In order to increase transmission capability and improve communication links on the Clunie-Coupar Angus and Couper Angus-Brikhill 132kV OHLs, NorPower was appointed principal contractor to carry out refurbishment works beginning in February 2017.

The north and south DC three-phase circuits between Clunie switching station and Coupar Angus substation-route length approximately 38km-were re-strung with 300mm2 EHC AAAC UPAS sub-conductor and earthwire was replaced with KEZIAH equivalent 48 fibre OPGW. Towers on this line were also painted in order to increase asset life.

With some sections of the Coupar Angus-Birkhill OHL having been refurbished previously, the 2017 works were to reconductor the remaining sections- approximately 4.5km route length-with 300mm2 EHC AAAC UPAS and replace earthwire with HORSE equivalent 48 fibre OPGW.

On both lines tower steelwork was strengthened as required to support the conductor systems, and insulators, fittings and damaged tower furniture were replaced as necessary.

Due to arduous terrain and access distance to individual tower locations, materials were transported to some work sites by helicopter thereby minimising impacts on the ground however, with the line being within, or in close proximity to, several Special Areas of Conservation, Sites of Special Scientific Interest and Special Protection Areas, helicopter operations were carefully planned and monitored. The potential impacts on these important environmental areas were managed through close communication and consultation between NorPower, the Client and the appropriate regulatory bodies. With the works taking place in nesting season, close attention was paid to the potential impact on the various bird species in the area, including kestrel, merlin and osprey;  Pre-start, in-process and post-operation surveys were carried out in areas where there was a high risk of disturbance and operations planned/amended as necessary.

The work was completed, without incident, in January 2018.

Client Project Manager feedback: ''...During each stage of the project [NorPower's] professionalism shone through by all staff involved. The project was delivered on time and in budget whilst meeting [the Client's] standards and specifications which, considering the significant environmental and ecological challenges in the locality was an outstanding effort.....[the Client] carried out regular site visits with only minor issues identified which were resolved in a prompt manner........I would certainly recommend NorPower to carry out any future OHL projects.''

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