A new model of phase shifter for its efficient integration in interior point optimal power flow

When phase shifters are used as control devices in optimal power flow (OFF), the symmetry of the admittance matrix is destroyed; this introduces ome difficulties in the implementation of interior point OPF. This paper presents an efficient approach to handle phase shifters in an interior point OPF algorithm. First, a new power/current injection model of phase shifters is proposed. Then, a detailed explanation of how to integrate this model into the existing interior point OPF code is presented. This integration of phase shifters only requires minor modifications to the existing interior oint OFF code by updating Jacobian/Hessian matrices of objective and constraints in each iterate. The distinguished features of the proposed approach are: (i) box constraints are used instead of implicit constraints; (ii) no additional buses are introduced, so the dimensions of Jacobian and essian matrices remain the same; and (iii) the admittance matrix is constant, and remains symmetric. Numerical studies on several power systems to 2383 buses indicate that the proposed approach is simple and efficient. Copyright (C) 2009 John Wiley & Sons, Ltd.