Effects of the exponentially decaying DC offset in the phasor estimation algorithms performance

This article aims to evaluate the performance of phasor estimation algorithms used in digital relays concerning immunity to the effects of the exponentially decaying dc offset, steady state response and sampling frequency. The algorithms: full cycle Fourier, modified Fourier, cosine filter, modified cosine filter and full cycle Fourier associated with adaptive mimic filter were compared. Two groups of signals were used in the evaluation of the filters: analytical signals and signals obtained by simulations in the software Alternative Transient Programs (ATP). In the evaluation, the adaptive mimic filter associated with Fourier of one cycle had the best performance.