Transmission System Restoration: Co-optimization of repairs, load pickups, and generation dispatch

This paper studies the restoration of a transmission system after a significant disruption (e.g., a natural disaster). It considers the co-optimization of repairs, load pickups, and generation dispatch to produce a sequencing of the repairs that minimizes the size of the blackout over time. The core of this process is a Restoration Ordering Problem (ROP), a non-convex mixed-integer nonlinear program that is outside the capabilities of existing solver technologies. To address this computational barrier, the paper examines two approximations of the power flow equations: The DC model and the recently proposed LPAC model. Systematic, large-scale testing indicates that the DC model is not sufficiently accurate for solving the ROP. In contrast, the LPAC power flow model, which captures reactive power and voltage magnitudes, is sufficiently accurate to obtain restoration plans that can be converted into AC-feasible power flows. Experiments also suggest that the LPAC model provides a robust and appealing tradeoff of accuracy and computational performance for solving the ROP.