International Journal of New Innovations in Engineering and Technology (IJNIET) Vol. 1 Issue 3 February 2013 61 ISSN: 2319-6319 Modelling and Analysis of Thyristor Controlled Series Capacitor using Matlab/Simulink Satvinder Singh Assistant Professor, Department of Electrical Engg. YMCA University of Science & Technology, Faridabad, India Pawan Kumar Instructor, Department of Electrical Engg. YMCA University of Science & Technology, Faridabad, India Atma Ram Assistant Professor, Department of Electrical Engg, Govt. Engineering College, Paniwala mota, Sirsa, India Abstract: The need for more efficient electricity systems management has given rise to innovative Technologies in power generation and transmission. Flexible AC Transmission Systems (FACTS) is one of such technologies that respond to these needs. It significantly alters the way transmission systems are developed and controlled together with improvement in asset utilization, system flexibility and system performance. Different types of FACTS devices are being used now-a-days. Thyristor Controlled Series Compensator is one of the series compensating FACTS devices. Thyristor Controlled Series Compensator (TCSC) consists of a series compensating capacitor shunted by a Thyristor Controlled Reactor (TCR). The basic idea behind the TCSC scheme is to provide continuously variable impedance by means of partially cancelling the effective compensating capacitance by the TCR. Transmission lines compensation by means of TCSC can be used to increase the power transfer capability, improve transient stability, reduce transmission losses and dampen power system oscillations. In this work device modelling of TCSC have to be carry out along using MATLAB7.5/Simulink. The thyristor of TCR branch are fired at firing angle  =60 0 degree. The Response of capacitor voltage, the response of TCR currents and response of capacitor currents at the given firing angle is studied. Keywords : Matlab , Thyristor Controlled Series Compensator, Transmission system I. INTRODUCTION The objective of this work is to model a Thyristor Controlled Series Compensator and Modelling and Simulation of Thyristor Controlled Series Compensator is carried out using MATLAB/ Simulink Power System Bockset. The simulation responses of TCR currents, capacitor currents and capacitor voltages presented for firing angle =60 o . In this simulation, it is advantageous to have small inductive reactance (XL) in providing well defined charge reversal and control of the time period of the compensating voltage which is important for handling sub- synchronous resonance. Small XL increases the magnitude of current harmonics generated by the TCR and circulated through the series capacitor and thus also increases the magnitude of capacitor voltage harmonics injected into the line. The impedance of the TCR reactor does not significantly alter the physical operation of the TCSC; provided that it is sufficiently small in relation to the impedance of the capacitor to facilitate the desired control of the series compensation. Since system oscillations are greatly influenced by line impedance, TCSC is effective in providing additional power oscillation damping. The harmonics in the system are also damped out in early cycles and there are no disturbances after that. The major benefits of TCSC are the abilities to schedule power flows along desired lines and to rapidly modulate the effective impedance in response to power system dynamics. It has been seen that with the increase in degree of compensation the power flow across the transmission line increases.