The excitation system regulates the voltage and reactive power of a synchronous alternating-current generator.

It monitors the operating point of the machine and maintains it within permissible limits. It is therefore an important component of a hydroelectric set.


  • Design of the (static) excitation system based on the characteristics of the alternator (and in the case of indirect excitation, the exciter)
  • Development of a wiring diagram
  • Supply of the excitation system (on a mounting plate or in cabinets)
  • Commissioning of the excitation system
  • Documentation

Specific skills

HYDRO Exploitation’s engineers have in-depth knowledge of excitation systems with ABB’s UNITROL1000 voltage regulators and have already equipped several dozen facilities.
Thanks to our own development work, we are in a position to offer excitation systems at several hundred amperes by combining standard manufactured components, using a thyristor bridge external to the UNITROL regulator.

On request, we can also offer synchronisation, which can be delivered inexpensively using the UNITROL internal synchronisation function and a syncro check relay. Alternatively, ABB SYNCHROTACT (5 or 6) devices can used, if the client wishes.

Client benefits

  • An excitation system adapted to their individual requirements
  • A system with easily replaceable manufactured components (except for the UNITROL1000 voltage regulation)
  • Support from HYDRO Exploitation even after commissioning

Rue de l’Industrie 10, 1951 Sion
HYDRO Exploitation SA
Rue de l’Industrie 10
CP 315 - CH-1951 Sion
Contact us
HYDRO Exploitation SA
Rue de l’Industrie 10 CP 750 - CH-1951 Sion +41 (0)27 328 44 11
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