Study on electromechanical dynamic of power systems based on trajectory eigenvalue sensitivity

Traditional small disturbance analysis method and eigenvalue sensitivity (ES) are unable to accurately analyze the electromechanical dynamic characteristics of power systems. Based on trajectory eigenvalue method, the power system models are linearized at non-equilibrium points (NEPs) and the trajectory eigenvalues are calculated. With the changes of trajectory eigenvalues, the factors affecting oscillating amplitude and oscillating period are studied. Combined trajectory sensitivity (TS) with ES at equilibrium points (EPs), the trajectory eigenvalue sensitivity (TES) is proposed and calculated by numerical perturbation method. Based on the WECC 3-machine 9-bus system, the influence of disturbance size, disturbance duration, the generator´s inertial and damping upon trajectory eigenvalues are analyzed. The TES to system parameters are calculated and the trajectory eigenvalues of different parameters are analyzed on different time sections. Finally, the advantages for TES than ES at EPs are verified in terms of research electromechanical dynamic characteristics.