Electricity Asset Management Plan 2019-2029
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Vector Limited://
Strategy Management of our zone substation fleet is undertaken in accordance with Vector’s asset strategy EAA701 Network Infrastructure and Facilities and corrective maintenance is used to respond to any asset non-compliance. Wherever practical, standardised design and modular design and construction are used to reduce capital costs and reduce asset stranding risks posed by new energy technologies. Vector’s ESE700 suite of design standards describe the standardised design requirements for zone substations. Security, Air and Fire Management Systems are maintained in accordance with ESM603 (Maintenance of Building Security, Air and Fire Management systems). These inspections are to identify any non-compliance with the afore- mentioned standards and perform minor maintenance tasks. The cyclic inspections are supplemented by real time monitoring of zone substations using SCADA to monitor and record each substation’s key parameters (e.g. switch status, temperatures, voltages, etc.) as well as provide operational alarms. In the medium term, condition based maintenance practices will be used more extensively to supplement cyclic maintenance and replace the cyclic inspection practice in the longer term. Data captured through inspection and monitoring of zone substations supports the asset management practice as described in more detail in Section 3. As part of our drive to improve sustainability we have embarked on a programme titled ‘Sustainable Substations’ and this includes the installation of solar panels with batteries at zone substations to provide auxiliary AC power. Installations are complete at five zone substations. Network investments like zone substations require long investment horizons, with much of the costs being carried by future generations. Power generation is shifting from stable, dispatchable resources connected to power transmission to variable, renewable resources connected to power distribution and the planning process needs to shift to address this new reality. Vector thus applies due diligence and scrutiny with regard to investment in a new zone substation to ensure the assets can serve the community throughout their lifetime, whilst avoiding intergenerational inequity. This means increasingly designing and valuing options that are agile, flexible and modular to respond to change. It means for example that we will buy land for a zone substation to secure our options to be able to supply electricity in the future but we might initially install a BESS system for a number of years to provide the peak demand in the area and only install the transformer assets when required. At such time, the BESS will be uplifted and deployed somewhere else for a similar scenario. Details of our future plans to procure land and develop zone substations are in Section 5.
4.3.1 POWER TRANSFORMERS Overview
Power transformers are used to transform one voltage to another and they are installed either indoors or outdoors at zone substations. Our transformers are a mix of Dyn11 and Dyn1 vector groups except for two 110 kV/11 kV transformers at Lichfield zone substation that are Ynyn vector group. In the Auckland region, zone substations have two and in some instances more power transformers, with most of the transformers radially supplied from a bulk supply substation or GXP.
No of 110 kV/33 kV power transformers
5
No of 110 kV/22 kV power transformers
8
No of 110 kV/11 kV power transformers
2
No of 110 kV/22 kV/11 kV power transformers
2
No of 33 kV/22 kV power transformers
1
No of 33 kV/11 kV power transformers
153
No of 22 kV/11 kV power transformers
45
Table 4-7 Key statistics for power transformers
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