P35.007: Line Design Tools and Practices for Construction and Maintenance

Update the EPRI AC Transmission Line Reference Book - 200 kV and Above (The Red Book): The Red Book intends to be published in 2027 with minor updates for the benefit of new members. The EPRI Red Book Application Suite (Desktop version) intends to be updated, and effort to migrate applets to the web-based version intends to be continued.

Update the EPRI Transmission Line Reference Book: 115–400 kV Compact Line Design (The Blue Book):** Minor (editorial) updates are expected on The Blue Book in 2027, which intends to be released for the benefit of new members.

Quantifying the Real Cost of Overhead Line Support Options: This multi-year research effort has been focused on helping engineers make the best decisions with regards to transmission pole material selection between wood, steel, concrete, fiber-reinforced polymer, and ductile iron. In 2027, the guide intends to be updated to include the cost of lattice towers, benchmarked to accommodate same loads and attachment heights as quantified for pole support options.

Allowable Compression in V-String Insulators: While V-strings assemblies offer a stable support point for suspended assemblies under most wind loads, few v- strings can accommodate extreme wind loads without one leg going into compression. Fundamental research and experimentation intends to be performed in 2027 to explore safe bending limits on composite long rod insulators and as well as ceramic captain pin insulators. This initiative intends to be performed as a shared deliverable in conjunction with project 35.011.

Develop Safe Design Tension Limits of ACSS Conductor: Determining a safe conductor tension is a multi-faceted problem that requires understanding of the self-damping performance and fretting fatigue endurance of a conductor. This new initiative, which is a collaborative effort with project 35.015, aims to help solve this problem for aluminum conductor steel-supported (ACSS) conductor, as its self-damping and fatigue properties vary significantly from aluminum conductor steel-reinforced (ACSR) conductor. In 2027, EPRI intends to continue empirical testing on conductors to define tension limits.

Transmission Line Design Bootcamp: In 2027, EPRI aims to launch a new 4-day seminar on overhead line design. This multi-disciplinary course is aimed at electrical, structural and mechanical disciplines with a goal of enhancing the engineering skill base of utility engineers.

Update the Optimal Line Tension Calculator (Op10): Op10 software is designed to determine the most cost-effective installed conductor tension, based on specific project variables, and to quickly determine the impact of a selected (or existing) conductor tension. Op10 intends to be updated to include new features as requested by users.

Update the Transmission Line Workstation Gen 2: Design and Vibration Module:** This EPRI software tool was developed to facilitate engineers in evaluating different design options effectively. Algorithms in some of the design programs may require updating based on EPRI research. Updating of this software may also be required to improve user features, add new functionalities, or to be compatible with other industry software used by the design engineers.

Revisiting Conductor Creep – Accuracy & Re-Tensioning Applications: While the time and load dependent phenomenon of conductor creep has been studied in early research efforts, recent questions arisen on the extent and speed of conductor creep when conductors have been re-tensioned. EPRI aims to perform fundamental testing to explore the rate of creep on both new and existing conductors in order that more accurate predictions may be made on conductor sag over extended periods of time.

Optimal Conductor Selection and Bundle Design: The selection of an optimal bundle configuration, which considers thermal limits, corona, aeolian, and cost has not yet been undertaken by EPRI. This research effort intends to be incorporated into the current Overhead Line Guide, and has the potential for development into a software tool.

Provide Tools and Resources on the Transmission Resource Center: The following calculators, tools, result summaries, and references are planned to be available on the Line Design Transmission Resource Center: