Methodology for activation of flexible resources and BESSs for optimal voltage support in medium voltage distribution grid

This paper introduces an innovative approach for the optimal utilization of flexible resources in voltage control, thereby mitigating the need for immediate power system upgrades in distribution grids facing voltage challenges. The proposed methodology focuses on pre-planning the activation of the most cost-effective flexible resources 24 hours in advance, based on load and generation predictions and a market for flexible resources. An Optimal Power Flow (OPF) problem is designed to minimize the overall cost incurred by flexible resources, Battery Energy Storage Systems (BESSs) managed by the Distribution System Operator (DSO), and distribution grid losses, all while adhering to voltage and current constraints. The costs associated with the degradation of BESSs due to cycling are accounted for using a nonlinear and adaptable function. Additionally, the paper elucidates a method for real-time updating of the OPF results, triggered by instances such as exceeding voltage or current limits or updates in load predictions. The methodology has been validated across various 24-hour scenarios on a reference grid and has demonstrated a significant reduction in costs for flexible resources incurred by DSOs.