Optimization of the Integration of Electrochemical Energy Storage to Improve the Energy Efficiency of Distribution Networks

The paper investigates the process of placing electrochemical energy storage (EES) in the primary networks of distribution system operators (DSOs). They are used to reduce peak loads on power grids and, as a result, reduce costs for purchasing electricity on the energy market, decrease electricity losses and improve voltage quality. It is shown that the optimization of EE connection points, their capacity and maximum charge/discharge power is associated with algorithmic difficulties. Due to the complexity of the efficiency indicator, it is necessary to apply complex optimality criteria and take into account active constraints. In addition, the investment climate in Ukraine, trends in the development of distribution networks and market mechanisms cause uncertainty in decision-making. The paper proposes a formalized formulation of the problem of optimizing the integration of EEs into distribution networks, and also develops a method for solving it. The obtained solutions increase the efficiency of planning investments in the development of energy storage systems, in particular, taking into account technical limitations on the part of DSOs, which contributes to their effective interaction with storage system operators (SSOs). To simplify the problem formulation, its decomposition was used, and to solve it, the method of ideal current distribution (by electricity losses). The results of the study show that this optimization problem can be reduced to a simpler problem — calculating current distribution in an equivalent circuit of electrical networks with active resistances. Economic factors are taken into account by introducing fictitious resistances into the equivalent circuit. Such an optimization algorithm is characterized by a smaller number of calculations and high reliability of obtaining a solution close to the extreme. Taking into account trends in pricing, consumption and generation of electricity over long periods contributes to the formation of justified design decisions for the integration of ENE into distribution networks.