Distribution Network Voltage Profile Optimization via Multi-Stage Flexible Optimal Power Flow

With distributed energy resources in distribution systems being installed at a rapid pace, controlling the voltage profile across a distribution system is becoming a critical task. This paper proposes a multi-stage flexible optimal power flow (F-OPF) to optimize the voltage profile across distribution networks. The multi-stage F-OPF formulation starts from modeling individual devices and forming the network. A standard syntax is used to achieve object orientation in modeling. Then, with the number of stages defined, the multi-stage F-OPF problem is formulated. A sequential linear programming algorithm that combines the improved move limit method with the costate method is proposed to solve the problem. The most violated constraints are identified and the solution is steered to feasibility accordingly. In addition, the move limits are adjusted based on the gradient of the objective function with respect to controls. Performance of the proposed method is demonstrated on a network that comes from an actual distribution feeder.