Lightning-Protection Software is Grounded in Reality
Staff -- Consulting-Specifying Engineer, 12/1/2002
New research on the grounding properties of various soil types promises to result in more effective modeling of potential lightning-related transmission-line damage, as well as produce guidelines for better transmission-line design.
The study was intended to improve the TFlash software—developed by the Electric Power Research Institute (EPRI)—by providing more accurate algorithms for its calculations of transmission-line lightning performance. The soil surrounding grounding rods and transmission-tower footings plays an important role in protecting the lines from lightning-related damage. However, the EPRI researchers say, ionization during a lightning strike diminishes the soil's grounding capabilities. As current increases, the soil's protective capability decreases. Additionally, different soil types offer varying degrees of protection.
Researchers used full-scale transmission structures and high-voltage equipment at EPRI's T&D Engineering Center in Lenox, Mass. to inject voltage into a range of soil types to study the effects. Resulting measurements have been incorporated into new modeling algorithms used by TFlash.
EPRI released a beta version of the upgraded software this summer, with a final version anticipated to be available in December. The findings will also be used to produce a series of design and construction guidelines for new transmission lines and structures.
From Pure Power, Winter 2002
