Supergrid transformer and SF6-free switchgear arrive at London Power Tunnels substation
Image courtesy National Grid
A 178 tonne supergrid transformer and specialist SF6-free technology have arrived at National Grid’s new 400kV Bengeworth Road substation, built by National Grid and construction partner Linxon as part of the £1 billion ($1.2 billion) London Power Tunnels 2 project.
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.
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.
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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 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.
Commenting in a release was Joe Senior, project director for National Grid’s London Power Tunnels 2 project:
“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, added:
“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 132kV 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.”
