Cable service for largest onshore wind farm in Australia

The contract covers the design, manufacturing, supply, installation and testing of the cable network and is worth over €12m (around A$20m), of which approximately €5.2m (around A$9.1m) will be attributed to Nexans.

Marais Laying Technologies Australia brings to the consortium its expertise in the automated trenching and laying of long lengths of single-core cable. The Marais SMC 200 R Trencher will be used to cut around 130km of narrow trench while simultaneously laying the cables and backfilling.

The highly automated approach provides close control of the trenching process. This enables the cross-section of the trench to be minimised while still providing the protection essential to maintain the cable ratings, so that less sand is used in the construction of the wind farm.

For the Stockyard Hill project Nexans is providing its range of Nexans WINDLINK solutions consisting of a variety of 33kV power cables manufactured at Nexans China facility in Yanggu, China, with aluminium conductor cross-sections ranging from 95 to 1,000mm2. Building on its expertise in network engineering, Nexans offers a capability to manufacture the cables in long continuous lengths, allowing for an optimised cable network layout with a minimum number of joints.

As part of its complete end-to-end service, Nexans Olex subsidiary Nexans Australmold is also supplying the underground junction cabinets for the cables, the indoor terminations for the substation connections and the tower end Ring Main Unit (RMU) connections.

A total of 275km of 33kV Nexans WINDLINK cables will be installed in trenches to collect the electricity produced by the individual wind turbines and feed it into three 33/132kV substations that will connect the wind farm to the local grid.

As the medium voltage (MV) collector system is one of the key expenditures in wind and solar farm projects, the Nexans and Marais Laying Technologies Australia consortium also created a unique design methodology to help Goldwind Australia address its CAPEX and OPEX challenges at Stockyard Hill.

Supported by Nexans Research Center in Lyon, France, the new integrated service allows to optimise the turbine collector grouping and MV system layout, design trench cross-sections, and choose the appropriate cables and accessories for the project. By avoiding splitting the design work among different companies involved in wind and solar farm construction, the service allows developers to exploit the existing synergies within their projects and consequently optimise the final costs all with a collector system warranty.

For instance, in the case of the Stockyard Hill project, the design optimisation service has allowed to take into account the detailed analysis of the soil thermal resistivity and its effect on cable temperature and has led to the redesign of the MV collector system to reduce the length and dimensions of trenches while protecting cable current ratings.

“We are delighted to bring our cutting-edge integrated solutions for underground network installation and existing network management to this ambitious project. This contract confirms the technological know-how Tesmec developed in the energy sector and renewable energy plants in particular,” commented Tesmec Chairman and CEO Ambrogio Caccia Dominioni. “This contract is the cornerstone of our partnership with Nexans that lays the foundation for our larger cooperation worldwide.”

“The Stockyard Hill Wind Farm is a perfect example of Nexans’ commitment to creating value for our customers by driving CAPEX and OPEX savings across their renewable energy projects,” said Veronique Stappers, Strategic Marketing Director for Industry and Solutions Business Group.

“We are honoured to join our forces with Tesmec in order to contribute to making wind and solar farm projects more competitive while driving the enhanced performance of the assets.”

Trenching and laying of the 33kV power cables, fibre optics and earthing cables for the first collector group of 13 turbines started in the fourth quarter 2018.

The 530 MW Stockyard Hill Wind Farm promises to be the largest wind farm in Australia and the Southern Hemisphere. The wind farm will have 149 turbines capable of producing enough electricity to power around 390,000 homes while also helping the state to save around two million tonnes of CO₂ emissions a year. Located 35km west of Ballarat in Victoria’s central highlands, the project is expected to create up to 300 jobs during construction peaks on site and employ up to 25 permanent maintenance staff once the wind farm is complete.