2014 Portfolio: Overhead Transmission - Program 35mydocs.epri.com/docs/Portfolio/P2014/2014_P035.pdf · Overhead Transmission - Program 35 ... • tools to increase efficiency of

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Overhead Transmission - Program 35

Program Overview

Program Description Transmission companies face issues such as improving safety and reliability, as well as reducing operations and maintenance (O&M) costs. They are also seeking ways to increase transmission capacity without making large capital investments. Reducing capital expenditures for new and refurbished equipment is another priority.

This EPRI research program is designed to address the research needs of transmission asset owners and operators. The program includes projects focused on specific components (e.g., insulators, compression connectors, conductors, composite poles, and crossarms) as well as projects focused on issues (e.g., lightning and grounding, live working, transmission capacity, and methods to assess the condition of overhead lines). The program delivers a blend of short-term tools such as software, reference guides, and field guides, together with longer-term research such as component-aging tests and the development of sensors for monitoring the performance of line components.

Research Value With the knowledge acquired through this research program, program members will have access to information that can provide them:

· improved management of aging transmission line components; · improved inspection and assessment tools and techniques; · enhanced lightning performance reliability; · tools to increase efficiency of transmission line design; · new live working techniques and procedures; · schemes to get more capacity out of existing overhead lines; · improved approaches to selecting, applying, inspecting, and assessing insulators; and · information on emerging transmission line sensing and inspection technologies.

Approach The EPRI research results are documented in a way that can easily be applied to increase reliability of the system while managing costs to help keep electricity affordable. Many results can be applied immediately while other research may yield benefits over a longer time frame.

Short-term results include:

· A comprehensive transmission line inspection and assessment reference guide, the Yellow Book, is continuously updated to provide members with the most up-to-date, comprehensive understanding of transmission component behavior, inspection technologies, and line effects.

· Field guides and training software help workers identify levels of component deterioration and take timely corrective action.

· Operators can learn to improve capacity through the use of thermal and corona models of overhead conductors operating at high temperatures and through understanding of the effect of high-temperature cycling on conductor systems.

· Methods and tools are being developed to maintain transmission components and extend their life. · Transmission line and foundation design tools enable members to incorporate the most current industry

knowledge into their development plans.


2 Electric Power Research Institute | Portfolio 2014

Medium- to long-term examples include:

· Laboratory testing and evaluation of coatings for structures and sub-grade corrosion applications · Remediation methods for concrete foundations · Transmission structure design guide · Forecasted transmission line ratings methodologies · Long-term laboratory experiments to better understand the aging and failure mechanisms of structures

and line components. Corrosion labs create environments to better understand the impact of corrosion above and below ground.

· Insulators are tested in an accelerated aging setup for aging and degradation to improve understanding of their long-term performance characteristics.

· Advanced coatings for insulator and conductor applications including specialty coatings such as hydrophobic nano-coating

Accomplishments The Overhead Transmission program has delivered valuable information that has helped its members and the industry in numerous ways. Some examples include the following:

· Compression Connector Inspection Guide helps identify high-risk connectors, the efficacy of compression connector tools, and actions to be taken when high-risk units are identified.

· Conductor Sensor: This device is applied on conductors and splices and measures conductor/splice temperature, current, inclination and vibration. It has a number of applications including ratings, vibration, and connector management.

· EPRI Software Insulator Calculation Engine (ICE): Version 1.0 is used to evaluate the corona performance of polymer insulators, whether in-service or as part of a new design. An EPIC 3D model can be created from scratch in under 15 minutes; whereas, the same model in traditional software can take hours. The software helps users reduce the risk of transmission line polymer insulator failures caused by the degradation of the rubber weathershed system due to corona activity.

· Inspection, Assessment and Remediation Methods for Concrete Foundations: This guide provides a hands-on understanding of how to apply electrochemical inspection techniques and what technologies are available to restore the condition of the concrete.

· Transmission Line Workstation (Generation 2) software is used to evaluate the performance of existing lines or help design new transmission lines. It enables users to build models of transmission lines and then analyze their susceptibility to electric and magnetic fields, corona, and lightning. The software provides many tools to help users design improvements to power lines.

Current Year Activities In the coming year, this research program expects to accomplish these objectives:

· Develop fleet management approach to assess the health and condition of assets · Develop tools and mitigation techniques to address sub-grade and conductor corrosion · Develop guidelines for compression connector management · Develop inspection and assessment approaches for composite poles and crossarms · Provide state-of-the-art methods for designing transmission line structures · Develop live working ropes for new applications · Evaluate the performance of lightning detection networks · Update the Lightning and Grounding reference book (the Gray Book) · Update Transmission Line Workstation—Generation 2 (TLW-Gen2) with new modules · Provide composite component accelerated aging results · Develop software to aid in selection of corona rings for polymer insulators and electric field calculations

on ceramic and glass insulators (ICE) · Develop ratings forecasting methodologies



· Transmission Ratings Workstation Version 1 · Development of additional instrumentation for increasing power flow · Develop guidelines for the selection and application of various types of high-temperature low sag

conductors

Estimated 2014 Program Funding $8.9M

Program Manager Fabio Bologna, 704-595-2590, [email protected]

Summary of Projects

Project Number Project Title Description

P35.001 Inspection, Assessment, and Asset Management of Overhead Transmission Lines

This project is a mix of tools, training, and information that will help members improve their line inspection and assessment techniques.

P35.002 Conductor, Shield Wire and Hardware Corrosion Management

This project identifies, develops, and evaluates tools and procedures required to deal with conductors, shield wires, and hardware exposed to atmospheric corrosion.

P35.003 Structure and Sub-Grade Corrosion Management

Structure and foundation corrosion management by understanding how the environment influences corrosion types, what practices should be used to locate the damage, and what methods are appropriate to remediate and mitigate the corrosion damage.

P35.004 Compression Connector Management

This project provides a holistic approach to the inspection and management of compression connectors.

P35.005 Crossarm and Composite Pole Management

Use of composite components and poles has become attractive due to competitive pricing, reduced shipping and handling costs, and lower logistical and equipment requirements during construction. Utilities are hesitant to embrace widespread use of composites due the lack of experience in both construction and maintenance practices, but also an understanding of performance as the material ages. The development schedule is as follows: · Material evaluations for short term and long-term performance · Material performance criteria for design will be completed with

supporting software · Inspection criteria and evaluation of technologies will be

developed for maintenance crews · Sensor development has begun and algorithm development will

follow · Population assessment methods for Fleet Management practices

are in study

P35.006 Lightning Performance and Grounding of Transmission Lines

This project is a mix of tools, training, and information that will help members improve their transmission line lightning performance.




P35.007 Transmission Line Design Tools and Design Approaches and Practices for Construction

This research provides the most current and comprehensive information covering different aspects of overhead line designs. It develops a single-source guide for the coordination of design, construction, and maintenance practices. It also develops software tools to assist designers in selecting optimal designs for overhead lines.

P35.008 Emerging Designs: Hardened and Compact Overhead Lines

This project develops comprehensive design guidelines to assist designers in evaluating, selecting, and designing cost-effective structures suitable for overhead lines. A practical reliability-based design approach is to be developed. Interaction among other components, such as the foundation, will be considered. The focus on the structure will be emerging tower configurations that are required to meet new right-of-way requirements. Tests will be performed, as required, in EPRI laboratory to address knowledge gaps for electrical and mechanical designs.

P35.010 Live Working: Research, Techniques and Procedures

This project develops tools, procedures, and training materials for live and de-energized work on HVAC and HVDC lines to enhance worker and public safety, work efficiency, and reduction in cost and duration of maintenance outages.

P35.011 Polymer and Composite Overhead Transmission Line Components

This project addresses the use and maintenance of composite transmission line components. Through this project, members learn how to select, install, inspect, and maintain composite transmission line components used throughout the world.

P35.012 Porcelain / Glass Insulator Integrity Assessment

This project focuses on how to assess the aging population of porcelain and glass insulators, and how to properly procure and apply new and replacement insulators.

P35.013 Ratings for Overhead Lines

This project develops technologies and methodologies for economically optimizing and increasing the power capacity of existing transmission assets, and provides state-of-the-science reference and training materials. It also provides software tools to optimize power flow in real-time, for predictive assessments of power capacities, and for performing off-line rating studies.

P35.014 High Temperature Operation of Overhead Lines

This project will collect all available information on high-temperature operations, conduct laboratory tests to address knowledge gaps, and prepare software to facilitate risk evaluations of high-temperature operations. The project addresses the impact of high-temperature operations on the mechanical, electrical, and thermal behavior of overhead lines.

P35.015 Performance and Maintenance of High-Temperature Conductors

This project conducts research to address outstanding issues related to high-temperature conductors. It investigates the long-term performance of all commercially available advanced conductors to complement the field demonstration project, which provided information on handling and stringing of these conductors. Maintenance tools and procedures for this new type of conductor will also be identified and established. A comprehensive guide for the selection and application of high-temperature conductors will be prepared.




P35.016 New and Emerging Inspection and Sensing Technologies

This project documents the latest inspection and sensing technologies for overhead transmission lines, as well as early adopters' experiences with these technologies. Some technologies are tested and evaluated and results made available. Test results and demonstrations help members make more informed decisions when deciding whether to deploy such technologies.

P35.001 Inspection, Assessment, and Asset Management of Overhead Transmission Lines (052001)

Description 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 extend the life of the assets while keeping the aging infrastructure performance at levels that meet the reliability expectations of the public.

New inspection and maintenance management practices and tools may be based not only on the application of advanced technologies such as unmanned aerial systems but also on advancements in the understanding of aging and degradation processes of line equipment and components.

Approach The Overhead Transmission research team recognizes the work processes and challenges of program members. This research project will employ a tiered approach that will develop a number of materials and then help utility workers quickly incorporate those materials into their everyday work routines. Application of the project's results may simplify their jobs and help them to do their jobs better. The research team does the following:

· Develops and documents an understanding of component degradation, indicators and symptoms of impending failures, as well as effective inspection practices and technologies in the Inspection and Assessment Methods (IAM) Reference Guide, the Yellow Book

· Maintains computer-based instruction systems to help in technology transfer of assessments, technologies, and components

· Maintains field guides for field personnel that help identify and provide information on the condition of components and remedial action if necessary

· Develop fleet management approaches to assess the overall health and condition of overhead transmission assets

· Develops and hosts hands-on tech transfer workshops and conferences · Develops techniques for systematically inspecting and assessing an in-service population of various line

components to identify the at-risk component classes · Provides a statistical analysis of overhead transmission line component history contained in EPRI

databases

Impact This research project may affect operations and benefit the public in a number of ways:

· Tools 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



How to Apply Results The research program is structured so the tools are ready to be incorporated into a member's standard procedures. Members will be able to supply field guides to their field inspectors. Managers can use guides to set up their assessment programs. Hands-on training can provide staff with knowledge that they can apply immediately in the field. Computer-based training can be used throughout all levels of the organization, including field personnel and managers, as they apply what they learn from the Yellow Book reference material. Managers can use utility and industry feedback to better assess where inspection and maintenance resources should be applied. Summaries of line component performance databases can help in assessing a population of similar line components.

