Utility Partner Solutions
POWER
DELIVERING ELECTRICAL WORKS FOR THE TRANSPORT SECTOR
In January 2016, Zinfra was awarded a significant project by Transport for NSW (TfNSW) as part of TfNSW’s Power Supply Upgrade Program.
T
fNSW is the lead agency of the NSW transport cluster, which includes Roads and Maritime Services, Sydney Trains, NSW TrainLink and State Transit. The Power Supply Upgrade Program involves construction of new electrical infrastructure and upgrades to substations, sectioning huts, overhead wiring and feeders across the Sydney Trains network - all required to meet expected power requirements of the future rail network. Under the Power Supply Upgrade Program, Zinfra is delivering the design, construction and commissioning of a new substation at Gosford South and a sectioning hut at Wyoming. The 2 x 5MW rectifier 66kV substation will support the 1,500 volt traction power supply needed to run the new fleet on the Central Coast and Newcastle rail line. The new substation at Gosford South and the Sectioning Hut at Wyoming will replace the existing Gosford substation. Zinfra General Manager, John Gardner, emphasised the significance of this project for Zinfra. "This project is strategically important as it represents an important step in our strategy of entering new markets, in particular the rail sector, leveraging off our core utilities capability."
80
UTILITY • FEBRUARY 2017
Zinfra's success in winning this work stemmed from an innovative approach to the tender, which included an internally generated engineering solution. This alternative approach provided TfNSW with cost savings, a reduced building footprint and improved operational capability and performance for the required electrical upgrades and assets. This project at Gosford is by no means straightforward - the location, the site conditions, the surrounding environment, the local community, and proximity to the rail corridor and road infrastructure all mean the project has many challenges.
CHALLENGING CONDITIONS The site of the new substation is challenging. The small site is sandwiched between the railway corridor with its live overhead power lines and trains, Fagans Bay, part of Brisbane Water National Park, and ecologically significant mangroves. The Brian McGowan Bridge flies over another side of the site, ferrying a constant stream of traffic on the Central Coast Highway. The ground, which is located only metres from the water’s edge, is sandy and unstable. A careful process involving extensive testing and sampling was needed to determine a suitable depth for
the footings for the substation. Ultimately, forty piles drilled to a depth of up to eight metres were required. The confined space means the demarcation and management of the respective parking, lay down area, construction zone and designated pedestrian walkways is critical for site safety. Once construction of the substation building begins, the tight space will present new challenges when using cranes to lift and manoeuvre the precast concrete walls, GIS (gas insulated switchgear) and other high voltage electrical equipment into place.
IN-SERVICE RAILWAY LINES Working alongside the active Central Coast and Newcastle rail line, with both up and down running mains and three active sidings, brings its own set of challenges. The construction team works with a wide exclusion zone alongside the rail corridor. When works are required within that exclusion zone, a whole new layer of safety controls and precautions come into play. A large part of the project, to date, has involved an underline crossing (ULX), the installation of conduits under the railway lines and the adjacent sidings.
WWW.UTILITYMAGAZINE.COM.AU