Scenario-based optimization of battery energy storage systems in low-voltage networks with high photovoltaic penetration: A Tunisian case study using MPSO

High photovoltaic (PV) penetration in low-voltage distribution networks (LVDN) introduces several operational challenges, particularly overvoltage issues and increased power losses. Conversely, excessive load demand, especially during nighttime periods, can result in voltage sags within the LVDN. To address these challenges, this paper proposes a novel simulation-based planning framework for Battery Energy Storage Systems (BESSs) applied to an IEEE 33-bus LV network. The proposed framework utilizes realistic daily load and PV generation profiles provided by the Tunisian Company of Electricity and Gas (STEG) to accurately represent the behavior of LV distribution systems with high PV penetration, while maintaining voltage magnitudes within the permissible limits. Furthermore, the framework employs a Modified Particle Swarm Optimization (MPSO) algorithm to optimize mixed discrete-continuous decision variables, which are evaluated through 24-hour power-flow (PF) simulations. To lead with, three scenarios are developed and discussed. Scenario S1 consists of BESS placement and size optimization across all non-slack buses, while Scenario S3 optimizes BESS size and placement for only buses associated with PV generators. Scenario S2 is dedicated to optimal PV sizing at fixed PV buses. Simulation results obtained through MATPOWER/Matlab demonstrate the superiority of the first scenario with a magnitude voltage maintained in permissible range of 0.92 pu to 1.02 pu , ensuring grid reliability and stability.