Improving phasor measurements under power system oscillations

A comprehensive description of the phasor estimation process leads to the ideal criteria that a digital filter must fulfill in order to provide more accurate phasor estimates under power system oscillations. The raised cosine filter, widely used in digital transmission, is described and proposed to approach those criteria. Simulation results corroborate an improvement in the performance (accuracy and speed) of these phasor estimates as compared with those obtained with the Fourier-boxcar filter, commonly used in present commercial applications.