Low frequency oscillations in the interconnected power systems are observed all around the world. In this paper, the authors studied the inter-area mode low frequency oscillations by analyzing the phenomena in Nashville area of the Tennessee Valley Authority (TVA) system. Our study revealed 4 dynamic groups of generators in this area. Within each group, generators swing together and have the same dynamic trend. Generators from different dynamic groups swing against each other. The authors studied the possibility of using a FACTS/ESS controller to damp the low frequency oscillations in Nashville area. The active power is controlled to damp the low frequency oscillation while the reactive power is controlled to keep the local bus voltage at a constant level. The simulation results of the actual TVA system showed that the energy storage devices can be used for power system low frequency oscillation damping. The study also showed that the wide area measurements could be used as inputs for improved FACTS/ESS control
