Low frequency oscillations in large power grids

Oscillations are inherent to power systems and the analysis of such phenomena is a fundamental issue for understanding the dynamical behavior of power networks. Knowledge of the system natural frequencies and its associated damping ratio, is useful information for understanding the system performance after being subjected to a disturbance. Topological changes in the transmission network of electrical power systems are quite common due to operational requirements. Such changes may drastically modify both frequency and damping values of the natural oscillation modes. In this paper, identification of the dominant oscillation modes in the Mexican power system is performed using both modal analysis and time domain simulations.