Imagery, Lidar, and GIS Transform Transpower’s Vegetation Management

Transpower, a state-owned enterprise since 1994, has a key role in New Zealand’s electricity sector, generating and transmitting electricity to distributors and major electricity customers across the North and South Islands of the country. It is both the transmission asset owner and the system operator. While it doesn’t own, generate, or sell electricity, Transpower is contracted by New Zealand’s Electricity Authority to operate the wholesale electricity market through which generators sell electricity to retailers, who then supply consumers. Transpower’s network comprises 25,000 transmission towers, over 11,000 kilometers of lines, and 174 substations.

Vegetation encroachment poses a significant risk to the reliability and safety of Transpower’s transmission network. New Zealand’s diverse landscape—characterized by dense forests and terrain that’s difficult to traverse—creates ideal conditions for rapid vegetation growth. If left unchecked, vegetation encroachment can interfere with transmission lines, leading to outages, service disruptions, and safety hazards. The established vegetation management methods that were in place, such as visual inspections and manual surveys, were labor-intensive, time-consuming, and often inaccurate. The ongoing challenge for Transpower is to effectively identify and mitigate vegetation-related risks while balancing operational efficiency and environmental considerations. While Transpower has leveraged some imagery to aid in identifying vegetation risk, management of the imagery data became cumbersome. There was a need to improve the consistency and effectiveness of communicating risks to the many stakeholders involved. 

Transpower is undergoing a change to the way in which vegetation across the network is captured and managed by capturing LiDAR data and Orthophotography imagery of its complete system. It leveraged Esri’s ArcGIS Online, ArcGIS Experience Builder, ArcGIS Image Server, and ArcGIS Dashboards for data management, visualization, and analysis. Aircraft were deployed to capture detailed three-dimensional data of approximately 100-meter-wide transmission corridors and surrounding vegetation. The imagery and LiDAR data are being processed by a contractor, who is associating the imagery with the transmission assets. Then, it is loaded into the spatial environment and published to ArcGIS Online as scene layer packages. AGOL is utilized to visualize the vegetation data by Transpower and its service providers to view vegetation encroachments, heights, and proximity to transmission lines. ArcGIS Dashboards will help communicate the progress of vegetation management to stakeholders. Data capture for the entire national transmission system was performed in late 2023. The visualization tool resulting from this classified data is expected to be rolled out for use by all users in mid-2024.

Although Transpower has used LiDAR for many years for engineering purposes, this is the first time it will be used for a national vegetation program. In the past, Transpower relied on service provider field inspections to identify and report vegetation encroachments. This triggered work orders within Transpower’s asset management system, which had limited access to a spatial view of progress.

The aim is to blend the good practices of the past with the opportunities that modern technology offers. With the new, improved system and processes both Transpower and its service providers now know where the problems are in advance of going into the field. The LiDAR data will provide more detailed and accurate information about vegetation encroachments, leading to better planning and scheduling of work, improved safety for workers and the public, and better visual aids to support discussions with landowners. Additionally, Transpower will be able to use LiDAR data to monitor for adequate ground-to-conductor clearances.

This approach enhances network reliability and safety, minimizing the likelihood of vegetation-related outages and service disruptions. The detailed vegetation data obtained from LiDAR surveys also facilitates targeted maintenance interventions, such as vegetation trimming or removal, further enhancing network resilience and operational efficiency. ArcGIS Image Server allows the ortho imagery captured to be accessed by Transpower employees and service providers across the organization to visualize specific areas of the transmission system for many uses, including routine inspections, planning, and environmental assessments. ArcGIS Dashboards also provides staff with the progress reporting of data capture and statistics on the number and location of risks to be managed.

Eagle Technology, an Esri distributor, has worked closely with Transpower on their needs assessment, prototyping, and implementation of GIS and Imagery technology. Eagle Technology continues to work with Transpower on its training and deployment strategies. 

LiDAR enables Transpower to detect and mitigate vegetation-related risks before they potentially escalate into outages. This in turn helps to reduce service disruptions and enhance customer satisfaction. The use of analytics optimizes maintenance schedules and resource allocation. Integration with the work management system eliminates the former time-consuming processes. By leveraging accurate vegetation data, Transpower and its service providers can make informed decisions regarding vegetation clearance requirements, ensuring compliance with regulatory standards while minimizing environmental impact. Additionally, the proactive identification and mitigation of vegetation risks contributes to cost savings by reducing reactive maintenance efforts and outage-related expenses.

GIS provides contractors with valuable online information on the field conditions before their field inspections. Having access to this information also allows for better planning, enabling contractors to prioritize their work and deploy crews.

Additionally, Transpower’s transmission network is located over various owners’ land. This tool will further support the relationship between landowners and Transpower as landowners will now be able to view areas in 3D where vegetation needs to be trimmed before work begins on their land. 

In addition to using vegetation management, ArcGIS Image Server will allow the engineers, designers, and operators to organize the captured LiDAR for asset management, maintenance, and repair. Transpower plans to continue the evolution that this data enables. For example, by using analytics and machine learning and leveraging the imagery with data sources such as past and present trends, Transpower can predict weather patterns and vegetation growth.