Transgrid PSCR: Maintaining safe and reliable operation of Molong substation

Market Network Service Provider
StageProject Specification Consultation Report
ConvenorAEMO NSP
Accepting submissions?Yes
Submissions close02/07/2024

Transgrid has published the Project Specification Consultation Report (PSCR) for Maintaining safe and reliable operation of Molong substation. Publication of this PSCR represents the first step in the Regulatory Test for Transmission (RIT-T) process.

Molong 132/66kV Substation is located in Transgrid’s central NSW network. It connects to Transgrid’s 132 kV Wellington, Manildra and Orange North substations. It also connects the Essential Energy 66 kV 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, environment and financial consequences. Replacing the transformer would also require replacing associated switch gear and secondary systems such as switchgear, protection and control systems.

Condition assessments performed through our 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.

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 presents two credible network options that would meet the identified need from a technical, commercial, and project delivery perspective. This PSCR finds that implementation of Option 1 is the preferred option at this draft stage of the RIT-T process. Option 1 involves the replacement of the Molong No.1 transformer with a new 132/66 kV 30 MVA transformer. 

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.

Transgrid welcomes written submissions on materials contained in this PSCR. Submissions are due on 2 July 2024.

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

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