A screening technique for optimally locating phase shifters in power systems

The authors discuss the problem of optimally locating phase-shifting transformers in power systems after a brief review of the effects of phase shifters on power flow. An exhaustive method of determining the optimal location is discussed based on the use of an optimal power flow (OPF) program. They review the OPF problem definition and the Newton-Raphson method of solving it, concentrating on the problem of identification of the binding inequality constraints. They also propose a new formulation of the constraint identification problem using quadratic programming. Finally, they propose a screening technique for greatly reducing the computation involved in determining the optimal phase shifter location, and discuss the validation of the screening technique using electric utility data