Modelling and validation of differential relay using real time digital simulator

Abstract

The differential relay is often used as a protective device for transformer and bus protection. This paper focuses on the design, testing and validation of a differential protection scheme using a real time digital simulator (RTDS). Hardware-in-the-loop (HIL) simulation has been done using the commercial differential relay hardware and the RTDS system. Simulation results obtained using developed software relay model were compared with simulation results of HIL to validate the basic functionality performance of the relay model. The developed model has increased flexibility and can be used to develop an advanced relay model with a dynamic pickup value for a system with frequent critical topological changes. Developed relay model and HIL hardware setup can also be used for power system education. Contributions of this paper is to develop a framework for model validation using HIL and real time simulation interface to be used in further power system research and education.