Reinforcing Adelaide

The Adelaide Central Reinforcement program achieved practical completion in December 2011. The major electricity infrastructure development for the Adelaide CBD is the largest project to be energised by South Australia’s high-voltage electricity transmission network owner and manager ElectraNet.

A new substation powers central Adelaide, connected via underground cables with cutting-edge monitoring technology and high-voltage transmission lines. The Adelaide Central Reinforcement (ACR) program will ensure continued security and reliability of electricity supply and facilitate the long-term growth and development of Adelaide and the South Australian economy. Representing an investment of nearly $180 million into the South Australian high-voltage electricity network, the program is transmitter ElectraNet’s largest project to date. The the technical energisation of the new City West substation took place in mid-December, while the official opening ceremony will take place in the first quarter of 2012.

“The collaboration of our various design and construction partners, the patience and support of the local community and the expertise of ElectraNet staff has enabled the energisation of this new substation to occur right on schedule, after a project construction period of nearly a year and a half,” ElectraNet CEO Ian Stirling said.

“Extensive community engagement was actively undertaken throughout the whole process enabling ElectraNet to work closely with businesses and residents in the area to effectively minimise impacts such as noise and traffic interruptions during construction.”

The independent energy regulator, the Essential Services Commission of South Australia (ESCOSA), determined that a second high-voltage transmission line was necessary to meet Adelaide’s projected electricity demand and ensure continued reliability and security of supply into the future. Previously, the Adelaide CBD was served by a single high-voltage, underground 275kV electricity transmission line from the Magill substation, and multiple 66kV distribution lines by ETSA Utilities.

A new substation was established at Keswick Terminal, named City West Substation, which is supplied from Torrens Island via a new underground electricity transmission line spanning a route of approximately 18km. It is connected to ElectraNet’s statewide communications network via a new underground fibre-optic cable.

A key milestone in the construction phase of the substation was the delivery of two power transformers from Brisbane. Each transformer weighed approximately 188 tonnes – the heaviest objects ever to be transported on Adelaide roads. The total weight of the road transportation for each single transformer was a significant 450 tonnes. The transformers were transported through Adelaide to the new City West substation at night in order to minimise the impact on traffic, local businesses and residents.

To manage the massive weight of the transformer, the delivery needed to be undertaken on two large platform trailers combined with a 250 tonne beams transporter, making a combined total length of approximately 10m. The 2122km distance took 16 days to complete.

The underground transmission cable route spans approximately 18km in length extending down the main thoroughfares – Grand Trunkway and Port Road between Torrens Island and Keswick Terminal substations. Construction of the cable was typically within road laneways and road reserves, including some car parks within the Port Road median. The cable also crosses the River Torrens via a new combined cycle and pedestrian bridge, passes through Bonython Park and crosses the Bakewell Bridge.

ElectraNet made it a priority to minimise impacts to motorists as well as businesses, residents and the community along the cable route. A comprehensive traffic management plan was prepared and implemented in collaboration with contractors, the South Australian Department for Transport, Energy and Infrastructure, stakeholders and local Councils to ensure traffic and parking disruptions were kept to a minimum during the construction phase.

The ACR program introduced a number of innovative engineering solutions. A new condition-monitoring system (CMS) has been used to monitor and control the underground transmission line. One of the first of such systems used in Australia, the CMS monitors every metre of the cable. A key component of the CMS is the Distributed Temperature Sensor (DTS). Resistance temperature detectors (RTDs) are used to calibrate the DTS. The permanently fixed RTDs along the cable route enable constant monitoring of the cable.

The River Torrens bridge crossing presented some unique design and engineering challenges. The solution, a combined cycle and pedestrian bridge, is not only an essential element of the cable alignment, but was also designed to blend with the natural environment, meet strict safety standards and provide a useable pathway for commuters and Park Lands users. The River Torrens Bridge was installed using four cranes in order to cater for the weight of the bridge. Three of the cranes lifted the bridge into place, while the other provided the footing to assist the lifting. This process required a very high level of planning and synchronisation.

The Grand Trunkway (North Arm Bridge) cable crossing at Torrens Island provided further design challenges. The North Arm Bridge has nine spans and its expansion is up to 250mm. An expansion chamber, therefore, had to be designed to accommodate this bridge expansion. This was achieved by constructing an underground room to allow for movement of the cable. The cable was positioned on rollers and pivoting clamps to allow for this movement and to cater for the bridge expansion and contraction.

