Sep 2015
Electricity Transmission
EPRI Research Collaboration on Overhead Transmission Lines Project
Sep 2015
Sep 2016
National Grid Electricity Transmission
Iliana Portugues
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Network Innovation Allowance
Electricity Transmission Networks

Inspection, assessment and asset management of overhead transmission lines

Utilities need to understand the condition of their overhead transmission lines to effectively manage and maintain them at their designed level of performance and safety. Inspection and assessment research is needed to understand the current condition of transmission assets, extend the life of those assets while keeping the aging infrastructure performance at levels that meet the reliability expectations of the public. 

Structure and Sub-Grade Corrosion Management

Transmission lines are affected by sub-grade corrosion damage resulting in costly outages, increased maintenance costs, and potential health risks. Visual inspection by excavation, which is the predominant method of condition assessment for sub-grade inspections, is costly and labor intensive. This project intends to identify corrosion issues, characterize corrosion types, and develop appropriate corrosion management solutions for funders. The project will develop the technical basis for decision support in dealing with subgrade corrosion of transmission line structures as well as the tools to make cost-effective corrosion management decisions. This may include the development of inspection techniques, improved assessment practices, and mitigation methods for specific corrosion types.

Live Working: Research, Techniques and Procedures

Higher transmission loads are forcing utilities to keep transmission lines in service every day. Outages for maintenance are more difficult to obtain. 

Performance and Maintenance of High-Temperature Conductors

Recently developed high-temperature conductors offer the advantages of higher current capacity, lower conductor sag, and lower line losses than conventional ACSR (aluminum conductor steel-reinforced) conductors. This project addresses issues related to the long-term performance of these conductors. 

New and Emerging Inspection and Sensing Technologies

 The project will deliver the following tasks:

  • Identify and document the technical capability and limitations of new and emerging inspection/sensing technologies,
  • Document use cases where new and emerging technologies have been utilized in the field,
  • Identify gaps in currently available inspection technologies and possible applicable technologies to meet ?members' requirements,
  • Conduct laboratory and field evaluation of new and emerging technologies. 

Inspection, assessment and asset management of overhead transmission lines

This programme of work aims to meet the following objectives:

•         Develop tools and/or methods to help improve reliability;?

•         Increase the effectiveness of the inspection and assessment process;

•         Increase the safety for the public and transmission operator personnel by helping to detect components with a high risk of failure before the actual event through new inspection methods and hands-on tech transfer.

Structure and sub-grade corrosion management

The objectives of this work package are to:

•         Provide new tools and inspection methods to identify and assess corrosion issues on structures and foundations;

•         Demonstrate new and emerging inspection, mitigation, and remediation technologies by evaluating accuracy, risk, efficacy, and cost; ?

•         Reduce maintenance costs by matching reject and ranking criteria with appropriate mitigation and remediation techniques;

•         Improve designs through better material compatibility and elimination of specific corrosion types ?

•         Develop fleet management practices for population assessment by screening geographic areas prone to support severe corrosion rates.

Live working: research, techniques and procedures

This programme of work aims to:

·         Increase worker safety;

·         Improve reliability and availability by enabling timely maintenance of transmission lines, both energized ?and de-energized;

·         Improve transmission performance;

·         Decrease maintenance costs;

·         Implement innovative ideas and tools to live work.

Performance and maintenance of high-temperature conductors

Work in this area aims to achieve the following objectives:

•         Provide information and tools that are currently not available to evaluate the performance of various high- temperature conductors;

•         Provide maintenance procedures and recommend tools to ensure the safety of utility personnel and the reliability of transmission lines.

New and emerging inspection and sensing technologies

The objectives of this programme of work are to:

•         Develop our knowledge and understanding of the latest technologies;

•         Have easy access to other utilities' experience and performance testing; ?

Identify gaps and possible technologies as well as future research and development needs.

Inspection, assessment and asset management of overhead transmission lines

If successful, this programme of work will deliver the following:

  • Report on New Version of OHTL Inspection, Assessment and Asset Management Reference Guide;
  • Report on Overhead Transmission Line Component Performance and Failure Summaries-2015;
  • Guidelines for Assessing the Condition of Overhead Transmission Line Components;
  • Guide for Data Collection Requirements to Evaluate Line Component Condition.

Structure and sub-grade corrosion management

Success in this area will be measured against the delivery of the following:

  • Report on Remediation Methods for Concrete Foundations;
  • Report in Corrosion Probe Development for Assessing Grillage foundations, Anchors and Steel Poles;
  • Report on Coating System Selection and Application Guidelines;
  • Report on Design changes for concentration cell corrosion in bolt details: pack-out in weathering steel and galvanized carbon steel construction.

Live working: research, techniques and procedures

The success criteria for this work package will be the delivery of the following:

  • Report on Basic Data for Calculation of Minimum Approach Distance (MAD) and Gap Factor for Live Work
  • Report on Electrical Performance of New Jacketed Rope for Live Work
  • Guide to the Design of Transmission Structures to Facilitate Maintenance and Live Working
  • Tool with Probable Causes of Recent Flashovers of Live Working
  • Report on the Impact of Recently Released Regulatory Requirements on Live Working

Performance and maintenance of high-temperature conductors

This project will delivery the following:

  • Guide for Selection and Application of High-Temperature Conductors;
  • Guide for Maintenance of High-Temperature Conductors.

New and emerging inspection and sensing technologies

This project will me measured against the delivery of the following:

  • Software Tool for with Inspection & Sensing Information;
  • Report detailing the Evaluation of Emerging Inspection or Sensing Technology.