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In this paper, we propose an AC optimal power flow (ACOPF) model considering distributed flexible AC transmission system (D-FACTS) devices, in which the reactance of D-FACTS equipped lines are
introduced as decision variables. This is motivated by increasing interests in using D-FACTS
devices to address system operational and cyber-security concerns. First,
D-FACTS devices can be incorporated in real-time operations for economic
benefits such as managing power congestions and reducing system losses. Second,
D-FACTS devices can be utilized by moving target defense (MTD), an emerging
concept against cyber-attacks, to prevent attackers from knowing true system
configurations. Therefore, system operators can use the proposed ACOPF model to
achieve economic benefits and provide the setpoints of D-FACTS devices for MTD
at the same time. In addition, we rigorously derive the gradient and Hessian matrices of the objective function and
constraints, which are further used to build an interior-point solver of the
proposed ACOPF. Numerical results on the IEEE 118-bus transmission system show the
validity of the proposed ACOPF model as well as the efficacy of the
interior-point solver in minimizing system losses and generation costs.