This presentation reviews the established principles and the advanced aspects of the selection and application of protective relays in the overall protection system, multifunctional numerical devices application for power distribution and industrial systems, and addresses some. This presentation reviews the established principles and the advanced aspects of the selection and application of protective relays in the overall protection system, multifunctional numerical devices application for power distribution and industrial systems, and addresses some. THIS DOCUMENT WAS PREPARED BY THE ORGANIZATION(S) NAMED BELOW AS AN ACCOUNT OF WORK SPONSORED OR COSPONSORED BY THE ELECTRIC POWER RESEARCH INSTITUTE, INC. NEITHER EPRI, ANY MEMBER OF EPRI, ANY COSPONSOR, THE ORGANIZATION(S) BELOW, NOR ANY PERSON ACTING ON BEHALF OF ANY OF THEM: MAKES ANY. Long term cost reduction (TCO) for trainings and maintenance by reduce variety of relays A fast and selective arc fault mitigation for air-insulated LV & MV switchgear and Relion protection and control relays and sensor technology protect staff and plant facilities for many years. To ensure that protective relays, circuit breakers, and other protection devices correctly and selectively isolate faults, minimizing damage to equipment and interruptions to customers while maintaining system stability. One-line diagrams and detailed network data (lines, transformers, buses). Configuration Management (CM) is a business process that enables organizations to identify, document, manage and control operational information related to assets (both physical and knowledge) and systems with consistency through out their life cycles. Their responsibilities entail. Although traditional relay protection systems can play a certain protective role, they have some limitations, such as the inability to comprehensively monitor the power system and the lack of accurate judgment. Developing and applying intelligent relay protection systems has become an important way.