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

0BInvestment Evaluation Summary
TNM-GS-809-0720
� would need outages of an extended duration for each transmission circuit because it would be required to replace
110 kV disconnectors and other infrastructure; and
� would require a higher capital cost than other options
7.5.4 CONCLUSION
This option is technically viable.
8 OPTION ESTIMATES
A comparison of the net present value of options is provided in Table 1.
Table 1 - Comparison of options considered
Option Net present value of costs ($M June 2007)
1 Manage existing assets -$4.01
2 Replace selected assets in-situ -$4.00
3 Staged replacement of selected assets in-situ -$4.02
4 Replace selected assets in new switch bays -$4.57
5 Complete redevelopment of Burnie Substation 110 kV -$4.79
The economic analysis includes the cost impact to customers in the event of a major circuit breaker failure using a
probabilistic approach based on current and forecast load data for each individual transmission circuit connected to
Burnie Substation 110 kV.
9 PREFERRED OPTION
Option 2 (replacement of selected assets in-situ) is the preferred option because it is the most cost effective solution to
address the identified safety and performance issues presented by the assets at Burnie Substation 110 kV. This approach
will also minimise the number and duration of transmission circuit outages due to reduced frequency and duration of
maintenance.
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