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
  • 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
  • Centralized account management with role-based access control

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