Distributed Optimal Power Flow using ALADIN

The present paper applies the recently proposed Augmented Lagrangian Alternating Direction Inexact Newton (ALADIN) method to solve non-convex AC Optimal Power Flow Problems (OPF) in a distributed fashion. In contrast to the often used Alternaring Direction of Multipliers Method (ADMM), ALADIN guarantees locally quadratic convergence for AC-OPF. Numerical results for IEEE 5–300 bus test cases indicate that ALADIN is able to outperform ADMM and to reduce the number of iterations by at least one order of magnitude. We compare ALADIN to numerical results for ADMM documented in the literature. The improved convergence speed comes at cost of increasing the communication effort per iteration. Therefore, we also propose a variant of ALADIN that uses inexact Hessians to reduce communication. Finally, we provide a detailed comparison of both variants of ALADIN to ADMM from an algorithmic and communication perspective.