Practical Evaluation of Overcurrent Protective Relay Performance in Power Distribution System

Power distribution system suffers several disturbances during its operation which cause problems in reliability of system. The reliability depends on the successful operation of protective relays that are used in protective scheme to detect disturbances and faults, thus reduce their effects by separating the faulty area from healthy one. In distribution system, overcurrent relays mainly are used. The failure of relay operation may cause damage of system components. The presence of overcurrent relays in distribution system has created the challenge of testing of these devices for evaluating of their performance. This paper presents practical evaluation of overcurrent protective relays performance using advanced test system (CMC test system). Advanced test system includes software that will be used for evaluating and performance analysis of overcurrent relay according to operating characteristics and relay settings. The process requires the review of work principle of overcurrent relays that were used to investigate the settings of relay in order to create test cases will confirm that the relay performance responds as expected or not.