LABORATORY OF ELECTRICAL PROTECTIVE RELAYS USING MATLAB\SIMULINK

In this report the background of electrical protective relays is given. This includes the functions of protective relays in a power system and the block diagram of the parts that make up a relay. The relevancy and feasibility of the project is presented in this report. A fault study literature review is given, in order to explain the different types of faults. This is because faults are the reason why electrical protective relays are utilized in the power system. Literature review about the over current earth fault relay is also given in this report. The methodology followed in project execution is also explained and shown with the aid of block diagrams and Gantt charts. An over current earth fault relay simulink based model design is shown and discussed. This is done for the definite time over current earth fault relay and for the inverse time over current earth fault relay. The relay models are then used to protect R-L loads. Simulation of the over current earth fault model protecting an R-L load is done on Matlab\Simulink. Graphical results for the different types of faults are shown with the breaker tripping times for the different types of faults. The results are discussed and conclusions are made based on the graphical data obtained. Finally the effect of the fault resistance is investigated. The definite time over current relay is simulated with a bolted fault and the fault resistance is increased with steps of multiples of 10 until 1000 Ohms is reached. The graphical results for this simulation are shown and discussed.