Modeling and simulation of digital negative sequence relay for unbalanced protection of generator

Modeling tools are useful for educational and industrial use. Such tools help the new engineers to simulate the power system under normal and faulty conditions. This paper presents the design and various data conversion steps of a digital negative sequence relay. The digital relay has a superiority over electromechanical relay in terms of accuracy and speed. The detection of negative sequence current and appropriate action is useful for protection of power system components. The operation of relay should be fast and reliable for minimum outage of power system in case of abnormality or electrical fault. In this paper, the relay performance under different system dynamics is also visualized on MATLAB / SIMULINK^® considering a 400V power system.