Accurate Dynamic Phasor Estimation Based on the Signal Model Under Off-Nominal Frequency and Oscillations

Accurate and fast estimation of power system phasors is the key to reliable operation of power system and its control/protective equipment. There have been many studies on phasor estimation techniques under dynamic and transient conditions. Although the performance under dynamic conditions of estimators based on the static phasor model has improved, significant errors still exist during large dynamic deviations. Two fast and precise dynamic phasor estimation algorithms under power system oscillations and off-nominal frequency conditions are described in this paper. The methods use the signal model under these dynamic conditions, linearize them by using Taylor's series expansion, and estimate the phasor using least squares technique. Frequency and its rate of change are also calculated using adjacent phasors with minimum complexity. Results obtained show that the performance errors of the proposed methods are way below the minimum requirement of the standard and better than other similar dynamic phasor algorithms.