Flexibility-Oriented Co-Planning of Renewable Generation, Network Reinforcement, Demand Response, and Battery Storage in Active Distribution Networks

Abstract

Planning network reinforcement and flexibility as separate tasks obscures when they substitute for, or complement, one another. We formulate a scenario-hour mixed-integer linear program (MILP) that selects photovoltaic and wind capacity, battery power and energy, energy-neutral demand shifting, photovoltaic-inverter reactive power, and branch-rating reinforcement under one planning budget. Every operating constraint is enforced for every scenario and hour; scenario probabilities enter only the secondary tie-breaking terms. The formulation is therefore a deterministic multi-scenario model with an all-scenario feasibility requirement rather than a conventional stochastic program. Electrical-distance zones tie flexible-demand potential to local load, root-path screening limits reinforcement candidates to electrically relevant branches, and inner polygonal limits keep the model linear. A nonlinear backward–forward-sweep alternating-current (AC) power flow then checks all 72 optimized dispatch points. On the MATPOWER case141 141-bus radial distribution system, the integrated plan accommodates 40.899 MW of renewable capacity, 5.28% more than the generation–network baseline. A capacity-matched sequential control, with the same BESS and demand-response totals, candidate set, and inverter support, accommodates 40.826 MW; the two results are effectively equivalent at the 1% MIP tolerance, showing that the larger gain over the originally prescribed sequential package includes resource-quantity and siting effects. The integrated plan adds 21.267 MVA of branch rating, 23.03% less than the generation–network baseline. All nonlinear AC operating points satisfy the 0.95–1.05-p.u. voltage band and post-investment ratings. Changing the branch-rating weight to 25% below and above its nominal value still selects reinforcement, and disabling reinforcement reduces hosting capacity by 49.35–53.19% across the tested weights. Operational flexibility improves the use of transfer capacity but does not supply sustained branch headroom.