Classifications of Relays are dividing into six purposeful categories:
Find defective lines, defective equipment, or alternative dangerous or intolerable conditions. These relays typically trip one or a lot of electrical fuse, however can also be accustomed sound associate alarm.
Verify conditions on the ability system or within the protection system. These relays embody fault detectors, alarm units, channel- watching relays, synchronize veriﬁcation, and network phasing. Power grid conditions that don't involve gap circuit breakers throughout faults are monitored by veriﬁcation relays.
Establish a closing sequence for an electrical fuse following tripping by protecting relays.
area unit activated once associate operative parameter deviates from planned limits. Control relays operate through supplementary instrumentation to revive the amount to the prescribed limits.
Operate in response to the opening or closing of the operative circuit to supplement another relay or device. These embody timers, contact-multiplier relays, protection units, analytic relays, opposition relays, closing relays, and trip relays.