Sydney Park to Haymarket 330kV Cable Circuits
Transgrid
Sydney, New South Wales, Australia
After previously working together to deliver TransGrid’s Cable 42 project, Diona formed a joint venture with J-Power Systems (JPS) to deliver this project, which involved installation of two separate cable routes traversing almost 20km through the Sydney metropolitan area.

This was Diona’s largest electrical infrastructure project to date and was the first time in Australia that XLPE insulation was used in cable of this voltage.
The project encompassed design, manufacture, supply, and install 330kV XLPE (cross-linked polyethylene) underground cable, and associated accessories, sub-systems and civil works for:
- A single circuit between the tunnel portal at Sydney Park, and Haymarket Substation
- Twin circuits between Holroyd and Rookwood Road Substations
Complexity delivered
The project required a large volume of high-risk work including deep excavations (up to 8m), tunnels and confined spaces, working at heights, live rail work, traffic, heavy equipment and high voltage electricity.
Detailed planning ensured that target deadlines were met and that over 200,000 man-hours were worked with no lost-time injuries.