In this book, a review of the different performance characteristics of Thyristor Controlled Series Capacitor and salient features of Power flow control using this device are elegantly discussed. MATLAB program is used to observe the variation of active and reactive power flow with different variable parameters, to implement active and reactive power flow with and without compensation. For each set of data, output is obtained. One of the significant advantages that a TCSC has over other series compensation device is that TCSC reactance is instantaneously and continuously variable. That means that TCSC can provide not only series compensation but can also be used to enhance the stability of the power system. In this thesis performance of TCSC is analyzed. Initially real and reactive power flow through the transmission line have been analyzed for fixed and then the same parameters are evaluated by inserting controllable parameter in the same transmission network. The considered topology of TCSC consists of back to back thyristors that controls the reactance of the TCSC. By changing the firing angles of these back to back thyristors it is possible to vary the reactance of the TCSC.