Electricity Asset Management Plan 2019-2029
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Vector Limited://
VEGETATION MANAGEMENT
NEEDS STATEMENT Vegetation encroaching within minimum clearances of OH power lines creates safety risks for the public and to Vector and Vector contractor workers. Vegetation in the proximity of OH power lines is a major factor in network outages especially during storms and high winds. Gap analysis between service level performance and target performance levels has identified outages caused by vegetation contribute 15% of SAIDI and 13% of SAIFI on distribution feeders (see Section 2). According to a NIWA study on the impact of climate change, the climate over the Auckland region will become more volatile over the next century and there is a real risk that this item will have a further negative impact on service levels. The report outlines that Auckland would be impacted amongst others with storm surges with more frequent strong winds and the April 2018 storm was a classic example where trees and branches caused outages to thousands of customers in Auckland. There is clear indication that faults due to ‘out of zone vegetation’ are on the increase (see the figures below), and Vector will place greater focus on managing ‘out of zone vegetation’. What Vector can do about trees is governed by 15 year old regulations which also set out what private landowners should do. The challenge for Vector is that under the current Hazard from Trees Regulations that only vegetation in a limited are can be trimmed. The MBIE has initiated a dialogue with distribution lines businesses and other interested parties for a full review of the Electricity (Hazards from Trees) Regulations of 2003. Notwithstanding the limitations for EDBs under the current regulations, Vector will continue and increase its programme of work to control vegetation (within the current rules in the Hazards from Trees Regulations). To achieve this we will deploy a leading approach to focus on controlling vegetation by SAIDI criticality. We will also work with Auckland City Council to reduce future conflicts between trees and power lines and initiate agreements to remove existing unsuitable trees and replace with power line ‘friendly’ trees. We will have done a LiDAR survey of our network by the end of FY19 and will utilise the data to identify trees close to powerlines a project planned for FY21 is to make further use of this data plus utilising data analytics tools to create a vegetation prediction model.
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 control vegetation. This option will not address the existing service level performance gaps and the network will continue to be impacted by vegetation and in light of the prediction that storms and high winds will increase such gaps in the service level will increase This solution will address the service level gaps that exist and will correct performance of the network to re-establish and maintain expected service levels. The significant contribution by vegetation to reliability indices will be reduced.
Rejected
Option 2: Proactively identify trees that are high risk and increase the investment to control vegetation. Utilising data analytics and create a vegetation prediction model.
$78.8M Selected
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