Middle-East Journal of Scientific Research 20 (1): 134-138, 2014 ISSN 1990-9233 © IDOSI Publications, 2014 DOI: 10.5829/idosi.mejsr.2014.20.01.11278 Corresponding Author: Ravi Kant Kumar, Department of EEE, Bharath University, Chennai, India. 134 Design of Thyristor Controlled Series Capacitor for High Voltage Controllability and Flexibility Ravi Kant Kumar, Sanjeet Kumar, Santan Kumar and K.S.S. Prasad Department of EEE, Bharath University, Chennai, India Abstract: In this paper a series controller from the Flexible AC Transmission System (FACTS) family called as ‘Thyristor Controlled Series Capacitor’ (TCSC) is designed using PIC microcontroller. Thyristor controlled series compensator (TCSC), is the first generation of FACTS controller, can govern line impedance through introduction of a thyristor controlled capacitor in series with the transmission line. A grid of transmission lines operating at high voltages is required to transmit power from generating stations to load. Inaddition to transmission lines that carry power from source to load, modern power systems are highly interconnected for economic reasons. The large interconnected transmission networks occur to faults due to the lightning discharges and reduce insulation strength. Changing loads and atmospheric conditions are unpredictable factors. This may cause overloading of lines due to which voltage collapse takes place. All the above said things are undesirable for secure and economic operation of a line. These problems can be erased by providing sufficient margin of working parameters and power transfer, but it is not possible due to expansion of transmission network. Still the required margin is reduced by introduction of fast dynamic control over reactive and active power by high power electronic controllers. The TCSC is used as series compensator in transmission system, it can be designed to control the power flow in order to increase the power transfer limits or to improve the transient stability. The paper also presents experimental results of a TCSC connected to a single-phase or three phase system. The TCSC controller can provide a very fast action to increase the synchronization power through quick changing of the equivalent capacitive reactance to the full compensation in first few cycles after a fault, hence subsequent oscillations are damped. The various problems existing on long distribution lines that can be occurs by the connection of variable series compensation, as a TCSC provides, are discussed. Key words: TCSC FACT TCR Series Compensator Harmonics Transmission line INTRODUCTION The proposed FACTS devices, possibly the TCSC To meet rising demand of power, FACTS devices are best results in terms of performance and flexibility. The introduced in the transmission line to enhance its power TCSC has been used in many applications: for controlling transfer capability; either in series or in shunt. The series the power flow, for damping system oscillations, for compensation is an economic method of improving power suppressing sub-synchronous resonance, for limiting transmission capability of the lines. Series compensation fault currents, etc. Therefore, the modeling of the device will: Increase power transmission capability [1]. Improve has become of great interest [3]. system stability. Reduce system losses. Improve voltage The main purpose of this paper is to furnish a profile of the lines. Optimize power flow between parallel concise study of TCSC in simple way. Thyristor lines. Thyristor-controlled series capacitors (TCSC) is also controlled series capacitors (TCSCs) have been used in a type of series compensator, can provide many benefits transmission networks to control then equivalent for a power system including controlling power flow in the impedance of transmissions lines and therefore the power line, damping power oscillations and mitigating sub flow in the network. They have renewed the interest in synchronous resonance [2]. transmission line series compensation because of their (Thyristor Controlled Series Capacitor) have given the