Investigation of modal interaction and its effects on control performance in stressed power systems using normal forms of vector fields

This paper presents a systematic scheme to evaluate nonlinear modal interaction in a power system with excitation control and determine the effect of the interaction on control performance using the normal forms of vectors fields. The proposed approach has been applied to a two-area, four-generator system. The results obtained showed that the control modes have significant interaction with the inertial modes, especially with the so-called interarea modes. The nonlinear interaction between modes following the excitation of certain specific modes could result in a detrimental effect on control performance when the controls are designed based on purely linear analysis