Transgrid has recently published a Project Assessment Draft Report (PADR) for managing increased fault levels in southern New South Wales. This Report offers an opportunity for consultation on these updates prior to the final step of the Regulatory Investment Test for Transmission (RIT-T) process, the Project Assessment Conclusions Report (PACR).
The expected commissioning of three actionable ISP projects in southern NSW in coming years (Project EnergyConnect, HumeLink and VNI West), as well as full commercial operation of Snowy 2.0 in December 2028, is expected to result in fault levels that exceed the existing fault level ratings of existing transmission assets at four Transgrid substations in southern NSW if action is not taken. Without action, (i.e., under the base case), this would cause equipment failure and likely significant unserved energy to end consumers in the NEM.
The four affected substations are:
• Lower Tumut 330 kV substation;
• Upper Tumut 330 kV substation;
• Murray 330 kV substation; and
• Wagga 330 kV substation.
Transgrid has therefore commenced this RIT-T to assess the options available for managing the expected increased fault levels to avoid these consequences and continue to maintain compliance with the relevant standards.
In the PADR Transgrid presented one credible network option that would meet the identified need from a technical, commercial, and project delivery perspective. Option 1 involves upgrading certain existing substation switchgear and earth grid at the four affected substations to meet the increased fault levels in the network.
The estimated capital cost of this option is approximately $52.1 million +/- 25 per cent. Transgrid is the proponent of the proposed network project.
Transgrid welcomes written submissions on materials contained in this PADR. Submissions are due on 10 February 2025.
In accordance with the requirements of the National Electricity Rules, a summary of the PSCR is made available on the AEMO website. A copy of the PSCR can be obtained from Transgrid’s website or by emailing regulatory.consultation@transgrid.com.au