Managing the Sydney East substation’s asset risks

Market Network Service Provider
StageProject Assessment Conclusions Report
ConvenorAEMO NSP
Accepting submissions?No

TransGrid has recently published a Project Assessment Conclusions Report for managing Sydney East substation’s asset risks.

The first three 400 MVA transformers at Sydney East 330/132 kV substation (located north of the Sydney CBD) were commissioned in 1974. A fourth transformer was installed in 2013 to accommodate growing demand in the region. The substation plays a critical role in providing reliable supply of electricity to areas north of Sydney Harbour including North Sydney, Ryde, Macquarie Park, Chatswood, and the suburbs along the Northern Beaches.

The three initial transformers are showing signs of deterioration such as carbon particle contamination, paper insulation embrittlement, paper insulation moisture, dissolved gasses in main transformer tanks, bushing deterioration, and large transformer losses due to mechanical failure of tapchanger switches. Without remedial action, the condition and performance of the transformers will continue to deteriorate, hence increasing the likelihood of prolonged and frequent failure.

In December 2018, TransGrid published a Project Specification Consultation Report (PSCR) identifying the proposed preferred option to decommission Transformer 1, replace Transformer 2 with a new asset, and replace Transformer 3 with a redeployed three phase 375 MVA transformer mitigates the increased risks of failure and claimed exemption from producing a Project Assessment Draft Report as allowed for under NER Clause 5.16.4(z1).

No submissions were received in response to the PSCR during the consultation period which closed in March 2019. No additional credible options that could deliver a material economic benefit were identified throughout the process and the outcomes of the economic analysis contained in the PSCR remain unchanged and maintained in this PACR.

The works for the preferred option are to be implemented from 2018/19 to 2021/22. The estimated capital cost of the proposed preferred option is $12.3 million. TransGrid is the proponent of the proposed network project.

In accordance with the requirements of the Rules, a summary of the PACR has been made available on AEMO’s website. A copy of the Project Specification Consultation Report can also be obtained from TransGrid’s RIT-T Consultations webpage or by emailing

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