ABB REJ521 Earth-Fault Protection Relay

ABB REJ521 Earth-Fault Protection Relay Supplier and Exporter in India

ABB REJ521 Legacy Relay – Price, Availability and Spare Enquiries

ABB REJ521 is a numerical earth-fault protection relay used for feeders, busbars and medium-voltage distribution systems. For price and availability, send the complete ABB order code, relay nameplate, quantity and destination country.

Description

ARP IMPEX supplies and exports ABB REJ521 earth-fault protection relays for existing switchgear panels, utility substations and industrial power-distribution systems.

REJ521 is a dedicated non-directional earth-fault relay. It monitors the residual or neutral current through a current transformer and operates when the measured earth-fault current crosses the selected setting. The relay can initiate circuit-breaker tripping, provide alarm signals and store fault information for checking after an operation.

The relay has two earth-fault stages: a low-set stage for normal or sensitive earth-fault protection and a high-set stage for higher fault currents. The low-set stage can work with definite-time or IDMT characteristics, while the high-set stage can operate instantaneously or with a definite time delay.

REJ521 was mainly used for feeder earth-fault protection and busbar protection in utility and industrial networks. It can also be used with other protection relays where a separate residual-current protection function is required.

For ABB REJ521 price, old stock availability or a matching spare, send the full relay code and a clear photograph of the existing nameplate. The current-input version should be confirmed before supply.

Technical Specifications

• Brand: ABB
• Model: REJ521
• Series: ABB REJ 52_ Series
• Product type: Earth-fault protection relay
• Product status: Not active since 2011
• Protection type: Non-directional earth-fault protection
• Measurement: Residual/neutral current
• Low-set earth-fault stage: Available
• Low-set timing: Definite-time or IDMT
• High-set earth-fault stage: Available
• High-set timing: Instantaneous or definite-time
• Current-input versions: 0.2 / 1 A and 1 / 5 A versions
• Rated frequency: 50 / 60 Hz
• Circuit-breaker failure protection: Included
• Disturbance recording: Included
• Local HMI: Alphanumeric LCD with operating buttons
• Communication: Front optical communication and rear communication facilities
• Self-supervision: Continuous relay hardware and software monitoring

The exact relay hardware and current-input arrangement should be checked from the complete ABB order number.

Features

• Two-stage non-directional earth-fault protection
• Sensitive low-set residual-current stage
• High-set earth-fault stage for heavier faults
• Definite-time operation
• IDMT characteristic for the low-set stage
• Circuit-breaker failure protection
• Flexible trip and signalling outputs
• Disturbance recording
• Fault and event data storage
• External digital input for blocking or control functions
• Local alphanumeric display
• Front optical communication
• Rear communication connection
• Continuous internal self-supervision

REJ521 keeps the protection arrangement relatively simple. It is suitable where the panel requires a dedicated earth-fault relay rather than a multifunction feeder protection device.

Applications

ABB REJ521 can be used for:

• Medium-voltage feeder earth-fault protection
• Incoming feeder protection
• Outgoing feeder protection
• Busbar earth-fault protection
• Cable feeder protection
• Industrial distribution systems
• Utility substations
• Switchgear protection panels
• Residual-current protection
• Neutral-current supervision
• Backup earth-fault protection
• Two-stage earth-fault protection
• Blocking-based busbar protection schemes
• Existing ABB REJ-series relay installations

ABB identifies the REJ52_ series primarily for feeder, substation and industrial power-distribution protection.

ABB REJ521 Order Codes

ABB supplied the REJ521 with different neutral-current input arrangements.

Examples from ABB documentation include:

• REJ521B 413BAA – 0.2 A / 1 A current inputs
• REJ521B 416BAA – 1 A / 5 A current inputs

ABB article numbers documented for these versions include:

• 1MRS091413-BAA
• 1MRS091416-BAA

This difference is important when checking an old relay. A request simply stating “ABB REJ521” may not be enough to confirm the correct unit.

For a matching spare, send the complete code exactly as printed on the relay.

ABB REJ 52_ Relay Series

REJ521 is part of ABB’s REJ 52_ protection relay series. The family contains four main models:

• ABB REJ521 – Non-directional earth-fault protection relay
• ABB REJ523 – Three-phase overcurrent protection relay
• ABB REJ525 – Combined overcurrent and earth-fault protection relay
• ABB REJ527 – Directional earth-fault protection relay

All four relays use a two-stage protection approach with low-set and high-set operating stages.

REJ521 is therefore the model to look for when the application mainly requires non-directional residual-current or earth-fault protection.

ABB REJ521 Legacy Spare Enquiries

ABB REJ521 is a discontinued legacy relay. For an existing installation, ARP IMPEX can assist with:

• ABB REJ521 part-code checking
• 0.2/1 A and 1/5 A version identification
• Legacy relay availability
• Existing-unit matching
• Replacement enquiries
• Single-piece requirements
• Multiple-quantity quotations
• ABB technical documentation
• Export packing
• International shipment

For an ABB REJ521 spare or replacement enquiry, please send:

• Complete ABB REJ521 order code
• Clear relay nameplate photograph
• Quantity required
• Destination country
• Required delivery date

Why Buy ABB REJ521 from ARP IMPEX?

ARP IMPEX supplies ABB protection relays for utilities, industrial plants, EPC contractors, panel builders, maintenance companies and electrical traders.

We can assist with ABB REJ521 price and availability, exact part-code checking, legacy spare requirements and export supply.

Request a Quote for ABB REJ521

For ABB REJ521 price, availability or legacy spare requirements, send the complete part number, relay nameplate, quantity and destination country.

Send your ABB REJ521 order code and quantity to ARP IMPEX for availability, price and export quotation.