Transient stability augmentations is an important requirement of any interconnected power system. It is well known that suitable placement of FACTS controllers in a power system can improve the stability performance of the system. To validate the effectiveness of different FACTS controllers it is essential to interface FACTS devices to an existing transient stability programme with minimal implementational and computational effort. In this book, FACTS controllers are modeled in a multi-machine transient programme by employing a generalized current-injection model. This approach provides a common procedure to model all types of series and shunt FACTS controllers. SVC, STATCOM, SSSC and UPFC have been modeled with typical control strategies.