Wires to carry electricity onto the UK electricity network have been installed on 36 of the Hinkley Connection project’s new ‘T-pylons’ in a process known as ‘stringing’. The Hinkley Connection stretches 57 km from the Hinkley Point C nuclear power station currently being built by EDF Energy to Seabank power station.
The T-pylons are a new pylon for UK overhead electricity lines, with a single pole and T-shaped cross arms, which feature suspension diamond insulators that hold the wires, or conductors. Some 48 of the new pylons have been constructed in Somerset and engineers have been putting in place the conductors that will carry the electricity.
The Hinkley Connection is made up of sections of traditional lattice pylons and 116 new T-pylons, with a section of underground cable running under the Mendip Hills Area of Outstanding Natural Beauty.
The conductors are transported to site on large drums, weighing up to 7.5 tonnes. Teams of engineers first pull a steel braided rope between sections of up to 12 T-pylons through circular running blocks suspended from the insulators. The heavier conductors are then attached to the rope via a rectangular headboard, which is then pulled back through the running blocks using large winches.
The span of cables between each pylon is up to 360 metres and the conductors are installed in sections of up to 12 pylons at a time, with each section taking around two weeks to ‘string’.
The T structure is the first amendment to the UK’s traditional lattice pylon design in nearly 100 years. The body of the T-pylons are made in China, while the diamond-shaped structures are made in the UK.
Stringing is now complete on 36 T-pylons between Woolavington and Loxton, and work is due to start in April to install the conductors on 12 T-pylons between Bridgwater and Woolavington. The 48 T-pylons will be energised in October 2022, says National Grid. There will be a total of 116 T-pylons along the route, to be completed, including stringing, by 2023.
The Hinkley Connection project will be ready to connect six million homes and businesses in the south-west of England and beyond with low-carbon electricity generated by Hinkley Point C and other sources of low carbon energy in 2024, says National Grid.
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