Switching control strategy for an energy storage system based on multi-level logic judgment

Abstract

Energy storage is a new, flexibly adjusting resource with prospects for broad application in power systems with high proportions of renewable energy integration. However, energy storage systems have spare capacity under stable working conditions and may be idle for some periods. These actions are primarily selected for peak shaving and valley filling, frequency regulation, and voltage regulation as the only control target; thus, energy storage cannot be used effectively, which weakens the effect of energy storage on grid support. To improve the utilization rate and economic benefits of the energy storage system and enhance the support performance of energy storage for the safe operation of the power grid, this article proposes a switching control strategy for an energy storage system based on multi-layer logic judgment to maximize energy storage benefits and ensure safe and stable power grid operation. First, this study analyzed the potential multi-ancillary service operation requirements of the energy storage system, combined with the auxiliary compensation benefits of the energy storage power station. Using this information, the study proposed a comprehensive index that considers the economy of the energy storage system and the stable operation of the power grid to support the evaluation needs of energy storage control. Based on this, the study then pre-set multi-layer judgment logic for the operation control of the energy storage system. A multi-objective judgment and smooth switching strategy for the coordinated operation of the energy storage system was proposed based on the typical operating conditions of the energy storage system participating in the grid peak shaving and valley filling, frequency regulation, and voltage regulation. This switching control method effectively utilized the idle capacity of the energy storage system and improved the energy storage system’s support effect on the power grid. Through the improved energy storage control model based on MATLAB/Simulink, this study also verified the effectiveness of the proposed smooth switching strategy of the energy storage system.