Engineering technology company, Rawwater, has worked with National Grid to deploy its M3 molten metal manipulation technology, ‘M3CollarCast’, to seal Sulphur hexafluoride (SF6) leaks in substations without requiring outages.
SF6 is an insulating gas often used in high voltage electricity equipment to prevent short circuits, keeping networks safe and reliable.
Small leaks most commonly occur as equipment ages; when this happens an outage is often required as the gas is removed, repairs carried out and the gas refilled again.
Rawwater’s ‘M3CollarCast’ solution, involves applying a mould to the leaking pipework, into which a low-melting point liquid alloy is injected. As the seal requires no curing time once solidified, the solution negates the needs for an outage as it can be applied whilst the equipment is in service.
The pilot trial at National Grid’s Deeside Centre for Innovation – jointly funded by the Network Innovation Competition (NIC) and Rawwater – the technology demonstrated that it was deployable and removable on high-voltage electrical infrastructure.
Following further testing at Cardiff University, the technology has now been rolled out to two of the country’s largest hydroelectric and nuclear plants – Dinorwig and Sizewell.
According to the engineering technology company, its ‘M3CollarCast’ solution achieved an average leak rate reduction of 98% when sealing against a seven barg flowing leak in tests.
“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,” said managing director of Rawwater Applied Technology, Kat Lennox.
“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.”
Following its success, National Grid is now said to be exploring the possibility of using the technology for repairs at its Stella West Substation.
“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,” said Nicola Todd, head of strategy and innovation at National Grid Electricity Transmission.
“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.”
National Grid has a target of eliminating SF6from its infrastructure by 2050, with an interim ambition of reducing emissions by 50% over this decade.
