Optimization of Centralized Control of Volt/Var in Transmission Systems Based on Economic Dispatch and Harmony Search Algorithm

Maintaining the voltage profile of the power system within the appropriate bound has been a key factor for the proper operation of system equipment, especially during disturbances. However, due to the uncertainty of the load powers and the limitation in equipment ratings, achieving this goal has become a challenge. High voltage substations play an important role in voltage control, because these substations can be a primary connection point between the high voltage transmission network and the distribution system. The nature of local voltage control, the variety of control tools and the interaction between them, have made this type of control difficult. In this paper, a centralized voltage/reactive power control method is presented based on phasors measured by PMUs installed in grid substations. In this method, the tap changing of transformers and step switching of capacitor banks have been determined by the central controller based on system voltages and network equations. In addition, the appropriate values of the operating point of the generators have been carried out based on economic dispatch in each period of optimization. The consistent and efficiency of the proposed method have been investigated through simulation in MATLAB software environment.