Ayman Abdal Mageed Ahmad Abdal Rhman2017-10-242017-10-242014-06http://hdl.handle.net/123456789/6402ABSTRACT The objective of this research is to improve the stability of power system by thyristor controlled series compensator (TCSC) .controller for damping power oscillations and improving transient stability and voltage stability margin. The proposed approach is carried out on two-area twomachine 3-bus as a model system to test .The system is controlled by power system stabilizer (PSS) and proportional-integral (PI) Controller with leadlag to add damping to the rotor oscillations of the power system . The proposed TCSC controller is tested on a multi-machine system and the simulation results are presented.Thyristor Controlled Series