ABB REX521 Feeder Protection Relay

ABB REX521 Feeder Protection Relay Supplier and Exporter in India

ABB REX521 Legacy Spare, Replacement and Retrofit Enquiries

ABB REX521 is a multifunction feeder protection relay used for incoming feeders, outgoing feeders, motor feeders and medium-voltage substation protection. For price and availability, send the complete relay code, configuration, nameplate, quantity and destination country.

Description

ARP IMPEX supplies and exports ABB REX521 feeder protection relays for existing medium-voltage switchgear, substations and industrial power-distribution systems.

REX521 combines protection, control, measurement and supervision in one relay. ABB used it mainly for incoming and outgoing feeders, but the relay can also protect medium and large three-phase AC motors with circuit-breaker-controlled drives. Other applications include substation protection, transformer backup protection and backup protection for high-voltage lines.

The relay was used in radial networks with isolated, resonant-earthed, solidly earthed and resistively earthed neutral arrangements. ABB supplied versions for conventional current and voltage transformers as well as hardware that could work with current and voltage sensors.

REX521 was offered with a number of standard configurations rather than one fixed protection package. The exact functions therefore depend on the hardware level and configuration fitted to the relay.

For ABB REX521 price, legacy spare availability or replacement, send us the full part number and a clear nameplate photograph. If the configuration code is available, include that as well.

Technical Specifications

• Brand: ABB
• Model: REX521
• Product type: Feeder protection relay
• Product status: Not active since 2012
• Main use: Incoming and outgoing feeder protection
• Motor feeder protection: Supported
• Protection: Overcurrent, earth fault and additional functions according to configuration
• Thermal protection: Available on applicable configurations
• Automatic reclosing: Available on selected configurations
• Voltage protection: Available on higher configurations
• Frequency protection: Available on applicable configurations
• Measurement: Current, voltage and electrical measurements according to hardware
• Inputs: Conventional CT/VT or sensor-input versions
• Control: Circuit-breaker control and supervision
• Disturbance recording: Available
• Communication: SPA, LON, IEC 60870-5-103, Modbus and DNP3 depending on relay version/
• configuration
• HMI: Local LCD with operating and fault information

For a matching REX521, the full ABB code and existing configuration should be checked before quotation.

Features

• Three-phase overcurrent protection
• Short-circuit protection
• Earth-fault protection
• Cable thermal overload protection on applicable configurations
• Automatic reclosing on selected versions
• Voltage and frequency protection on higher-function versions
• Circuit-breaker control
• Trip-circuit supervision
• Breaker condition monitoring
• Current and voltage measurement
• Fault and disturbance recording
• Local alarm and status indication
• Communication with substation automation systems
• Conventional CT/VT and sensor-input hardware options

The protection package varies considerably between REX521 configurations, which is why the configuration code is useful when checking a replacement.

Applications

REX521 can be used for:

• Incoming feeder protection
• Outgoing feeder protection
• Medium-voltage cable feeders
• Radial distribution feeders
• Motor feeder protection
• Medium and large three-phase AC motors
• Utility substations
• Industrial power distribution
• Single-busbar switchgear
• Isolated-neutral networks
• Resonant-earthed networks
• Resistively earthed networks
• Solidly earthed systems
• Transformer backup protection
• High-voltage line backup protection

ABB identifies incoming and outgoing feeders, motor feeders and substation protection among the main REX521 applications.

ABB REX521 Versions and Standard Configurations

REX521 is one relay platform supplied with Basic, Medium and High/Sensor hardware versions and a number of standard application configurations.

Basic Versions

• B01
• B02

These cover the more basic feeder protection functions. B02 adds functions such as automatic reclosing compared with the simpler B01 arrangement.

Medium Versions

• M01
• M02

The Medium hardware level provides additional protection, control and measurement capacity compared with the Basic version.

High / Sensor Versions

ABB documentation lists:

• H01
• H02
• H03
• H04
• H05
• H06
• H07
• H08
• H09
• H50
• H51

These higher configurations provide wider protection and measurement functions. For example, some configurations include voltage, residual voltage, frequency and autoreclose functions in addition to overcurrent and earth-fault protection.

When sending an enquiry, include the REX521 hardware/configuration code if it is visible on the existing relay documentation or nameplate.

ABB REX521 Replacement and Retrofit

ABB has an official Relay Retrofit Program for REX521. The program replaces supported REX521 installations using selected Relion 615-series relays, together with a mounting assembly, prewired terminals and configuration migration support.

The retrofit arrangement is intended to reduce panel rewiring and shutdown work compared with a completely new relay installation.

ABB also continues to list Maintenance Exchange Unit support for REX521 versions A, B, C, E and F.

For an ABB REX521 enquiry, please send:

• Complete ABB REX521 part/order code
• Standard configuration, if known
• Relay revision, if available
• Clear nameplate photograph
• Quantity
• Destination country
• Required delivery date

Why Buy ABB REX521 from ARP IMPEX?

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

We can assist with:

• ABB REX521 part-code checking
• B/M/H configuration identification
• Existing relay matching
• Legacy spare availability
• REX521 retrofit enquiries
• Single and multiple quantity quotations
• ABB technical documentation
• Export packing
• International shipping

Request a Quote for ABB REX521

For ABB REX521 price and availability, send:

• Complete REX521 part number
• Configuration code, if available
• Clear relay nameplate photograph
• Quantity required
• Destination country
• Required delivery date

Send your ABB REX521 part code, configuration, quantity and destination country to ARP IMPEX for availability, price and export quotation.