ANALYSIS OF THE INTER-AREA MODE PHENOMENON IN POWER-SYSTEMS FOLLOWINGLARGE DISTURBANCES

This paper deals with the analysis of the inter-area mode phenomenon i n stressed power systems following large disturbances. It is shown tha t the inter-area mode phenomenon could occur as a result of a nonlinea r interaction of the natural modes of oscillation in the system. A tec hnique to determine the interaction is developed and the machines part icipating in the interaction are identified. A procedure to predict th e onset of the inter-area mode is presented. The analysis and the proc edure developed are tested on two systems: a 50-generator system and a 126-generator system.