with minimum delay. We introduce a novel algorithm based on Gabor transform for the estimation of the instantaneous frequency. Also we review a number of frequency estimation algorithms dealt with in the literature, namely the Zero Crossing algorithm, The Three-level Discrete Fourier Transform algorithm and the Differential Evolution algorithm. Simulation tests are made to compare the relative performance of the 4 algorithms. These tests include stationary frequency, the tracking of a changing frequency, the case when both frequency and amplitude are time varying, and also when the signal contains harmonics, white noise or DC component. Simulation tests revealed that under these conditions Gabor Algorithm provided the lowest Root Mean Square Error (RMSE) almost in all cases. It takes Gabor Algorithm a frame of 4 cycles or less with a sampling rate of 200samples/s to estimate the instantaneous frequency precisely. By overlapping the frames an accurate estimation can be even deduced each cycle. Zero RMSE is achieved by Gabor algorithm for stationary frequency case, under the above conditions of sampling rate and number of cycles