Protection and control REX640

All-in-one protection for advanced power generation and distribution applications

REX640 is a powerful all-in-one protection and control relay for advanced power generation and distribution applications. REX640 offers unmatched flexibility throughout its entire life cycle – from ordering through testing and commissioning, to upgrading the functionality of its modular software and hardware to meet new application requirements.

As a member of ABB’s Relion® protection and control family of relays, REX640 further reinforces Relion’s position as the range of relays to rely on.

All-in-one protection and control


  • Complete application coverage with one freely configurable device for flexible and cost-effective tailoring to application-specific requirements
  • Ready-made application packages for convenient and smooth ordering
  • Fully modular hardware and software for maximum flexibility and easy adaption to changing protection requirements throughout the entire relay life cycle
  • Optimal situational awareness and usability with application-driven LHMI/SHMI (switchgear HMI)
  • Ready-made application-based LHMI pages – including support for a 64-channel alarm annunciator (SACO) – saving both time and efforts
  • Savings of up to 15% on relay costs with SHMI instead of LHMI – while still maintaining full LHMI functionality on panel/bay level for optimal visibility


  • IEC 61850 Edition 2.1 – certified by DNV/GL (KEMA) – and Edition 1 and with redundancy support based on HSR and PRP
  • Ability to receive four streams of sampled measured values (SMVs) and send one via IEC 61850-9-2 LE-based process bus communication
  • DNV type approval certificate for installations onboard ships and offshore units
  • Support for high-speed bus transfer in case of a failing incoming feeder to secure electrical supply for critical parts of a system
  • Synchronizer functionality for both generator and non-generator breakers
  • Four supervised arc sensor inputs, either loop or lens-type

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Technical documentation portal

The newest technical documentation for this product is on our technical documentation portal. On this portal, you can quickly search topics in all available technical documentation. You can also print topics of your choice to PDF format. As a registered user you will be able to bookmark and add your own comments in your own personal book. You can save the documents you need the most as collections and you can use them also in offline mode.

ABB Library

In ABB Library you can find other product related material. For now, please also use ABB Library to find technical documentation of earlier product versions.
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