Nowadays, the use of flexible AC transmission systems (FACTS) is an economical and interesting approach to improve power transfer capability. The thyristor-controlled series capacitor, as a member of the FACTS family, can control interrelated parameters with dynamism due to its ability of rapid control and stabilization. Regardless of all of the works in this area, the control of transmitted power through the design of the firing angle controller is still missing. In this paper, first, the open-loop firing angle controller and its sensitivities are analyzed to fill in this gap. Next, closed-loop controllers such as PID and fuzzy controllers are designed and simulated in MATLAB/Simulink software. Simulation results show that the fuzzy logic controller has a better response, although it is designed with minimum, simple, triangle membership functions and reduced rule bases.