2014 Products

Product Title & Description Planned Completion Date Product Type

New Version of OHTL Inspection and Assessment Methods (IAM) Reference Guide (Yellow Book): This guide helps members initiate a new overhead transmission line inspection and assessment program or refine an existing one. It focuses on degradation and inspection of line components, and procedures and technologies for inspecting and assessing components.

12/31/14 Technical Update

Methods to Assess the Condition of Overhead Electric Transmission Lines: Utilities have expressed interest for analytical tools/methods to assess overhead line performance in a more protective and risk based approach. Different methods are used by utilities to evaluate and compare the overall condition and operational status of their overhead transmission line assets to better manage and assess where inspection and maintenance resources should best be applied to reduce the risk of line failures. In 2013 work was initiated to collect information and understand what approaches are being employed by utilities to manage transmission assets, establish asset maintenance and inspection priorities and condition assessment. EPRI plans to use this information to develop and recommend an approach for establishing TL asset condition metric.


Population Assessments of Line Components: Currently no common methodology exists for the inspection and assessment of a population of all the various overhead line components in-service. This task aims to develop these techniques and build upon the initial concepts put forth for EPRI for polymer insulators and compression connector line components. Utilities employing these methodologies and procedures should be able to detect, in a systematic and cost effective way, line components that are high risk as well as mitigate the effects of these high-risk units.


Overhead Transmission Line Component Performance Summaries: Over recent years EPRI has developed a number of overhead transmission line component performance databases (e.g. polymer insulators) containing actual failure data or information from line components removed from service for various reasons. This technical update report will provide members with a synopsis of findings resulting from a periodic analysis of the data contain in each line component database. It is expected that new line component summaries will be added over time as EPRI continues to expand and populate the number of component databases created.




P35.002 Conductor, Shield Wire and Hardware Corrosion Management (063280)

Description Atmospheric corrosion is an unavoidable phenomenon that can lead to failure of conductors, shield wires, hardware, and components and can result in momentary or even sustained outages. Airborne salts, acid rain, and exposure time to wetness are the primary environmental controlling factors influencing corrosion severity. Equally important is the condition of the protection systems such as galvanized coatings. Understanding these factors and the corrosion timeline better enables utilities to establish inspection cycles based upon levels of risk, population assessments, and utilizing new inspection tools or techniques.

Approach This project provides tools and processes for inspecting and assessing overhead conductors, shield wires, and hardware. It produces management and engineering guides and provides guidance to asset managers. The project’s research results will be documented in guidelines for inspection, selection and application. This project will also explore fleet management methodology to perform population assessment of phase conductors and shield wires. The following tasks are planned:

· Prior research has shown that the EPRI-developed non-contact, near infra-red (NIR) spectroscopy inspection technology can be effectively applied as a screening tool for identifying the presence of corrosion byproducts on aluminum conductor steel-reinforced (ACSR) conductors or ground wires. This technology identifies iron oxides that were created by the corrosion of the steel core, leached through the aluminum strands and deposited on the lower side of the conductor. In 2014 the focus will be to explore the possibility of using this technology to determine degradation rates and remaining conductor life, and to predict when remedial action will be necessary.

· Develop application of NIR spectroscopy technology for condition assessment of degraded hardware or component surfaces by identification of zinc oxides or aging coating systems.

· Develop assessment methods and approaches for components by measuring corrosion rates on test specimens and determining the remaining structural strength of the hardware. Through laboratory testing and field surveys the effects of the environment may then be understood and correlated with environmental data to derive aging algorithms for specific geographic locations. This will allow utilities to establish inspection cycles based upon actual corrosion rates and allowable sectional losses.

· Assess and evaluate new and emerging inspection and assessment technologies by implanting known flaws with specific sectional losses. The inspection methods under evaluation will be assessed on the ability, probability, and accuracy of locating the damage.

· Workshops to disseminate research findings, technology demonstrations, and hands- on technology transfer for inspection and assessment techniques.

Impact The project will help improve inspection and population assessment of components. It could also provide a more accurate picture of the status of the power delivery infrastructure, enabling more informed maintenance and fiscal decisions.

How to Apply Results Transmission designers, engineers, operators, asset managers, and inspectors will use the results of this project to inspect and assess overhead shield wires, conductors, and hardware. Employing the knowledge gained from the project's results will help members develop a cost-effective maintenance program that will improve reliability by identifying and assessing high-risk shield wires and conductors prior to failure.



2014 Products


NIR Spectroscopy Development for Steel Core Conductor Condition Assessment: The NIR spectroscopy development goal is to identify spans or attachment points that have steel core oxides leaching out of the conductor onto the outside surface of the aluminum strands. This technology has proven its ability to identify pitted aluminum and discriminate between dirty conductor strands and strands stained with iron oxide. The development goal is to identify levels of degradation based upon the intensity of staining on the aluminum strands. This will allow NIR spectroscopy to be used as a predictive tool and allow time for allocation of maintenance funds while optimizing the remaining conductor life without exposure to risk. This technology requires extensive environmental testing, field evaluations, and repackaging to result in a robust tool for field use. This project focuses on a series of field surveys and subsequent sampling to confirm the development status in establishing reject and ranking criteria for ACSR, ACSS and other steel core conductors.


Fleet Management Strategies for Population Assessment of Conductors, Shield Wires and Hardware in Atmospheric Service: This project focuses upon development of a technology to screen large geographic areas for components, hardware, and structures exposed to high levels of corrosion. The results will allow maintenance groups to optimize their O&M budgets by targeting areas that are statistically significant based environmental models, supported by laboratory corrosion testing and confirmed through field surveys for condition assessments. the focus is for initial model development to be based upon Gaussian plume models and eventually replaced by more accurate La Grangian models as databases develop and the process becomes more refined.


P35.003 Structure and Sub-Grade Corrosion Management (063281)

Description The total cost of corrosion to the U.S. economy is more than $276 billion annually, of which more than 30% could be prevented through the use of existing corrosion-management practices. Within the power generation and delivery sectors, the costs associated with corrosion range from $5 billion to $10 billion each year, according to NACE.

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 research is needed to identify corrosion issues, characterize corrosion types, and develop appropriate corrosion management solutions for funders.

Approach This project addresses the issues surrounding corrosion of transmission line structures by providing personnel with the tools to make the most-informed and cost-effective management decisions. Improved corrosion management may be achieved by developing new inspection techniques, improved assessment practices, and mitigation methods for specific corrosion types. The result of this effort will be the development of a comprehensive corrosion management program that reduces maintenance costs and the risk of outages or possible health hazards. The following core tasks are under way:

· Evaluation of new and emerging coating systems to understand failure modes, corrosion initiation mechanisms, and cycle times for future inspections



· Performance evaluation of new and emerging inspection technologies and mitigation methods provided by vendors, including technologies specific for lattice grillage foundations, tubular structures, and anchors

· Provide new field survey techniques for corrosion rate measurements on structures and grounding systems, which will help prioritize circuits and develop inspection cycles

· Provide an understanding of inspection techniques to characterize corrosion of reinforcing steel in concrete structures and foundations

· Determine the affects of the environment on different corrosion types and corrosion rates for the development of population assessment methods supporting fleet management practices

· Solutions for locating and mitigating corrosion on the internal surfaces of tubular structures · Transfer of new learning through workshops and conferences by providing education and training for new

corrosion inspection, mitigation, and remediation techniques

Impact This program may:

· Reduce outages by understanding corrosion initiation mechanisms, identifying failure modes, and determining life cycles of various structure construction styles

· 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 components of 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

How to Apply Results Transmission personnel will use the new tools and learning to increase maintenance program efficiencies through novel inspection and assessment practices, new methods for corrosion mitigation, and improved remediation practices. This program may improve system reliability by identifying high-risk foundations and structures before end of life replacement or failure.

2014 Products


Remediation Methods for Concrete Foundations (final): This product evaluates remediation methods for concrete, which can include structural repairs but also advanced coating selection, installation of cathodic protection, and technologies to restore the integrity of the concrete. This product explores the efficacy of each technique, outlines the barriers to implementation, and outlines procedures for each method based upon initiation mechanisms, failure modes and the severity of damage.


Inspection and Assessment State of the Art Report (final): This deliverable is the summary report of inspection techniques or technologies for the condition assessment of structures and foundations. Included are the test results of many diverse technologies including guided wave, light reflectance, electrochemistry, ultrasonic inspections, and direct assessments. The conclusion and recommendations list an evaluation of each inspection methods based upon accuracy, sensitivity, risk, and cost of implementation.





Evaluation of New and Existing Corrosion Sensors (draft): The application of corrosion sensors is a critical aspect of future fleet management practices. This product is designed to evaluate new and emerging sensors but also to identify gaps in the assessment of atmospheric and sub-grade degradation. These sensors may be classified by the type of failure, a measurement of an environmental factor such as temperature or a direct measurement of the corrosion rate. Each type of sensor then allows an understanding of how a structure or foundation ages by providing real time data for trending and forecasting by development of condition assessment algorithms.


P35.004 Compression Connector Management (065547)

Description Predicting the remaining life of compression connectors (splices and dead-ends) is a major challenge. Compression connector failures are expected to increase with increased demand for heavier loading operations. Due to the limitations of existing inspection techniques, isolating the components early enough to avoid failure is difficult. Inspection techniques and population evaluation methodologies are needed.

Technologies currently used to inspect compression connectors are not always reliable and repeatable, and application methods and threshold levels for these technologies are not well defined. This project will increase understanding of the currently available techniques, their performance, and their application. Guidelines will be provided for their application, and promising new techniques will also be sought and identified.

The performance of compression connectors is directly related to installation practices and procedures. Conductor preparation and field personnel training remain two key priorities to address these issues. This project addresses the issues surrounding inspection, assessment, remediation, and population assessment of compression connectors by providing tools and information to make the most informed and cost-effective decisions.

Approach The tasks addressed in this project are:

Guidelines for Compression Connector Inspection: Guidelines will be developed to assist utilities with the inspection of overhead transmission line compression connectors. The guidelines will based on extensive work done by EPRI over the last five years and will include utility best practices. The guide will also cover the fleet management of connectors by using updated information obtained from the EPRI compression connector performance database.

