A power system is becoming more complex and heavily loaded day by day. Earlier electric power systems were small and localized. Thus, Real and reactive power compensation in transmission line is essential which will improve the stability of ac system. Flexible Alternating Current Transmission System (FACTS) technology provides new opportunity to control the power and enhancing the capacity of the present as well as new line sit is used to investigate the effect of this device in controlling active and reactive powers as well as damping power system oscillations in transient mode. A Transmission line needs controllable compensation for power flow control and voltage regulation. This can be achieved by FACTS controllers. The employed compensators are three-phase (IGBT) based, Pulse Width Modulation (PWM) operated Converter (VSC). The proposed control employ proportional-integral (PI) controller to generate a constant error. Static Synchronous Series Compensator (SSSC) is series reactive power compensation to a power system. The output of an SSSC is series injected voltage, which leads or lags line current by 90°, thus emulating a controllable inductive or capacitive reactance. SSSC can be used to reduce the line impedance and enhance the active power transfer capability of the line. With the parameters and control, the SSSC is found effective to regulate load voltage during sudden change of the loads. The SSSC also provides stable operation with dynamic induction motor load and mitigates the unstable and oscillating behaviour that is resulting during the operation of compensated Alternator with dynamic motor load. The presented results prove that SSSC systems provide satisfactory performance The advantage of this approach is that it can handle the nonlinearities, at the same time it is faster than other conventional controllers and it improve the reactive power of the system. Simulation studies will be carried out in MATLAB/Simulink environment to evaluate the effectiveness of the proposed Static synchronous series compensator (SSSC). Results will show that the proposed SSSC based damping controllers improve the damping performance event of a major disturbance as well as Reactive power control.