Project 36.002 – Extruded Dielectric Cable Systems
Objective
Utilities rely on extruded dielectric cable systems to meet growing demands for new underground transmission lines. This project is intended to address several key research issues, including specific goals of:
- Improving engineering-based design and installation procedures to accommodate electrical, mechanical, and thermal requirements for long-term performance, considering thermo-mechanical behaviors of cables and accessories
- Achieving better understanding of cable and component aging, failure mechanisms, and end-of-life criteria
- Developing effective inspection and monitoring methods for cable system condition assessment
Underground transmission engineers, designers, and managers can use the guidelines, methods, and technologies developed or assessed in this project to improve productivity and reduce costs of designing, installing, commissioning, testing, operating, and maintaining extruded dielectric cable systems. Engineers may use the improved understanding of the behavior of extruded dielectric cables under normal and emergency loading scenarios plus analytical or software-based tools to achieve effective and economical system designs. Operators and maintenance personnel can deploy new inspection and monitoring methods and tools to obtain real-time and near-real-time information on cable system conditions.
Research Value
The new materials, devices, and methods produced in this project could improve the performance of extruded dielectric transmission cable systems to meet power system safety, reliability, and maintainability requirements and to contribute to improved technical standards. For example:
- Full-scale laboratory testing may validate and improve theoretical understanding of thermo-mechanical behaviors of extruded dielectric transmission cables. The results would support improved specifications and standardized designs, leading to higher system reliability, fewer circuit outages, and lower life-cycle costs.
- Laboratory testing can deepen the industry’s understanding of cable and accessory performance and help determine the system end-of-life criteria.
- Development and deployment of advanced inspection and monitoring techniques may assist in asset management, improve utility operational efficiency, and increase system reliability.
- Research results can help to assess existing underground transmission lines and develop fact-based maintenance and replacement strategies to reduce costs and improve reliability.
- Application of research results can reduce overall installation, construction, operation, and maintenance costs.
Approach
This project investigates methods and technologies for extruded dielectric transmission cable systems. Solutions are applicable to design, selection, installation, commissioning, testing, operation, and maintenance of these systems. The project seeks to answer research questions and address industry issues through the following activities:
Laboratory testing to validate engineering design models
Laboratory testing to understand failure mechanisms and system end of life
Development and evaluation of innovative inspection and assessment tools, methods, and technologies
Laboratory testing and field demonstration of developed or available diagnostic methods
| Deliverable | Description | Date |
|---|---|---|
| Guidelines for Thermo-Mechanical Design of Extruded Dielectric Cable Systems in Pipes and Ducts (Technical Reports) | This multi-year task builds on and continues EPRI’s research in laboratory verification of thermo-mechanical behaviors of extruded dielectric cables in ducts, pipes, and manholes. Reports in multiple volumes include development of practical engineering knowledge to assist cable engineers in designing extruded dielectric cable systems with respect to their thermo-mechanical effects. The reports cover design principles, cable mechanical parameter measurements, finite element analysis modeling, engineering software tools, full-scale laboratory validation, applications at utility sites, and subject matter training. | December 2027 |
| Life Evaluation and Management of Extruded Dielectric Cable Systems and Components (Technical Reports) | Volume 1 – Composite Cable Termination Long-Term Aging Tests: Built on prior EPRI research, this multi-year effort continues to investigate the reliability of transmission extruded dielectric cable accessories. Included are technical and investigative results from accelerated aging tests at EPRI’s Lenox laboratory on terminations with composite insulating housing, material deterioration test results on field-aged cable terminations, and results from demonstrations of condition assessment tools. | December 2027 |
Volume 2 – Cable Mechanical Bending Aging Tests & Volume 3 – Cable Thermo-Mechanical Aging Tests: Many extruded dielectric cable circuits are approaching 30–40 years in service. The industry needs an approach to study their life management and expectancy. This task starts as a series of laboratory experiments to better understand extruded dielectric cable system aging and failure mechanisms and expands into three different tests:
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December 2027 | |
| Volume 4 – This task provides a state-of-art technology review to assist utility cable users in making engineering decisions for reliable and cost-effective in-service operations. The report captures evolving technologies, success and failure experiences, and lessons learned to enforce the needs for continuous vigilance during design, manufacturing, and installation processes of both cables and accessories. | December 2027 | |
| EPRI Guide on Extruded Transmission Cable System Condition Monitoring and Diagnostics (Technical Report) | This multi-year task is a continuation of the study on advanced monitoring techniques for inspection of cable system condition and operational status. The task covers developments of test rigs and performs tests to evaluate the effectiveness of available technologies and to demonstrate emerging technologies. | December 2027 |