The Challenges of Offshore Power System Construction - Troll A, Electrical Power Delivered Successfully to an Oil and Gas Platform in the North Sea

In February 2005 the world’s first offshore HVDC transmission was successfully commissioned. It consists of two parallel 40 MW transmissions connecting the Troll A gas platform in the North Sea, with the mainland 132 kV grid via compact polymeric DC cables. A compact and lightweight offshore module was designed by ABB in collaboration with the client Statoil. The project has allowed valuable experience in the design and construction of high voltage plant in a salt laden, hostile environment to be obtained. With safety as a primary consideration, considerable experience in offshore construction techniques has been gained. The success of the Troll project has been one of the key components for British Petroleum, who in June 2005 placed a second offshore HVDC Light order with ABB for their 78 MW transmission to the Valhall field. The engineering design and construction challenges overcome in these pioneering offshore projects is directly transferable to the new high power, high voltage, offshore substations required to enable, safe, reliable operation of the future very large offshore wind farms.