Estimation of power system dominant modes

The aim of this paper is to propose an approach to estimate the nature (damping and frequency) of a dominant mode. The suggested method, based on Prony analysis, aims to directly evaluate dominant modes of electromechanical oscillations. The basic idea is to fit the given oscillation with a fitting function having one mode only whose parameters need to be identified by any identification process. When the transient of the given signal vanishes, modes having high damping attenuate reaching a quasi linear behavior and revealing the dominant mode only. In this sense, the fitting function gains characteristic parameters (damping and frequency) of the dominant mode. For the identification process we suggest a nonlinear analysis approach based on the Lyapunov method applied to the Sensitivity theory. The proposed methodology is tested on the New England 39-bus system.