Transgrid has published a Project Assessment Conclusions Report (PACR) for Maintaining safe and reliable operation of Tamworth substation. Publication of this PSCR represents the final step in the Regulatory Test for Transmission (RIT-T) process.
Tamworth 330 kV substation is located in Transgrid's Northern NSW network. It connects to Transgrid's 330 kV Armidale, Liddell and Muswellbrook substations as well as Transgrid's 132 kV Narrabri, Tamworth and Gunnedah substation, which all support Essential Energy's 66 kV network.
There are three transformers at Tamworth's 330 kV substation. The No.1 and No.2 transformers were commissioned along with the substation in 1967 and the No.3 transformer was commissioned in 1998.The No.3 transformer at Tamworth substation is in satisfactory condition and not part of this need.
Replacement of the Tamworth transformers will significantly reduce the likelihood of prolonged and involuntary load shedding in the northern region and help Transgrid manage its safety obligations.
The key economic benefits associated with addressing this need are summarised as:
- Reduction of risk as valued as direct impact to Transgrid and consumers including:
- Changes in involuntary load shedding
- Safety and environmental hazards associated with a catastrophic failure.
- Avoided operating expenditure related to an escalation of corrective maintenance.
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.
In the PSCR Transgrid presented two 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 1 (replacement of the No.1 and No. 2 transformer at Tamworth substation) – 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 1 remains the preferred option at this stage of the RIT-T process. The estimated capital cost of this option is approximately $20.32 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.