A nonlinear interior point based optimal power flow algorithm incorporating series FACTS devices

This paper presents a new method to incorporate flexible AC transmission system (FACTS) devices in optimal power flow (OPF) problem. Through power injection model of FACTS devices, their control to power system is expressed as the additional power equations at the nodes and the branches where FACTS devices are located. These additional power equations are convenient in combination with OPF algorithm based on nonlinear interior point (IP) programming. A two-part calculation structure is introduced in order to make full use of the existing OPF algorithm and related software in EMS. Digital simulations of the modified IEEE 30-node system located with multiple FACTS devices are present to test the effectiveness and efficiency of this work. The study also shows that FACTS devices are capable of providing an economically and technically attractive solution to power systems congestion problems.