Tri-level optimization-based resilient island city distribution network planning against terrorist attacks

Power distribution networks are known as a key infrastructure of smart cities. The safe operation of suchnetworks is generally threatened by terrorist agents to disrupt the activities of smart cities. Therefore,distribution network planners attempt to find a solution for increasing the resilience of a distributionsystem against terrorist attacks. The hardening of distribution lines and allocation of electrical energystorage units are generally performed for reaching planner goals. However, investment for obtaining aresilient distribution network against terrorist attacks is limited by a hardening budget. This budget canbe increased by considering other distribution network plans (such as increasing the expansion of renewableenergies) and using the geographical features of the studied distribution networks. This paperproposes a tri-level optimization problem for allocating and sizing the offshore pumped storage units forincreasing an Island city distribution network resiliency against terrorist activities and minimizing thenetwork operation cost by solving the stochastic nature of ocean wave generation powers. The proposedtri-level problem is solved based on the Benders decomposition method using primal cuts. The simulatingresults obtained by using the IEEE distribution test system validate the effectiveness of the proposedtri-level model and highlight that offshore pumped storage units can enhance the resiliency of a distributionsystem located on an island against terrorist attacks and reduce the total operation cost during normalconditions.