Protective Relay Basics - Part 2: Coordination and Digital Multifunction Relays

The protective relay is a fundamental element in all medium voltage systems. Devices used in medium voltage protection can be very different from their counterparts in the low voltage world, but the fundamentals are the same. This presentation, given by Andrew Legro, P.E. Field Application Engineer at ABB, and Nikita Mishra, FAE at ABB is the final session of a 2-part series on protective relays. Andrew discusses relay coordination with other protective devices including relay to relay, relay to fuse, and relay to LV breaker. Digital multifunction relays, which provide multiple solutions in a single package, are also discussed.