Jan 2014
Electricity Transmission
EPRI Research Collaboration on Underground Transmission
Jan 2014
Jul 2015
National Grid Electricity Transmission
Iliana Portugues
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Network Innovation Allowance
Electricity Transmission Networks
Underground ratings and Increased Power Flow

This programme focuses on developing methods and tools for increasing and optimizing the power throughput of existing assets. It does so through three parallel tasks:

1. Increased Power Flow Guidebook: The development of the Increased Power Flow Guidebook (Platinum Book) will be updated and additional material developed on the state-of-the-science and best practices for increasing and optimizing power flow through existing (and new) underground cables and their associated circuits. The output of this work will be an entire guidebook, which in addition to underground cables includes the topics of overhead lines, substation equipment, entire circuit ratings, and economics.

2. Transmission Ratings Workstation (TRW) Version 1.0: The development of a software tool, Transmission Ratings Workstation (TRW), incorporating 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 underground cables and entire transmission circuits. Comprehensive documentation will be included, and the workstation’s ultimate goal is to provide all the tools related to circuit ratings at the users fingertips.

3. Soil and Special Backfill Thermal Resistivity Considerations for Underground Cables: A Technical Update will be developed and delivered which covers the following topics related to soil thermal resistivity and backfills: performing accurate measurements, implications for ratings, use of the thermal property analyser, obtaining and transporting soil and backfill samples, testing techniques, interpreting results, and evaluation of thermal backfill requirements and applications.

Technology Transfer for Underground Transmission

This programme will focus on providing transferred technologies, captured knowledge, and educational materials that will support the execution of a reliable and cost-effective transmission cable systems. It will do so through three parallel tasks:

1. Underground Transmission Education Workshop: Topics will include design, construction, installation, operation, and maintenance of both extruded and laminar dielectric cable systems utilizing research and development as well as industry resources.

2. Diagnostic Techniques for Underground Transmission Cable Systems: As an educational introduction, this task is intended to evaluate existing and developmental diagnostic techniques as applied to both extruded and laminar dielectric cable systems. The task will include a technical assessment of the effectiveness and applicability of these techniques based on world-wide utility experience. To the extent practical, the task will include techniques outside the power cable industry and an assessment of their potentials to be developed for transmission cable systems.

3. EPRI Underground Transmission Systems Reference Book (Green Book)

Underground ratings and Increased Power Flow

The main objective of this project is to deliver the tools, information, training, and guidance to assess and implement increased and optimized power flow strategies for specific needs, with continued reliability, safety, and public acceptance.

Technology Transfer for Underground Transmission

The main objective of this project is to provide educational sessions and reference materials on various topics related to the design, installation, operation, and maintenance of underground transmission systems

The success criteria for Underground ratings and Increased Power Flow will be:

  • Reference guide to act as guidance as well as reference and training

  • Development of the Transmission Ratings Workstation and successful testing.

The success criteria for Technology Transfer for Underground Transmission will be:

  • Improved knowledge of underground transmission system design options

  • Improved cable project execution

  • Retention and/or transfer of institutional knowledge