Electricity Asset Management Plan 2019-2029
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Vector Limited://
Once in service, assets are maintained across the operational phase of its lifecycle in accordance with our maintenance standards. Asset inspections are also carried out and inspection data is captured in the asset management system to inform asset management practices, service level performance analysis and root cause analysis. This inspection data is also used to identify any network components that require replacement due to an unacceptable failure risk (see risk management below). Operations & Maintenance is also responsible for operating the assets to manage system performance, implement planned changes to the network’s static configuration and for providing access to undertake planned or emergency works. Delivery of Operations and Maintenance is contracted to FSPs and is managed under a contract based performance framework. NETWORK PLANNING PRACTICE Vector’s incremental probabilistic planning practice forms an important specialist aspect of Needs Management that applies across the segment, focusing on network development. Our network planning practice involves processes to manage network peak demand and improving network resilience, delivery of electricity capacity to meet customer's needs and major asset relocations. The need for asset services initiated directly by customers includes network connections and minor asset relocations. Section 2 describes the service level metrics for connections and asset relocations, and consider the need for these services. In most cases, network connections and minor asset relocations are managed directly by FSPs who undertake design, execute necessary works and maintain associated asset records, in accordance with our standards. Where practical, opportunities to combine network development or asset replacement works with customer initiated works are leveraged to achieve cost savings and other advantages. Vector has also compiled a set of standards and standard designs for customer connections and substations in customer supplied buildings to drive cost efficiencies, standardisation and safety. Growth in network electricity demand is managed under the SoSS service level discussed in Section 2.5.1. with analysis of the performance of the SoSS service level based on Vector’s demand forecast (see Appendix 10 in Section 7). The SoSS service level captures a cost quality trade-off that reflects the ability of our assets to meet the forecast electrical demand without breaching SoSS and to provide restoration capacity that supports planned and unplanned supply interruption events. Performance against the SoSS service level is managed through an annual network planning cycle that involves: • Development of a network demand forecast in accordance with the Network Load Forecasting Process. An overview of Vector’s load forecasting process is provided later in this section • Ensuring the demand forecast is scenario-based to enable understanding of how the impact of uncertain future technologies (e.g. EV, solar/PV uptake) or lifestyle changes (e.g. energy efficiency) may impact future demand and ultimately, the ten year expenditure profile shown in this AMP. The scenario-based forecast takes a longer term view (30 years) than is represented in the AMP. The scenario methodology is fully described in Section 1 • Ensuring the demand forecast is geographically based, enabling different areas across the network to have different growth rates. Overlaying the 11kV distribution feeders allows the geographical-based demand forecast to be converted to a distribution feeder forecast. Summating feeder forecasts provides zone substation and GXP forecasts • Individual capacity equipment ratings available from equipment specifications (e.g. transformers, switchgear) or specialised software (e.g. CymCap) being used to calculated cable ratings. Details of the primary plant ratings are set out in Appendix 9 in Section 7 • Circuit ratings being derived by identifying the piece of equipment with the lowest capacity rating thus limiting the circuit overall • Calculating the impact of climate change on circuit ratings and adjusting the operating thresholds accordingly • Comparing the feeder demand forecast, circuit ratings and Security of Supply standards to identify potential network security breaches • Identification of possible SoSS breaches which is initially undertaken using Excel spreadsheets and refined using Digsilent modelling software where required. This models the capacity of both subtransmission and HV distribution networks against various scenarios including contingency conditions or other alternative demand scenarios, and the effectiveness of any proposed reinforcement solutions • Where a breach of the SoSS service level is forecast, identifying solutions and developing options as outlined under Asset Engineering (see above). Any proposal to respond to an expected breach will be developed to address the breach on a just-in-time basis, and are developed in accordance with corporate and asset strategies and with the System Design Network Parameters standard
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