Multi-step island formation and repair dispatch reinforced by mutual assistance after natural disasters

Extreme weather events can devastate parts of power grids. Thus, the appropriate post-disaster reaction is a crucial duty for power utilities. To address this important concern, a new two-stage framework is proposed in this paper. Stage I optimally coordinates disaster mutual assistance between affected and supporting utilities. To this end, distance between the damaged and supporting utilities, extent of damage, and repair resources are taken into consideration as decision criteria. Then, a novel formulation in the form of mixed integer linear programming (MILP) is developed for mutual aid management problem. The results of stage I are used as inputs to stage II. A new multi-horizon restoration strategy is proposed in stage II. At each decision time, a MILP problem is solved for the current and next time steps. In this regard, the proposed strategy in stage II co-optimizes “prioritizing repairs” in the current time step and “island formation” in the next time step. In doing so, the proposed scheme can deal with multiple unforeseen events. The main goal of stage II is to maximize the total weighted sum of supplied energy to critical facilities. The presented framework is applied to the IEE 33- and 123-bus distribution test systems, and its effectiveness in terms of improvement in maximizing supplied energy and adaptability to new situations is demonstrated through realistic case studies.