Application of the Conductor Cleaning Tool for High Temperature Low Sag (HTLS) Conductors: Testing will be undertaken to determine the performance of HTLS conductors after being cleaned by the conductor cleaning tool. Tests will consist of thermal mechanical aging in the Charlotte laboratory as well as forensic analysis of the aged conductor core after being cleaned by the conductor cleaner.

Evaluate the Life Expectancy of Compression Connectors Operating at 100°C and Below: This task will build on previous EPRI work done at elevated temperatures (125°C and above). Both single-stage and two-stage compression connectors will be tested in accelerated thermal mechanical aging tests to determine performance and uncover issues. Additional data will be obtained by subjecting compression connectors with specific installation to the same tests.



Evaluate Compression Connectors with Known Defects: Compression connectors with known defects will be tested in accelerated thermal mechanical aging. Connectors with defects such as under crimping, over crimping, and lack of thermal compound will be created and evaluated. The test results will provide information on inspection approach and time to failure per defect type.

Connector Performance Database: Maintain a failure/performance database. Information provided by utilities will be analyzed and results provided to funders. The results will also be used to develop a population management approach

Impact This research project may affect members' operations in a number of ways:

· Increase safety by reducing line drops · Reduce sustained unplanned outages due to compression connector failure · Optimize spending of O&M funding · Improve productivity of field personnel with training and field tools · Address the loss of institutional knowledge by providing training

How to Apply Results Members can modify their current inspection practices as a result of the research. Operations and maintenance personnel can implement the population assessment methodology and use failure database information to make informed decisions. Field personnel will be able to use the inspection guide and case studies to improve their inspection practices and as part of their in-house training programs.

2014 Products


Guidelines for Compression Connector Inspection: Guidelines for compression connector inspections using various inspection techniques and technologies will be presented based on test data, field data and information from the EPRI compression connector performance database. The document will be based on previous EPRI tests and collaboration with member utilities.


Application of the conductor cleaning tool for High Temperature Low Sag (HTLS) Conductors: Based on the tests done in 2013, further testing and or development will take place in 2014. Performance issues will be addressed and the suitability of a conductor cleaning tool for high temperature conductor applications will be assessed. Evaluation techniques could include long term aging of connectors made using the conductor cleaning tool to clean the conductor ends inserted into the connectors.


Evaluate the life expectancy of compression connectors for lines operating at 100°C or below: Initial Testing: Previous EPRI tests have focused on the high temperature performance (temperatures of 125°C and above) of compression connectors. This work will study the performance of compression connectors operating at temperatures of 100°C and lower. Accelerated thermal and mechanical tests will be undertaken in the laboratory to determine the life expectancy of connectors operating under these conditions.




P35.005 Crossarm and Composite Pole Management (067437)

Description This multiyear project addresses a range of composite design and maintenance concerns, including mode of failure, degradation rates, and the environmental factors that start the degradation process. Exposure to the environment changes both the material performance and the performance of the final design so the material attributes are measured first and then evaluated again in short and long-term aging conditions. After the design incorporates the new learning of material performance, the design is resubmitted into the exposure testing for short and long-term performance verification. This will confirm that the mode of failure, the initiation mechanisms, the time interval required for maintenance, and the overall service life of the design.

As the composite pole plant matures there will be a need for maintenance crews to provide a condition assessment and apply some method of remediation to restore the original structural strength. Evaluation of inspection and remediation methods must be completed on control samples that have been aged and that new learning is passed along in the form of design guides, management guides, or electronic training modules.

Approach Structure designs require an understanding of new material attributes including mechanical and electrical properties but also how those properties change when exposed to the environment and how they age over time. This learning is supported by identifying the failure modes of the material, the initiation mechanisms leading to the degradation, and the aging rates of that material. This information leads to an understanding of future maintenance requirements and an estimate of the service life.

An evaluation of a material in a controlled exposure test will provide an understanding of how material performance may change while accelerated aging may determine the initiation mechanism and failure mode. Long-term aging in the field may then confirm failure modes and service life estimates.

Once that material is incorporated into a structure or component design, the evaluation process is focused upon geometry- dependant degradation modes. Each design must then be submitted for performance testing and evaluation of short and long-term exposure testing. As those structures and components are placed in service and begin to mature, the maintenance crews will need tools to provide condition assessments. To evaluate those tools or inspection technologies, control samples must be aged and presented to service providers for demonstration and assessment. The results of those evaluations may be provided to funders in the form of management guides or computer-based training modules.

The last aspects of this project are to develop remediation methods for composite materials and sensors to remotely trend the aging of the structure or component. Each of these tasks require an understanding of the material and how the geometry of the design changes the initiation mechanisms. Once that mechanism is identified and understood, a remediation method may be designed and implemented or a sensor may be developed to monitor that attribute.

Project activities include the following:

· Establish a baseline of mechanical and electrical properties when exposed to the environment · Confirm the degradation rates and failure modes based upon the type of aging mechanism and the

duration of the exposure test · Evaluate emerging inspection and assessment tools or techniques based upon accuracy, cost to

implement, probability for finding degradation, and risk of missed problems. · Develop new inspection and assessment technologies · Develop design and management guidelines to help utility groups incorporate new learning · Provide a field guide to help maintenance personnel identify issues, categorize the severity, and assign a

corrective action · Develop sensors in laboratory environmental chambers to monitor and trend degradation rates in the field · Develop algorithms for degradation rates from laboratory environmental data



· Demonstrate population assessment methods using sensor deployment at structures combined with algorithms derived from laboratory exposure testing

· Demonstrate an E-learning module for inspection and assessment techniques, application of reject and ranking criteria and documentation control

Impact This project may have the following impacts:

Reduced outages, increased reliability, and better transmission system sustainability

· New learning in the area of composite performance and degradation due to environmental exposure · Training to address new methods of construction and maintenance practices · Reduced construction and maintenance costs through the use of new materials · Improved productivity through the application of new field tools and techniques

How to Apply Results Engineering groups may increase structure life and reduce maintenance costs through the better use of composite materials in design and an understanding of material performance in specific environments.

Construction groups may reduce installation and framing costs by reduced equipment requirements and logistics of support groups due to increased material performance.

Maintenance groups may provide life extensions by identifying initiation mechanisms before degradation of the structure or component occurs.

Maintenance groups can implement Fleet Management practices of population assessment and optimize inspection practices by trending degradation and forecasting maintenance funding requirements.

2014 Products


Mechanical and Electrical Performance of Composite Materials used in the Manufacture of Poles and Crossarms and the Effects of the Environment on Short and Long Term Performance: This project is a multiyear effort to understand the short and long term effects of the environment on composite material performance. Tests will be developed to understand how baseline mechanical and electrical performance is affected by exposure to the environment, which will also identify the degradation rates, initiation mechanisms and failure modes. Long term accelerated aging tests will then be evaluated to extrapolate the service life and validate the failure modes from short term testing.


Installation and Framing Issues for Composite Poles and Crossarms: Surveys have identified gaps in areas related to installation and framing of composite poles. This product will outline procedures for each aspect of the operations including shipping and handling, receiving inspection, pole setting and framing, troubleshooting of the installation.




P35.006 Lightning Performance and Grounding of Transmission Lines (051989)

Description Lightning activity is the leading cause of momentary outages on transmission lines. Finding the most effective measures to improve the lighting performance of lines is not always straightforward. There are many options, such as shielding, grounding, insulation, and transmission line surge arresters to be considered to determine cost effectiveness. Some options may also impact other design aspects of the line. For example transmission line grounding influences both the lightning performance and safety of transmission lines, and the most effective ground electrode design depends on a variety of factors. This project generates engineering and maintenance tools to understand lightning and grounding performance, and evaluate effectiveness of grounds and grounding designs using traditional and new materials.

Approach The tasks addressed in this project are:

Lightning Performance Prediction Software (TFlash Module in TLW -Gen2): In 2014, the TFlash module will be updated to include the latest research information, in particular incorporating an improved insulator flashover model based on the results of laboratory impulse testing of insulator design configurations. Participants in this project will get access to the TFlash module of TLW-Gen2.

Grounding Software (Module in TLW -Gen2): In 2013, the module for calculating AC fault current division between ground and return conductors was developed. For the first version of this module only single circuit lines were considered. In 2014 this module will be expanded to include new features. Participants in this project will get access to this module of TLW-Gen2.

Grounding: Companies are currently struggling with issues related to copper theft and corrosion. This task will investigate the use of alternative materials and electrode designs for grounding connections. Issues such as design practices, life expectancy, corrosion, material compatibility, and current-handling capabilities will be addressed. In 2012 methods for extending the service life of aluminum and steel counterpoise were determined. In 2013, practices and options for grounding near substations were documented. In 2014 alternate materials designs and in-service experience for ground electrode connections will be identified and documented.

Effect of Seasonal Variations in Transmission Line Grounding Measurements: Meteorological and geological factors can have a considerable impact on structure grounding values. Changes in the impedance of ground electrodes may be the direct result of variations in the soil resistivity but could also be the results of permanent changes to the electrode itself (corrosion, for example). Monthly grounding measurement data collected over a two-year period will be analyzed and the results documented.

Quantification of Lightning Detection Networks: In 2011 a document comparing the lightning data provided by three lightning location networks in the United States was developed. In 2012 data provided by vendors for areas of low, medium, and high lightning ground flash densities were compared. In 2013 information from vendors was compared to utility fault data. In 2014 the 2012 study will be repeated to determine improvements to the networks (if any) and include vendor(s) who did not participate in the 2012 study. Results could help understand the accuracy and enhance the usefulness of lightning detection and location information.

Determining the Strength of Line Insulation Under Lightning: Design calculations require detailed knowledge on the lightning incidence, line configuration, geography, ground impedance, and insulation level of the line. Some parameters, such as the line configuration and geography, may be known to a great level of detail, while there may be uncertainties in others—for example, grounding impedance or insulator flashover under lightning conditions. These parameters may have a significant influence on the accuracy of design calculations. Currently most of the body of knowledge in this area is related to porcelain or glass insulators, which is considered less representative of current designs using polymer insulators. In 2012 and 2013 laboratory work to quantify the lightning flashover strength of typical line insulation was completed. In 2014 these test results will be documented and used to "calibrate" flashover models utilized in TFlash module in TLW -Gen2.



Field Tool to Evaluate Transmission Line Grounds (EPRI Zed-Meter®): Commercial ground electrode measurement techniques do not accurately measure structures that are grounded in multiple locations, such as transmission lines with overhead ground wires, steel lattice structures with grillage foundations, and two-pole structures. From 2004 to 2012, a technology that enables effective measurement of transmission line ground electrodes was developed and demonstrated, and an application guide was developed. In 2013 a method using shorter leads and providing soil resistivity value was incorporated into the Zed-Meter software to increase the functionality and versatility of the instrument. In 2014 extensive field testing will be done and additional functionality added.

