Analysis of the inter-area mode phenomenon in power systems following large disturbances

The authors analyze interarea mode phenomena in stressed power systems, following large disturbances. It is shown that the interarea mode phenomenon could occur as a result of a nonlinear interaction of the natural modes of oscillation in the system. A technique for determining the interaction is developed and the machines participating in the interaction are identified. A procedure for predicting the onset of the interarea mode is presented. The technique was tested on two realistic sample test systems: a 50 generator system and a 126 generator system. The results of this analysis indicate that the procedure can detect the onset of the interarea mode phenomenon and also detect the machines which participate in the interacting natural modes of oscillation