Powering Sydney’s Future involves the installation of a new 20km 330kV underground cable between Rookwood Road Substation to Beaconsfield Substation and extending the life of the existing cable from Sydney South Substation to Beaconsfield Substation by derating this cable from 330kV to 132kV.
Transgrid engaged Zinfra to modify the substations at Sydney South and Beaconsfield to accept the new 330kV cable and the derated existing cable, which included civil and electrical works, and the testing and pre-commissioning of all the control and protection systems.
Zinfra worked closely with Transgrid to solve the various problems and complete the works within the time and budgetary constraints of the project.
Innovative and practical solutions
Zinfra Project Manager, Karl Littlemore, said Transgrid awarded Zinfra the contract for two reasons – their demonstration of a solid plan and their innovative design.
“During the tender negotiation process, Zinfra took the time to really try and understand the project,” Mr Littlemore said.
“We developed a detailed presentation, which showed that we had a comprehensive plan to deliver the project from start to the end, including all the network outages we'd need.
“This shown we had a good understanding of some of the challenges, one of these being ground conditions. By working with Transgrid to minimise the number and duration of outages as much as possible, this avoids unnecessary disruption to the network.”
One of the main project objectives was completing the works on time, without the need for extending outages and causing further disruptions to the electricity network.
Working within these scheduled outage windows, Zinfra and Transgrid developed an innovative approach to reduce the time needed for the network to be turned off.
The design included a simple and short HV conductor connection which when disconnected disconnects one of the transformers from the 330kV network. This innovation reduces the time of an outage to isolate this transformer which again reduces risks to the network.
Ground conditions posing a problem
While Zinfra had previously worked with Transgrid on many other infrastructure projects and were used to the many challenges that come with working on a live electrical site, the Beaconsfield Substation posed unique problems in terms of ground conditions.
“If there was an issue on the project, we would work with Transgrid, we would raise the issue early, and then we would try and work through it with Transgrid as a partner, as opposed to a normal contractor-client confrontational relationship,” Mr Littlemore said.
For the project, Mr Littlemore said Zinfra decided to use local crews because of their extensive experience working in substation construction.
“The majority of Zinfra employees have at least five years and most of them ten year’s experience working in substation environments,” Mr Littlemore said.
But working in the middle of the COVID-19 pandemic, Zinfra realised the importance of using local crews to ensure reliability.
With most of the crews being Sydney-based, and some from the central coast, it meant Zinfra employees could comply with lockdown orders.
“A lot of the work was done during the peak of the COVID restrictions, so the use of local personnel to minimise the potential of the spread was a key part of the project,” Mr Littlemore said.
“That just increased the need to make sure that the people who went to the project were Sydney-based.”
While some employees caught COVID during the works, there were no major outbreaks within the crews.
“Transgrid implemented a requirement that everyone be tested twice a week with RAT tests, to try and avoid a potential outbreak, and if there was an outbreak, to try and limit the spread of that outbreak,” Mr Littlemore said.
“Karl gave special thanks to his Site Managers Daniel McKenna and Ashish Banga who worked diligently to ensure that the regular (almost daily) rule changes that occurred during the peak of COVID were complied with and that the project was able to continue to progress.”
“All of the requirements resulted in no significant outbreaks on the project, which meant that we had our work crews available to deliver the project as planned.”
Commissioning equipment and working collaboratively
Zinfra didn’t just work with Transgrid to ensure the design and construction works ran smoothly, they also performed a large part of the testing and commissioning of the installed equipment.
Commissioning is an important stage of any electrical installation project, as it ensures all the equipment will operate correctly within its parameters and will integrate well with the rest of the network.
“The other element we brought to the project was our commissioning technicians, who have got numerous year’s experience of working in substation environments, ensuring that the equipment is operating appropriately, including the control and protection systems,” Mr Littlemore said.
The collaboration also continued into the commissioning phase of the project.
“There's a large portion of the commissioning that Zinfra perform, but there's also portions that Transgrid appropriately perform as part of the scope. The personnel worked as a single cohesive team and really did work collaboratively as one unit to get the project to be a success. The personnel driving this team should be singled out for their enthusiasm and commitment, Sam Hubbard of Transgrid, and Agesh Sharma of Zinfra. This collaboration was found at all levels on the project from the Project Director, Colin Mayer, to the initial and final Project Managers Louise Poole and Matthew Lee.” Mr Littlemore said.
By collaborating with Transgrid from construction through to the testing and commissioning stage, Zinfra ensured that from concept to completion, the project objectives could be achieved with innovation and safety in mind.