Project Assessment Conclusions Report Addressing the secondary systems condition risks at Tangkam

Powerlink has recently published a ‘Project Assessment Conclusions Report’ (PACR) to address the secondary systems condition risks Tangkam Substation.

Tangkam Substation was established in 1999 as part of the Oakey Gas Turbine Power Station connection, and is approximately 30km north west of Toowoomba. Planning studies have confirmed there is a long-term requirement to continue to supply the existing electricity services provided by Tangkam Substation.

The secondary systems at Tangkam broadly perform the functions of transmission element protection, data collection, remote (and local) control and monitoring. The majority of Tangkam’s secondary systems are nearing the end of their technical service lives and are increasingly at risk of failure, with many items of equipment no longer supported by the manufacturers and limited spares available. Increasing failure rates, along with the increased time to rectify 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 October 2022 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 January 2023. 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 Option 2, the single stage replacement of all 110kV secondary systems at Tangkam Substation into a new demountable building by June 2025. The indicative capital cost of this option is $14.6 million in 2022/23 prices. Powerlink is the proponent of this network project. Under this option, initial design work will commence in early 2024, with the installation and commissioning of the new secondary systems completed by June 2025.

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 PACR can be obtained from the Powerlink Website on the RIT-T Consultations page or by emailing networkassessments@powerlink.com.au.