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

6 BENEFITS
The direct benefits of redeveloping Creek Road Substation 110 kV include:
� contributing to the achievement of the capital expenditure objectives identified in the Rules;
0BInvestment Evaluation Summary
TNM-GS-809-0720
� provision of a safe, secure and reliable electricity supply to customers connected to Creek Road Substation, in
particular Hobart’s CBD by replacing obsolete, unreliable assets that are in poor condition;
� life-cycle cost savings due to reduced operations and maintenance requirements;
� reduced burden on spare parts management by using standard equipment; and
� alignment with strategic asset management plans.
7 OPTIONS ANALYSIS
The following options have been considered for the redevelopment of Creek Road Substation:
1. manage existing assets and defer replacement;
2. replace assets in situ;
3. staged replacement of assets in situ over three years;
4. redevelop using air insulated switchgear;
5. redevelop using gas insulated switchgear; and
6. redevelop using hybrid switchgear.
Other options considered at a high-level, but discounted for the reasons mentioned:
� Off-site greenfield redevelopment - not considered to be a cost effective alternative as other solutions can be
implemented within the existing perimeter of Creek Road Substation at a lower cost. This option has advantages
over other options in terms of outage requirements, however the additional costs associated with purchasing new
land and easement for deviation of transmission circuits outweigh the benefits of reduced outages.
� Replace selected assets only - replacement of selected assets has already been undertaken in order to defer major
works at Creek Road Substation. The need to replace the large number of assets that present safety, condition and
performance issues means that combining the works as part of a major redevelopment is the most cost-effective
solution.
7.1 OPTION 1 - MANAGE EXISTING ASSETS AND DEFER REPLACEMENT
7.1.1 SCOPE
The scope for this option includes:
� continue existing maintenance practices for the majority of assets, albeit accelerated due to the declining condition
and aging of the assets;
� replace assets that are known to present a significant safety risk, including voltage transformers, current
transformers and post insulators in 2014;
� replace identified disconnectors that do not provide the required electrical clearances for compliant operation at
110 kV in 2014;
� replace the SCADA and bus bar protection scheme in 2014;
� replace the underground 110 kV power cable that is in poor condition in 2014; and
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