Dunipace Sub-station construction case study
Substations are required to transform electricity to a lower voltage to supply local homes and businesses, and switch electricity flow over different routes to supply different areas of the country or provide backup in the event of a fault.
The new substation at Denny, near Dunipace was required as the location was situated where a number of over-head transmission lines crossed and met, and therefore formed a key hub in the existing local electrical network. When complete, it would for the final link in a chain from Beauly to Denny, carrying electricity from windfarms and other renewable sources in the North of Scotland, to consumers in the South.
The substation was to consist of a control building and fenced compound, containing electrical apparatus, including transformers, 400kV and 275kV AIS switchgear and large terminal towers. The upgrade of a 2km stretch of unclassified road leading to the substation site was also necessary, as well as the creation of a concrete pad for mechanical and electrical infrastructure to be installed upon – this equipment can weight up to 180 tonnes!
The site was located on a habitat of raised peat bogs, so as part of the project SP Energy Networks undertook an innovative process of peat deposition to ensure that peat removed from the site, to facilitate the substation would be used to improve habitat and deliver an overall ecological benefit on the remaining area.
The AB2k Solution
With a significant amount of earthworks to be carried out, proving a reliable plant solution was key to ensuring the project progressing. AB2K was approached to provide an operated plant solution to deliver site clearance, and the construction of the new concrete pad for the base of the substation, and were delighted to be involved.
With operations throughout Scotland and strong local knowledge, the AB2K regional teams were familiar with the management of the raised peat bogs – a habitat that covers 23% of Scotland’s land area – and were able to liaise with the SPEN environmental team working at Torwood Mire (adjacent to the site) whenever required, allowing safe access for visual surveys and testing.
Coming in ahead of schedule, the Denny sub-station was energised in December 2015, is now an integral part in a five-stage substation ‘chain’, costing over £820m and stretching 220km, the longest transmission line to be built in the UK in recent times.
Described as the ‘power super highway’, this significant investment should help secure Scotland’s electricity network for years to come, and ensure that the Christmas tree lights stay on in 600,000 across the country!