TransGrid Project Assessment Conclusions Report: Managing safety and environmental risks from corrosion on Line 959/92Z

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

TransGrid has recently published a Project Assessment Conclusions Report for Managing safety and environmental risks from corrosion on Line 959/92Z.

Constructed in 1965, Line 959/92Z is a double circuit steel tower 330 kV transmission line connecting Sydney North and Sydney East 330 kV substations. The 23.7 km long transmission line passes through national parks and certain sections pass through urban areas in Sydney.

A significant proportion of the 61 transmission structures of Line 959/92Z are corroded, including steel towers, insulators, conductor fittings and conductor/earth wire. Corrosion greatly increases the likelihood of conductor drop. Owing to the nature of the terrain traversed by Line 959/92Z, the failure of the corroding transmission structures and/or physical conductor drops presents bushfire risks and safety risks.

TransGrid has put forward for consideration two credible options that would meet the identified need from a technological and project delivery perspective. Refurbishment of the line with optical ground wire (OPGW) retrofitting remains the most economical and preferred option at this stage of the RIT-T process.

No submissions were received in response to the PSCR during the consultation period which closed in June 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 are maintained in this PACR.

The works for the preferred option are to be completed by 2021/22. The estimated capital cost of the proposed preferred option is $7.28 million. TransGrid is the proponent of the proposed network project.

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 Project Assessment Conclusions Report can be obtained from TransGrid’s website on the RIT-T Consultations page or by emailing

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