Dynamic measuring of frequency and frequency oscillations in multiphase power systems

Abstract
Instantaneous system frequency is defined, and a method of frequency measurement is proposed which determines the angular velocity of the rotating voltage space phasor. Impulses in frequency caused by steps in phase are blanked out, whereas harmonics and noise are suppressed by FIR filters. Using an optimized observer-based filter, frequency modulations are split into and frequency drift and frequency oscillation signals, which can be used in power control and power system stabilization.