Normal modes and mode shapes applied to dynamic stability analysis

A power system of n generators has n-1 normal modes of oscillation. If any of these modes is poorly damped, persistent or disruptive oscillations may occur. Knowledge of the normal modes and mode shapes of a specific system provides important insight into its dynamic behavior. Calculation of normal modes and mode shapes yields data that permits a systematic approach to dynamic stability Studies. The theoretical basis for normal mode analysis of power systems is presented. Methods for calculating normal modes and mode shapes are described, with illustrations to small systems. Techniques for simulating normal modes for the analysis of mode damping are shown. A companion paper describes the application of modal analysis to a large area in the MAPP system.