Transgrid Project Assessment Conclusions Report: Maintaining safe and reliable operation of Molong substation

Market Network Service Provider
StageProject Specification Consultation Report
ConvenorAEMO NSP
Accepting submissions?No

Transgrid has published the Project Assessment Conclusions Report (PACR) to assess options for maintaining the safe and reliable operation of Molong substation. The PACR is the final step in the Regulatory Investment Test for Transmission (RIT-T) process and follows the Project Specification Consultation Report (PSCR) published in April 2024.
Molong 132/66kV substation is located in Transgrid’s Central NSW network. It connects to Transgrid’s 132kV Wellington, Manildra and Orange North substations. It also connects the Essential Energy 66kV distribution network and supports renewable generation from Molong Solar Farm.

The condition of the Molong No.1 132kV transformer has been identified as reaching the end of its technical life leading to an increasing risk of failure which could result in reliability, safety, environmental and financial consequences. Replacing the transformer would also require replacing associated secondary systems such as switchgear, protection and control systems.
Condition assessments performed through Transgrid’s routine maintenance program has shown degradation in the condition of the power transformer which will increase its risk of failure. Without intervention, other than ongoing business-as-usual maintenance, the asset is expected to deteriorate further and more rapidly. This will increase the risk of supply interruptions to our customers as well as safety, environmental and financial consequences.

Transgrid published a Project Specification Consultation Report (PSCR) for maintaining the safe and reliable operation of Molong substation in April 2024. In the PSCR Transgrid presented two credible network options that meets the identified need from a technical, commercial, and project delivery perspective. Option 1 involves the replacement of the Molong No. 1 transformer and Option 2 involves the refurbishment of the same transformer.

No submissions were received in response to the PSCR during the consultation period which closed in July 2024 and no additional credible options have been identified.

The assessment in this PACR finds that Option 1 is the preferred option to meet the identified need at this stage of the RIT-T.
The estimated capital cost of this option is approximately $7.08 million ($2023-24) +/- 25 per cent. Transgrid is the proponent of the proposed network project.

In accordance with the requirements of the Rules, a summary of the PACR is made available on the AEMO website. A copy of the PACR can be obtained from Transgrid’s website or by emailing

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