Transient stability and power flow model of the Unified Power Flow controller for various control strategies

This paper describes and validates transient stability and power flow model of a Unified Power Flow Controller (UPFC), and presents a detailed comparison of different controls strategies, proposing novel, efficient and simple controls for this controller. The proposed model accurately represents the behavior of the controller in quasi-steady state operating conditions, and hence is adequate for transient as well as steady state stability analyses of power systems. The model is validated with the help of the Electromagnetic Transient Program (EMTP), where a detailed model of the controller is implemented and then compared to the suggested stability model. A realistic 11-bus test system is used here to validate the proposed model and compare the different controls. The UPFC is simulated in this test system under different operating conditions using both the detailed and “reduced” models and diverse control strategies.