Comparison between Centralized and Decentralized Oscillation Damping Controllers in Power Systems

In this paper, a supplementary controller for static var compensator is designed to enhance the damping of inter-area oscillation mode. Proper SVC location and stabilizing feedback signal are selected on the basis of controllability, and observ-ability, respectively. Wide-area signals, required for effective damping of inter-area oscillations, introduce practically unavoid-able time-delay that can offset effectiveness of a controller and, therefore, delay compensation is required for such applications. Deterioration of oscillation damping due to time-delay, while transporting wide-area signals, negates the advantages of using the most observable feedback signal. Moreover, employing wide-area damping control adds to the cost of the controller. Therefore, the impact of communication delay on oscillation damping is investigated and comparison is made with a decentralised control, which employs less-observable local signal.