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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 device for optimal flexibility and cost-effectiveness
  • Ready-made application packages for convenient and smooth ordering
  • Fully modular hardware and software for maximum flexibility throughout the entire relay life cycle
  • Easy adaption to changing protection requirements
  • Optimal situational awareness and usability with application-driven LHMI/SHMI (switchgear HMI)
  • Ready-made application-based LHMI pages – saving both time and efforts
  • Relay costs reduced by up to 15% with SHMI instead of LHMI


  • Freely configurable relay for flexible tailoring to application-specific requirements
  • IEC 61850 Edition 1 and Edition 2 – certified by DNV/GL (KEMA) – 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
  • 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
  • SHMI for optimal visibility – with full LHMI functionality available on panel/bay level by selecting one at a time

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