THE upgrading of nearly 100 miles of power lines in the north east of Scotland has been completed at a cost of £94 million in a project which revealed a medieval farm along the way.

Scottish Hydro Electric Transmission, which is part of SSE, undertook to refurbish the 275 kilovolt (kV) overhead line on the main west to east transmission route from Beauly north of Inverness via Blackhillock to Kintore near Aberdeen.

It was originally constructed in the early 1960s, spans the local authority areas of Highland, Moray and Aberdeenshire, and is supported on 476 pylon towers.

According to the power company this project has allowed for an 85 per cent increase in the capacity of the overhead line route. This will help meet the needs of developers seeking connection to the transmission network in the north of Scotland, because of more green energy generation planned for the Highland area.

Restringing began in 2010 and at the peak of its activity was employing a workforce of 82. The work was carried out safely, on time and to budget, but it was not without its problems.

SHE Transmission Project Manager Simon Robertson said: “In a number of locations it was necessary to temporarily divert the circuits away from the overhead line route on to new towers in order for the works to be carried out safely, all the while maintaining the transfer of power on the system. On completion of the works the line was returned to the original towers.”

During the five year works the Knocknagael substation, south of the Highland capital, was commissioned and connections to two wind farms were made, Berryburn south of Forres in 2013 and Clashindarroch near Huntly the following year.

Mr Robertson added: “This has been a highly challenging project; from ensuring that the security of the transmission network was unaffected for the duration of the works, through the difficulties of working in the rugged terrain and all the while ensuring that disruption to the residents, the wildlife and the environment was kept to a minimum.

"Along the way we even came across the remains of a medieval farm building at Leylodge in Kintore, which allowed archaeologist to explore the site and log details of this area’s heritage that may otherwise have lain undiscovered."