Application of Combinational Adaptive Load Shedding Schemes to Improve Power System Voltage Stability - Part II: Simulation Results

paper is part II of a two-part paper. In the first part, several adaptive combinational load shedding schemes were proposed to enhance the power system voltage stability. The main objective of the proposed schemes is to improve the voltage stability margin of the system following large and combinational disturbances. For major disturbances the frequency and voltage stability of the system are jeopardized simultaneously and the conventional schemes might fail to operate correctly. In this part, the proposed methods are simulated in a real network to evaluate their performance. To achieve realistic results, dynamic model of generators, automatic voltage regulators, governors and loads are considered in the simulations. Considering the importance of load modeling in these studies, the frequency and voltage dependence of static loads have been modeled accurately. Dynamic motor loads have also been modeled using aggregate equivalent induction motors at load buses. Performance of the proposed schemes is compared with each other also with performance of the conventional scheme for various combinational disturbances. Considering the obtained simulation results it is concluded that by using the proposed algorithms the power system becomes more robust against large disturbances and the probability of the power system instability is decreased.