Solutions   for   Protecting   andManaging   the   Electrical   Network

RMSD   7912 / 7921

Digital multicurve directional overcurrent relays

The object of devices in the RMSD 7900 series id to provide directional overcurrent protection of three-phase electrical networks.
They are modular in design and can be totally integrated into the PROCOM structure, or just as easily they may be used independently in any other classical protection scheme.

The RMSD 7900 incorporates two different devices:

  • RMSD 7912: designed for the protection of loops or the rapid separation or "islanding" of networks having several sources in parallel
  • RMSD 7921: designed for directional earth fault protection on looped networksor those having multiple earthing points


  • Earth directional overcurrent [67N] (RMSD 7912)
  • Phase directional overcurrent [67] (RMSD 7921)


  • 3 programmable output units with 2 contacts each
  • Programmable dependent or independent time curves
  • Self-monitoring unit
  • Measurements of phase currents including harmonics up to 7th (RMSD 7921)
  • Measurements of the earth current including harmonics up to 7th (RMSD 7912)
  • Settings via local HMI
  • Modbus communications with Current Loop interface


  Device Doc Type Lang. Ref. Index
RMSD 7000 Leaflet EN / FR -- --
RMSD 7912
RMSD 7921
User manual EN M.1802 A
RMSD 7912
RMSD 7921
User manual IT MI.1802 C
RMSD 7912 Connection/Definition Diagram EN / FR 07A8 C
RMSD 7921 Connection/Definition Diagram EN / FR 05A8 C