A Two-Stage Decomposition Approach for AC Optimal Power Flow

The alternating current optimal power flow (AC-OPF) problem is critical to system operations and planning, but it generally hard solve due its nonconvex large-scale nature. This paper proposes a scalable decomposition approach in which the network decomposed into master number of subnetworks, where each has own AC-OPF subproblem. formulates two-stage optimization requires only small amount communication between subnetworks. key contribution smoothing technique that renders response subnetwork differentiable with respect input from problem, utilizing properties barrier formulation naturally arises when subproblems are solved by primal-dual interior-point algorithm. Consequently, existing efficient nonlinear programming solvers can be used for both subproblems. advantage this framework speedup obtained processing subnetworks parallel, convergence guarantees under reasonable assumptions. readily extended instances stochastic loads. Numerical results show favorable performance illustrate scalability algorithm able more than 11 million buses.