National Grid has rolled out “anti-leak” technology at Sizewell and Dinorwig while keeping the substations in service.
The technology has been developed in partnership with engineering technology company Rawwater to fix leaks of greenhouse gas SF6 while keeping substations safely in service.
The M3CollarCast technology is used to seal flowing leaks without the need to shut down substations. Under traditional methods, such a fix would require a planned outage.
While SF6 infrastructure is designed to be effectively sealed, small leaks do occur as equipment ages and it often requires an outage for the gas to be removed, the repairs carried out, and the gas refilled again.
Rawwater’s solution involves application of a mould to leaking pipework into which a low-melting point liquid alloy is injected. The seal requires no curing time once solidified, so it can be applied to equipment that is in service.
Following an initial pilot trial at National Grid’s Deeside Centre for Innovation, and further studies at Cardiff University, Rawwater’s technology has been successfully rolled out in the field at Dinorwig and Sizewell substations.
Nicola Todd, head of strategy and innovation at National Grid Electricity Transmission, said: “SF6 is a potent greenhouse gas with a global warming potential many thousand times greater than CO2, and it’s a significant contributor to our company’s climate footprint.
“We have a programme of work underway to reduce our dependency on SF6 technology in England and Wales, but initiatives like this innovation project with Rawwater are critical in mitigating its impact in the meantime.
“This clever and cutting-edge new technology is helping us reduce SF6 leaks while keeping our critical infrastructure in service, reducing the need for outages. That’s a double benefit for consumers as we reduce environmental impact and keep electricity flowing around the country.”
The new technology was initially developed as part of a Network Innovation Competition project and is being further developed as an innovation project through the Network Innovation Allowance.
National Grid is also exploring using the technology for repairs at its Stella West substation.
Kat Lennox, managing director of Rawwater Applied Technology, said: “Even though the phase-out of SF6 is planned around the world, it will be many years before this highly insulating greenhouse gas is eradicated completely from electricity supply networks.
“Until that day, a rapidly deployable solution is required to seal or mitigate SF6 leaks. We are proud to have worked in partnership with National Grid to adapt our M3 Molten Metal Manipulation technology for the reduction of SF6 leakage in high voltage electrical equipment, and to be continuing its development to further meet the needs of the electricity transmission sector.”
National Grid has an ambition to eliminate SF6 from its infrastructure – and therefore reduce SF6 emissions to zero – by 2050, with an interim target of reducing emissions by 50% over this decade. Activity is focused on leak identification and repair, and investment in SF6 alternatives.