Managing the Risk of Corrosion between Vales Point and Sydney North on Line 22

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

TransGrid has recently published a Project Assessment Conclusions Report for Managing the Risk of Corrosion between Vales Point and Sydney North on Line 22.

Constructed in 1962, Line 22 is a single circuit steel tower 330 kV transmission line connecting Vales Point and Sydney North 330 kV substations. The 86 km long transmission line predominately traverses small rural holdings, heavily timbered ridgetops and national parks. It crosses the M1 Motorway, Pacific Highway, Main Northern Railway line and numerous local roads.

TransGrid’s ongoing routine asset monitoring and maintenance revealed that many of the 190 transmission structures of Line 22 are corroded, including steel towers, insulators, conductor fittings and conductor/earth wire. Corrosion greatly increases the likelihood of conductor drop and presents consequent bushfire risks and safety risks.

In August 2018 TransGrid published a Project Specification Consultation Report (PSCR) identifying the proposed preferred option to mitigate the risks 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 October 2018. 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 PACR recommends the replacing or refurbishing corroded components from 2018/19 to 2021/22. The estimated capital cost of the proposed preferred option is $9.08 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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