Transmission Line Surge Arrestors (TLSA) Research: This task develops information resulting in information for applying, installing, and inspecting TLSA's. In the past years, application guides were developed and related workshops were held. In 2011 a review of current knowledge on gapped line arrestors was completed. In 2012 this project developed techniques for monitoring the condition of in-service transmission line surge arresters and a test plan for mechanical testing. In 2012 and 2013 a mechanical testing protocol was developed and mechanical testing of arrestor leads was done. In 2014 additional mechanical testing may be done including testing of disconnectors. In addition, evaluation of units removed from service and the TLSA failures database will be updated.

Lightning & Grounding Reference Book: This reference book provides the latest research results and is a resource to assist utilities in improving the lightning performance of their overhead transmission line. The book is based on previously published EPRI work and will be updated with new information.

Review of Grounding Measurement Techniques: There is a wide range of commercial instruments available for the measurement of ground electrode impedance. These instruments may utilize different techniques that, depending on the situation, may result in significant variation in values obtained for the ground impedance. During 2014 a survey of available instruments and grounding measurement techniques will be made with a view of pointing out strengths and weaknesses of each method. Comparative measurements will be made with a range of devices.

Impact This project is expected to have the following impacts:

· Improve lightning performance and safety of transmission lines by providing engineers with effective tools and an improved knowledge base

· Address the loss of institutional knowledge by providing guides and tools for engineering staff who are new to the field of lightning and grounding

· Reduce costs by providing improved tools (e.g., Zed-Meter and TFlash) for field inspection and engineering staff

· Improve public and worker safety, as well as transmission reliability, by identifying alternative ground electrodes

How to Apply Results Operations and maintenance (O&M) personnel can apply the EPRI Zed-Meter to measure the tower footing resistance of structures on their systems. Transmission line engineers can use the lightning performance prediction software to optimize the lightning performance of transmission lines with internal resources, or they can outsource this work to the EPRI Lightning and Grounding Team. Information on transmission line surge arrestors (TLSAs) will provide design and O&M maintenance personnel with knowledge on the application and inspection of TLSAs.



2014 Products


Transmission Line Workstation (Gen 2): Lightning Performance Module update: The Lightning and Grounding (TFlash) module will be updated to include the latest research information in particular incorporating an improved insulator flashover model based on the results of laboratory impulse testing of insulator design configurations.

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Mechanical Testing of TLSA's leads and Disconnectors: This product will document the test results of test protocols developed in 2013. 12/31/14 Technical

Update

Review of Transmission Grounding Measurement Techniques: New technologies will be tested and evaluated. The results will be documented in a report.


Evaluate the Performance of New and Current Lightning Detection Networks: There are new and currently operated Lightning Detection Networks that have undergone significant technical upgrades over the past few years. Utilities are interested in the accuracy and new information these networks provide. This product will compare vendor information for areas of low, medium and high lightning areas.


Transmission Line Workstation (Gen 2): Grounding Module update: In 2013, the module for calculating AC fault current division between ground and return conductors was developed. For the first version of this module only single circuit lines were considered. In 2014 this module will be expanded to include new features.

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P35.007 Transmission Line Design Tools and Design Approaches and Practices for Construction (060457)

Description The objective of this project is to provide the most current information and tools to overhead line designers for them to make informed decisions in designing new or upgrading existing overhead transmission lines. The goals are to produce reliable and safe designs, select the lowest life cycle cost options, decrease design times, reduce construction, and facilitate ease of maintenance.

The project may include research results, techniques, equations, methodologies, practices, guides and software.

Cost-effective overhead line designs must be constructed and maintained easily. In 2014, the former project 35.007 "Transmission Line Design Tools" and project 35.017 "Design and Construction—Approach and Practices" are combined into one single project to achieve this objective.

Under the "Transmission Line Design Tools" project, design modules are developed within the TLW-Gen2 software program. By the end of 2013, the AC Electrical Effects and the Single Conductor Vibration design modules are available. Under the "Design and Construction—Approach and Practices" project, a best practice procedure was proposed and recommended specific design features for structures to facilitate construction and maintenance. A guide to assist the designers in selecting of overhead line components and design parameters has also been initiated.



Approach A cost-effective line design not only performs well but it also can be constructed and maintained easily and safely. The design information needs to be well-coordinated between design, construction, and maintenance staff. The best practice for the design of overhead transmission lines to facilitate the construction and maintenance of these lines is therefore required and is developed in this project.

Prior research throughout the overhead transmission program has developed, among other results, guidelines for selecting line components, maintenance procedures, and work practices. This project integrates the resulting knowledge and experience into the EPRI AC Transmission Line Reference Book-200 kV and Above, Third Edition (the Red Book) and the Transmission Line Design Workstation (TLW-2).

This project will continue to update the Red Book through updates of existing chapters or by adding new chapters. Similarly, the TLW will be updated as necessary, or new functionality added to address emerging issues or new design and construction practices. In 2014 a module will be added to the TLW to assist designers to evaluate life-cycle costs of overhead lines. A Beta-version will be released by the end of the year. The final version will be completed in 2015.

Development of structure design requirements to facilitate construction and maintenance will continue and the highest two topics for the design guide will be completed. Furthermore, another chapter of the Red Book will be updated. The updated Red Book will be available in electronic format at the end of each year.


· Help designers select proper design parameters, line components and the least life-cycle cost design · Improve the productivity of designers · Improve the reliability of overhead lines · Enable members to build and maintain lines easily and safely · Reduce construction, operation, and maintenance costs

How to Apply Results The design modules in TLW-Gen2 provide an efficient and effective tool to help overhead line engineers design lines. They allow designers to evaluate different aspects of designs—electrical, mechanical, and others—without duplicating input data. All modules have the same look and feel to facilitate design evaluations to improve productivity. The AC Electrical Effects module is for electrical designs, while the Single Conductor Vibration module is for mechanical designs. The Life-Cycle Costing module is for general design applications. New chapters for the Red Book will meet members' additional needs. Members can take advantage of the most current information available in the revised Red Book, which has been a core reference for transmission line engineers for decades. Overhead line designers may apply guidelines developed under this project in selecting proper and cost-effective designs, materials, and components that can be installed easily and safely.

2014 Products


TLW-Gen2: Life-Cycle Costing Design Module - Beta: The life-cycle costing software will be brought into TLW-GEN2. The software is used by engineers in selecting the optimal design for an overhead line taking capital, operating, and maintenance costs into consideration. The software currently in the spreadsheet format will be upgraded to a proper software language, and the user interface will be improved. Input from members will be sought for these improvements. A beta version will be available in 2014.

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Updated Red Book - An Additional New Chapter: Revisions of the Red Book is carried out continuously, chapter by chapter, according to the needs of the members and funding available for the year. The chapter with the most outdated information will generally be chosen for the year. In some years, a new chapter may be added instead of revising an existing chapter. Input from members will be sought for the final decision. The updated Red Book will be available in electronic format.


Design and Construction - Approach and Practices: Research data on maintenance and construction practices influenced by designs will be assembled. The impacts on the practices by different designs will be reviewed. Construction approach will be evaluated and practices will be developed. Some of the topics to be considered are: utility practices for minimum clearances, ladder clips, rigging holes, grounding pads, acceptable construction quality, and a process for coordination among design, construction and maintenance.


Guide for Evaluation and Selection of Overhead Line Components: Research data on different line components from the Overhead Transmission program will be assembled and reviewed for suitability of its use for the Transmission Line Design Guide. One or more components as prioritized by task force advisors will be reviewed each year, and a document will be prepared to help designers select a proper component for their application. The selection will include both technical and economic evaluations.


P35.008 Emerging Designs: Hardened and Compact Overhead Lines (067438)

Description New transmission lines are being built to meet increasing demand for electric power or to improve system reliability. In addition, selectively transmission structures are upgraded to withstand specific hazards applying a proposed reliability-based design approach. Lines or structures using this method will be designed to meet a specific reliability level that will allow easier identification of line components that can be upgraded to improve the overall reliability of an existing line. The reliability-based design approach will allow identifying the structures and components to harden an overhead transmission line.

In addition, compact lines at 230kV and higher are being built to accommodate narrow right-of-ways. Novel compact tower designs are being developed to fit the right-of-way. As the line spacing becomes more compact, the tower clearance becomes more critical, requiring flashover-withstand capability needs to be defined more accurately. Smaller spacing is a concern when conductor galloping occurs.

The objectives of this project are to develop a design approach for overhead line designers that will allow them to determine the reliability of overhead lines and to develop the electrical clearance and mechanical requirements for reliable high-voltage compact lines.

Approach Overhead line design using the reliability-based approach was initiated in 2013 with a review of the current information on the design of transmission line structures from publications, standards, and manuals such as those from the International Electrotechnical Commission (IEC Publication 60826), the American Society of Civil Engineers (ASCE Manual 74), the Institute of Electrical and Electronic Engineers (IEEE), and the International Council on Large Electric Systems (CIGRE). A survey was conducted among electric power utilities on their experience on extreme weather events such as tornadoes, hurricanes, ice and wind storms and their subsequent design changes as a result.



In 2014, this project will evaluate line structure designs for hardening of a transmission line to enhance resiliency applying a reliability-based method. A survey of emerging designs to meet new right-of-way requirements will be initiated in 2014 and their electrical and mechanical issues identified. Tests will be proposed and conducted to create decision support information for designers to select the desired level of reliability. This may include flashover tests. Mechanical tests will be identified.


· Provide state-of-the-art methods for designing transmission line and structures · Provide information to evaluate risks and reliability of new and emerging designs · Avoid expensive maintenance and repair costs · Improve and provide uniformity to overall transmission line reliability.

How to Apply Results The project provides members with the most current information for emerging overhead line and structure designs. Transmission line designers may apply this information to their design concepts to produce reliable and cost-effective transmission line and structures that are properly coordinated with other overhead line components. The knowledge transfer to members, especially those with less experienced staff, is enhanced by attending training offered under this project.

2014 Products


Transmission Line Designs for System Hardening - Draft: A draft report on proposed options that may be adopted by members for hardening of an overhead line to enhance resiliency for extreme weather events will be prepared. The increased level of resiliency is to be evaluated using the reliability-based approach. The draft report will be reviewed by members. Comments will be addressed and input will be incorporated into the final report to be prepared in the following year.


Emerging Structure Designs - Survey: A survey is to be conducted on emerging structure designs that have been adopted by members. Issues, both electrical and mechanical, are to be identified. The state-of-technology of emerging structures is to be determined. New information will be developed by testing as required to address knowledge gaps in following years. The performance levels of these emerging designs are to be evaluated by the reliability-based approach.


