Modelling, Simulation, Analysis and Implementation of Series Type FACTS Controller

Abstract

The power transfer capability of long high voltage transmission line is often limited by the inductive reactance of the transmission line. Series compen- sation is in some instances employed to lower the inductive reactance of the transmission line which increases the transmission line power transfer capabil- ity. Numerous methods have been employed to provide series compensation of a transmission line. One such method is to use a thyristor controlled series capacitor (TCSC). A thyristor controlled series capacitor (TCSC) belongs to the exible al- ternating current transmission systems (FACTS) family of devices. It is a variable capacitive and inductive reactance device that can be used to provide series compensation in high voltage transmission lines. One of the signi cant advantages that a TCSC has over other series compensation devices is that the TCSC's reactance is instantaneously and continuously variable. This means that the TCSC can be used not only to provide series compensation but can also be used to enhance the stability of the power system. The TCSC consists of back to back thyristors that control the reactance of the TCSC by changing its trigger angle. The reactance characteristic be- comes highly non linear at higher levels of compensation; at such operating points the trigger angle of the thyristors needs to be accurately controlled to avoid small variations in the thyristor trigger angle causing signi cant vari- ation in the reactance of the TCSC. The TCSC simulated in PSCAD4.2 & MATLAB 7.12.0.635(R2011a) simulink software and hardware model for the same is prepared.