Solutions   for   Protecting   andManaging   the   Electrical   Network

NP.I 800

Phase and Earth Overcurrent Protection

NPI800 provides the three-phase and earth fault overcurrent protection for medium and high voltage electrical networks. This multi-function relay supervises phase to phase and phase to earth faults, negative sequence currents, thermal state of the protected device and the good operating of the circuit breaker and its trip circuit.
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.
Version NP.IR 800 also integrates a 4 cycle recloser function.


  • Overcurrent with 3 thresholds [51-1] [51-2] [50]
  • Earth fault with 2 thresholds [51N] [50N]
  • Thermal overload for cable and transformer [49]
  • Negative phase sequence overcurrent [46]
  • Broken conductor with 2 thresholds [46BC]
  • Latching of the output contacts [86]
  • Trip circuit supervision of the breaker [74TC]
  • Breaker failure [50BF][50N_BF]
  • Recloser 1 fast cycle and 3 slow cycles [79] (NP.IR 800 version)


  • Configuration and parameter setting by local MMI or off-line / on-line PC
  • Measurement of electrical quantities:
    – Instantaneous, integrated and maximum values of phase and earth currents
  • Logical selectivity on the three phase thresholds and the two earth thresholds
  • 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
  • 3+1 assignable output units / 4 assignable digital inputs (option: additional card with 4 assignable output relays and 4 assignable 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
NPI 800
NPIR 800
Leaflet EN A528 F
NPI 800 First Handling Guide EN A335 I
NPI 800 User Manual EN A333 J
NPI 800 Connection/Definition Diagram EN / FR S38018 G
NPI 800 - S1 Connection/Definition Diagram EN / FR S41022 A
NPIR 800 Connection/Definition Diagram EN / FR S38023 G