Fast transformer delivery brings Sizewell A back to full production

Together, Sizewell A’s two reactors produce more than 10 million kWh of electricity enough power to serve the energy needs of a third of East Anglia. However in March 2004 one of the two GSUs, which step up the power station’s 17.5kV terminal voltage to the 132kV required for the National Grid, came to the end of its 38-year life causing Reactor One to be taken off-line. Although Sizewell A is scheduled to stop generating for good at the end of 2006 there was a clear business case for British Nuclear Group returning Reactor One to power as the cost of lost production far outstripped the cost of a new transformer.

British Nuclear Group gave ABB the task of fast track manufacturing and installing a brand new transformer. including low voltage busducting, high voltage cable works and sitepreparation. David Sullivan, UK general manager for ABB Power Transformers, says, Within just ten days of the initial enquiry, we were able to specify the new transformer, pass British Nuclear Group’s factory quality audit, achieve factory approval, produce a quotation and agree the contract. Crucially, we were also able to guarantee delivery within seven months, so that Reactor One would be back on-line for the start of December. The new 17.5/145kV 340MVA generator transformer is based on ABB’s Trafostar common design and engineering platform for power transformers.

As well as manufacturing the transformer quickly, delivery presented an extra challenge. The 168 tonne load had to be moved through Poland to the Baltic Coast, out through the Kiel Canal and then sailed across the channel from Cuxhaven, Germany to Lowestoft. Excellent co-operation between ABB and British Nuclear Group meant that delivery was not just on schedule but nine days ahead.