Abstract: With the ever increasing complexities in power systems across the globe and the growing need to provide stable, secure, controlled, economic and high quality power especially in the deregulated power market. It is envisaged that FACTS controllers will play a vital role in power systems. This paper investigates the improvement of transient stability of a test system under three phase fault using facts devise. TCSC- Thyristor Controlled Series Capacitor and STATCOM- Static Synchronous Compensator are utilized as a series and shunt compensation respectively. UPFC-Unified Power Flow Controller is considered as a shunt-series compensator.