Program Description Program Overview 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. 1
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 the Lightning and Grounding reference book (the Gray Book) 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
3 Electric Power Research Institute Portfolio 2014 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, fbologna@epri.com Summary of Projects Project Number Project Title Description P35.001 Inspection, Assessment, and Asset Management of Overhead Transmission Lines P35.002 Conductor, Shield Wire and Hardware Corrosion Management This project is a mix of tools, training, and information that will help members improve their line inspection and assessment techniques. 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.
4 Electric Power Research Institute Portfolio 2014 Project Number Project Title Description P35.007 Transmission Line Design Tools and Design Approaches and Practices for Construction P35.008 Emerging Designs: Hardened and Compact Overhead Lines P35.010 Live Working: Research, Techniques and Procedures P35.011 Polymer and Composite Overhead Transmission Line Components P35.012 Porcelain / Glass Insulator Integrity Assessment P35.013 Ratings for Overhead Lines 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. 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. 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. 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. 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. 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 P35.015 Performance and Maintenance of High- Temperature Conductors 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. 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.
5 Electric Power Research Institute Portfolio 2014 Project Number Project Title Description 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
6 Electric Power Research Institute Portfolio 2014 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 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. 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.
7 Electric Power Research Institute Portfolio 2014 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.
8 Electric Power Research Institute Portfolio 2014 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
9 Electric Power Research Institute Portfolio 2014 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.
10 Electric Power Research Institute Portfolio 2014 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 twostage 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.
11 Electric Power Research Institute Portfolio 2014 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.
12 Electric Power Research Institute Portfolio 2014 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
13 Electric Power Research Institute Portfolio 2014 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.
14 Electric Power Research Institute Portfolio 2014 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.
15 Electric Power Research Institute Portfolio 2014 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.
16 Electric Power Research Institute Portfolio 2014 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. Mechanical Testing of TLSA's leads and Disconnectors: This product will document the test results of test protocols developed in 2013. 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. Software Software 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.