Electricity Asset Management Plan 2019-2029
213
Vector Limited://
OPTIONS CONSIDERED Options to address the need identified above have been assessed and are summarised in the following table.
DESCRIPTION
DISCUSSION OF OPTION
ESTIMATED COST (NPV IF APPLICABLE)
STATUS
Option 1: Do nothing
‘Do-nothing’ means that Vector will be exposed to the risk of failure of ageing electro-mechanical TMS systems and PLC based systems that are not technically supported anymore. Loss of TMS systems will result in loss of automatic voltage control that in turn will result in the risk of violation of statutory voltage levels and could even lead to damage to transformers and tap change equipment Modern fully software configurable TMS systems will ensure reliable and vastly extended monitoring of the costly power transformers in zone substations. This option will allow on-going automatic control of busbar voltage levels. The risk of failure is reduced and the risk of violation of statutory voltage levels as well as the risk of damage to primary plant is reduced
Rejected
Option 2: Undertake a staged and scheduled programme of work to replace electro- mechanical and PLC based TMS systems
$8.00M Selected
PROPOSED INVESTMENT SUMMARY ($MILLION NOMINAL)
DESCRIPTION
FY20
FY21
FY22
FY23
FY24
FY25
FY26
FY27
FY28
FY29 TOTAL
Auckland TMS replacement
0.25
0.25
0.50
0.50
0.50
0.50
0.50
0.50
0.50
4.00
Northern TMS replacement
0.25
0.25
0.50
0.50
0.50
0.50
0.50
0.50
0.50
4.00
Total CAPEX
0.00
0.50
0.50
1.00
1.00
1.00
1.00
1.00
1.00
1.00
8.00
AUCKLAND AND NORTHERN EXTENDED RESERVE
NEEDS STATEMENT The provision of Extended Reserve is a statutory requirement in the Electricity Industry Participation Code. The Electricity Authority is replacing the current Automatic Under Frequency Load Shedding (AUFLS) scheme with the new Extended Reserve scheme, which is intended to be a low-cost and more efficient scheme consisting of four demand blocks of load. If load is not shed during frequency excursions, there is a risk of major loss of supply. The Extended Reserve scheme uses a methodology which centrally selects demand units from the entire North Island and prioritises the disconnection of customers with the lowest cost of interruption. The new scheme may require up to 60% of Vector’s demand to be armed for load shedding. The transition to the Extended Reserve scheme requires the phased decommissioning of the existing AUFLS scheme. It requires the re-programming of existing numerical protection and control relays, and installation of some new protection relays dedicated to Extended Reserve. In October 2017, the Electricity Authority decided to put the implementation of the Extended Reserve scheme on hold due to a number of technical and design issues. The Authority subsequently advised in April 2018 of its decision to obtain the findings of the System Operator’s scheduled technical requirements review, which will inform the resolution of the design issues, prior to any further implementation of the Extended Reserve scheme.
TARGETED OUTCOMES
CUSTOMER EXPERIENCE
SAFETY
RELIABILITY
RESILIENCE
OPERATIONAL EFFICIENCY
CYBER SECURITY AND PRIVACY
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