Recent trend towards higher specific loading of generators along with the tendency to operate these in the leading power factor region adversely affects the transient performance of modern power systems. Short fault clearing times that are now being achieved make it possible to maintain the stability'of generators. However, the transients following the removal of a fault may be large and may take a long time to dissipate. The study presented in this thesis is concerned, mainly, with the design of feedback controllers for improving the transient performance of synchronous generator following a large disturbance. A theoretical development of feedback controllers, based on the locally linearised system model, is presented and their application to a simplified single machine/infinite bus system model is considered. Development of a non-linear feedback controller, which ensures system stability, and its application to the simplified system model is also considered. A performance index which includes the generator terminal voltage deviation and the rotor speed deviation terms,and ,which leads to an overall improvement of the system transient performance has been proposed. Mathematical models for a detailed single machine/ infinite bus and a multimachine power system model have been developed in state-space form. These models also include the a.v.r. and the turbine-governor. The application of saturation-type feedback controller to the detailed single machine and the multimachine power system model is considered. This study includes the case where a single controller is used over a range of system operating conditions. In the case of the multimachine system the effect, on the system transient performance, of using controllers employing only the local state feedback, is considered. Some aspects of the digital computing techniques used for developing the feedback controllers and for the simulation of the system transient behaviour are also discussed.