A bilevel optimal power flow based on Fritz-John normalized optimality conditions

This paper describes a bilevel optimal power flow (OPF) model to determine the participation of generators in reactive power supply. The OPF is formulated for predominantly hydro systems, in which power dispatch is carried out taking into consideration target values of active power generation available from long and medium term operational plans. To solve the bilevel OPF, the objective functions of the upper and lower problems approximated by smooth functions. The bilevel OPF is transformed into a single level OPF by substituting the optimality conditions of the lower level problem into the upper level one. The solutions of the resulting problem are expressed via Fritz-John (FJ) optimality conditions and obtained using the primal-dual interior point method. Results obtained for the IEEE 14-bus test system and a 352-bus equivalent of the Brazilian system indicate that the optimization model can be a useful tool to establish how generators participate in the provision of reactive support.