The SEL-551C Relay provides overcurrent relay users with new flexibility in distribution system protection. The SEL-551C provides six inputs and three outputs, with up to two communications ports, for more control options. The SELOGIC®control equations have added rising and falling edge triggers and latches for custom logic applications.
The SEL-501 Dual Universal Overcurrent Relay provides two complete and independent groups of protection functions in one compact unit. The unit contains Relay X and Relay Y, each having separate optoisolated inputs, output contacts, and three-phase current inputs.