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

� reduced burden on spare parts management by using standard equipment.
7 OPTIONS ANALYSIS
0BInvestment Evaluation Summary
TNM-GS-809-0720
The following options have been considered for the redevelopment of Meadowbank Substation:
1. Manage existing 110 kV assets and defer replacement;
2. Replace selected 110 kV assets; and
3. Replace all 110 kV assets.
Other options considered at a high-level, but discounted for the reasons mentioned include:
� Off-site greenfield development - not considered to be a cost effective alternative as other solutions can be
implemented within the existing perimeter of Meadowbank Substation at a substantially lower cost. This option was
also discounted for the following reasons:
- the terrain surrounding the area is rugged and uneven, which makes it difficult to find a level ground suitable
for a new development within close proximity to the power station and transmission lines; and
- part of the switchyard has been redeveloped in recent years (high voltage switchgear replacement, building
and security fence).
7.1 OPTION 1: MANAGE EXISTING 110 KV ASSETS AND DEFER REPLACEMENT
7.1.1 SCOPE
The scope for this option includes:
� replace assets that present a safety risk, including post insulators, voltage transformers and current transformers;
� continue existing maintenance practices, albeit accelerated due to the declining condition and ageing of assets.
� undertake repairs and corrective maintenance as required.
� defer replacement for up to five years.
The capital cost of this option includes an initial $4.51 million ($June 2007) to address safety issues followed by a
deferred capital cost of $1.05 million ($June 2007) to replace remaining 110 kV assets five 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 allow Transend to achieve the capital expenditure objectives;
� does not address the performance, reliability and design issues associated with circuit breakers and current
transformer identified in section 4;
� does not address the NER compliance issues associated with the Meadowbank–New Norfolk 110 kV transmission
line protection scheme;
� 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, in particular the circuit breakers and
current transformers;
� incurs longer and more frequent outages due to maintenance regimes that are required to maintain the existing
assets; and
� involves an increased risk of loss of supply events at Meadowbank Substation when compared with other options;
� has the potential to cause voltage issues in the southern region of Tasmania; and
� does not align with the recommendations made in respective asset management plans for primary and secondary
equipment.
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