The differential current relay type NT10 is intended for the protection of two-winding power transformers, auto-transformers, generator- transformer units and short lines.
No matching CTs are required.

Applications
• Transformer
Protection functions
• Pt100 thermometric probes (26)
• Phase undercurrent (37)
• Negative sequence overcurrent (46)
• Thermal image (49)
• Phase overcurrent (50/51)
• Residual overcurrent (50N/51N)
• Low impedance restricted ground fault (64REF)
• High impedance restricted earth fault (87NHIZ)
• Biased differential for transformer (87T)
• Breaker failure (BF)
Monitoring and control functions
• CB diagnostic
• Cold Load Pickup (CLP)
• CTs monitoring (74CT)
• Digital Fault recording (DFR)
• Fault and event logging (SER & SFR)
• Logic selectivity
• Multiple setting profiles
• Programmable Logic Controller
• Second harmonic restraint
• Self-test
• Trip circuit supervision (74TCS)
Hardware
• 2 binary inputs + 6 output relays + 8 LEDs
• Auxiliary power supply 110-230 Vac/dc
• Auxiliary power supply 24-48 Vac/dc
• Flush, projecting, projecting, rack, with separate MMI
• Network module with Ethernet FX port (optical fiber)
• Network module with Ethernet TX port (copper RJ45) + RS485 port
• Nominal current 1/5 A selectable by DIP-switch
• RS485 port (unavailable with Ethernet FX port)
• Standard CT amperometric inputs 1/5 A
Communication
• IEC 61850 Protocol
• Modbus RTU RS232 protocol
• Modbus RTU RS485 / IEC 870-5-103 / DNP3 protocol
• Modbus TCP/IP protocol (network board must be provided)