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

� defer replacement of remaining assets by up to two years.
0BInvestment Evaluation Summary
TNM-GS-809-0720
The capital cost of this option includes an initial $4.86 million ($June 2007) to address the highest priority issues,
followed by a deferred capital cost of $22.57 million ($June 2007) to replace the remaining assets two years later.
7.1.2 BENEFITS
The benefit for this option is the deferral of capital expenditure.
7.1.3 DRAWBACKS
The drawbacks for this option are that it:
� does not address the performance, reliability and design issues identified in Section 4;
� incurs increased ongoing operating expenditure due to increased maintenance, condition monitoring requirements
and corrective maintenance requirements;
� is not sustainable given the reliability issues associated with the 110 kV assets;
� does not address the operational issues associated with the 110 kV ring bus arrangement;
� incurs the longest, and most frequent outages due to maintenance regimes that are required to maintain the existing
assets;
� involves an increased risk of loss of supply events at Creek Road Substation; and
� does not align with the recommendations made in the independent report by Ascension Consulting and APC-
Worley. Knowingly operating existing assets with identified performance and condition issues potentially exposes
Transend to litigation issues in the event of a supply disruption to Hobart’s CBD caused by an asset failure at Creek
Road Substation.
7.1.4 CONCLUSION
Although option 1 has the least capital cost option in the short term, it is not the preferred option because it does not
ensure the reliable operation of Creek Road Substation.
7.2 OPTION 2 - REPLACE ASSETS IN SITU
7.2.1 SCOPE
The scope for this option includes:
� in-situ replacement of the existing live tank circuit breakers with dead tank units with integral current transformers;
� replacement of all 110 kV disconnectors with new motorised units in situ;
� replacement of all bus bars with aluminium conductor and compression fittings;
� replacement of protection and control schemes; and
� implement revised maintenance practices.
This option includes redeveloping the site using the existing ring-bus arrangement.
The capital cost of this option is $27.27 million ($June 2007).
7.2.2 BENEFITS
The benefits for this option are that it:
� addresses most of the asset issues in Section 4; and
� reduces the ongoing maintenance requirements and costs associated with the site.
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