Section 2 REF615 overview
2.1 Overview
REF615 is a native IEC 61850 feeder protection IED for selective short-circuit,
overcurrent and earth-fault protection. It is applicable to all types of radial isolated
neutral networks, resistant earthed networks and compensated networks. REF615 is
part of a product family that will cover many protection applications for utility and
industry customers.
The IED features draw-out-type design, compact size and ease of use. Depending on
the IED variant, the protection functions may include:
• Three-phase non-directional overcurrent protection, 4 stages
• Three-phase directional overcurrent, 3 stages
• Directional earth-fault protection, 3 stages
• Non-directional (cross-country) earth fault, using calculated I
0
• Non-directional earth fault, 3 stages
• Transient/intermittent earth-fault protection
• Non-directional sensitive earth fault
• Negative-sequence overcurrent protection, 2 stages
• Phase discontinuity
• Three-phase overvoltage protection, 3 stages
• Positive-sequence undervoltage protection
• Negative-sequence overvoltage protection
• Residual overvoltage protection, 3 stages
• Three-phase undervoltage protection, 3 stages
• Three-phase transformer inrush detector
• Three-phase thermal overload, lines and cables
• Circuit-breaker failure protection
• Electrically latched lockout relay
Depending on the IED variant, the optional functions may include:
• Auto-reclose
• Arc protection, three lens sensors for arc detection
1MRS756378 D Section 2
REF615 overview
REF615 15
Application Manual