An Approach to Controlling Voltage Instabilities in Large-Scale Power Systems

Abstract

Several researchers have dealt with the problem of voltage collapse as a loss of equilibria or by noting the singularity of the Jacobian at the onset of the phenomenon. In these cases the problem is characterized as a quasi-static bifurcation occuring in response to a slowly varying increase or decrease in load. However, dynamic load characteristics have long been known to have an effect on system stability and in fact, assumptions about the load model will significantly affect any predictions. In this paper, we discuss voltage stabilities as a function of the load model. We investigate the stability characteristics of a simple basic configuration consisting of a generator, a static load, and an aggregate dynamic representation. We then describe an approach to controlling voltage dynamics by using a simple representation of a static VAr compensator as the control mechanism and applying a pointwise control strategy as the algorithm for implementing the control.