Engelmann, AlexanderAlexanderEngelmannBandeira, Maisa BeraldoMaisa BeraldoBandeiraFaulwasser, TimmTimmFaulwasser2025-02-102025-02-102025-01-07IEEE Transactions on Control of Network Systems (in Press): (2025)https://hdl.handle.net/11420/54187Safe and economic operation of networked systems is challenging. Optimization-based schemes are frequently considered, since they achieve near-optimality while ensuring safety via the explicit consideration of constraints. In applications, these schemes often require solving large-scale optimization problems. Iterative techniques from distributed optimization are frequently proposed for complexity reduction. Yet, they achieve feasibility only asymptotically, which induces a substantial computational burden. This work presents an approximate dynamic programming scheme, which is guaranteed to deliver a feasible solution in "one shot", i.e., in one backward-forward iteration over all subproblems provided they are coupled by a tree structure. Our approach generalizes methods from seemingly disconnected domains such as power systems and optimal control. We demonstrate its efficacy for problems with nonconvex constraints via numerical examples from both domains.en2325-58702025IEEEADP | flexibility aggregation | hierarchical optimization | large-scale optimization | tree structures | TSO-DSO coordinationTechnology::600: TechnologyJournal Article10.1109/TCNS.2025.3526715Journal Article