National Grid has installed overhead conductors on all 116 of the new T-pylons that will connect Hinkley Point C to the grid.
The 57km Hinkley Connection Project runs between National Grid’s new Shurton substation on the Hinkley Point C site and its existing Seabank substation in Avonmouth. Of that, 48.5km is overhead lines – mostly T-pylons – with 8.5km underground through the Mendip Hills Area of Outstanding Natural Beauty. There are short sections of traditional lattice pylons at each end of the route at Shurton and Avonmouth – the latter to ensure safe height over the Port of Bristol area.
The T-pylon design has six conductor spans attached to each diamond-shaped insulator on either side of the structure. Each T-pylon supports 12 conductors, so National Grid and its contractor Balfour Beatty have installed a total of 460km of power line between the T-structures weighing 1,288 tonnes.
Wires were installed in sections of up to a dozen T-pylons at a time, taking two weeks for each section. Conductors were transported to each stringing site on large drums weighing up to seven tonnes and standing eight foot tall, before engineering teams set about hoisting the wires across the T-pylons.With the help of a steel braided guide rope and circular running blocks suspended from the insulators, the heavy conductors are winched back through the running blocks, with engineers controlling the speed to guide them into position and fix them to the insulators.
Steven Haskayne, project director for National Grid, said: “With the T-pylons fully strung, our Hinkley Connection Project is really starting to take shape. It’s a proud moment for all the teams involved, from our National Grid colleagues to our contractors, all of whom have helped us reach this milestone safely and on schedule.
“We’re grateful to all of the local communities we’ve been working alongside for their patience as our project team continues its work, which is moving us closer to a resilient and secure low carbon energy supply for millions in the region.”
T-pylons make up the majority of the Hinkley Connection Project’s 57km route through Somerset, with.
High voltage electricity is already flowing through 36 T-pylons, a new National Grid substation at Sandford, and the underground cables through the Mendip Hills. All the remaining T-pylons will be energised by the end of 2024.
As part of the project, National Grid is also removing 67km of existing overhead lines and pylons – 249 in total – from Somerset. That includes 30 pylons running parallel to the new undergrounded section in the Mendip Hills, which will leave the landscape pylon-free for the first time in nearly a century.
(Photo: National Grid)