Detail ABB OVER CURRENT RELAY REJ 521 And REJ 525
REJ 525 is a combined phase and neutral
overcurrent relay for short-circuit and time
overcurrent protection and non-directional
earth-fault protection of overhead lines
and cable feeders.
REJ 527 is a two-stage directional earthfault
relay for the protection of distribution
network overhead lines and cable feeders.
The relay can also be set for non-directional
operation. A special feature of the REJ 527
relay is that its two directional residual
overcurrent stages can be set to function
as residual overvoltage stages, giving three
separate residual overvoltage stages.