High voltages and high pressure

In the electric power laboratories at SINTEF Energy Research and NTNU we have been working with high voltages and high currents for a long time. As oil and gas production is being moved out to greater water depths and more of the processing is subsea, interest in electric power technology from the oil industry sector is increasing.

This can be seen in our laboratories where we are conducting development tests of various systems for electric power supply and use on the seabed.

The now deceased Gunnar Klevjer was a pioneer in this area. Together with his research group, he developed the concept for electrical heating of oil/gas pipes on the seabed. After long and careful consideration Statoil decided to use this concept for several oilfields. And as has been seen many times before, new applications bring new requirements for the components that are used.

Our established expertise in the lifetime characteristics of insulation materials and our specialist knowledge on the growth of water trees in polymers are in demand when the materials are subject to huge hydrostatic pressure and temperature variations. It seems that new and so far unknown phenomena may occur during aging in such conditions. In close cooperation with our  clients, we have invested in a dozen or so pressure tanks in which aging-tests of components and materials can be done at atmospheric pressures of up to 100 bar and temperatures of 120 to 150 degrees C. Some of these tanks can be filled with seawater, which is highly corrosive at high temperature. For this reason we have purchased tanks of titanium which among other purposes can be used to simulate the environmental forces on cables at depths of 300 metres. Others tanks are used to evaluate the water intake by polymers under high pressure.


Published July 27, 2012

Contact:
Rolf Hegerberg


Aging of cables for offshore power supply. Inside the tanks are pressurized and contain seawater. The heating elements are on the outside. Photo: SINTEF Media