An application of interior-point based OPF for system expansion with FACTS devices in a deregulated environment

This paper presents the formulation of AC optimal power flow (OPF) with deregulation issues and the effect of flexible AC transmission systems (FACTS) devices. A predictor-corrector interior-point nonlinear-programming (PCIPNLP) algorithm has been developed to solve the problem. Only minor changes are required to the present OPF function in a modern EMS for social welfare maximization to obtain the optimized bid-based dispatch and nodal spot prices. The incorporation of FACTS devices for system expansion can ease the difficulties caused by transmission congestion. It is found that PCIPNLP technique is very effective for the modified OPF solution for congestion relief under deregulation. Test results suggest that the incorporation of FACTS devices can not only utilize the existing lines, but also reduce load curtailment and increase market profit