In this work, electromechanical oscillations in single-area power systems can be effectively reduced by the influence of energy storage unit, and it helps in the load leveling process and performance improvement of the system. This proposed paper describes the application of super magnetic energy storage (SMES) unit and redox flow battery (RFB) in single-area non-reheat, single, and double reheat thermal power system. The commonly used industrial PID controller act as a control strategy and the optimal gain values are obtained using three different cost functions with stochastic particle swarm optimization technique (SPSO). The dynamic performance of the investigated power system is obtained and examined with one percent step load perturbation.