Workshop for Overhead Line Designs - Structures: A member workshop will be conducted on the design of overhead lines. The reliability-based approach will be explained. Different system hardening options to enhance resiliency for extreme weather events will be presented and discussed. Merits of various alternatives will be compared. Input is to be solicited from attendees for improvements to the draft report.

12/31/14 Workshop, Training, or Conference

P35.010 Live Working: Research, Techniques and Procedures (051995)

Description Deregulation and the economic realities of today’s electric utility business are forcing utilities to ensure that transmission and distribution lines remain in service every day. Outages for maintenance are more difficult to obtain. In search of solutions, transmission owners are increasingly turning to live-line working techniques as standard practice to perform required maintenance. Live-line work must be performed safely.



Work on de-energized lines, when it is possible, still faces hazards that include step-touch-transfer and induced voltages. These hazards in de-energized work must also be recognized and mitigated. New techniques, tools, and procedures are needed for work on high-temperature conductors; minimum approach distances for helicopters in energized environments; design of structures to facilitate safe, efficient, and economic execution of live work; energized rescue; live reconductoring and replacement of conductors and hardware; and training of crews to promote safety during both energized and de-energized work, including situations such as construction in the vicinity of energized lines.

Approach Over more than two decades, EPRI has helped many transmission companies achieve significant safety improvements and cost savings in the areas of live working and de-energized work by developing and implementing new technologies, tools and training materials for maintaining and refurbishing transmission lines. The results of this effort were consolidated with industry practices into a comprehensive Live Working Reference Book (the Tan Book Ed. 3, 1024142) published in 2012. Building on that foundation, project activities in 2014 will address specific issues in live and de-energized work high voltage lines. These activities may include research and full-scale tests in the following areas:

· ropes for live work and energized rescue · live work on HV lines · live work with high-temperature conductors · design of structures to facilitate safe, efficient, and economic execution of live work · technology transfer through updating the Tan Book, training videos/DVDs, meetings, and webcasts

Impact The impacts of this program can:

· 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 · apply innovative ideas and tools to live work

How to Apply Results Participation in this project will help overhead transmission owners, maintenance service providers, and linemen improve safety and transmission performance, enhance reliability, and reduce maintenance costs by supporting worker safety when conducting live-line and de-energized work on overhead transmission equipment—as well as through the development of new tools, equipment, and procedures. New methods will be documented in written reports. Training materials will be developed in electronic media using slides, live-action videos, computer-generated scenarios, and live narration.

2014 Products


Emerging Issues in Live and De-Energized Work above 800 kVAC and 600 kVDC: Transmission systems at voltage levels above 800 kVAC and 600 kVDC have moved from the research stage to construction and full operation. When these lines need to be maintained live, new tools and procedures must be developed, and new as yet unknown issues must be addressed. De-energized work near such lines also raises many new questions that have not been researched. This product will initially monitor live and de-energized issues on new lines operating at voltages above 800 kVAC and 600 kVDC, and in later years develop guidelines, tools, and training materials for linemen. Technical Update reports will be published periodically.





Live working ropes for new applications: New jacketed ropes suitable for energized environments have come to the market. This project will continue the development and adaptation, together with manufacturers, of ropes for new live working applications that could lead to the development of "flexible hotsticks".


Critical defects in polymer insulators: This product is a continuation of research started in 2013. The new tester for polymer insulators, developed by EPRI, needs to be calibrated against the most severe ("critical") defects in the polymer insulator that do not degrade the worksite withstand and worker safety. This product will determine the characteristics of the "critical" defect through research and testing on various full-scale structure mockups (for example, steel lattice, steel pole).


EPRI Live Working Reference Book Update: The EPRI Live Working Reference Book is a living and evolving document. This product will continue to update the EPRI Live Working Reference Book. Updates will include new live working tools, procedures, technologies, standards, lessons learned, and examples.


P35.011 Polymer and Composite Overhead Transmission Line Components (051993)

Description Due to their reduced cost, ease of handling, improved contamination performance, and resistance to vandalism—as well as a lack of availability of traditional components—composite components such as polymer insulators are considered more often. These components, however have certain disadvantages and uncertainties. This project will address a range of composite component concerns including selection, application, inspection, and population assessment, and can help to increase member confidence and reliability in using these components.

Approach This multi-year project addresses a range of composite component concerns and includes examination of composite components, such as polymer insulators, guy strain insulators, and fiberglass crossarms.

Specific topics and tasks are added and removed under the direction of the Insulator Task Force. Activities in 2014 include:

· 230kV multi-stress accelerated aging chamber to monitor aging and degradation of polymer insulators, guy-strain insulators, fiberglass crossarms, and composites poles. In 2014, samples will either continue aging or be removed for analysis.

· Development of short-term tests to evaluate the impact of corona on the end fitting seal of a polymer insulator.

· Failure database information to optimize population assessment decisions. · Continued assessment of service-aged insulators provided by utilities. Information is used to refine the

Population Assessment Software (PIPA) and correlated to the 230kV multi-stress chamber. · Updated version of Insulator Calculation Engine (ICE) software to calculate electric fields and aid in the

correct selection of corona rings for different Insulator applications. Updates considered are improvised E-field overlay displays and display of E-field around corona rings.

· Continued development of the Population Assessment software (PIPA) including tutorial improvements and failure database features.



· Determining the corona threshold value on end fitting seals of polymer insulators. · In 2012, an insulator reference book was developed based on existing EPRI material. The book will be

updated and revised continuously, chapter by chapter with new material and research findings. The number of chapters to be revised/updated each year may be adjusted according to the needs of the members and funding available for the year. The book will be available in electronic format.

Impact The project may have the following impacts:

· Reduce construction costs and improve performance by correctly applying composite components · Avoid sustained outages by improved methods for inspecting and assessing both individual and

populations of insulators · Help members develop effective specifications, ensuring long-term performance of composite

components · Improve engineer productivity by providing information and tools

How to Apply Results · Engineers will use the multi-stress aging test results to assess existing populations of composite

components and evaluate different composite component designs. · The failure database information will help evaluate aging populations of units and selection of new

designs. · The inspection of service-aged insulators will aid in understanding how insulators age and the factors of

aging. Members can use this information to improve applications for improved reliability and performance. · The Insulator Calculation Engine software is used when designing new applications and evaluating the

performance of existing applications in service. · Members can use the Population Assessment software to determine the potential condition of in-service

populations of insulators. · Understanding the impact of corona on the end fitting seal of polymer insulators will help transmission line

design approach by increasing component life.

2014 Products


Guide to Specifying and Procuring Guy Strain Insulators: 1st Edition: Fiberglass guy strain insulators, while similar to polymer insulators, have different design specifics and applications. This guide is being developed to help utilities understand the important design parameters of guy strain insulators and how to specify them for specific applications and environments.


E-field Modeling Software (ICE): ICE (formerly EPIC) continues to grow as a simple-to-use yet powerful transmission line E-field modeling tool. In 2014, the user interface and visualization of the E-field and equipotential lines will be refined based on user feedback. A new feature may include evaluating the E-field gradient on grading rings.

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Results from the 230 kV Aging Chamber: 2014: The 230 kV Accelerated Aging Chamber has been running for a number of years, with more than 40 components being aged. In 2013, signs of end of life degradation such as cracking appeared. This product documents the aging test results throughout the test in a electronic format that is easy to navigate.

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Short term tests to Polymer Insulators: Impact of Corona on the End Fitting Seal: Year One: Short-term testing of polymer insulators plays an important role in evaluating design characteristics and improves understanding on how different applications and environments can affect service life. This report highlights the degradation observed and describes how the test can be used to better understand the corona performance of in-service polymer insulators.


Polymer Insulator Population Assessment Software: Ver. 4: Each year the assessment algorithms used in PIPA are validated against real world cases to ensure correlation and are adjusted as needed to provide users with the best decision making information. Insulator failure data and a tutorial section will be updated to reflect the latest information for performing inspections.

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Polymer Insulator and Fiberglass Component Failures Report: 2014 Update: This report summarizes the failures of polymer insulators and other fiberglass transmission line components recorded through 2014.


P35.012 Porcelain / Glass Insulator Integrity Assessment (060456)

Description Currently, millions of ceramic insulators are approaching or have exceeded the end of their intended service life. Since a large number of transmission lines were built in the 1950s and 1960s, these ceramic and glass insulators are 50+years old. Although the performance of ceramic and glass insulators has traditionally been very good, the number of problems observed is rising. Concerns are growing about performance issues with the current population of insulators and the availability of inspection techniques to identify high-risk units prior to failure.

Concerns have also been raised over the performance of new insulators acquired from manufacturing facilities that have not supplied utilities with insulators in the past. Lessons that traditional manufacturing plant personnel have learned over past decades of manufacturing may not have been transferred to the new plants. In addition, many utilities that have not traditionally used glass insulators are considering this technology. Glass and porcelain insulators that are coated with silicone rubber in manufacturing are also being considered, and utilities lack experience with this technology.

Approach This project will initially focus on suspension insulators, addressing the following areas:

· Insulator Identification: When performing population assessments, it is important to know what manufacturer is installed and the year of manufacture. This project will develop a guide to identify insulators and describe their design characteristics so that informed decisions about population management can be made.

· Evaluation of New Porcelain/Glass Discs Units: This task evaluates porcelain and glass insulators that utilities have little to no experience with to provide necessary data to make design and procurement decisions. This project also evaluates how different stresses to the insulators impact strength performance by performing thermal-mechanical cycling and breaking insulators into "stubs".

· Electric Field Modeling Software: This project will improve the Insulator Calculation Engine (ICE) software by adding a library of manufacturer designs.

· Tracking Insulator Failures: This task tracks in-service failures and provides information to members.




· Help members evaluate and identify high-risk porcelain/glass insulator strings or populations of insulator strings prior to failure

· Provide members with test data about insulator technologies, enabling lower cost or improved technical solutions

· Help members address existing and new insulation applied in contaminated environments

How to Apply Results · Operation and maintenance personnel can apply the new inspection technologies developed to evaluate

in-service populations of porcelain insulators. · Design and procurement personnel will use the information provided on the testing of new porcelain discs

and glass insulators to make better-informed decisions when selecting and procuring insulators. · The ICE electric field modeling software will help users to understand the magnitude and impact of

electric field grading designs on insulator strings. · Knowing the make and model of insulators will help personnel assess in-service populations.

2014 Products


Insulator Calculation Engine Update: The ability to add insulators with specific cap and pin designs will added to accommodate the addition manufacturer specific designs.

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Testing and Evaluation of Porcelain/Glass Disc Insulators: EPRI is continuing to evaluate the porcelain and glass insulators to understand how they perform in various conditions. Testing will investigate how punctured insulators in a string impact the lightning flashover performance and if mechanical failure can occur.


