Network topology reconfiguration has long promised to reduce power system operating costs by strategically opening and closing transmission lines and breakers while simultaneously optimizing generator dispatch. However, existing methods identify only the target operating point without addressing how to safely reach it—a significant practical limitation. This research introduces Optimal Transition Planning (OTP), a systematic framework that bridges this gap by co-optimizing both the sequence of switching operations and the dispatch trajectory throughout the entire transition.
The core challenge lies in intermediate feasibility. Each network topology defines its own feasible dispatch region bounded by thermal limits and AC power flow equations. A naive approach that switches first or redispatches independently can inadvertently drive power flows beyond safe thermal limits during the transition, even if both the initial and final states are feasible. OTP solves this by ensuring every intermediate operating point satisfies AC power flow constraints and equipment ratings.
The methodology employs a receding-horizon optimization framework where a DC power flow planner proposes a candidate transition trajectory. This proposal is then verified against an AC feasibility filter that certifies whether intermediate states violate physical constraints. When infeasible topologies are identified, combinatorial cuts exclude them from future optimization iterations, making the computational approach reusable and efficient.
Case studies on realistic test systems from PGLib-OPF, including networks with up to 1,354 buses, demonstrate that the method produces AC-feasible transition paths while achieving cost reductions up to 18.4% compared to static solutions without switching. The approach runs on standard computing hardware, making it practical for operational implementation.
This work addresses a critical implementation gap between theoretical optimization and real-world grid operations, where safe intermediate states are as important as the final optimized configuration. The results suggest that grid operators can confidently pursue topology reconfiguration strategies without risking stability or constraint violations during the switching process.
