Is the oil and gas offshore industry ready for all-electric subsea fields? A lot of work has been done on the development side towards closing the gap between traditional subsea production equipment operated by hydraulic control systems and systems that are operated all-electric. Is the gap closed? Is the supplier industry ready?

Oceaneering-owned Ifokus Engineering has developed and qualified the subsea actuators for the Ormen Lange Subsea Compression Pilot (OLSCP). The challenge was to develop compact all-electric actuators that meets safety integrity level (SIL) requirements and has a subsea lifespan greater than 25 years; quick response, high accuracy, full redundancy, remotely operated vehicle (ROV) interchangeability; and full failsafe. These actuators were defined in the early phase of the OLSCP as critical components that had to be developed for a fully operational, all-electric operated, subsea gas compression installation to be successful.

The development has faced numerous technical issues (which have now been solved), and extensive testing for qualifying the components and complete assemblies has been undertaken. Since there are no standards that cover this type of equipment directly, the process of establishing procedures and test criteria has been difficult.

This paper describes the electric linear and rotating actuators developed for the OLSCP, as well as present experience gained from the extensive testing and the project execution. It highlights the lack of standards covering this type of equipment and aids in defining future design and test criteria.


For many years there has been a drive to convert hydraulic subsea applications to electric. Holding back a wider acceptance of subsea electrification previously was the mixed experience with subsea electric distribution systems and subsea electronics. Typical failures were caused by subsea cables, connectors, terminations and electronic components. These failures caused downtime and a need for re-cabling of subsea installations and frequent change-out of components, since designs have trended towards keeping the electrical components to a minimum level.

In the 1990s, initiatives were taken to run power and communication on inductive couplers in the subsea distribution systems, but these couplers had weak points and were only utilised for a short time period. After a number of failures, the systems were changed back to conventional coupler concepts.

Different qualification programmes for cables and connectors have been performed with the goal of establishing connector programmes that are more robust solutions and have low failure rates. The quality achievements through qualification programmes have clearly decreased the failure rates and increased the acceptance of standard subsea connectors and cables.

With today's available technology and the extended need for electrical connection points on subsea structures, it is Ifokus Engineering's perception that the increased flexibility offered by inductive coupler technology will again be utilised on low-power and control applications subsea. This is due to the advantages of there being no galvanic connections between supply and consumer.

Why Subsea All-Electric?

Reasons for looking at electrification include: increased energy efficiency, quicker response time, fewer converting processes (between trigger signal and actuation)

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