Resilience Enhancement Strategy for Distribution Systems Under Extreme Weather Events

This paper proposes an optimal hardening strategy to enhance the resilience of power distribution networks to protect against extreme weather events. Different grid hardening techniques are considered, such as upgrading poles and vegetation management. The problem is formulated as a tri-level optimization problem to minimize grid hardening investment and load shedding in extreme weather events. The first level is to identify vulnerable distribution lines and select hardening strategies, the second level is to determine the set of out-of-service distribution lines so that the damage caused by extreme weather events is maximized, and the third level is to minimize load shedding costs according to load priorities and the set of damaged lines. Since the selection of hardening strategies is coupled with the uncertainty set of out-of-service lines, the original tri-level model is transformed to be an equivalent bi-level problem, which is subsequently solved by a greedy searching algorithm. Case studies demonstrate the effectiveness of the proposed method under multiple severe weather events and different simulation settings.