Porcelain / Glass Insulator Vintage Guide: Information about porcelain and glass insulators and manufacturers will be updated bi-annually to help utilities keep up with the latest designs available and back check that designs no longer manufactured but still in service are recorded.


P35.013 Ratings for Overhead Lines (069259)

Description The demand for electric power over transmission circuits is increasing at a faster rate than transmission assets can manage. This trend is pushing the capacity of many existing transmission circuits to their design limits. In addition, much of the grid has already aged beyond its original design specifications. These issues are affecting the grid with an increasing number of bottlenecks, brownouts, and other congestion and reliability problems. The power industry recognizes that the electric power infrastructure requires attention, and there is a need to identify and develop methods and tools for increasing and optimizing the power throughput of existing assets. And there are recent mandated regulatory requirements on the establishment of transmission circuit ratings, and power companies need to have tools to establish line ratings in a scientifically rigorous manner. Much work has already been done by EPRI in the area of static and dynamic ratings—and that work continues—however, the focus of this science is moving toward the topic of forecasted ratings for day-week ahead needs, and EPRI has placed itself at the front of the curve in this area.



Approach To meet the research needs of the power industry, EPRI will continue to develop software tools and methodologies related to the design, engineering, system planning, and operation of overhead transmission lines (and other transmission circuit components). The project will also investigate and document information on the state-of-the-science and best-practices of increasing and optimizing power flow through existing assets. Information on improvements in applications, thermal models, instrumentation, secure telemetry, and case studies will be identified, developed, and documented. Training and technology transfer activities and tools, such as tutorials, guides, workshops, and conferences, will continue to be developed in parallel with the research and development work.

This project focuses on overhead transmission lines, and is executed in coordination with corresponding projects for underground cables and substation equipment. Feedback from EPRI member engineers, operators, designers, and planners is sought during advisory meetings and workshops to identify future improvements.

Application of the R&D products that result from this project will aid electric power companies to more fully utilize their existing assets economically, and with continued reliability, safety, and public acceptance.

Impact The results from this project will provide the tools, information, training, and guidance needed by power companies to assess and implement increased and optimized power flow strategies for their specific needs, and with continued reliability, safety, and public acceptance. These results will help enable power companies to

· provide guidance for experienced technical staff, as well as reference and training materials for the next generation of power industry technical leaders,

· increase and optimize power flow through overhead lines and entire transmission circuits, · defer capital expenditures and new construction, · improve transmission circuit reliability and safety, · optimize energy transactions through rating forecasts, · ride out emergency situations safely and reliably, and · avoid unnecessary system outages.

How to Apply Results Transmission engineers, operators, planners, researchers, and IT personnel will use the computer programs and methodologies of this project to increase and optimize the ratings of their circuits. Software products can be applied for the benefits described above, and the methodologies on how best to apply all results can be obtained through EPRI guidebooks, reports, and training materials.

Members can use delivered reports as reference sources and guides for implementing increased power flow strategies, and for training their engineers on increased power flow technologies. Reports and references also compare the economic benefits of increased power flow technologies, enabling EPRI members to make informed decisions when choosing options for their specific applications.

2014 Products


Transmission Ratings Workstation Version 1.0: The Transmission Ratings Workstation (TRW) was initiated in 2012, and developments will continue for several years. TRW will incorporate the capabilities of EPRI's Dynamic Thermal Circuit Rating (DTCR) software and other ratings-related software modules into one comprehensive computer program. The product will be designed for performing rating studies, evaluating and optimizing static ratings, real-time ratings, and forecasted ratings for overhead lines and entire transmission circuits. This will be a multi-year effort, and in 2014 it is expected that the first fully released version will become available.

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Increased Power Flow Guidebook - 2014: The Increased Power Flow Guidebook (Platinum Book) will continue to be augmented with updated and additional material on the state-of-the-science and best-practices for increasing and optimizing power flow through existing (or new) transmission lines and their associated circuits. The needs for the guidebook are identified by industry experts and EPRI member advisory groups.


Forecasted Ratings Methodologies: For several years the power industry as a whole, including EPRI, has been addressing the need for improving the specification of ratings for their transmission assets, particularly overhead lines, which are the bottlenecks in circuits most of the time by far, and the most expensive component to upgrade to higher ratings. A lot of work has been done, and continues, on methodologies for performing static rating studies and real-time ratings on existing assets. However, interest is rapidly growing on the need to perform day-week ahead forecasted ratings. EPRI and others have considered some possible methods for forecasting ratings, and have experimented with some novel methods. This report will document these activities and recommend future actions.


P35.014 High Temperature Operation of Overhead Lines (069260)

Description An electric power company may increase the power transfer capacity of its transmission lines by raising the conductor operating temperature. The effects of high conductor temperature include a reduction in conductor ground clearance, loss of conductor strength, and damage to connectors and other overhead line components. In addition to these mechanical effects, transmission line owners, operators, and designers must also be aware of the effects of high temperatures on the existing corona and thermal models that were developed based on a conductor temperature that is much lower than the temperature that the overhead line encounters today. Inaccurate models produce values that may exceed the limits imposed by state or federal regulatory agencies.

Research is needed to investigate premature failures of conductors and conductor accessories due to thermal cycling from high-temperature operations. Conductor accessories include conductor splices and dead-ends, dampers, spacer dampers, and all hardware attached to the conductor of an overhead line. Research and investigation of the high-temperature effects on corona, thermal, and other models used in evaluating electrical effects, heat-transfer capability, and other performance indicators of an overhead line is required.

With accurate data, electric power companies are able to assess the risks of high-temperature operations. They can then establish a temperature limit below which overhead lines can operate reliably and safely. With appropriate measures to mitigate the high-temperature effects, this limit can be raised further.

Approach This project evaluates the impact of high temperatures on the mechanical, electrical, and thermal performance of overhead lines. Solutions are developed and models enhanced to allow power companies to raise transmission line capacities safely, reliably, and with confidence.

Every component of an overhead line will be studied. The project started with the investigation of the most vulnerable component. Because fittings at the connection point are the weakest links in a transmission system, the project first focused on establishing temperature and duration limits for these fittings beyond which they may experience thermal or mechanical failure. The project will then investigate and test different mitigation methods to alleviate the thermal impact. The project also will assess the accuracy of existing thermal and corona models at elevated operating temperatures. Research results will be used to update these models. All other knowledge gaps for high-temperature operations will be identified. Research and tests will be performed to address these gaps. Some topics to be investigated are resistance values of aluminum conductor steel-reinforced (ACSR) and



aluminum conductor steel-supported (ACSS) conductors at elevated temperatures; behavior of aluminum strands at high temperatures; effects of high temperature on overhead line accessories such as hardware, AGS, and other types of suspension clamps; and effectiveness of various types of mitigation devices.

A report is prepared every year, summarizing all research results conducted by both EPRI and other organizations on the performance of conductors and conductor accessories operating beyond the conductor annealing temperature of 93°C. The information is updated each year. To facilitate the users in selecting the right temperature for an overhead line, a high-temperature matrix software is also developed. The matrix identifies readily the line components that may fail when an overhead line is operated at a given temperature. Detailed information can be accessed by drilling down into the matrix. In addition, calculators for conductor annealing, current capacity at various temperatures, and methodologies to evaluate component lives (when available), are included in the matrix. The project provides a holistic approach to high-temperature operations.


· Raise confidence in operating overhead lines at high temperatures to increase transmission capacities · Avoid damage to overhead line components and subsequent line failures · Adopt mitigation measures to achieve additional transmission capacity · Provide accurate prediction of electrical and thermal performance of overhead lines

How to Apply Results Transmission engineers can use information from the project to evaluate the risks of raising a conductor to a given temperature. Mitigation methods developed in the project can be adopted to further increase the operating temperature of an overhead line. By using this information and the methods, transmission engineers can evaluate the electrical and thermal performance of overhead lines more accurately. Members can then establish internal guidelines for the high-temperature operation of their overhead lines.

2014 Products


Guide for Operating Overhead Lines at High Temperatures - Progress Report: The guide provides an holistic approach for high-temperature operations and is updated annually with new information from internal and external research. Preliminary test data on the impact of high temperatures on conductor hardware and accessories may be reported. The section on fundamentals of high-temperature operations will continue to be expanded. Information on mitigation devices used for High Temperature Operation will be reported.


HTC (High-Temperature Conductor) Matrix: Version 5.1: The HTC Conductor Knowledgeable Matrix applet will be updated with new information, data, and research results from the previous year. The software will be updated with the addition of a Sag and Tension calculator tool.

12/31/14 Software

Increased Transmission Capacity Workshop Proceedings: The proceedings of the Increased Transmission Capacity Workshop will be compiled into a technical update. Various new technologies and applications of technologies, as well as utility use cases, may be presented at the workshop.




P35.015 Performance and Maintenance of High-Temperature Conductors (065550)

Description 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. These conductors are also known as advanced conductors, high-temperature low-sag conductors, or simply HTLS conductors. Short-term experience of these conductors was gained through an EPRI field demonstration project that was completed in 2009. Knowledge of the long-term performance of these high-temperature conductors, especially those with a carbon fiber composite core, and specifications for the purchase and evaluation of these conductors are required. A number of issues have to be addressed to enable the electric power industry to adopt this new technology properly. These high-temperature conductors may also change the conventional approach to conductor maintenance. Existing tools and procedures for conventional conductors have to be reviewed and evaluated for applications to these high-temperature conductors.

Approach This project addresses critical issues related to the long-term performance of high-temperature conductors. The most immediate needs are for carbon fiber core conductors, which are the least known and the most novel of all high-temperature conductors. The core of this type of conductor consists of carbon and glass fibers that are more sensitive to heat and other environmental conditions than steel used for conventional ACSR (aluminum conductor steel-reinforced) conductors.

The project developed a test protocol for qualifying carbon fiber core conductors in 2009. In subsequent years, the performance of three carbon fiber core conductors was evaluated using this protocol. The tests confirmed the validity of the protocol to qualify carbon fiber core conductors. Concurrently, an accelerated aging test is being carried out on a range of commercially available high-temperature conductors for evaluating the long-term performance of these conductors, their splices, and dead ends. Results of the accelerated aging test, which takes more than a year to complete, will be compared with this much shorter qualifying test to further verify its validity. Specifications for the purchase and evaluation of carbon fiber core conductors will be developed. Reference will be made to the experience gained on non-ceramic insulators that apply similar technology for their core in developing future tests to evaluate other aspects of these high-temperature conductors.

Started in 2012, an outline of a comprehensive guide for the selection and application of various types of high-temperature conductors was developed. Details are to be added to a few chapters of the guide each year. The guide will include the most current information from manufacturers, experience gained from users, results obtained from research, and purchase specifications for procurement, as well as maintenance tools and procedures for high-temperature conductors. The guide will be updated annually as new research results and data become available.

