“This new process has allowed us to see what was previously hidden in a fog of data from multiple sources and use this insight to make our network safer and more reliable.”
GIS DRIVES POWERCO TO QUADRUPLE ASSET RENEWALS
Powerco, New Zealand’s largest electricity distributor (by network length), headquartered in beautiful New Plymouth, serves over 300,000 customers across a diverse North Island geography.
Powerco built the bulk of its network during intense development in the 1950s when it supplied many of New Zealand’s rural communities with electricity for the first time. These networks are now of an age where their condition and performance are deteriorating. They needed renewal. However, identifying and prioritizing overhead line assets for replacement is not a straightforward task. Renewal need is only loosely related to age. Determining need depends on other factors such as material quality, environment, past maintenance practices, visual assessments of condition, and fault history.
The large asset footprint, combined with a range of information from diverse and sometimes sparsely populated areas, made it difficult for Powerco to assess where it needed investment and package projects of efficient scale. These difficulties led to inefficiency in identifying and scoping projects.
Powerco implemented Esri products, such as ArcGIS Insights, ArcGIS Survey123, ArcGIS Enterprise, ArcGIS Field Maps, and ArcGIS Pro, to collect data and perform spatial analysis and smart mapping. These have enabled Powerco to ensure that it repaired the right assets or replaced them at the right time in the right locations.
“Powerco needed to build a unique smart tool that would enable us to visualize what was happening across the network. We wanted to visualize the various types of materials and loading conditions (mechanical and electrical) to find out to what degree Powerco’s assets were performing correctly.”—Ken Pattie, Powerco Asset Fleet Manager, Overhead Assets and Investment Delivery
In 2018 Powerco began to carry out a substantial five-year renewal program and is constantly expanding its use of the ArcGIS tools in the renewal program.
The Process, Phase 1
Powerco’s solution combines diverse data sources to produce visualizations informing the company of where the most needed network renewal is. First, the company’s approach divides the network into hexagons on a map. Then, the solution assigns a score to each hexagon-shaped bin based on weighted combinations of input variables and color-coded to show different asset health scores. Calculations include the following:
- The historic location of network failures
- Observed condition score
- Assets’ ages
- Known problem asset types
The resulting condition scores enable the visualization of the network condition as a heat map. This process provides quick and compelling insight into renewal needs. Hexagon grids and bins of various sizes enable the higher resolution required when moving from a macro network view to a localized project view. Viewable layers include assets (wires, poles, transformers), faults, conditions, asset health, and environmental factors.
Asset condition is not the sole criteria for renewal. The solution produced another layer of hexagon-shaped bins, with bin scores characterizing the potential impact of asset failure. It combined information from diverse sources to visualize what had been previously unseen—the number of customers potentially affected by equipment failure.
Census-derived population density data were used as a proxy for the likelihood of equipment failure causing injury. Finally, the condition and criticality layers were combined to produce a layer that visualized asset risk. The resultant visualizations representing condition and criticality enable renewal planning engineers to see what others can’t—risk.
Visualization of risk allows renewal planners to see where investments will provide the greatest benefits in improving public safety and supply reliability. By visualizing the abstract level of risk, engineers can balance trade-offs and target investments.
“It was very experimental in the beginning. However, engineers liked the hexagonal bin approach, so we applied it to other datasets, such as defects and conditions. The hexagonal heat maps gave us a large-scale overview. They showed us the hot spots where there were areas that potentially needed attention. This guided our engineers to where there were potential project areas. They could identify these hot spots and zoom in for further investigation.”—David Haberkorn, Powerco Senior GIS Specialist.
The Process, Phase Two—Conductor Condition Assessment
Overhead conductors (the wires in an overhead network) are traditionally among the more difficult asset types to assess and plan for renewal. Removing samples for a laboratory test is the best way to get reliable condition information, but this is expensive and causes service interruptions. Powerco wanted to gain additional insight into the conductor renewal problem by developing a predictive model to estimate conductor health based on the following:
- Expected life of the conductor
- Corrosion environment assessment, modified by data on historical failures
- Visual observations
The resultant model provides visualizations of current and predicted conductor health. These visuals help target areas for more intensive testing. Finally, the model assigns a calculated health score on each span of an overhead conductor based on the industry-standard Ofgem Common Network Asset Indices Methodology (CNAIM). OFGEN stands for the Office of Gas and Electricity Market based in the UK.
Powerco was able to contain the CNAIM algorithms entirely within ArcGIS. In addition, engineers leveraged the geospatial analysis features of ArcGIS software to improve how the methodology was implemented. For example, the methodology used corrosion environment and wind-speed data models generated by the National Institute of Water and Atmospheric Research (NIWA) to provide more accurate and location-specific information for the model.
Using ArcGIS, Powerco engineers could view the health scores organized by material, type of conductor, or conductor location within the network. They could also drill down further to visualize the exact locations of the assets with a low health score.
Using ArcGIS to Plan Asset Management More Effectively
Powerco’s renewal project made extensive use of the integrated ArcGIS applications and tools. GIS teams developed models in ArcGIS Pro and Python scripts to create functionality that enhanced the methodology.
ArcGIS Insights provides different ways to slice and dice the data, enabling users to view the data in various ways via interactive visualization tools. In addition, Insights produces summary statistics and visualizations to assist in calibrating and navigating the models. Powerco uses these statistics to fine-tune the models and present high-level information on renewal needs.
Powerco’s engineers share projects in ArcGIS Dashboards to achieve general dissemination of results. Engineers use ArcGIS Filed Maps to leverage field observations that are cost-effectively incorporated into the modeling methodology. This process provides verification and continual improvement. The app is used to calibrate and continually improve the accuracy of Powerco’s asset model.
Although field-based visual observations are not as accurate as laboratory assessments, the high volume, consistency, and low cost provided by the data collector are still useful for verifying and improving the model.
Powerco also used ArcGIS Survey123 to create smart forms to analyze captured data quickly and securely for further analysis.
The Powerco project team consists of Andrea Galliegue, business relationship manager; David Haberkorn, Senior GIS specialist; Kenneth Pattie, asset fleet manager overhead assets and investment delivery; Dr. Paul Blackmore, asset fleet manager; and Waseem Awan, asset engineer overhead network.
Powerco engineers now have more in-depth and accurate knowledge of what’s out in the field. They have interactive maps that show the predicted health score of different network parts, enabling more effective expenditure planning and deployment. The ability to virtually look down on the network and see previously disparate data sources combined to produce views of asset condition and risk has transformed how planning engineers identify and package network renewal projects.
Users can perform a task in days that previously took months and involved much subjective judgment. They perform tasks based on logical and consistent rules-driven transparently from available data.
Renewal work has quadrupled. With ArcGIS, Powerco’s renewal planning engineers have prepared a significantly larger portfolio of planned renewal projects with longer lead times, which help deliver procurement and delivery efficiencies. For example, Powerco previously could undertake 30 renewal projects annually in the overhead space (poles, conductors, crossarms), whereas now the company carries out 120 such projects annually.
The conductor model significantly increases engineering insights available for this asset type. These new insights inform changes in strategy, which will improve safety and service level outcomes for consumers.