REACTIVE POWER MARKET MODEL BASED ON THE DIVISION OF THE ELECTRIC POWER SYSTEM INTO VOLTAGE ZONES AND ON THE TWOLEVEL OPTIMIZATION ALGORITHM

Abstract

The article presents a reactive power evaluation methodology which in terms of time comprises the action of the reactive power market in the stage of short-term planning. The methodology is based on the division the electric power system (EPS) into voltage zones by using the electrical distance method, whereby local reactive power markets are established. Within each local market a separate TSO cost optimization is performed by means of the optimal power flow applying the criterion of minimal required payment for reactive power. The said optimization is the first step within a developed methodology, the purpose of which is to determine the share of each of the available control systems in reactive power generation within each of the established zones. Based on optimal reactive power generation, an auction procedure is conducted by which a uniform price of reactive power generation within a zone is defined. In the second optimization step the optimization of the whole network is carried out by the criterion of minimal energy procurement costs to cover the network losses and simultaneously by the criterion of minimal reactive energy procurement costs, using the optimal power flow. The methodology has been tested on the Croatian EPS model for the maximum network load scenario. The proposed approach is warranted by the results, whereas the detected problems can at once serve as guidelines for future development and potential improvements in the proposed methodology.