London Power Tunnels substation takes delivery of supergrid transformers and UK-first SF6-free switchgear
- First of two 178 tonne supergrid transformers arrives at new Bengeworth Road substation
- New high voltage SF6-free switchgear also being installed at substation in UK first
- Developments are latest milestone in National Grid’s £1 billion London Power Tunnels 2 project
A 178 tonne supergrid transformer and specialist SF6-free technology arrived at National Grid’s new 400kV Bengeworth Road substation, which is being built by National Grid and construction partner Linxon as part of the £1 billion London Power Tunnels 2 project to reinforce the capital’s electricity network.
Weighing the equivalent of 30 African elephants, the first of two transformers was delivered to the substation in Lambeth from the Port of Tilbury – with haulage experts Allelys delivering the giant device through London’s streets on a specialist vehicle under police escort (see editors’ notes for route details, images and video).
High voltage EconiQ™ gas-insulated switchgear (GIS) and gas-insulated lines (GIL) developed by Hitachi Energy have also arrived for installation at Bengeworth Road, marking a key milestone in the construction of the country’s first substation to be free of sulphur hexafluoride (SF6) gas.
SF6 is commonly used in high voltage electrical equipment around the world owing to its chemical stability and insulating properties – which help prevent short circuits, and keep supplies safe – but it is among the most potent greenhouse gases.
The installation of SF6-free EconiQ GIS and GIL at Bengeworth Road as part of the London Power Tunnels 2 project represents a crucial step towards National Grid’s ambition to reduce emissions of the gas from its network by 50% by 2030.
SF6-free technology has been trialled on National Grid’s transmission network before, notably at its 400kV Richborough substation in Kent where engineers successfully removed SF6 from an existing gas-insulated busbar and replaced it with a greener alternative.
The recently energised 400kV Littlebrook substation in Kent is also partially SF6- free featuring GE Vernova’s g3 gas-insulated busbar equipment, which is helping National Grid to save 5.6 tonnes of SF6 from its network.
Substations and their technologies play a vital role in helping to ensure safe and reliable electricity supplies, with transformers and switchgear changing voltage levels up or down and switching electricity flows to make sure power can be transmitted and distributed safely around the country.
National Grid’s new Bengeworth Road substation is situated in the centre of its 32.5km London Power Tunnels 2 route between Wimbledon and Crayford, and will provide a 132kV connection for local grid operator UK Power Networks to distribute electricity on to homes and businesses in the area.
A second transformer is planned to arrive at Bengeworth Road on the first weekend in February, with two further transformers planned for delivery to National Grid’s New Cross substation – also part of the London Power Tunnels 2 project – in February and over spring.
Last year National Grid energised the first of the project’s new electricity transmission circuits installed deep underground across the south of the city.
Joe Senior, project director for National Grid’s London Power Tunnels 2 project, said: “The arrival of these supergrid transformers and SF6-free switchgear is a key milestone for our Bengeworth Road substation build and for the London Power Tunnels 2 project.
“We’re rewiring the capital to help ensure secure energy supplies into the future, and by using sustainable technology we’re also able to minimise the environmental impact of our operations to support the transition to net zero.”
Rajesh Balakrishnan, Linxon’s project director for the London Power Tunnels 2 project, said: “Linxon’s London Power Tunnels project team has been working collaboratively over the past several months with National Grid, Hitachi Energy and Hyosung, the transformer supplier, to achieve this milestone.
“The delivery of the transformer to the Bengeworth Road site marks a significant step forward, as it will connect to the first EconiQ 132 kV connection and 400kV GIS. Hyosung has specially procured and type-tested bushings compatible with EconiQ gas, ensuring the transformer aligns with our shared commitment to sustainability and innovation.”
