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NC20

MULTIFUNCTION PROTECTION FOR BANK CAPACITORS/HARMONIC FILTERS WITH UNDER/OVERVOLTAGE ELEMENTS

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The relay type NC20 provides protection of shunt capacitor banks and harmonic filter circuits. The capacitor banks may have the following configurations:

  • Single Wye grounded.
  • Single Wye ungrounded (with a resistor on the output of the neutral unbalance voltage transformer in order to develop the appropriate input current for the unbalance protection).
  • Double Wye ungrounded.
  • The capacitor banks may be: internally/externally fused or fuseless capacitor units. A suitable compensation method is provided to compensate the inherent unbalance neutral current
    Protections 37, 49 and 50/51 (RMS) are based on RMS value measurement of the three phase currents (fundamental and harmonics up to the 11th)
NC20 - Pro-n ()

Specifications


Key:   standard standard optional optional alternative alternative


Applications

  • Bank capacitor / harmonic filter

Protection functions

  • Pt100 thermometric probes (26)
  • Undervoltage (27)
  • Phase undercurrent (37)
  • Negative sequence overcurrent (46)
  • Neutral unbalance overcurrent with inherent unbalance compensation (46N)
  • Thermal image (49)
  • Phase overcurrent (50/51)
  • RMS phase overcurrent (50/51(RMS))
  • Residual overcurrent (50N/51N)
  • Overvoltage (59)
  • Breaker failure (BF)
  • Discharge Timer (TD)

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
  • 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)