Impact The project may have the following impacts:

· 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

How to Apply Results The test protocol developed under this project provides design engineers with a tool to qualify and compare different carbon fiber composite core conductors. The accelerated aging test provides useful information on the long-term performance of these high-temperature conductors. All research results provide members with information for comparing and selecting proper high-temperature conductors for their applications. Developed maintenance procedures and recommended tools for advanced conductors can be incorporated into members' maintenance manuals. All this information is to be collated into a single and easy to follow advanced conductor application guide.



2014 Products


Guide for Maintenance of High-Temperature Conductors: A guide will be developed for maintenance of high-temperature conductors. It will include the latest findings of research conducted by EPRI and other sources. Topics may include the effects of Live Working tools on the HTLS conductors and the inspection of these types of conductors.


Guide for Selection and Application of High-Temperature Conductors: Case Studies: Utility case studies on the application of HTLS conductors will be presented. Information will be provided on the specific process used and the way in which the application of the HTLS conductors was done.


Workshop on the Applications of High-Temperature Conductors: A workshop will be conducted for training on the applications of high-temperature conductors. The workshop will include various case studies to demonstrate how high-temperature conductors can be applied successfully.

12/31/14 Workshop, Training, or Conference

P35.016 New and Emerging Inspection and Sensing Technologies (070600)

Description As assets age beyond their design margin, the ability to inspect and assess their condition has become vital. New and emerging inspection and sensing technologies are essential to meet this need. Many utilities are unaware of new technologies, and in many cases unsure of their performance due to lack of field experience. As new issues emerge, new technologies must be identified and possible solutions investigated.

Approach The project will take a three-pronged approach to addressing the research needs:

· Identify and document new and emerging inspection/sensing technologies to increase members' awareness.

· 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.

In 2013 an information system with applicable technologies was updated with additional inspection and sensing technology information, enabling members were able to look up the component to be inspected (e.g., insulators, sub-grade components, or others) and determine applicable sensing and inspection technologies. The database also included use cases documenting utility experiences with specific technologies. A report evaluating an emerging technology for steel core corrosion or damage on conductors or wires was also delivered. Building on that foundation, project activities in 2014 will:

· update the inspection/sensing technologies information system based on member input and new information,

· add utility case studies to the information system, and · conduct laboratory and field evaluation of new and emerging technologies.

In future years, if experience with new inspection/sensor technologies is not available, round-robin-style testing will be performed in controlled and field environments to provide members with knowledge and performance information on inspection/sensing technologies that they have not applied to date.



Impact By being aware of the latest technologies and having easy access to other utilities' experience and performance testing, members will be able to identify appropriate technologies more easily and have more confidence in their application.

By identifying gaps and possible technologies, future research and development needs can be addressed.

How to Apply Results When faced with an issue concerning a specific component, members would use the database to become aware and informed of all applicable inspection/sensing technologies. In addition, they would have easy access to other members' experiences and EPRI testing evaluation results.

2014 Products


Update Inspection & Sensing Technology Database (including use cases): This is an update to the database initiated in 2012. This product will contain new inspection and sensing information and will include additional utility use cases.

12/31/14 Software

Evaluation of Emerging Inspection or Sensing Technologies: New and emerging inspection and sensing technologies will be evaluated. This product will document the performance and provide users with a basis for their application. Members will be invited to attend a demonstration of the technologies being evaluated.




Supplemental Projects

Daytime (UV Imaging) Discharge Inspection Interest Group (063972)

Background, Objectives, and New Learning The technology for viewing corona and arcing discharges in full daylight has been around for a number of years. Many utilities now possess this technology and are using it for inspecting and assessing power networks. One of the difficulties in fully applying this technology is the interpretation of the data or visual images. This is because arcing is often interpreted as corona and vice versa, and the location of the discharges and their impact are sometimes misdiagnosed. Misdiagnosis can lead either to unnecessary intervention or to equipment failure.

The objectives of this project are to move this technology forward by

· developing training material and updating existing material with new research findings, · undertaking fundamental research on ultraviolet (UV) and infrared (IR) inspection of components, and · providing a hands-on workshop and training.

The Daytime Discharge Inspection Interest Group was initiated in 2007 to help the industry maximize the use of Daylight UV camera technology for inspection and maintenance of power networks. An ongoing challenge remains the improved understanding and diagnosis of the visual images. Over the years this project has developed a number of products, provided training workshops, and undertaken fundamental research. These include:

· Field Inspection Guide with embedded video · Daytime Discharge Inspection report · Online computer-based training module · Report documenting industry approach to inspection, including inspection cycles and video management · Animated slide show for training/educational purposes · Inspector Standards (Level 1) source book · Inspector Standards (Level 1) training material · Inspector Standards (Level 2) source book · Inspector Standards (Level 2) training material · Document on how utilities integrate Daylight UV detection as part of a maintenance program · Research into UV and IR inspection of polymer and porcelain insulators with internal defects · Research in UV inspection of All Dielectric Self-Supporting optical fiber · Annual hands-on workshop (includes sharing of member experience and vendor interaction) · Access to EPRI experts on daytime discharge inspection results

This research meets EPRI’s criteria for the use of tailored collaboration funding in the following way:

· The daytime UV & IR inspection of power network components are unknown. There is limited to no experience with a number of components so there will be substantial learning.

· The knowledge developed by this project will result in field guides, reports, training and training material that will be made available to the public through the normal EPRI channels. The results will also be incorporated in the EPRI Inspection and Assessment Methods Guideline (Project 35.001). Meetings and training session will also be open to members of the public for a prescribed fee.

· By being able to identify high risk components prior to failure using daytime UV technology unscheduled outages may be reduced increasing the quality of supply to the public.



Project Approach and Summary This project focuses on the Daytime Discharge Inspection Interest Group (DDIIG), a forum by which utilities can maximize the benefit of using this technology. In essence, the DDIIG will allow participants to share information, including vendor and utility experience, and have access to field guides, training, and a bulletin board for queries and advice. It will also provide the framework for setting inspector requirements.

The Interest Group will be non-vendor-specific, encompassing all of the optical daytime corona inspection technologies currently available. Its mission will be to provide unbiased, technically sound, current information.

Benefits · Improve decision making when using Daytime UV Imaging technology · Receive training · Share utility experiences · Ensure consistent inspection standards

These benefits can ultimately translate into O&M cost savings.

Field Trial of ACCC Carbon-Fiber Core and ACSS HS285 Ultra-High Strength Conductors (072391)

Background, Objectives, and New Learning High-temperature low-sag (HTLS) conductors are being considered by the electric power industry as an alternative to the conventional ACSR (aluminum conductor steel-reinforced) conductors. This type of advanced conductor is also known as an HTLS conductor. An HTLS conductor is able to tolerate higher temperatures and produce lower sags than conventional ACSR conductors. These features enable overhead power lines to attain higher power transfer capacities on the same corridor.

As of today, a number of high-temperature low-sag conductors are commercially available. They are listed below. Suppliers of the conductors and their origins are provided in parentheses.

ACSS – Aluminum Conductor Steel-Supported (Southwire-US, General Cable-US, Alcan-Canada)

GTACSR – Gap conductor (J-Power-Japan)

Invar Conductor (J-Power-Japan, Furukawa-Japan, Fujikura-Japan, LS Cable-Korea)

ACCR – Aluminum Conductor Composite Reinforced (3M-US)

ACCC – Aluminum Conductor Composite Core (CTC-US)

Other Carbon Core (Nexans-Europe, Mercury Cable-US)

The industry’s experience with each of the HTLS conductors varies. Aluminum Conductor Steel-Supported, Gap, and Invar conductors have been around much longer than the other HTLS conductors. The Gap conductors have been used in Japan for more than ten years, where the need for increased power flows occurred sooner than in North America. The Invar conductors have been used in Asia for a number of years. Although ACSS conductors have been around for a long time, they have not been used extensively. The composite-core HTLS conductors were developed in recent years, and consequently, the power industry has the least experience with these conductors. The needs for evaluating each of these HTLS conductors differ and are dependent on the experience with the technology and materials used for the conductor. To assess the risk of using HTLS conductors, EPRI is conducting research to address the following issues:

· Handling and Stringing; Operating and Maintaining; Material Behavior; Long-Term Performance; Life Expectancy Prediction; and Specifications



Utilities are concerned about the performance of ACCC conductors for prolonged exposure to temperatures above 150ºC, as well as for their sag characteristics under ice loads. There is little experience with ACSS HS285 conductors under extended high-temperature operations and heavy weather loads. This conductor was developed in 2009. Hydro One Networks has a site in Ottawa, Canada, that is available to EPRI members for field trials of HTLS conductors. At that site, the circuit normally carries a large amount of power. It is also common to experience heavy ice loads and cold temperatures at this location. It is therefore an ideal location to field trial the ACCC and the ultra-high strength ACSS HS285 conductors.

The objective of this field trial is to determine the performance of these two conductors under extreme electric and mechanical loading conditions in a real operating system by monitoring their behaviors in order to gain confidence in the applications of these conductors.

The research results on the ACCC and ACSS HS285 conductors may enhance the industry’s understanding of these conductors and offer the potential for line designers to apply these conductors properly, which could lead to improved reliability and safety for the public.

Project Approach and Summary The following approach is adopted.

This research project seeks to provide participating utilities with information on the operational performance of ACCC and ACSS HS285 under extreme electrical and mechanical loading conditions through approximately three years of field experience.

The ACCC and ACSS HS 285 conductors will be installed at the Hydro One test site in Ottawa, Canada. The line at this site carries a large amount of current from Ottawa to eastern Ontario customers, and it is exposed to extreme weather of ice, wind, and cold temperature. Instrumentation will be installed to monitor the performance of the conductors continuously by recording key line parameters and weather data. The information is transferred by cellular communication to EPRI for evaluations and assessments of the line performance.

Through this project, the performance of these conductors, and associated splices and dead-ends, will be evaluated, based on field-trial and laboratory tests.

Benefits This project may offer a number of benefits including:

· Improve the understanding of ACCC and ACSS HS 285 conductors · Allow members to evaluate the risks of these conductors · Enable members to take advantage of the new conductors



Empirical Evidence to Confirm or Refine Gap Factor Utilized in Insulation Coordination Calculations of Minimum Vegetation Clearing Distances (MVCD) (105303)

Background, Objectives, and New Learning A potential cause of blackouts may be vegetation-related outages. Although the industry has made progress in reducing the instances of flashovers due to vegetation, the Federal Energy Regulatory Commission (FERC), and subsequently the North American Electric Reliability Corporation (NERC), are focused on reducing vegetation related risks. NERC has submitted the Reliability Standard FAC-003-2 (Transmission Vegetation Management) to the Commission-certified Electric Reliability Organization. In the submittal, NERC proposes a methodology for calculating the minimum vegetation clearance distances (MVCD) based on the Gallet Equation and the use of a gap factor. Subsequently FERC, in reviewing the NERC standard, commissioned a study by the Pacific Northwest National Laboratory (PNNL) to investigate the applicability of the Gallet Equation approach to vegetation clearances. Pursuant to Section 215 of the Federal Power Act, FERC proposes to approve the standard, but seeks empirical evidence of the efficacy of the approach.

