National Grid trials temporary encapsulation to capture switchgear gas leaks

Managing fugitive greenhouse gas emissions from ageing high-voltage transmission equipment presents a persistent operational challenge for electrical network operators. High-voltage gas-insulated switchgear and circuit breakers rely heavily on sulphur hexafluoride for electrical insulation and arc quenching. However, as switchgear assets mature, flange seals, valves, and enclosures degrade over time, resulting in minor gas leaks that are difficult to repair without taking critical transmission circuits offline.

The live deployment of temporary encapsulation technology on high-voltage grid assets offers a non-intrusive containment method to capture escaping gas before it enters the atmosphere. Traditional leak remediation typically requires immediate circuit de-energisation, complete gas evacuation, and mechanical joint replacement. By applying a flexible temporary enclosure around weeping flanges or leaking joints, network operators can capture escaping gas directly at the source while maintaining normal energized operation of the substation.

This containment strategy provides transmission and distribution engineers with essential operational flexibility. Outage windows on primary transmission corridors are severely constrained by high grid utilisation and tight security of supply requirements. Capturing fugitive emissions without de-energising equipment allows asset managers to defer intrusive maintenance until scheduled outage windows, avoiding costly unsupplied energy events and system constraint penalties.

Additionally, temporary containment aids utilities in achieving strict environmental compliance targets without forcing premature capital replacement of functional assets. As regulators tighten limits on fluorinated gas releases, capturing localized leaks offers a practical bridging solution for switchgear that remains electrically sound but suffers from localized sealing degradation.

What this means for asset owners in the UK and Ireland: Network operators and industrial high-voltage asset owners in the UK face strict regulatory expectations to curtail fugitive gas losses from switchgear. Employing temporary capture containment on leaking joints enables asset managers in Great Britain to prevent environmental releases, avoid emergency de-energisation of critical substation assets, and coordinate permanent repairs during planned maintenance windows without compromising grid reliability.