Self-powered feeder protection REJ603

Entry level protection in secondary distribution networks

REJ603 is designed for selective short-circuit and earth-fault protection of feeders in secondary distribution networks and for protection of small transformers in utilities and industries. REJ603 is a current-transformer-powered numerical feeder protection relay designed for applications where auxiliary power is not available or cannot be guaranteed, thereby making it an ideal choice for installation at remote locations. The relay is primarily used in ring main units and secondary distribution switchgear within distribution networks. Relay variants 1.5 and 3.0 support special and conventional current transformers respectively.


  • Overcurrent and earth fault protection

Product benefits

  • High suitability of operation with low-energy trip coils
  • Built-in hand-reset electromechanical flag
  • Powering through front USB port eliminates the need for a built-in battery and also enables access to events/fault information when CT power is not available
  • Speedy commissioning through selective test function for protection functions and binary output contacts including test trip to circuit breaker
  • Fault analysis with event log/disturbance record facility (3.0 variant)
  • Extensive self-supervision of relay hardware and software

Key features

  • Used in cable or transformer feeders in solidly earthed, resistance-earthed or isolated networks where auxiliary power is not available or cannot be guaranteed
  • Non-directional overcurrent, earth-fault protections, thermal overload protection, inrush current detection, remote trip and measurements
  • Low-energy trip output and bi-stable outputs to trip circuit breaker
  • Disturbance records downloadable from front USB port, also used for powering up relay with desktop or laptop PC or power bank in absence of aux. supply; functions available through USB powering-up relay in absence of current input (3.0 variant)
  • Designed for Ring Main Unit (RMU) and compact switchgear

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