The optimal management of electrical power systems is based in particular on the reliability, availability and communication skills of protection, measurement and automation devices.
NPTA915 is a voltage regulating IED. It comes with current and voltage based protection functions as well making it suitable for combined transformer voltage regulation and back-up protection. Transformer monitoring module included as a standard feature provides for statistical information for preventive maintenance purposes.
The NPTA915 communicates using various protocols including IEC 61850 substation communication standard.

MAIN FEATURES

  Hardware (standard)

• Large graphic display with customizable mimic
• Push buttons for local control of the up to 5 objects
• 16 freely configurable leds
• 5 current inputs
• 4 voltage inputs
• 5+1 output units (standard)
• 3 digital inputs (standard)
• 1 Front Ethernet port, 1 rear Ethernet port, 1 rear RS485 port

  Protection Functions

• Transformer thermal overload [49T]
• Three-phase overcurrent, 4 stages INST, DT or IDMT [50/51]
• Earth-fault (sensitive), 4 stages INST, DT or IDMT [50/51N(S)]
• Harmonic overcurrent / inrush blocking, 4 stages INST, DT or IDMT [50H/51H/68H]
• Current unbalance / broken conductor, 4 stages INST, DT or IDMT [46R/46L/46]
• Restricted earth fault protection (low-imp) / Cable-end differential protection [87N]
• Overvoltage, 4 stages INST, DT or IDMT [59]
• Undervoltage, 4 stages INST, DT or IDMT [27]
• Zero sequence overvoltage, 4 stages INST, DT or IDMT [59N]
• Positive sequence under/overvoltage, negative sequence overvoltage, 4 stages INST, DT or IDMT [59P/27P/47]
• Overexcitation protection [24]
• Breaker failure protection [50BF/52BF]
• Arc protection (option) [50ARC]

  Disturbance and Event recording

• Up to 100 recordings @ 64 samples/cycle (3.2 kHz)
• Recording lenght configurable from 0.1 to 1800 seconds
• Pre trigger configurable from 5 to 95%
• Non-volatile event records: 15000

  Measurement and Supervision

• Phase and residual currents (IL1, IL2, IL3, I01, I02)
• Voltage measurements (UL1-UL3, U12-U31, U0, SS)
• Current and voltage harmonics (up to 31st)
• Current THD
• Frequency (f)
• Power (P, Q, S, pf)
• Energy (E+, E-, Eq+, Eq-)
• Disturbance recorder (3.2 kHz)
• Current transformer supervision (CTS)
• Fuse failure (VTS)
• Trip circuit supervision [74TC]

  Control

• Automatic voltage regulator [90]
• Controllable objects: 5
• 8 setting groups

  Communication protocols standard

• IEC 61850
• IEC 60870-5-103/101/104
• Modbus/RTU, Modbus TCP/IP
• DNP 3.0, DNP 3.0 over TCP/IP
• SPA

  Options (3 slots)

• Digital inputs optional: +8 per card
• Digital outputs optional: +5 per card (2 cards max.)
• Arc protection (12 sensors +2xHSO +BI)
• 2 x mA input + 6-8 x RTD input (2 cards max.)
• Double LC Ethernet 100Mb
• RS232 + serial fibre PP/PG/GP/GG (option)