A huge £500m project that will connect the electricity grid on either side of the Moray Firth in northern Scotland, will also bear the indelible mark of HBPW’s engineering team.
In 2014 Zurich based ABB corporation was awarded the contract by Scottish Hydro Electric Transmission plc (SHE Transmission), part of Scottish and Southern Energy (SSE), to create the subsea Caithness Moray high-voltage direct current (HVDC) power transmission link.
And, as part of the half a billion pounds project, ABB decided to work with Graham Construction and HBPW to design, engineer, supply and commission two 320 kilovolt (kV) land-based HVDC Light converter stations, one rated at 1,200 MW at Blackhillock in Moray and another rated at 800 MW situated at Spittal in Caithness.
Managing Partner, Paul Withers, said: “Each of these sub stations contain hi-spec equipment which produce intensive, and dangerous, electromagnetic waves. We were asked to produce engineering and fabrication drawings for the aluminium lining that will encase each of the steel superstructures to effectively create a Faraday Cage. This special type of enclosure is used to block potentially damaging electric fields and is formed by conductive material or by a mesh of such materials.”
The challenge was to determine how best to anchor the aluminium walls and mesh ceiling to the cage cladding and frame. It took some considerable planning and thought but we achieved a good outcome despite some early challenges.”
The generation of electricity from renewable sources in the north of Scotland has been growing rapidly in recent years, with the growth forecast to continue with proposed wind, wave and tidal generators contracted to connect.
However, to provide the capacity needed to accommodate this significant new generation capacity, a major reinforcement of the transmission network serving the north of Scotland was needed.
As a key element in this reinforcement SHE Transmission identified the need for a subsea power link, capable of carrying up to 1,200 megawatt (MW) of electricity – equivalent to the needs of around 2 million Scottish residents – between Caithness and Moray.
With associated reinforcement of the existing onshore network, this project represents the largest investment in the North’s electricity network since the hydro development era of the 1950s.