On March 21, 2013, the Federal Energy Regulatory Commission (FERC) issued its Final Ruling of the Revisions to Reliability Standard for Transmission Vegetation Management. In the October 18, 2012, Notice of Public Rule (NOPR) titled, ”Revisions to Reliability Standard for Transmission Vegetation Management”, FERC proposed to incorporate new minimum vegetation clearance distances (MVCD). “While we propose to approve NERC’s use of the Gallet equation to determine the minimum vegetation clearing distances, we believe it is important that NERC develop empirical evidence that either confirms the MVCD values or gives reason to revisit the Reliability Standard. Accordingly, consistent with the activity that NERC has already initiated, the Commission proposes to direct that NERC conduct or commission testing to obtain empirical data and submit a report to the Commission providing the results of the testing.”

Specifically, PNNL, in its final Report on the Applicability of the “Gallet Equation” to the Vegetation Clearances of NERC Reliability Standard FAC-003-2 expresses, “concern about NERC’s use of an assumed gap factor of 1.3, asserting that that figure has not been adequately supported for use with vegetation…” The NERC Standard Drafting Team (SDT) relied on the “widely regarded” Insulation Coordination for Power Systems, by Andrew Hileman, to develop the proposed gap factor of 1.3.

Determining the appropriate gap factor to utilize is challenging as a statistically valid scientific conservative approach is required. Utilizing “real” vegetation in switching impulse test has limitations because:

1. A statistically valid number of flash-over impulses cannot be derived from a single tree, because each successive flash-over changes the electrical characteristics of the tree.

2. There are an astronomical number of variations of trees, tree combinations (single versus clusters), live and dead trees, wet and dry trees, soil conditions, altitude variations, air moisture variations, etc. Consequently if one utilizes one type of tree in testing one has to be confident that it poses the worst case from a flashover perspective and that there is not another type of vegetation that exists that is a worst case, e.g. more conductive, has a lower footing resistance, etc.

The objective of this project is to determine the appropriate gap factor (kg) for utilization in calculating minimum vegetation clearance distances (MVCD) utilizing the method documented in NERC Reliability Standard FAC-003-2.

Project Approach and Summary This project will pursue a statistically valid scientific approach based on testing comprising the following steps:

· Representative conductor bundle-to-vegetation gap configurations will be determined, based on a vegetation geometry that is deemed to have the lowest flashover stress.

· The gap factor of these representative conductor bundle-to-vegetation gap configurations will be determined by impulse testing. For these tests the vegetation shape will be represented with a fully conductive and well-grounded object.



· Voltage withstand tests will then be performed on select real trees, to statistically demonstrate that the gap factor determined for a fully conductive, grounded vegetation represents a conservative estimate of the gap factor to real vegetation.

· Finally, the applied impulse voltage magnitudes will be successively increased until flashover to the real vegetation occurs to obtain an estimate of difference between the simulated, low resistance conducting trees and the real trees. This final step will be performed for completeness, and not to tighten the clearance distance.

Benefits The research in this project may enhance the understanding of how vegetation causes flashover on transmission lines and establish scientifically the appropriate gap factor to be utilized in the NERC approach to calculating MVCD. Validation or refinement of the gap factor will both improve our confidence that standards will support reliable operation, while at the same time avoiding undue costs or regulatory violation of NERC critical clearance standards.

Application of Nano Technology Coatings for Transmission Components (Phase 2) (105296)

Background, Objectives, and New Learning New advances in material science have resulted in the development of a family of nano-structured polymer coatings that can be engineered to provide surfaces with specific desirable properties. These so-called nano-coatings have found application in the aero-space industry to keep surface ice free and in architecture to provide self-cleaning properties for windows. Other properties nano-coatings can provide are scratch, corrosion and chemical resistance as well as super hydrophobicity.

These coatings can potentially benefit the electric power industry where the self-cleaning and super hydrophobicity properties are particularly attractive for application on insulators in contaminated environments and coatings with ice-repelling qualities may reduce the risk for flashovers in winter storms. Ice-repelling coatings are also of interest for application to conductors in areas where there is a risk for mechanical overload due to ice accretion in winter months.

Before applying these new breed of coatings on a large scale utilities need confidence in their performance and life expectancy. Critical factors are that these coatings, when aged, will not result in a reduction in performance below that of uncoated surfaces and that they will not require a high level of maintenance in the long run. It is therefore vital to identify suitable test methods, which can be included in a functional specification, to qualify nano-coatings as part of the procurement process.

During phase 1 of this project, small and full-scale laboratory testing of insulator coatings from seven different vendors was completed. Only small-scale testing was completed on conductor coatings. Phase two of this project will a) extend the full-scale laboratory testing to conductors; b) perform extended laboratory testing on insulator coatings that were identified as promising in phase 1, and c) initiate field demonstrations of promising insulator coatings. By performing field demonstrations at utility sites on real equipment the coatings will be exposed to a typical service environment.

The objectives of this project are:

· Identify coating technologies that are applicable to both insulators and conductors and ensure that they do not have a fatal flaw which would preclude their application.

· Gain field experience on utilizing nano-coatings on insulators and conductors with a view of providing guidance to member utilities on the application and procurement of such coatings.

· Identify appropriate test methods that can be used to evaluate and specify nano-coatings for use on electrical insulators and conductors.

· Develop functional specifications that utilities can use to procure high-performance products.



Project Approach and Summary This project follows a three-phase approach beginning with small-scale material tests (i.e., Tier 1 testing). During phase 1 of this project, a series of small samples were coated with a range of commercially available nano coatings and subjected to a range of environmental, mechanical and electrical tests. These tests are based on the degradation and failure modes determined for specific applications as well as the performance requirements. Additional testing will be performed on promising coatings identified in Phase 1.

In this phase coatings will be applied to insulators and conductor samples and subjected to a range of service-oriented laboratory tests (i.e., Tier 2 testing). Following this, promising coatings will be tested on selected members systems, and their performance and degradation will be monitored under real-life conditions (i.e., Tier 3 testing).

Based on the results, suitable tests that may be included by a utility when specifying and procuring coatings will be developed.

Coating and component manufacturers will be engaged in this effort. Utility participants will be an integral part of the EPRI project.

Benefits This project has the potential to improve the reliability and reduce the cost of transmission assets by verifying and enabling the application of super hydrophobic and ice-phobic coatings on insulators and conductors.

If the coatings prove to be feasible, this project will provide utilities with a set of test methods that can be used in their procurement and specification documents. With a thorough qualification process, the risk of applying inferior coating can be greatly reduced. These test methods may also allow utilities to identify with confidence appropriate nano coatings that can be used on their network to solve specific contamination, ice, or corrosion-related problems.

Insulation Coordination Approach for Advanced Structures (105297)

Background, Objectives, and New Learning A number of utilities are considering new line designs that include advanced structure designs. These advanced structures may have interphase insulators or shorter than normal phase-to-ground or phase-to-phase insulation. The needs for these advanced structures is driven by a number of factors that include engineering requirements and lack of public acceptance of traditional overhead lines due to perceived health, aesthetic, or environmental concerns. Advanced structure designs present significant technical challenges to line designers as they can no longer utilize experience with current line designs as a method to predict the new line performance. One important electrical design consideration is insulation coordination. Insulation coordination is the methodology that is used to determine the line insulation levels and identify overvoltage protection measures to achieve a required line outage performance under power frequency, temporary overvoltage, switching, and lightning conditions.

Some notable differences from traditional designs include:

· The application of interphase insulators. · For traditional line designs grounded structure members are typically positioned between phases so that

flashovers always occur phase to ground. In contrast many advanced line designs achieve compact phase spacings by using air as separation between phases. In these cases phase-to-phase insulation coordination needs careful consideration.

· The ratio of the phase-to-phase insulation clearances to phase-to-ground clearances are typically much smaller than conventional designs and in some cases may be smaller than phase-to-ground clearances.



· Aesthetic structure designs dictate the shape of the structure and positioning of phase conductors and ground wires. These factors may have a significant impact on the lightning performance since slender structure shapes are often considered to have a higher surge impedance than traditional lattice structures and the ground wires may not be optimally placed.

· The implementation of compact line designs may also need to be considered from a system operation perspective. Aspects that may impact insulation coordination are the possible use of shunt reactors to compensate the line capacitance and resonances as a result of the stronger inter-phase coupling

· Close phase spacing and inter-phase insulators may result in electric field distributions along insulator strings. Especially in the case of composite (also called polymer or non-ceramic) insulators this may result in premature aging if not managed correctly.

The objective of this project is to provide a roadmap or approach on what critical aspects need to addressed for effective insulation coordination and how to address these aspects.

The outcome of this project intends to provide utilities with guidance on how to implement an effective insulation coordination study and how to specifying appropriate tests to confirm the advanced insulation design strengths. In the future this may include appropriately sharing of results of insulation coordination studies and associated laboratory testing implemented by participating utilities to confirm the appropriate specifications for insulators, clearances, hardware, tower grounding and terminal equipment.

Project Approach and Summary Insulation coordination experts will be engaged and a roadmap will be developed outlining an approach to performing an insulation coordination study and key considerations that need to be taken. An approach to developing a test plan to assess the insulation strength will be documented together with important considerations that need to be accounted for in the test specification, implementation and reporting process.

As part of this process information will be collected from utilities that have experience in the design and operation of advanced line designs. A workshop to share best practices and knowledge will be held. Utility and workshop information will be documented and knowledge gaps identified.

In the future as participants implement insulation coordination studies and test programs the sanitized results will be shared as well as lessons learned.

Benefits Adopting advanced transmission line designs are attractive as they may increase public acceptance for new transmission lines. At the same time utilities may also be hesitant to adopt new and untested concepts on a large scale due to reliability concerns and a fear for public failures. It is therefore important to carefully consider all performance aspects of advanced line designs. With this project utilities will gain knowledge and avoid pitfalls when contemplating the application of unconventional line designs.

Documents

2014 Portfolio: Overhead Transmission - Program 35mydocs.epri.com/docs/Portfolio/P2014/2014_P035.pdf · Overhead Transmission - Program 35 ... • tools to increase efficiency of