TransGrid has recently published a Project Assessment Conclusions Report for managing safety and environmental risks on Line 17 (Avon – Macarthur).
Constructed in 1964, the 41km single circuit 330kV transmission line is comprised of 101 steel tower structures between Avon switching station and Macarthur 330kV substation. Line 17 forms a key link between the Wollongong region and the Sydney metropolitan area.
Condition issues that will impact the safe and reliable operation of the network have been found on Line 17. The condition issues raise a number of risks associated with asset failure, including safety and environmental (bushfire) risks. Investment to address the deterioration of the assets along Line 17 due to corrosion is needed to mitigate risks to safety and the environment.
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 safety and environmental risks on Line 17 (Avon – Macarthur) in July 2020. No submissions were received in response to the PSCR during the consultation period which closed in October 2020.
TransGrid put forward for consideration one technically and commercially feasible option: refurbishing the existing line by remediating or replacing the identified components. This option (Option 1) involves the refurbishment of Line 17 including replacement of asset components, earthwire, remediation of steelwork and foundations.
The primary driver for the identified need is to mitigate bushfire and safety risks associated with condition issues on Line 17 caused by corrosion. Two other options to address the need were considered but were not progressed further as they were determined technically or commercially non-feasible when assessed against the preferred option.
Option 1 (line refurbishment) remains the preferred option at this stage of the RIT-T process. This option is estimated to have a capital cost of $6.6 million +/- 25% and is expected to be completed by 2022/23. TransGrid is the proponent of the proposed network project.
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