Research Status & Deliverables
Task: Rapid Response Emergency Restoration Tower – Container Development
Task Description:
- EPRI is currently engaged in the development of a concept demonstrator to gauge the feasibility for radically reducing the restoration time for transmission towers in the 230-500kV class.
- In 2024 fabrication of the of the emergency structure will commence (pending funding).
Update:
- EPRI has completed fabrication of the customized shipping container that will host the rapid emergency restoration structure.
- The shipping container was designed not only to host the emergency structure and components but includes a collapsible work platform, guy wire reels and lifeline spool, hardware and insulator storage containers and tubes.
Task: Dynamic Impact Test Line – Broken Wire Simulations
Task Description:
- EPRI is has been engaged in ongoing research to quantify dynamic impact loads produced from broken wire events. These loads, once quantified, may be used to design more resilient transmission structures that can withstand broken wire events.
- Since August 2021, EPRI has conductor 28 broken wire simulations on its dynamic impact test line in Lenox, MA with a variety of span lengths, conductor types, conductor tensions and insulator lengths.
Update:
- In June 2023, EPRI completed 6 broken wire tests using its largest conductor size to date, Chukar ACSR.
- In July further tests focused on the effects of variable structure stiffness on dynamic impact loads.
- A live demonstration of the dynamic impact test line was held during the 2023 Fall Task Force.
- In 2024, testing is expected to take place on the longest (1200ft) span.
Effect of Climate Change on Probabilistic Loads Used for Transmission Line Design: Climate change has resulted in the increased frequency and severity of extreme weather events experienced by transmission lines. Current design codes specify climatic loads with 50, 100, or greater year return periods, but are these loads still valid in a changing climate?
In 2024, EPRI plans to conduct a literature review on this topic to provide engineers with the most up-to-date information in the field of climate change as it relates to transmission line design. The information presented will help engineers to make more informed decisions as they try to achieve the highest levels of resiliency in their designs.
Quantification of Transverse Cascading Loads: For engineers looking to design transmission lines to achieve the highest levels of resiliency, the incorporation of cascading resistance into their designs is of key importance. Several utilities incorporate reinforced “stop structures” at intervals into lines of relatively weaker strength. While this method has proven effective, there is no established procedure for the optimal design of stop structures both in terms of strength requirements and ideal frequency.
In 2024, EPRI plans to develop a procedure for the design of stop structures which will include the quantification of and resistance against transverse cascading loads. This work will be conducted in coordination with EPRI project 35.005 which covers composite pole materials, a common stop structure material type.
Improved Guidance on Forensic Investigations: When an overhead transmission line fails the immediate objective is to make the affected area safe as soon as possible. This process often hinders the ability for forensic evidence to be collected. Forensic evidence is a crucial element required in investigations to determine the cause of the failure which in turn can be used to mitigate future failures.
In 2024, EPRI plans to update the guideline on Forensic Investigations (currently Volume 1, Chapter 4 in the Yellow Book – Inspection and Assessment Reference Book). This task will be performed in collaboration with P35.001.
2024 Planned Deliverables
| Product ID | Name |
Type |
|---|---|---|
| TBD | Practical determination of Dynamic Load Impact Factors: 2024 Edition |
Technical Update |
| TBD | Learning from Failure - Case Studies in Improved Engineering |
Technical Update |
| TBD | Quantification of Transverse Cascading Loads |
Technical Update |
| TBD | Effect of Climate Change on Probabilistic Loads Used for Transmission Line Design |
Technical Update |
| TBD | Improved Guidance on Forensic Investigations |
Technical Update |
2023 Deliverables
| Product ID | Name |
Type |
|---|---|---|
| 3002026995 | Effect of Seasonal Moisture Variation on Helical Guy Anchor Reliability |
Technical Update |
| 3002026998 | Practical determination of Dynamic Load Impact Factors: 2023 Edition |
Technical Update |
| 3002027002 | Learning from Failure – Case Studies in Improved Engineering |
Technical Update |
| 3002027006 | Tools and Solutions for Effective Emergency Line Restoration |
Technical Update |