Transend - Appendix 5 Renewal capital expenditure - Australian ...

0BInvestment Evaluation Summary
TNM-GS-809-0720
7.3 OPTION 3: STAGED REPLACEMENT OF SELECTED ASSETS IN-SITU
7.3.1 SCOPE
The scope for this option is essentially the same as option 2, but implemented using a staged approach based on
transmission circuit criticality. This option includes:
� initial replacement of assets that have an assigned transmission circuit criticality rating of four or five (three bays);
and
� initial replacement of other assets that are known to present a safety risk, including post insulators, voltage
transformers and current transformers; and
� deferred replacement of the remaining 110 kV assets by up to three years (two bays).
The capital cost of this option includes an initial $1.55 million ($June 2007) to replace critical assets and to address
safety issues followed by a deferred capital cost of $6.36 million ($June 2007) to replace remaining 110 kV assets three
years later.
7.3.2 BENEFITS
The benefits for this option are that it:
� allows Transend to achieve the capital expenditure objectives in the mid-term;
� addresses the safety issues associated with the 110 kV assets identified in section 4 of this document;
� defers capital expenditure associated with replacing the 110 kV disconnectors;
� defers capital expenditure associated with lower criticality assets for up to 3 years;
� addresses the performance issues identified in section 4 of this document, with the exception of those transmission
circuits that have a criticality less than four; and
� reduces the ongoing maintenance requirements and costs associated with the site.
7.3.3 DRAWBACKS
The drawbacks for this option are that it:
� results in a higher overall capital cost than option 2, primarily due to the use of live tank circuit breakers, contractor
remobilisation and increased internal costs;
� does not align with Transend’s policy to utilise dead tank circuit breakers when replacing 110 kV live tank current
transformers and circuit breakers for two 110 kV bays; and
� will need additional transmission circuit outages to undertake the works.
7.3.4 CONCLUSION
This option is technically viable.
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