This paper presents brief investigations on performance of Installed Thyristor Controlled Series Compensator (TCSC) projects world around. The main and basic objective of TCSC's in power system is to enhance power flow and improve system stability. The deployment of TCSC in transmission line also improves SSR mitigation, Power Oscillation Damping (POD) and Transient Stability (TS). The paper intends to discuss some important TCSC projects installed world around and highlights the benefits derived in terms of enhancing power networks. Test results of installed TCSC projects are reviewed from published research works. The authors use technical data of these installed projects to investigate the reactance characteristic, the factor 'ω', the resonance region and possible capacitive operating range. The paper also investigates the maximum power transfers on lossless symmetrical transmission line with Fixed Series Capacitors (FSC) and TCSC device installed with possible power improvement at these locations are calculated and tabulated. The simulated results show the working performance of Installed Thyristor Controlled Series Compensator (TCSC) projects manifestly. ©2011 IEEE.