Electricity Asset Management Plan 2019-2029
183
Vector Limited://
We have also recently, Nov 2017 and Jan 2018, experienced failures of 1980s vintage vacuum CB interrupters in our GEC VMX CB fleet and in response we procured a test set specifically for the testing of vacuum interrupters and have now completed tests on all 1980s vintage vacuum interrupters. Tests have shown that 1980s vintage vacuum interrupters, especially in the GEC VMX CB fleet, should be replaced in the next two to three years and our investment programme makes provision for this replacement. Further to the above, there is no vendor product support for 60s and 70s vintage oil filled 11kV CBs and obtaining spare parts is a challenge. However, we have prudently retained 60s and 70s vintage oil-filled switchgear from previous replacement projects and these are cannibalised for spares. To ensure the reliability of our zone substations we will undertake a programme of works to replace our fleet of Brush and New South Wales oil filled CBs with modern arc flash rated and arc flash segregated switchgear, replace oil filled CBs in our Reyrolle fleet with modern vacuum CB trucks and arc flash doors and replace vacuum interrupters in GEC VMX 11kV CBs.
TARGETED OUTCOMES
CUSTOMER EXPERIENCE
SAFETY
RELIABILITY
RESILIENCE
OPERATIONAL EFFICIENCY
CYBER SECURITY AND PRIVACY
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: Business as usual – no additional investment: continue with current level of investment to maintain ageing 11kV zone substation switchgear
Maintaining the fleet of 60s and 70s vintage oil-filled 11 kV switchgear is becoming an increasing challenge with no vendor/supplier product support available and no availability of spare parts apart from spares that can and are cannibalised from 11kV CBs that were recovered from previous replacement projects in the past by Vector. 60s and 70s vintage oil filled switchgear also pose a H&S risk to maintenance and inspection personnel. Failure of oil filled CBs is usually catastrophic and spectacular with a commensurate risk of fire and thus a risk of complete loss of a zone substation. This vintage switchgear also do not provide mitigation against the risk of arc flash as found in new generation switchgear that is fitted with arc chutes that guide arc flash products away from the equipment user. New technology options are simply not suitable as an alternative for the risks posed by our ageing fleet of 11 kV zone substation switchgear To ensure the continued long-term reliable performance of the primary 11 kV CB fleet in our zone substations and ensure the safety of maintenance and operational personnel we have selected to undertake a programme of works to replace 60s and 70s vintage oil filled switchgear, install vacuum CBs in our Reyrolle fleet and replace vacuum interrupters in our GEC VMX fleet.
Rejected
Option 2: Use new network technology options to offset the requirement to replace subtransmission circuits Option 3: Undertake a staged and scheduled programme of works to replace primary 11 kV zone substation switchgear
Rejected
$93.03M Selected
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