Solutions   for   Protecting   andManaging   the   Electrical   Network

NP.G 800

Multi function generator protection

NPG800 protects generators connected to three phase network and driven by any type of prime mover: steam, hydraulic or gas turbine and also diesel or gas engine.
The various functions and connection possibilities are suitable for hundreds kVA to tens MVA generators.
As well as the usual protection functions, NP800 relays provide monitoring, measurement and recording of the electrical quantities of the network.
The relays can be set locally, using either the keypad and display or the RS232 port, or remotely using the RS485 port. Setting, reading, measurement and recording are all available locally or remotely.


  • Minimum of impedance with 2 thresholds [21]
  • Overfluxing with 2 thresholds [24]
  • Undervoltage with 2 thresholds [27]
  • Maximum [32P] reverse [32RP] and minimum [37P] of active power
  • Maximum with 2 thresholds [32Q] and minimum [37Q] of reactive power
  • Field failure with 2 thresholds [40]
  • Negative phase sequence overcurrent with 2 thresholds [46]
  • Thermal overload with 2 thresholds [49]
  • Overcurrent with 3 thresholds [51-1] [51-2] [50] with voltage control unit [51-1V] [51-2V] [50V]
  • Max of zero sequence voltage with 2 thresholds [59N]
  • Overvoltage with 2 thresholds [59]
  • Max of zero sequence current with 2 thresholds [64]
  • Overfrequency with 2 thresholds [81O]
  • Underfrequency with 2 thresholds [81U]
  • Latching of the output contacts [86]
  • Trip circuit supervision of the breaker [74TC]
  • Breaker failure [BF]


  • Configuration and parameter setting by local MMI or off-line / on-line PC
  • Measurement of electrical quantities:
    – Instantaneous and integrated values of phase currents and S, P, Q powers
    – Values, according to the wiring: phase to phase or phase to neutral voltages, residual voltage, zero sequence current
    – Thermal image value
    – Impedance
    – Frequency
    – Power factor, Cos φ
  • 2 setting groups, locally or remotely selectable by digital input or by the communication channel
  • Self-diagnosis: Memories, output relays, A/D converters, auxiliary supply, cycles of execution of software, hardware failure
  • 7+1 programmable output units / 8 programmable digital inputs
  • Event recording: 250 locally recorded events, 200 saved in case of loss of auxiliary supply
  • Disturbance recording according to Comtrade® format: storage of 4 recordings of 52 periods
  • Optional Communication by Modbus® RS 485 or Ethernet by Modbus/TCP


  Device Doc. Type Lang. Ref. Index
NPG800 Leaflet EN A497 E
NPG800 Leaflet FR I496 E
NPG800 First Handling Guide EN A501 C
NPG800 User Manual EN A505 C
NPG800 Connection/Definition Diagram EN / FR S39494 B