A comprehensive Newton-Raphson UPFC model for the quadratic power flow solution of practical power networks

A new and comprehensive load flow model for the unified power flow controller (UPFC) is presented in this paper. The model is incorporated into an existing Newton-Raphson load flow algorithm. Unlike existing UPFC models available in open literature, it can be set to control active and reactive powers and voltage magnitude in any combination or to control none of them. A set of analytical equations has been derived to provide good UPFC initial conditions. Hence, the algorithm exhibits quadratic or near-quadratic convergence characteristics. Suitable guidelines are suggested for an effective control coordination of two or more UPFCs operating in series or parallel arrangements. Test results are presented which demonstrate the effectiveness of the new model