A Complementary SVC-Based Controller Design for Damping Both Local and Inter-Area Oscillating Modes Using NSGA-II Algorithm

Abstract

Static Var compensator (SVC) is one of flexible AC transmission system (FACTS) elements mainly used for reactive power and voltage control in power systems. This paper deals with multi-modal electromechanical oscillations damping in the presence of severe disturbances. These oscillations include local modes, inter-area modes and inter-plant modes. To enhance the damping of the oscillations, the complementary controller is added to voltage regulator of SVC. In order to design such a controller, as a significant contribution of this paper, either of oscillating modes is considered as a distinct objective function and a multi-objective optimization model is employed to improve all these oscillating modes simultaneously. Accordingly, in this paper, the non-dominated sorting genetic algorithm-II (NSGA-II) approach is used to optimize all the parameters of complementary controller with the aim of minimizing all three objective functions. By applying NSGA-II method 10 non-dominated solutions are generated, and a fuzzy method is utilized to select the best compromise solution among the produced solutions. The well-tuned complementary SVC-based controller is examined on a two area power system and results obtained through simulating different cases illustrate the robustness and the efficiency of the proposed controller.