Protective relaying on medium and high voltage systems, some lessons to be learned

The on-line performance of petroleum industry operations, such as production and refining facilities, is directly impacted by the medium and high voltage protective relay devices used and their settings. Unusual outages, such as nonselective device operations during a fault, were reviewed at different petroleum industry facilities. Results of protective relay coordination studies on medium and high voltage power systems suggested changing some types of protective device and modifying device settings. Implementation of the recommended changes and modifications improved the on-line performance of the facilities