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. 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. The global energy transition is ushering in a new era of power electronic-dominated grids (PEDGs), to complement the increase in the widespread integration of renewable sources like wind and solar. It is reshaping traditional grid architecture and making way for more flexible, efficient and. Protective relays and devices have been developed over 100 years ago to provide “lastline”of defense for the electrical systems. They are intended to quickly identify a fault and isolate it so the balance of the system continue to run under normal conditions. For example, unselective protection operation during a medium voltage network fault will cause an outage for an unnecessarily large number of consumers. While this is bad, It's not a. Scope Concepts of power bus protection are discussed in this guide. Consideration is given to availability and location of breakers, current sensing devices, and disconnect switches, as well as bus-switching scenarios, and their impact on the selection and application of bus protection. Today's modern relays are much more than. In order to improve the reliability of relay protection from the point of view of data center as a whole, the relay protection system of power dispatch control center is designed entirely, and an integrated relay protection idea is proposed. Method Starting from the entire.