Inside the high-wire helicopter operation powering the Hunter REZ

To most people, flying a helicopter anywhere near power lines might sound like sheer lunacy.

However, the highly skilled process of helicopter stringing to install electricity conductors is helping to accelerate Ausgrid's mission to upgrade the transmission lines for EnergyCo's Hunter-Central Coast Renewable Energy Zone (HCC REZ).

Eight kilometres of the 85km of transmission lines were completed on Monday and Tuesday in Lovedale and Keinbah. This followed a trial in April at Muswellbrook.

Crews are expected to work through upgrading existing distribution poles and wires, rather than build entirely new transmission lines, between Kurri Kurri and Muswellbrook until 2028.

Helicopter stringing is a specialised method of installing electricity conductors.

The helicopter flies a lightweight draw-wire along the route between structures. Ground crews then use that wire to pull, tension and secure the permanent conductors.

Ausgrid's HCC REZ project director, Jason Wall, said 18 months of planning went into the installation project.

"It does relate to some very unique circumstances," Mr Wall said.

"Making sure it's all done safely and you're not getting too close to existing power lines.

"The real benefit of this, though, is it's really efficient. So, it can be done quite quickly with less impact on the local community than traditional pulling, which would involve many more trucks and people on the ground."

Queensland-based Leading Edge Helicopters is contracted to complete the one-pilot work for Ausgrid.

"It's amazing how he does it," Mr Wall said. "He gets up there on his own with some ground support, but he's kind of flying the helicopter sideways, pulling a wire behind him and looking out the back as he goes and tries to hook it into the pulleys that are sitting there on the pole.

"He's got about a 10-centimetre gap that he has to drop that wire on each of those pulleys, which he manages to do with great skill."

The Hunter-Central Coast Network Infrastructure Project is the first REZ project to upgrade existing distribution poles and wires instead of building all new transmission lines.

EnergyCo has commissioned Ausgrid to deliver the upgrade to its distribution network and unlock 1 gigawatt of network capacity in the region by 2028.

Mr Wall said upgrading existing poles would benefit the community.

"We feel that this solution is a great outcome for our communities," he said.

"It's lower impact, lower cost, and more efficient in its delivery, so we can do it faster."