Influence of the Load Models in the Dynamic Voltage Stability of an Electric Power System

Abstract

Voltage stability plays a very important role during the planning and design stages of an electric power network as well as during the system operation. In the last years in various countries worldwide, several power network collapses (blackouts) caused by voltage problems have been reported. This can be produced by a lack of sufficient reactive power reserve during heavy load or by the occurrence of severe contingencies. In this paper it is studied and analysed the influence of the load models in the dynamic voltage stability assessment of an electric power system. It was used the BPA test power network. A severe contingency situation was simulated to perform the study. The automatic voltage regulators of the generating units and the turbine speed governors were modelled as well as the transformer taps. The simulation results were obtained using the commercial transient software package EUROSTAG. Finally some conclusions that provide a better understanding of the voltage collapse phenomena are pointed out.