Distance Relays Characteristic Improvement on TCSC Integrated Transmission Lines

The paper presents a voltage compensation method to enhance impedance Characteristic of distance relays used in Thyristor Controlled Series Capacitor (TCSC) integrated lines. At first changes on the reach of first and second zones of distance relays and probable mal-operation of relays caused by TCSC are shown, then the voltage compensation method is formulated and used to improve the characteristics of relays. A four buses system is used for simulation and results show the efficiency of proposed method.