Digital and experimental study of voltage collapse and instability in power system

A model of a power system with load dynamics is studied by investigating vo ltage collapse phenomena and sustained oscillation with a fast exciter. In the case of voltage collapse, the reactive power demand at a load bus is sl owly increased until the voltage magnitude sharply falls to a very low leve l. In the case of instability and sustained oscillation, the small signal v oltage instability is studied at a particular point with a fast exciter hav ing hard limits. It is shown that the divergent response eventually results in sustained oscillations when hard limits in the fast excitation system a re imposed. The paper presents both digital simulation and experimental res ults. A brief introduction to bifurcation theory is also included in the pa per for completeness. (C) 2000 Elsevier Science Ltd. All rights reserved.