PressPack

Power electronics for subsea applications

The realization of subsea oil and gas processing is demanding new technologies within electrical power systems and components. There is currently a need for local supply systems close to wellheads serving equipment such as gas boosters, oil pumps and separators. In the future we anticipate the development of supply systems for long step-outs where high voltage DC represents a viable solution. Due to the very high reliability and operability demands for subsea processing equipment there will also be a very high reliability and ruggedness demands for electric the components and systems.

Large power converters like for gas boosting are assumed to be located on the seabed at various depths, possibly in excess of 3000 metres. Current designs offered by the industry for subsea converter operations are based on concepts in which the power circuits are assembled in their entirety in steel vessels at atmospheric pressure. As operational water depths and converter power rating increase, pressure vessels become increasingly heavy and unwieldy due to the need to increase wall thickness. Consequently, heat transfer from the power electronics components to the seawater becomes problematic. For this reason, the oil companies are looking for less cumbersome subsea power electronics systems. The development of pressure tolerant power circuits is a significant step in the right direction, opening the door to reducing device weight and volume. Furthermore, systems such as this will provide opportunities for improved power component cooling systems that will increase reliability and reduce costs. The availability of reliable pressure tolerant converter systems will enable the introduction of new concepts for subsea transmission and electrical power distribution, including the use of DC and frequencies other than the 50/60Hz range. Indeed such enabling technologies will also open up for quite new concepts for electric power transmission and distribution within the renewable energy sector such as for offshore wind power.

Our services

SINTEF has wide-ranging experience from development of power electronics components and systems. Furthermore, new expertise has been gained by three recent research projects addressing power electronics for subsea applications and two research projects addressing reliability and ruggedness of power electronics. We are well equipped to assist industry and the energy companies in the fields of analysis, development, testing and qualification of systems, components and materials for such applications. This includes the development, testing and qualification of pressure tolerant converter systems.

Projects

We assist industry with the development, testing and qualification of converter products for subsea applications, including components for pressure tolerant applications.

We assist the industry, engineering and energy companies with the analysis and simulation of complete subsea power systems, from the onshore or platform power supply to the subsea load.

We carry out analysis and verification studies using numerical and hardware-in-the loop simulations of power grids and plants in order to resolve potential converter operation problems.

We offer special laboratories and equipment for the testing and qualification of pressure tolerant converter components, including pressure vessels for live component operation up to 500 bar, corresponding to 5000 metres water depth.

Status

• Two completed R&D projects to provide technologies for enabling pressure tolerant convert components – PressPack and Feasible power electronics for demanding subsea applicationsOne accomplished R&D project to provide accurate models for numerical simulation of complex subsea power systems - Subsea Power Systems
• References from several completed studies for the industry clients of subsea power transmission and conversion concepts.
• References from several analytical projects to solve problems related to unintended interaction between power grid components and converter loads.