Construction of the T-pylon test line has commenced at National Grid’s Eakring Academy in Nottinghamshire – a major step towards the introduction of the innovative support structures into UK’s high-voltage electricity grid.
The test line, to consist of six high-voltage pylons, will include five variations of the T-pylon design, developed to meet different operational needs in the field such as turning corners or terminating overhead lines and taking them underground.
“The test line has a major role to play in the successful delivery of the T-pylon,” said David Wright, National Grid’s director of electricity transmission asset management.
“It will enable us to develop construction techniques before we use the T-pylon on a new transmission line and we will be able to train engineers on maintenance and cabling of the pylons – all vitally important with such a new design”.
Having been selected in a 2011 competition from 250 proposals, the T-pylon features a shorter, slimmer design than existing lattice power towers, thus promising to blend more easily into the landscape.
“The T-pylon is not set to replace the familiar steel lattice pylon but it is an alternative option we can offer communities when we are building new transmission routes,” Wright explained.
Since the competition in 2011, held jointly by the UK Department of Energy and Climate Change, the Royal Institute of British Architects and National Grid, the latter has been continuously refining the T-pylon’s design in cooperation with Danish architecture studio Bystrup, which developed the concept.
Its trademark T-shaped design and characteristic layout concentrating all cables and insulators into two diamond-shaped formations enabled the height of the pylon to be lowered to just 35 metres.
The T-pylons will provide an alternative for National Grid to limit impact of the electricity infrastructure on the countryside where high costs prohibit burying the cables underground.
A prototype structure was built and tested in Denmark. However, the test line, to be completed by the summer of 2015, will represent a major qualitative leap as it will include T-pylons for the first time equipped with electrical insulators that hold the cables or conductors.
The contract to install the foundations and erect the T-pylons at Eakring was awarded to Balfour Beatty, which has already completed piling for the foundations. The work to form the base for the T-pylon will be completed in January 2015.
The specialist steel manufacturer, Mabey Bridge, will produce the six prototype T pylon structures for the test line at its factory at Chepstow, South Wales. The assembly and erection is expected to take place in spring 2015.