CitiPower’s $55 million greenfield Southbank zone substation is the jewel in the crown of inner-Melbourne’s energy network.
• 66kV gas-insulated switchgear
• ABB three-phase enclosed 72.5kV EXK type GIS
• 2500 A-bus
• 31.5kA three-second fault rating
• ABB Unigear ZS1 metal clad switchboard
• 2000 A bus
• 20kA three-second fault rating
• ABB 55MVA 66/11/11kV dual-winding ODAN transformer with detached radiators
Tourists, shoppers and pedestrians enjoying inner-city Melbourne’s Yarra River might give the blocky, grey and red-paneled building situated on Dodds Street no more than a curious glance as they walk past. With a design fusing practical science with a tinge of modern art, the recently commissioned $55 million Southbank zone substation blends into its surroundings, exactly as intended by Melbourne distributor, CitiPower.
The substation is a key electricity distribution hub for CitiPower’s distribution network, ensuring the security and reliability of electricity supply in one of Melbourne’s most sophisticated and busy inner-city precincts, while catering for significant expected growth in demand for electricity in the area. With nearly three times the capacity of its predecessor, it will supply a larger area including the southern parts of the CBD.
CitiPower and Powercor Australia’s chief executive officer, Shane Breheny said the Southbank zone substation marked a significant step forward in terms of design, technology and capacity for the CitiPower network.
“The Southbank zone substation provides innovative solutions for our rapidly changing city which will also enhance CitiPower’s ability to supply surrounding areas including the CBD and inner suburbs south of the Yarra,” Mr Breheny said.
It is the first new fully indoor facility to be constructed in CitiPower’s network and uses the latest technology, including enclosed gas-insulated switchgear, which requires far less maintenance and can be used in a confined space.
Years of preparation were needed before construction could begin on the project in the busy precinct. Powercor network services project leader, Geoff Gravestocks led the team that has worked on the project for more than four years. The 49-year-old project manager brought decades of power line experience to the most extensive major projects he has ever worked on.
“It’s without a doubt the jewel of our crown as far as the business (is concerned), in terms of the aesthetic appeal of the building. It’s the first new zone substation in the area, so it’s the first time that Powercor or CitiPower have been able to go out and spend their regulated money on a project that people can see,” Mr Gravestocks told Energy Source & Distribution.
In order to demolish and reconstruct the old South Melbourne zone substation, substantial works were needed to shift power load to nearby zone substations. For reasons of safety and cost, infrastructure was first built to completely off-load the previous smaller zone substation, which then helped the construction phase by full demolition to a greenfield site rather than re-building the station while keeping part of the station alive.
“We weren’t putting any new load on, but there is extreme complexity about matching it into the existing loads in the system,” Mr Gravestocks said.
Another key point for the project is that it gave the busines an opportunity to build a greenfield zone substation – the first time they have ever done so.
“By shedding the load off the station (four or five years ago) and increasing the capacity of the outer zone substations we were able to shed the load,” Mr Gravestocks said.
“So that’s given us a significant reduction in cost, because we can work in a greenfield situation plus the added benefit that you end up with a brand new complex.”
Powercor offloaded demand on the station by gradually increasing the size of the other stations in the area, providing a three-to-four year timeframe as a greenfield site, as opposed to a traditional brownfield site.
ABB won the tender for the switchgear due to its price and the proven history of its 66 kV, seven bay ring bus ELK-04 gas-insulated switchgear (GIS). The size of the gear was particularly important, as its compactness allowed Powercor to house all the gear in one room.
“Traditionally when we’ve built an outdoor insulated 66 bus work, we would need a separate story of a building to house that infrastructure. So here we’ve been able to put it into a room, which has saved us a story of the building and we’ve been able to leave the building at street level rather then having to go up another story,” Mr Gravestocks said.
The switchgear’s circuit breakers are equipped with self-blast interrupters, which require minimum maintenance and only a low amount of switching energy.
Being maintenance free was another major factor in their selection.
“If there is less maintenance, we are presuming at this stage we will get an increase in reliability in the performance of the equipment. Less moving parts should mean less maintenance and less breaking points,” he said.
Two ABB 55MVA 66/11/11kV dual-winding ODAN transformers with detached radiators have been installed, with provision for a third to be added in the future. Depending on future load trends, CitiPower may add the remaining 33 per cent capacity in five years or so.
The substation is CitiPower’s first indoor station that doesn’t have water-cooled radiators, instead using air convection. Water-cooling can cause health concerns and ongoing maintenance, but in Southbank’s system the hot air rises while specially designed air vents maintain the temperature.
“We haven’t got any of those (water-cooling) issues, which once again improves your reliability for your transformers and your capacity,” Mr Gravestocks said.
Dealing with the complexities of a new zone substation without any prior experience was a major challenge, but Mr Gravestocks is pleased with the project’s planning and execution.
“We now have the ability to take the learnings from this project and it gives us a lot of information in regards to greenfields versus brownfields rebuilds. It just adds another dimension to your business case that you can then put forward,” he said.
The new substation provides more flexibility as it can share load with other sites. In the event of a catastrophic failure, CitiPower will be able to share capacity where it is needed.
“That’s more where your resilience is, it’s in the flexibility and the ability to manage your loads throughout the CBD in Melbourne now,” he said.
The hard work has also paid off in other ways. In late August the substation project was named the 2011 Winner in the Construction/Engineering< $100M Category by the Australian Institute of Project Management Victorian chapter. The submission will now compete at the national level in October.
Learnings from the Southbank project will now be carried into the CBD metro project, another major rebuild in the city.
“That was the idea: trialling a lot of this plant and a lot of these systems and process on a greenfield site so that we can develop their greenfield situation and then move and implement that technology into a brownfield situation.”
Power to the people
Victorian electricity distribution business CitiPower’s Southbank zone substation was officially opened by Victorian Energy Minister, Michael O’Brien in August.
The new substation has nearly three times the capacity of its predecessor and will also be used in future to supply a larger area including the southern parts of the CBD.
Minister O’Brien was joined by Melbourne Lord Mayor, Robert Doyle, CitiPower and Powercor chairman, Peter Tulloch, CitiPower and Powercor CEO, Shane Breheny and other directors and senior managers.
“It’s essential that Victorians have access to a reliable, secure and affordable electricity supply. We see today the practical benefits of that dynamic investment environment with the opening of this new substation,” Minister O’ Brien said at the opening.
“The new substation is great news for Southbank and for Melbourne. It will guarantee reliability of supply, and add capacity and resilience to the electricity system,” he said.
Mr Breheny said the substation marked a significant step forward in terms of design, technology and capacity for the CitiPower network.
“The Southbank Zone Substation provides innovative solutions for our rapidly changing city which will also enhance CitiPower’s ability to supply surrounding areas including the CBD and inner suburbs south of the Yarra,” Mr Breheny said.
The project was one of the largest ever undertaken by CitiPower and it gave several graduate engineers the opportunity to work on their first-ever major project.