P35.008: Line Resiliency

Practical Determination of Dynamic Load Impact Factors. EPRI has been conducting ongoing fundamental research into quantifying loads experienced by structures during broken wire events. These loads are then translated into dynamic impact load factors used by engineers to design high-resiliency structures. In 2025, EPRI aims to conclude this research effort by developing a procedure to apply dynamic impact load factors in the transmission design process.

Failure Event Loading Workshop. Engineers looking to enhance the resiliency of their systems may incorporate failure event load cases into the design process. Not all failure events are identical, however, because broken conductors affect a system far differently than cascading structures. This workshop is planned to present EPRI’s recommendations on the subject built on research into broken conductor and cascading events. The workshop aims to enhance the knowledge of transmission engineers at all experience levels.

Learning from Failure: Case Studies in Improved Engineering. With every structural or mechanical failure event, there is a potentially valuable lesson to be learned by line design engineers. The continued increase in failure events means that there is no shortage of potential events from which valuable design lessons may be extracted. Very often the events leading to failure are multi-dimensional and not the result of a single point of discrepancy. When the root causes and possible preventive actions from these events are documented, they can teach engineers how to become better designers. In 2025, EPRI aims to add multiple case studies to its current guide on documented failures related to how structures have failed in the past and how future generations of engineers may use this information to achieve more resilient designs.

Quantification of Transverse Cascading Loads. Although EPRI and other institutions in the transmission industry have conducted research into longitudinal cascading events, transverse cascading loads remain a knowledge gap. EPRI aims to build and operate a transverse cascading test line to quantify loads experienced by structures during these events and ultimately help engineers design against them. In 2025, EPRI aims to design a test line and develop a research methodology for transverse cascades to then execute upon in subsequent years.

Impact of Soil Investigation Frequency on Design Reliability. Engineering practices with regard to soil investigation frequency for transmission line projects vary widely. Every foundation that is designed and installed without an adequate soil investigation presents risk to a utility. In 2025, EPRI aims to complete a study to correlate the impact of soil investigation frequency on foundation design reliability.

Rapid Response Emergency Tower. The Rapid Response Emergency Tower is performed under EPRI’s Technology Innovation Program, in support of P35.008. In 2025, EPRI aims to demonstrate the operation of the completed emergency restoration system and to document improvements to the prototype.