Powerlink has recently published a ‘Project Assessment Conclusions Report’ (PACR) to address the secondary systems condition risks at Cairns Substation.
Cairns Substation was established in the mid-1950s, as the principal connection point for all 132kV circuits in the Cairns area. In 2002, Woree Substation was established, which allowed the Cairns Substation to be rebuilt with a reduced configuration. It now acts as the major injection node for the southern section of the Cairns 22kV network, which is supplied via Ergon Energy (part of the Energy Queensland Group).
The secondary systems at Cairns Substation broadly perform the functions of transmission element protection, data collection, remote (and local) control, and monitoring. Commissioned approximately 20 years ago, these secondary systems are reaching the end of their technical service lives, and are increasingly no longer supported by their manufacturer, with limited spares available. Increasing failure rates, along with the increased time to rectify the faults due to the obsolescence of the equipment significantly affects the availability and reliability of these systems and their ability to continue to meet the requirements of the National Electricity Rules (the Rules).
In May 2020 Powerlink published a ‘Project Specification Consultation Report’ (PSCR) identifying the proposed preferred option to address the risks and claiming exemption from producing a ‘Project Assessment Draft Report’ as allowed for under NER Clause 5.16.4(z1).
There were no submissions received in response to the PSCR, which closed in July 2020. As a result, no additional credible options that could deliver a material market benefit have been identified and the outcomes of the economic analysis contained in the PACR remain unchanged from those published in the PSCR.
The PACR recommends implementation of Option2; full replacement of all secondary systems at Cairns in a new building by December 2024. The indicative capital cost of this option is $7.84 million in 2019/20 prices. Powerlink is the proponent of this network project.
Under this option, initial design work will commence in mid-2021, followed by fabrication of the new building and panels in mid-2023, with all work completed by December 2024.
In the context of engagement activities with consumers and the general community, Powerlink has assessed this project as ‘minor’ on the RIT-T Stakeholder Engagement Matrix.
A copy of the Project Assessment Conclusions Report is available below.