1. A digital rate of change under frequency protective relay for power systems;Widrevitz;IEEE Trans.,1977
2. A new FFT-based digital frequency relay for load shedding;Girgis,1981
3. A new measurement technique for tracking voltage phasors, local system frequency, and rate of change of frequency;Phadke;IEEE Trans.,1983
4. Under-frequency protection of the Ontario Hydro System;Berry,1970
5. Optimal estimation of voltage phasors and frequency deviation using linear and non-linear Kalman filtering: theory and limitations;Girgis;IEEE Trans.,1984