Tuesday 2nd August 2005
Special fire detectors manufactured by Groveley Detection have formed part of the solution for Troll A's unique ability to power large gas export compressors by importing high voltage DC current from shore.
The giant platform, Norway's largest gas-producer operated by Statoil, is the first offshore platform to use ABB's new high voltage DC transmission called HVDC Light.
But with massive magnetic fields generated by the process of reconverting DC current back to AC offshore, fire detection needed a special solution as normal detectors will not operate under those conditions.
So ABB called on Groveley Detection to devise a fire detection system based on its aspirators to sense smoke in the onshore rectifier station at Kollsnes and in the offshore inverter station on Troll
Groveley installed a total of eight smoke aspirator systems outside the magnetic cages to draw samples through special, non-metallic parts from inside the stations.
Groveley director Robert Bennet said: "The system is a double first - no platform has previously imported DC current, and it's also the first time anyone has overcome the problem of fire detection in a DC-AC converter."
The benefits of the HVDC Light system - due for scheduled start up on Troll A in October this year - are clear; DC current travels a lot further via sub-sea cable than AC and it beats the cost of generating electricity from gas turbines offshore and its inherent problem of creating carbon dioxide.
When Troll A was installed in 1995 it was said to be the largest man-made structure ever to be moved - a concrete platform weighing 678,500 tonnes and standing 472 metres high.
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