Optimal Placement of Grid Battery Energy Storage Systems for Congestion Mitigation and Enhanced Power‐Flow Control Considering Uncertainties in Photovoltaic Deployment

Amidst the global drive toward carbon neutrality, the integration of large‐scale photovoltaic (PV) systems introduces significant challenges related to grid congestion. Battery energy storage systems (BESSs) are increasingly recognized as an effective solution for addressing these challenges and improving grid operations, especially under the management of grid operators. However, given the substantial investment and immobility of BESSs, determining their optimal placement and capacity while considering future PV‐deployment uncertainties is crucial. Moreover, selecting locations that satisfy grid constraints and offer multifunctional contributions is desirable. One promising approach is to select sites where the voltage impact of battery charging and discharging is minimal, which is expected to enhance BESS flexibility in output regulation. Therefore, this paper considers multiple PV‐deployment cases to simulate high PV penetration that induces grid congestion in distribution networks, and evaluates optimal BESS sites—selected from candidates satisfying operational constraints—based on voltage margins relative to the acceptable range. Additionally, the study examines the interplay between optimal BESS positioning, the distribution of load and PV systems, and overall power‐flow dynamics. Numerical simulations using a rural feeder model from CREST 126‐feeder model are used to quantitatively assess the impact of BESS sites on voltage margin while satisfying constrains. © 2025 The Author(s). IEEJ Transactions on Electrical and Electronic Engineering published by Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.