Researchers studying the effects of lightning on transmission lines at the Electric Power Research Institute (EPRI) have developed information that may help save millions of dollars annually by reducing lightning-caused outages and improving transmission line design.

"Lightning is the most frequent cause of transmission outages and service interruptions in the U.S.," says EPRI project manager Andrew Phillips. "Some 30 percent of all power outages are lightning-related, with total costs approaching one billion dollars annually. The improved tools and knowledge developed in this work will help the power industry increase transmission system reliability and reduce costs associated with lightning-caused damage and service interruptions."

Foremost among lightning protection tools is EPRI's TFlash software package. TFlash is a design tool that allows engineers to analyze the effects of specified lightning events on a given transmission line, as well as specified mitigation techniques such as shielding, improved grounding, line arresters, and upgraded insulation. Engineers can analyze the degree of lightning protection of an existing line, define changes to the line to improve protection, or design a new line with economical lightning protection.

Studies at EPRI's Transmission and Distribution Engineering Center in Lenox, Massachusetts, have shown that the dynamic resistance of ground electrodes and concrete tower footings, and the electrical properties of the underlying soils have a profound effect on the lightning performance of transmission lines. This is helping researchers evaluate and optimize the lightning performance of transmission lines and develop guidelines for the cost-effective design, construction, and maintenance of transmission line grounding systems.

The T&D Center in Lenox has an array of transmission structures and high voltage test equipment to allow full-scale engineering testing that replicate real-world conditions.

"This work has really advanced our understanding of how transmission grounding systems react," says Phillips. "Based on that understanding we can predict the lightning performance of transmission lines better, and optimize that performance by designing surge arresters and other protective measures in a more cost-effective manner."

Study results have already been put to work in improved TFlash algorithms that represent soil ionization and ground electrode performance with much greater accuracy. The improved TFlash 4.0 software is now available.

Kyle King, Director of EPRIsolutions in Lenox adds that the EPRIsolutions technical team can train staff to use it, offer membership in the TFlash Users Group, and provide consulting services for improved lightning performance. EPRI will conduct a TFlash 4.0 software training workshop for utility engineers at the EPRI Lenox Center on April 22-23, 2003. For additional registration information, contact Kyle King, EPRIsolutions, phone (413) 448-2459, fax (413) 499-5718, or lightning@eprisolutions.com.

TFlash includes data on a wide variety of components and most power line structures, and it contains historical lightning data for the entire U.S. from the National Lightning Detection Network (NLDN).

EPRIsolutions is a premier engineering and consulting company created by EPRI and dedicated to applying the latest technology - from EPRI and others - to help clients meet the challenges of the competitive power marketplace. EPRIsolutions provides an array of coordinated services in all areas of electric power generation, including asset optimization and environment services as well as transmission and distribution.

EPRI, headquartered in Palo Alto, Calif., was established in 1973 as a non-profit center for public interest energy and environmental research. EPRI's collaborative science and technology development program now spans nearly every area of power generation, delivery and use. More than 1,000 energy organizations and public institutions in 40 countries draw on EPRI's global network of technical and business expertise.

EPRI. Electrifying the World Visit EPRI's electronic press room at http://www.epri.com/corporate/discover_epri/news/index.html

Refer to a more extensive article on this subject in the EPRI Journal Online at http://www.epri.com/journal/

Photos available; contact Jackie Turner (650) 855-2272, jturner@epri.com

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