Cook Strait Cable Lay
Building inter-island connections
The backbone of our national grid is a system of HVDC cables which connect the electricity networks of the North and South Islands. Travelling 610km from Lake Benmore on the Waitaki River to Oteranga Bay, near Wellington, the cables supply North Island homes with cheap power from the South Island’s hydroelectric power schemes.
Arguably the most integral piece of cable is the 40km section that carries power under the turbulent waters of the Cook Strait. We played a key role in both the laying of the original cable in the sixties, and the new cables twenty five years later.
We played a key role in both the laying of the original cable in the sixties, and the new cables twenty five years later.
When the original cable was laid in 1964, we constructed sealing end-supports, protection for jointing and joint pits on the shoreline at Oteranga Bay (North Island) and Fighting Bay (South Island).
By the late eighties, New Zealand’s growing population and increasing demand for electricity prompted Transpower to upgrade the inter-island link. Brian Perry Civil was engaged as part of a subcontract to the Alcatel STK/ABB Cables AB Consortium to undertake all shore based works and maritime assistance associated with the laying of three new 350 KV DC power cables and two fibre optic cables across the Cook Strait, and new cable terminal stations at Fighting Bay and Oteranga Bay. In Joint Venture with Wendell Offshore Services, Brian Perry Civil’s work scope included:
- Land route preparation including trenching, bedding and backfilling
- Landing cables on shore at both ends and winching into the terminal buildings
- Maritime assistance during cable laying and beach landings including standby tug support to the cable laying vessel, ROV assistance and diving support.
- Burial of cables into the seabed within 200m of MHWM by underwater jetting.
- Assistance with electrical termination of cable
- Installation of additional cable protection at suspensions, cross-overs and in surf zones.