Introduction to the overhead distribution assets project

Project Description

Key Research Question

Managers of overhead distribution systems are frequently challenged to improve system performance, manage a fleet of aging assets, and deploy new technology that is expected to perform for decades. Emerging technologies can offer opportunities to improve performance, but utilities lack objective performance assessments. Because total replacement of aged assets is impractical, utilities must strategically plan resources to best maintain system reliability while promoting safety, reliability, and environmental stewardship. The Overhead Assets project investigates new designs and approaches for overhead assets, asset degradation and failure, inspection methods, and emerging technologies to enhance component reliability, longevity, and cost-effectiveness. Asset managers can use the test data generated by the research to make informed decisions about selection, installation, inspection, maintenance, and replacement.


This research investigates overhead asset performance through application of well-documented and repeatable performance and aging tests. Asset managers can use test results to make effective asset decisions over an asset’s life cycle. Application of this information can:

  • Enhance procurement equipment specifications
  • Inform asset selection and installation
  • Enable effective application of inspection technology
  • Inform inspection and maintenance cycles

This project also intends to capture and document knowledge regarding overhead asset design and application. This material could be incorporated into guides, videos, and other training material for utilities.

Planned 2022 Research

This project conducts material and structure testing, evaluates inspection tools and technologies, and documents leading practices to inform overhead asset life-cycle decisions. The 2022 project includes the following tasks:

Overhead Structure Performance: Overhead structures should withstand decades of exposure to the environment and intermittent storms. Utilities consider structural loading, clearances, and cost, but often lack the data necessary to perform a complete performance analysis. This task examines the mechanical and electrical performance of overhead structures and components through laboratory testing. In 2022, this task intends to apply and expand upon the structural test framework developed in 2021 using specific overhead structure designs and considering performance metrics including mechanical coordination, basic insulation level (BIL), falling branch resistance, conductor slap, flammability, and susceptibility to wildlife interruptions.

Composite Pole and Crossarm Analysis: This task examines the short- and long-term performance of alternative pole and crossarm materials, such as composites, steel, ductile iron, and concrete. In 2022, this task plans to study the mechanical performance of composite crossarms in response to forces experienced in service using typical line hardware.

Wood Pole Inspection Tool Testing: Pole condition assessment provides a means of prioritizing pole replacement to better optimize O&M budgets. This task investigates tools used to assess wood pole health. In 2022, this task will examine the accuracy of traditional, modern, and emergent pole inspection technologies by comparing inspection results with the data on pole remaining strength collected through laboratory testing. This task also plans to report existing inspection options for steel, composite, and concrete poles.

Grounding and Lightning Performance: This task examines the application and performance of grounding systems and lightning protection approaches. In 2022, this task plans to investigate the performance of pole butt grounding plates, ground rods, and the use of conductive cements. This task also investigates the performance and degradation of surge arresters.

Overhead Connector Testing and Analysis: Connectors are a common source of overhead line interruptions. This task tests the electrical and mechanical performance of connectors under varying load and/or environmental conditions.

Wildlife Guard Testing and Materials Analysis: Many outages are attributable to wildlife, including squirrels, raccoons, birds, snakes, and other animals capable of bridging energized and/or ground connections. Properly specified and installed wildlife guards can help mitigate these outages. However, wildlife guards that are improperly specified or installed may cause additional issues. This task examines the specification and application of wildlife guards. In 2022, the task intends to examine and document the electrical, mechanical, and aging performance of a variety of wildlife guards.

Online Monitoring and Inspection of Overhead Systems: As sensor capabilities increase and costs decrease, utilities are looking to leverage the technology to improve system performance, identifying and locating issues before they cause outages. This task examines online monitoring systems and inspection tools that could improve overhead distribution system reliability by identifying potential asset failure or vegetation contact before it causes an outage.

