Subsea Power Control

Powering installations on the seabed

The Subsea Power Control system is a very important component of the Subsea Power Grid.

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It ensures several important functions in the subsea power distribution:

  • Direct transfer of every command given in the topside control system to the respective subsea control module,
  • Transparent communication of status and information from the respective subsea modules like variable-speed drive (VSD) and switchgear to the topside control system,
  • Delivery of standardized interfaces (e.g. SIIS to other subsea application like sensors and/or pump systems).
  • Delivery of a transparent communication channel from topside all the way to the subsea variable-speed drive (VSD). This enables configuration of the VSD, update of VSD software, as well as diagnostics and service being done the same way as with a topside VSD.


The Subsea Power Control system is connected with topside control via an embedded fiber in the subsea power umbilical.

 The fiber is terminated and connected to a subsea electronic power control unit (EPCU) - the “brain” of the Siemens Energy Subsea Power Grid. This controller unit processes commands and information and generates the correct commands locally to the respective subsea modules like variable-speed drive (VSD) and switchgear. All data flow subsea is sent to and from the respective units via a remote termination unit (RTU) in an Ethernet data network.