Paper Title
Closed Loop Performance Evaluation of Line Differential Relay on RTDS

Abstract
Line current differential protection of transmission lines is preferred due to its speed, sensitivity, security, and selectivity. As these relays are located independently at each terminal of a line, they depend on reliable communications to exchange and align the currents. Testing of such relays requires application of system conditions that more closely replicate power system conditions. Appropriate and Realistic Relay testing provides one of the means of defense against relay failures. It helps to validate the design of relay logic, compare the performance of different relays, verify adopted relay settings, and identify system conditions that might cause mal-operation of relays. Real-Time Digital Simulator (RTDS) equipped with highly accurate voltage and current amplifiers was used to simulate various power system configurations and conditions. This paper discusses the simulation results of the closed loop performance of a typical line differential relay under various power system conditions as per the requirements of working group 04 of CIGRE study committee 34 on protection. Keywords - Area-efficient, Line Differential Relay, Real Time Digital Simulator (RTDSTM), Current Transformer (CT), Capacitive Voltage Transformer (CVT), Power Swing, Time domain simulation.