Optimal power flow incorporating FACTS devices and power flow control constraints

This paper presents an alternate approximating algorithm to solve the optimal power flow (OPF) problem with flexible AC transmission systems (FACTS). The proposed method integrates the power flow control needs into the OPF problem to fully use the new characteristic of FACTS devices. The FACTS devices controllable parameters are divided into three types, which are included in active power OPF (APOPF) or in reactive power OPF (RPOPF) as control variables respectively. The active and reactive power flow equations of unified power flow controllers (UPFC) are introduced into RPOPF and APOPF separately to improve the convergence property. The LP-based algorithm is used in APOPF and the successive quadratic-programming algorithm is used in RPOPF. Case studies on IEEE test systems show the effectiveness of this algorithm.