Optimal Energy Storage Allocation and Network Reconfiguration in Countywide Photovoltaic Integrated Distribution Systems: A Coordinated Optimization Approach for Reactive Power and Storage Operation

With the growing penetration of county-level photovoltaic (PV) generation, distribution networks are facing increasing challenges in maintaining voltage stability, reducing network losses, and ensuring economic operation. This paper proposes a coordinated optimization framework that integrates energy storage system (ESS) allocation and network reconfiguration for distribution systems with high PV integration. The optimization jointly considers reactive power compensation and storage operation over multiple time periods, aiming to enhance system efficiency and reliability. A two-stage method is developed: the first stage determines the optimal allocation of ESS and initial network topology, while the second stage conducts timeseries operation optimization considering active/reactive power dispatch of ESS and PV. The proposed approach is validated on a modified IEEE 33-bus distribution system with real PV generation and load data. Simulation results demonstrate that the proposed method significantly reduces network losses, improves voltage profiles, and enhances the overall economic performance of the system.