Solutions   for   Protecting   andManaging   the   Electrical   Network

NP.IHD 800

Directional Earth Overcurrent Relay

NPIHD800 provides the directional earth fault overcurrent protection for medium and high voltage electrical networks. This multi-function relay also supervises phase to earth short-circuits and the good operating of the circuit breaker and its trip circuits.
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.


  • Earth fault with 2 thresholds [51N] [50N]
  • Earth directional [67N]
  • Latching of the output contacts [86]
  • Trip circuit supervision of the breaker [74TC]
  • BF Breaker failure [50N-BF]


  • Configuration and parameter setting by local MMI or off-line / on-line PC
  • Measurement of electrical quantities:
    – Instantaneous, integrated and maximum values of earth currents
    – Residual voltage value
  • Logical selectivity
  • 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
NPIHD800 Leaflet EN A532 E
NPIHD800 First Handling Guide EN A338 C
NPIHD800 User Manual EN A336 F
NPIHD800-S1 User Manual EN A777 A
NPIHD800 Connection/Definition Diagram EN / FR S38022 G
NPIHD800-S1 Connection/Definition Diagram EN / FR S38827 C