The 18km of 275kV high-voltage electricity transmission line required for the ACR program was manufactured in sections of approximately 650m in factories owned by the LS/Taihan Consortium – formed by LS Cable and Taihan Electric Wire Company, both from South Korea – as the transmission line principal contractor. For the City West substation, the Alstom/ETSA Consortium – formed by Alstom Grid from France and ETSA Utilities from South Australia – was in charge of delivering the new substation at Keswick Terminal. Subcontractors Diona and York, construction partners for the transmission line and substation respectively, worked collaboratively with ElectraNet in order to facilitate the delivery of the ACR program efficiently and with minimum disturbance to the general public. Strict monitoring of the various contractors activities has been required as a remarkable amount of interfacing activities were implemented to achieve the overall project completion.

ElectraNet’s executive manager network services Phil Court-Kowalski acknowledges that having close working relationships with contractors and subcontractors is of paramount importance when delivering large-scale infrastructure projects.

“The rich mixture of nationalities, languages and cultural backgrounds involved in the ACR program proved to be one of the first challenges for our team,” Mr Court-Kowalski said. “However, through regular two-way communications and our ‘one Tteam’ culture, we overcame the challenges imposed and are now close to delivering these new assets on budget and schedule. Well done to all.”


Stakeholder engagement

ElectraNet’s communication and stakeholder engagement strategy was designed to deliver a robust process that would build ongoing trust and credibility with stakeholders and the broader community. The philosophy underpinning the design and delivery of this engagement strategy was to involve stakeholders and impacted communities in the project’s planning and decision making process and to keep them informed throughout construction. ElectraNet’s community liaison officers were on call 24 hours a day, seven days a week to respond to queries and then to inform the construction team of any issues as required.

The ACR program team worked closely with the LS/Taihan Consortium and its subcontractor Diona throughout the project to ensure stakeholder issues were identified early. This essential information fed into the design process and the development of the construction methodology and traffic management plans.

ElectraNet was aware of the need for continued road access and parking for local businesses and residents and undertook a significant stakeholder engagement to communicate the project and construction needs and to identify opportunities to minimise construction impacts.


Blending with the environment

ElectraNet’s new City West substation at Keswick Terminal was architecturally designed to blend with the local environment and minimise visual and noise impacts. The City West substation has adopted urban design, landscape and architectural principles to reflect the desired character for the local area. The site will undergo ongoing landscaping treatment with native plant species to enhance the modern design of the first hybrid-design substation in South Australia. The substation had been so well converted that one passerby remarked to the crew working there, “When will they start selling the apartments?”

The installation of the gas-insulated switchgear (GIS) was a particular challenge as the site was still well into construction phase. ETSA Utilities successfully completed the installation and build of the two 300MVA transformers within a very tight schedule.

Additional features of the substation include associated control and protection equipment; high-voltage 275kV underground transmission line entering City West substation; and low-voltage 66kV underground distribution lines leaving City West substation to supply the CBD, southern and western suburbs with electricity.

During the 150,000 man hours on site, not a single LTI was recorded, a safety record which ETSA Utilities consistently works to maintain across their workforce.

ElectraNet’s new City West substation at Keswick Terminal was architecturally designed to blend with the local environment and minimise visual and noise impacts. The City West substation has adopted urban design, landscape and architectural principles to reflect the desired character for the local area. The site will undergo ongoing landscaping treatment with native plant species to enhance the modern design of the first hybrid-design substation in South Australia. The substation had been so well converted that one passerby remarked to the crew working there, “When will they start selling the apartments?”

The installation of the gas-insulated switchgear (GIS) was a particular challenge as the site was still well into construction phase. ETSA Utilities successfully completed the installation and build of the two 300MVA transformers within a very tight schedule.

Additional features of the substation include associated control and protection equipment; high-voltage 275kV underground transmission line entering City West substation; and low-voltage 66kV underground distribution lines leaving City West substation to supply the CBD, southern and western suburbs with electricity.

During the 150,000 man hours on site, not a single LTI was recorded, a safety record which ETSA Utilities consistently works to maintain across their workforce.