Incremental Model Building Homotopy Approach for Solving Exact AC-Constrained Optimal Power Flow

TL;DR

This paper introduces a homotopy-based method leveraging grid physics to efficiently find local solutions for large-scale AC-OPF problems, addressing the challenge of convergence in complex power systems.

Contribution

It presents a novel incremental model building homotopy approach that improves convergence guarantees for large AC-OPF problems using primal-dual interior point methods.

Findings

Effective on U.S. Eastern Interconnection test networks

Provides robust local convergence for large AC-OPF problems

Demonstrates computational efficiency and reliability

Abstract

Alternating-Current Optimal Power Flow (AC-OPF) is framed as a NP-hard non-convex optimization problem that solves for the most economical dispatch of grid generation given the AC-network and device constraints. Although there are no standard methodologies for obtaining the global optimum for the problem, there is considerable interest from planning and operational engineers in finding a local optimum. Nonetheless, solving for the local optima of a large AC-OPF problem is challenging and time-intensive, as none of the leading non-linear optimization toolboxes can provide any timely guarantees of convergence. To provide robust local convergence for large complex systems, we introduce a homotopy-based approach that solves a sequence of primal-dual interior point problems. We utilize the physics of the grid to develop the proposed homotopy method and demonstrate the efficacy of this approach on U.S. Eastern Interconnection sized test networks.