Pole Hardware Quality Testing and Material Analysis: Utilities deploy innumerable nuts, bolts, and washers when constructing and repairing overhead structures. There are many options available when selecting hardware such as cast or forged materials, hot-dipped or thermal diffusion galvanization, and others. This task intends to examine how material and processing choices affect performance and long-term reliability.

Evaluation of Unmanned Aircraft Systems Technologies: 2022 Update. This report will document emerging technologies, leading practices, and test results from laboratory testing.

Research Value

The results from this research will provide distribution utility personnel with information and tools to improve specification and selection decisions for new overhead assets, increase system reliability and resiliency, enhance inspection and assessment effectiveness, lower inspection and maintenance costs, and increase awareness of emerging technologies.

Overhead Distribution (P180.001) Deliverables & Value Propositions

2021 Result





Capital Project Support

O&M Cost Management


Resilient Design Approaches Optimize structural design to improve reliability and resiliency
Alternative Pole and Crossarm Material Evaluation Enables intelligent selection of crossarm type and manufacturer
Grounding and Lightning Performance Improve system's ability to withstand lightning strikes
Overhead Connector Performance Testing Reduce risk of downed conductors due to connector failure by improved connector specs
Pole Hardware Quality Testing and Material Analysis Improve pole hardware specs to maximize long-term structure resiliency and reliability
Design and Application of Wildlife Guards to Promote Reliability Improve wildlife guard specs and application practices to maximize long-term system reliability
Evaluation of Pole Inspection Technologies Ability to prioritize replacement and repair based on objective inspection data
Online Condition Monitoring of Overhead Systems Lab testing of new online monitoring systems that provide situational awareness
Evaluation of Umanned Aircraft Systems Technologies Lab testing of UAS tech to test capabilities and provide data to facilitate industry development
: Primary : Secondary

Task Force

This task force consists of utility subject-matter experts in areas related to overhead line construction, materials, and standards. The task force is focused on the life-cycle of overhead assets including poles, crossarms, conductor, line hardware, arresters, cutouts, wildlife protection, and more. This task force meets several times per year by WebEx or in person. There is usually one in-person meeting per year held in conjunction with the other P180 task forces.

Members are encouraged to participate in several ways:

  • Attend task-force meetings
  • Provide equipment for testing or evaluation
  • Provide information on your utility’s standards or practices (a survey for example)
  • Review and comment on reports and findings
  • Attend testing at EPRI laboratories
  • Present to the task force on utility issues or initiatives
  • For equipment failures, submit equipment to EPRI for forensic analysis
  • Reach out to Joe Potvin on matters related to overhead distribution assets

This task force is also a good opportunity to meet and network with overhead distribution asset experts from other utilities.

Common Questions

Who can attend task-force meetings?

  • Task-force meetings are for funders of the overhead assets project (P180.001). This includes task-force members and guests from sponsoring companies.

Are there specific membership requirements?

  • The only requirement is to fund the overhead assets project (P180.001). There are no meeting attendance requirements. However, members find that they get the most value when actively participating in the research.

How do I join this task force?

  • Just send a request to Joe Potvin or Eric Cornwell. Similarly, if you’d like to be removed, let one of them know.

Can my company have more than one task-force member?

  • Yes and is encouraged to do so.

Can I share task-force material within my company?

  • Yes and is encouraged to do so.

Can I share task-force material outside my company?

  • Generally, not. There are exceptions, so if you have a need, please contact Joe Potvin.

Are discussions covered by a non-disclosure agreement?

  • Yes. All EPRI member agreements include non-disclosure clauses.

If my company isn’t funding this, how can I sign up?

  • Each company has their own methods for selecting components of the annual EPRI research portfolio. Contact your METT for more information. Technical advisors from EPRI’s member services can also help. Find contact information here.

