Transgrid has recently published a Project Assessment Conclusions Report (PACR) for managing risk on Line 82/95 (Tomago – Seahampton).
This double circuit 330 kV transmission line runs between Tomago substation and a field location in Seahampton near Newcastle substation, where it splits into the single circuit sections of Line 95 and Line 82. The 67 structures on the double circuit section of the transmission line covered by this RIT-T span over a route length of 20 km, which traverses mainly bushland and agricultural areas to the west of Newcastle. The line is a key part of the network in the Newcastle and Central Coast region and supply infrastructure for Tomago Aluminium.
Detailed analysis of asset condition information has identified that 64 of the 67 structures on Line 82/95 have several condition issues which require refurbishment to address asset health and maintain appropriate risk levels across the network. A significant proportion of the steel transmission structures are impacted by various levels of deterioration and corrosion. Further, recent testing has also identified that some insulators have reached end of life due to deteriorated insulation resistance. Corrosion increases the likelihood of conductor drops and presents consequent safety and bushfire risk to our personnel and the public, as well as resulting in reactive maintenance costs to repair the failed elements.
Transgrid manages and mitigates bushfire and safety risks to ensure they are below tolerance levels or ‘As Low As Reasonably Practicable’ (‘ALARP’), in accordance with Transgrid’s obligations under the New South Wales Electricity Supply (Safety and Network Management) Regulation 2014 and Transgrid’s Electricity Network Safety Management System (ENSMS). The proposed investment will enable TransGrid to continue to manage and operate this part of the network to a safety and risk mitigation level of ALARP. Consequently, it is considered a reliability corrective action under the RIT-T.
Transgrid published a Project Specification Consultation Report (PSCR) for managing risk on Line 82/95 (Tomago - Seahampton) in September 2024 and presented two credible network options that would meet the identified need from a technical, commercial, and project delivery perspective.
One submission was received in response to the PSCR during the consultation process. Transgrid has responded to the submission and no additional credible options were identified during the consultation period following publication of the PSCR. Option 1 remains the preferred option at this stage of the RIT-T. This involves remediating all identified condition issues for line components which have experienced greater deterioration and/or reached the end of their functional lives. This option is estimated to have a capital cost of $11.53 million +/- 25% and is expected to be completed by 2026/27. Transgrid is the proponent of the proposed network.
In accordance with the requirements of the National Electricity 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 RIT-TConsultations@Transgrid.com.au