Transgrid has published a Project Assessment Conclusions Report (PACR) for Maintaining safe and reliable operation of Buronga substation. Publication of this PSCR represents the final step in the Regulatory Test for Transmission (RIT-T) process.
The X2 transmission line (from Buronga to Broken Hill) is a radial feed to Broken Hill substation so maintaining a reliable supply to the area when Line X2 is out of service requires significant planning and coordination with Broken Hill loads in addition to running the gas turbine generators to supply the Broken Hill 22 kV load.
During asset replacement planning of Buronga X2 feeder circuit breaker (CB), it was identified that the condition of the bus disconnector, line disconnector and bypass disconnector prevent outage access for the CB replacement. Due to the disconnector functional failure a X2 transmission line, outage is required to access the CB.
Transgrid notes the recent outage of the X2 line following an extreme weather event that began on 16 October 2024. Transgrid confirms that this event has not impacted the identified need, or the credible options considered. Line X2 travels 250km from Buronga to Broken Hill and the seven towers that were damaged were located close to Broken Hill.
We have classified this RIT-T as a ‘market benefits’ driven RIT-T as the economic assessment is not being progressed specifically to meet a mandated reliability standard but by the net benefits that are expected to be generated for end-customers. Given the quantity of CBs that have been identified for replacement, Transgrid considers it prudent and cost effective to manage this risk through a single asset replacement program. This replacement will help limit the amount of in-service failures that occur (along with the associated interruptions to customer load, and safety and environmental consequences).
In the PSCR Transgrid presented three credible network options that would meet the identified need from a technical, commercial, and project delivery perspective. The optimal commercially and technically feasible option presented in this PACR – Option 3 (replacement of identified assets with double bus selectable feeder bays) – is the preferred option to meet the identified need at this stage of the RIT-T.
No submissions were received in response to the PSCR during the consultation period which closed in November 2024 and no additional credible options have been identified.
Option 3 remails the preferred option at this stage of the RIT-T process. The estimated capital cost of this option is approximately $8.44 million (in $2024/25) +/- 25 per cent.
In accordance with the requirements of the Rules, a summary of the Project Assessment Conclusions Report is made available on the AEMO website. A copy of the PACR can be obtained from Transgrid’s website or by emailing regulatory.consultation@transgrid.com.au.