Hierarchical Optimal Allocation of Battery Energy Storage Systems for Multiple Services in Distribution Systems

This paper addresses the optimal allocation of battery energy storage systems (BESS) in radial distribution systems for bus voltage regulation and energy cost reduction. A hierarchical planning model is proposed to obtain the optimal configuration (number, locations, and sizes) of BESS. The three interacting levels in the proposed model are: (1) determination of the optimal BESS number; (2) use of a heuristic strategy based on voltage sensitivity analysis to select the most effective locations for a given BESS number in the network; and (3) sizing the BESS capacity to realize optimal operation objectives. The final BESS configuration is selected based on minimization of total life cycle cost, which takes into account the investment cost, residual value of BESS, and system operation cost. The voltage regulation objectives are modeled as constraints. The proposed method reduces computational burden significantly and provides a comprehensive sensitivity analysis and locate the most effective buses to mitigate voltage violation. The effectiveness of this optimal allocation method was demonstrated for a modified IEEE 15-bus and IEEE 69-bus distribution network.