During a routine inspection at Huntly Power Station, Genesis Energy identified an oil leak affecting a critical 220kV oil cable outdoor termination on Unit 2. With Unit 4 already offline for scheduled maintenance, continued system stability and security of supply across the Auckland and northern networks depended on a rapid and effective response.

Northpower’s Auckland subtransmission team was engaged to assess the issue and carry out the termination repair. Our role was to remove and replace the compromised termination, safely restore the asset, and return the unit to service within a constrained timeframe and a live operational environment.

Termination repairs of this nature require highly specialised technical skills and careful execution. On arrival at site, the team quickly identified a hairline crack at the base of the red phase porcelain insulator as the source of the oil leak. A rapid action plan was developed to remove the damaged termination and replace it using a spare insulator stored on site.

After confirming the spare insulator was a precise match, scaffolding was erected and oil pressure stabilised to allow safe removal. The 2.5‑metre insulator was dismantled and replaced within two high‑intensity workdays. The repair was carried out in the Transpower yard, adding complexity due to crane operations and site constraints, which were managed through detailed planning and co-ordination.

Once installed, the termination was vacuumed down and underwent final oil testing to confirm performance and integrity.

Health and safety were critical throughout the repair. The work involved crane lifts, pressurised oil‑filled equipment and activity within a live transmission environment, requiring strict controls and disciplined site management.

The team implemented clear lift plans, controlled exclusion zones and closely sequenced work activities to manage risk. Collaboration with Genesis Energy, Transpower and the Huntly Power Station team ensured permits, access and safety requirements were aligned, enabling the repair to be completed safely and without incident.