Delivering vital transmission infrastructure for the future grid

In November 2020, Zinfra completed construction of the Stockdill 330/132kV Substation and transmission line rearrangement works. The project, completed for TransGrid, provides a key link in the High-Voltage Electricity transmission network by providing a second supply for the ACT, ensuring the ongoing reliability of the network for many years into the future.

The works comprised a new 330/132kV substation at Stockdill Drive, a new 6km transmission line between the new Stockdill Substation and the existing Canberra Substation, and numerous line-rearrangement works in the area to suit the revised transmission network configuration.

Zinfra is known for making a positive contribution to Australia’s energy infrastructure, having completed five end-to-end greenfield substation projects and approximately 25 additional upgrade projects in similar facilities for its clients over the past three years.

Despite being a construct-only contract, the project did not come without its challenges – several of which were a result of external events outside of Zinfra’s control. With works taking place between April 2019 and November 2020, construction was impacted first by the summer bushfires and more recently by COVID-19.

The poor air quality caused by the bushfire smoke was a particular concern, and the project team decided not to restart after the holiday period on the 6 January as planned, instead using this time to develop a proposed standard to manage the risk.

Using the advice from ACT Health, this standard was expeditiously and comprehensively documented and approved by Zinfra’s senior management, and discussed and accepted by the project safety committee. The document was then used as a template across the remainder of Zinfra’s projects.

A testament to Zinfra’s responsive, flexible and supportive culture, this unique set of challenges was managed without any delay to the overall project schedule. TransGrid was also highly impressed with the quality of the workmanship for the project’s electrical works, which was performed entirely by Zinfra’s in-house electricians and linesmen.

Going above and beyond to protect vulnerable wildlife

Given the nature of the works, many environmental considerations were required to minimise the effects of the project on the environment. One of these centred around protecting the Pink-tailed Worm-lizard – a listed vulnerable species important to the biodiversity of the area.

“Zinfra engaged an ecologist to attend site prior to any construction works occurring in the area, and do a exploratory investigation, checking under rocks in the area which would form habitat for the Pink-tailed Worm-lizards, a species native to the area, and categorised as vulnerable,” Karl Littlemore, Zinfra’s Project Manager, said.

“We were required to perform this activity in high potential habitat areas only under the EIS, but we went one step further and also examined all medium potential habitat areas. This resulted in finding two Pink-tailed Worm-lizards in an area of medium potential habitat and relocating them to a suitable area well away from the earthworks.

“Without this additional step it is likely that the Pink-tailed Worm-lizards found would have been injured during the works. We were pleased to go above and beyond to minimise our impact.”

“Additionally, there were a number of trees that needed to be removed, and fallen trees can often create excellent habitat for local wildlife species. In consultation with TransGrid and the landowners, and in accordance with the environmental requirements of the project, we worked together to understand the best location for the felled trees to provide this habitat.”

The project also generated a significant quantity of excess soil and rock. Rather than spread and bury this rock on site or dispose of the material, ACT Parks advised that this rock could make excellent habitat and improve the environmental conditions in other areas.

In the knowledge of this, Zinfra suggested, at Zinfra’s cost, collecting and transporting this rock to the conservation area requested by ACT Parks. This resulted in over 3,000 tonnes of rock being re-used to improve local habitat.

Safety first

Mr Littlemore said safety is Zinfra’s number one priority, and it was important to be able to demonstrate to internal management and to the client that all safety policies and procedures were being completed appropriately.

“One of the ways Zinfra demonstrates this high regard for safety is the frequency of senior management site visits and safety inspections. Whilst this was impacted by COVID-19, every effort was made by the senior leaders to conduct regular safety leadership visits whilst abiding by the local rules and ensuring social distancing was maintained,” Mr Littlemore said.

There were 90 Zinfra personnel and 507 subcontractors inducted to work on the project and although they invested over 175,000 man hours, it was able to be completed without any medical treatment or lost time injuries. This is a result of the detailed planning by Zinfra and TransGrid, and the professionalism of the Zinfra and TransGrid labour forces.

This planning included the performance of HAZCONS. These HAZCONS are an industry standard technique of reviewing the risks associated with the works and developing the control measures.

Instead of performing a single HAZCON and trying to develop controls for the entire project, it was split into many sections. In total 13 sessions were held which enabled a healthy discussion on the practical solutions of a small part of the project, and ensured all parties had a clear understanding of the work practices.

Embracing continuous improvement to maximise opportunities for innovation

Zinfra is always looking to understand, improve and innovate in the areas where it can add the most value.

The Stockdill project was the first new build using the AS61850 communication protocol within TransGrid’s network. This is the latest technology and provides the asset owner with greater visibility of the performance of their asset, whilst simultaneously lowering the cost for construction of future projects.

Achieving the right outcomes by being a trusted delivery partner

Zinfra is committed to building and maintaining genuine partnerships with its clients and communities.

Part of the transmission line spanned over an existing golf course, this course being an important leisure facility in the Belconnen area.

“The golf course was hosting tournaments and events throughout the 2019/2020 spring and summer period. Therefore, to minimise the disruption to the golf course, TransGrid agreed to have that section of the transmission line completed by September 2019,” Mr Littlemore said.

This agreement demonstrated a better understanding of the stakeholder’s expectations and fears, and resulted in a more productive relationship – especially when this deadline was achieved.

When asked why TransGrid had selected Zinfra as its preferred contractor, Mr Littlemore explained that Zinfra’s relationship with the client has always been positive and is founded on open, proactive communication.

“TransGrid trusts us to deliver a project safely, on time and to a high standard, and trusts that if any issues arise we’re going to be open and honest, and work with them to find the best solution,” Mr Littlemore said.

“The result of that is we’re back on-site now doing an extension to the substation. We’re one of TransGrid’s trusted partners because we’ve got that proven track record, an excellent safety and environmental record, and we can deliver a comprehensive range of engineering, project management, construction, operations and maintenance services for a competitive price.

“On behalf of Zinfra, I’d like to thank TransGrid for entrusting us with this project. We are looking forward to a long, sustainable and trusting relationship.”

This partner content is brought to you by Zinfra – your trusted partner in energy. For more information on Zinfra’s engineering, construction and maintenance services, visit

We acknowledge the Traditional Owners of the lands upon which we operate and recognise their continuing connection to land, waters, and culture. We pay our respects to their Elders past and present.

Pictured: Artwork by Aboriginal artist Chern’ee Sutton from Mount Isa for our Group’s Reconciliation Action Plan.