Since the 1920s, the Preston distribution network has operated with a primary voltage level of 6.6kV from its two zone substations, Preston (P) and East Preston (EP). As the surrounding substations operate at 22kV, the difference in voltage meant that it was not possible to transfer load during to feeders supplied from adjacent zone substations in times of peak demand or during fault restoration.
Jemena’s Preston Conversion Strategy (PCS) involves a staged conversion of the 6.6kV area supplied by the P and EP zone substation to 22kV. Zinfra is currently undertaking Stage 5 of the conversion project, which involves decommissioning a number of 6.6kV assets along Bell St, Preston and surrounding areas.
As Zinfra Project Manager, Louis Angelopoulos, explains, Stage 5 is an integral part of the PCS, which will allow Stage 6 project to commence.
“Stage 5 is really setting up the basis for future works within the EP zone substation,” Mr Angelopoulos said.
Zinfra Construction Manager, James Hoseason, said Stage 5 is broken up into sections to minimise the number of customers without power while the conversion is taking place.
“We're working through sections of the network and upgrading the overhead poles and wires to accommodate the 22kV voltage level. Aging indoor substations on customer properties which do not meet current standards are being decommissioned and replaced with the latest 22kV infrastructure,” Mr Hoseason said.
“Modern equipment and operating voltages increase the security, flexibility and accessibility of Jemena’s electricity network. Ultimately Jemena’s customers then benefit from increased supply reliability as installations are bought up to existing standards.”
Upon Completion of Stage 5 in May 2023, the Jemena and Zinfra teams will commence the EP Conversion Stage 6 project, which involves relocating the remaining feeders from Switch House A to Switch House B inside the EP zone substation. Switch House A will then be demolished, and the existing zone substation control building expanded. EP Conversion Stage 6 is planned for completion in Q3 2025.
Working as one team
The trusted partnership between Jemena and Zinfra is integral in delivering such a complex project successfully.
According to Mr Angelopoulos, the key to maintaining a trusted partnership is “transparency, honesty, and teamwork”.
For example, Jemena and Zinfra have created a joint set of processes that ensures the safety of team members in preparation for the risks of handling ageing switchgear.
“Procedures include things like risk assessments prior to undertaking any works, adhering to safe approach distances, turning off certain functions of the equipment – specifically the auto reclose function on circuit breakers, and wearing appropriate PPE,” Mr Angelopoulos said.
“To date, we haven't had any incidents whilst delivering Stage 5. We are working hard to uphold that record throughout the remaining project stages by continuing to concentrate on safety and maintaining a high standard of work practices”.
The ‘one team’ mindset extends to how Zinfra manages the varying interests of stakeholders, including Jemena’s customers; Zinfra views Jemena’s customers as its own.
Mr Angelopoulos said while managing customer relationships can sometimes be a challenge, the team’s strong leadership has been the key to success.
“From the perspective of the end customer, these works may seem quite irrelevant as they won’t see any advantages immediately,” Mr Angelopoulos said.
Mr Angelopoulos explained that ensuring safe decommissioning and upgrading of the ageing substation assets remains an important factor in network stability and consumers' access to energy. For Zinfra, engaging with customers to ensure they understand why the project is necessary and how it will benefit the community in the future is paramount.
Customers face the impacts of road closures and power outages that are required to get the work done safely. Major roads are unable to be closed on weekdays because of the sheer volume of traffic, so work must be undertaken on the weekend.
“We schedule our work to accommodate as many customer requirements as possible and ensure that the impact to both business and residential customers power supply is minimised as far as practicable.”
Mr Hoseason said that managing customers relationships starts with identifying the various stakeholders, visiting the impacted sites in-person, getting to know the customers and explaining that they may be affected by power outages or road closures, and determining whether there is anything Jemena and/or Zinfra can do to help mitigate the impact.
Zinfra has worked with customers to find appropriate parking, liaised with businesses to ensure power outages occur when production times are slow, and supported an easy transition back to normal supply.
“Ambulance Victoria were operating in one of the impacted business parks, so we liaised with them to ensure their needs were considered in our traffic management plans,” Mr Hoseason said.
Strong leadership gets results
Mr Angelopoulos praised Mr Hoseason for his ability to connect with stakeholders of all levels while keeping the project schedule on-track.
“Taking the customer along for a journey is important so that they understand the greater impact of what we're trying to achieve,” Mr Angelopoulos said.
“James has been instrumental in developing those relationships and negotiating mutually beneficial outcomes, especially in relation to concerns regarding power outages and providing temporary generators where appropriate.”
The project has faced some delays related to the impacts of the pandemic but engaging customers directly and maintaining communication has allowed revised timelines to be met.
Mr Angelopoulos said successes come in the form of every stage that is completed, whether it's big or small because “it means that we've overcome the next hurdle and it's brought us a step closer to the final goal”.
“That said, some of the larger, more significant stages have a particular air of accomplishment about them due to the sheer scale of work undertaken and the coordination that required.”
The final section of the Stage 5 of the conversion project is expected to be complete in May 2023. Stage 6 works are scheduled to commence at EPN in Sep 2023.