Electricity Asset Management Plan 2019-2029
153
Vector Limited://
Option 2: Install a third transformer. The existing transformers are 1966 vintage. Installing a third transformer instead of replacing the existing two transformers will require extension of both the 33kV and 11kV switchboards with additional switchgear as well as civil works associated with the additional transformer enclosure. To achieve a break-even point an additional 18 years life is required from the existing transformers. This is unlikely to be achieved Option 3: Move load to adjacent substations. The distribution backup to Te Atatu substation is from the single-transformer Woodford substation. Loss of a transformer at Te Atatu at peak times results in both the remaining transformer at Te Atatu and the Woodford transformer being overloaded; the constraint is transformer capacity Option 4: Non-network solutions: A network battery can afford a short term solution but the demand forecast margins are quite tight. If demand grows by more than 1.5MVA over the next ten years then based on cost, Option 1 is preferable. Option 6: 11kV feeder upgrade – Lincoln Rd: The feeder is to be upgraded in conjunction with adjacent SH16 motorway widening works
Rejected
Rejected
Rejected
$0.8M Selected
FORECAST INVESTMENT SUMMARY
DESCRIPTION
FY20
FY21
FY22
FY23
FY24
FY25
FY26
FY27
FY28
FY29 TOTAL
Load control - Riverhead
0.60
0.70
0.03
0.03
0.03
0.03
0.03
0.03
1.48
Upgrade transformers at Riverhead zone substation
0.50
0.50
11kV feeder upgrades – Kumeu
0.38
0.38
Establish Redhills zone substation
0.50
5.85
6.35
SH16 Henderson – Westgate – future-proofing ducts Establish Hobsonville Point zone substation SH18 Hobsonville Point – future- proofing ducts
0.20
1.20
1.40
1.44
1.44
1.00
1.00
11kV feeder upgrades – Greenhithe
1.00
0.88
1.88
Upgrade transformers at Te Atatu zone substation
3.40
3.40
11kV feeder upgrades – Te Atatu
0.80
0.80
Total CAPEX
2.44
0.88
5.00
1.50
0.03
0.03
0.61
1.23
0.53
6.38
18.63
NEEDS STATEMENT – HEPBURN The Hepburn area extends from Te Atatu and Ranui to New Lynn, extending westwards out to the coast. Relatively low growth is forecast except for pockets of re-development around the old Brickworks site in New Lynn and Sabulite areas. New transformers are proposed for Sabulite substation (Sabulite - 33/11kV transformer capacity upgrade) to increase their capacity. One of the key areas of focus is the resilience of the network towards the western coast. Two projects have been included, namely the installation of a micro-grid at Piha (Henderson Valley - new micro-grid (Piha)) and the linking of two remote 11kV feeders (Piha/Scenic Drive feeders)
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