Collaborative Supplemental Projects

frames Overhead Distribution Design for Resiliency and Reliability

This project seeks to investigate the mechanical performance of modern distribution construction options including components such as fiberglass-reinforced polymer and CCA-ET poles, fiberglass crossarms and standoffs/candlesticks, and post insulators.
  • Reduce outage duration.
  • Compare mechanical performance of different pole types and treatments.
  • Identify more resilient designs.
  • Reduce weak points.
frames Advanced Distribution Inspection

When it comes to inspections, O&M spending is prioritized based on value to the customer and utility. While Distribution inspections could improve reliability, there are cases where the return does not justify the investment. However, the ROI may be improved by using automated UAVs for data capture and then artificial intelligence for data review. This approach has promise, but we need to understand how it works and how it performs before we can confidently deploy a hands-off automated solution. In the Advanced Distribution Inspection project, we plan to evaluate this new method.
  • Guidance on technologies and approaches for automating distribution inspection
  • Learn through laboratory and field experience how to collect the right inspection data
  • Understand the feasibility of using automated image analysis for defect detection
  • Quantify performance of artificial intelligence predictions with objective processes and datasets
  • Provide objective data to inform deployment decisions such as inspection processes, vendor selection, and purchasing decisions
frames Assessment of DCOI and Alternative Wood Pole Treatments

A large percentage of wood poles in North America are currently treated with pentachlorophenol (penta). However, production of penta is expected to end in 2022. As such, utilities are seeking alternative wood pole treatment options. One potential option is 4,5-dichloro-2-N-octyl-4-isothiazolin-3-one (DCOI), approved by the American Wood Protection Association (AWPA) for ground contact use in 2017. This project intends to compare the performance and environmental impact of DCOI with other existing pole treatments, such as penta, chromated copper arsenate (CCA), copper naphthenate, and others.EPRI also plans to investigate the engineering performance of different treatment types applied to various pole species, such as southern yellow pine, Douglas fir, and western red cedar.

For more on supplemental projects, see here. To discuss project ideas, contact Joe Potvin.

Implementation Opportunities

Supplemental projects can also be one-on-one efforts. Companies allocate their self-directed funds in different ways. Options for these projects can include:

  • Field pilots of technologies
  • Integration of research results
  • Teardowns of failed equipment
  • Test specific equipment or scenarios

Examples related to current research could include:

  • Full-scale structure testing, mechanical or electrical
  • Implementation of online condition monitoring technologies for identifying abnormal system conditions

Services and Capabilities

EPRI has several capabilities available to utilities as part of research work, supplemental projects, or service agreements:

  • Arc-flash testing of equipment
  • Forensics and material analysis of equipment failures
  • Custom tests of fuse cutouts, arresters, transformers, or other overhead line equipment
  • Mechanical and electrical testing of full-scale distribution structures
  • Evaluation of online condition monitoring equipment

Other Programs

EPRI research related to overhead distribution assets is found in several other areas.

Program 1: Power Quality

P1 | portfolio

Program 1 has leveraged power quality data to identify electrical system issues, including approaches to detect degraded and failing distribution assets. This information is helpful as utilities try to improve situational awareness to prevent outages before they occur.

Program 51: Transmission & Distribution: Environmental Issues

P51 | portfolio

Program 51 examines environmental issues related to distribution and transmission infrastructure. Recent research has investigated the environmental impact of wood poles treated with DCOI, as well as advanced methods of detecting hazard trees in right-of-ways. P51 is also collaborating with the overhead assets project on wildlife guard research.

Program 60: Electric and Magnetic Fields and Radio-Frequency Health Assessment and Safety

P60 | portfolio

This program considers environmental health and safety issues related to public and worker exposure to electric and magnetic field (EMF) and radio frequency (RF) environments associated with electric power system infrastructure.

Program 180: Distribution Systems

Equipment failures can often pose safety risks. Worker safety technologies and practices are investigated in the distribution safety project (P180.004). Research considering wood pole failure rates that can help with future capital planning can be found in the Asset, Reliability and Resiliency Analytics project (180.005).