Design and Implementation of Protective Relays Benches

Inverse Time Overcurrent, Differential and Directional Overcurrent relays are some of the types of protective devices used for the protection of electrical power systems. Undergraduate students, studying protection of power system courses, can benefit greatly if given the opportunity to work with these relays in their labs. To provide a small setup for demonstrating the working of overcurrent, differential, and directional overcurrent relays, two test benches have been designed and implemented. The first bench consists of electromechanical inverse time overcurrent relays and microprocessor-based feeder protection relays. The second bench consists of two independent circuits to demonstrate the working of differential and directional overcurrent protection devices. The first circuit in this bench is implemented to show the operation of a microprocessor based differential protection relay. The second circuit is intended to show the working of electromechanical and microprocessor based directional overcurrent protection relays.