Improvement of transient stability using FACTS devices
Electrical power system angle stability can be improved by a wide variety of controls. Some methods have been used effectively for many years, both at generating plants and in transmission network. In this work, we present, first of all, the dynamic behavior of high power synchronous machines following a significant perturbation by determining the critical time of elimination of the defect and the corresponding critical load angle. The fault studied is a balanced three-phase short circuit which causes a significant imbalance between the motor torque and the resistive torque. Next, we also present FACTS (Flexible Alternative Current Transmission System) systems to improve transient stability. The application is made on a real 400 Kv network associated with a UPFC (Unified Power Flow Control) whose design, operating principles and mathematical model will be determined. A reduction of complexity for transient stability of multimachine is employed. Results of simulation using matlab-simulinck are presented after validation on 6-bus test system.