(1) Transmission owns and operates over 33 245 circuit kilometres of power lines, and regularly conducts asset health reviews on all its infrastructure, including the power lines, using international benchmark standards. Our last power lines condition assessment report was published in 2021 (the next revision is due in March 2024). The response below applies to the 2023/24 financial year:
(a) Transmission’s asset management approach prescribes that power lines do not generally reach life expectancy to the extent that they must be completely rebuilt. It is the transmission line components that reach the end of life and that are replaced. This applies to conductors, insulators, towers (steelworks), foundations and hardware. Therefore, individual parts are assessed for their performance and risk, and replaced or refurbished as needed.
Only when critical structural components such as foundations and/or tower member steel are condemned would an entire power line be deemed to have reached its expected life. A refurbishment or replacement project for such a power line would then be initiated.
(b)Same response as above.
(c) Projects are classified into two groups: Projects to address the end-of-life components, and projects to address the performance of lines.
More projects are planned for future years as Transmission continuously reviews the status of its transmission lines.