Attendees:Chang, Chisholm, Hensel, Ishii, Kim, Longo, Maltempi, Matsuda, McDermott, Mousa, Patel, Prikler, Rozek, Sawada, Vargas, Wilson, Zaima (17)
The meeting began with a presentation by Ishii on tall structure modeling with NEC-2. This paper will be published in the transactions.
Chang presented results from CN tower measurements and announced an International Workshop on Electromagnetic Radiation from Lightning to Tall Structures at the University of Toronto on August 20-22, 2001. Email to janisch@ecf.utoronto.ca or call 416-978-3116 for more information. On the CN tower, measurements of two H components agree well enough for two measurement systems (Canadian and Swiss), but the Ez agreement needs another look.
The Flash software has been updated on the WG web site. The spreadsheet front end should work now on Windows 95/98, and a bug has been fixed in the Sargent cone tower surge impedance. This bug was introduced in the recent conversion to C. Approximately 4-5 parties have received "support" for Flash since January. Rozek supplied a test case to start the new Flash verification data set.
The 1243 guide must be reaffirmed or revised by the end of 2002. We haven’t been able to get an electronic copy from IEEE standards for editing, despite their indicating twice that it’s "on the way". Later, Wilson indicated we may need to request this through our standards coordinator.
McDermott summarized material on line arresters recently submitted for the C62.22 application guide for metal oxide surge arresters. The WG should review this and comment on what should be included in the next version of 1243. A method of estimating line arrester energy discharge was briefly discussed, to include in a future version of Flash.
McDermott showed sample data from the Optical Transient Detector (https://thunder.msfc.nasa.gov/otd/) project, which is a possible replacement for the isokeraunic map in areas that have no access to lightning detection network data. The WG decided to proceed with such a map for the next version of 1243. Despite many known limitations, it is still better than keraunic levels.
Ishii summarized a contribution on positive strokes. It does not appear these require special handling, with the possible exception of winter lightning.
We still need expanded references on the charge transfer system.
Mousa summarized a report on lightning protection of radar sites done for the National Severe Storms Lab. An appendix of this report seems to support the electrogeometric model by an independent development. Mousa provided copies of 2 papers by Newman on strokes to a sailboat mast at sea, he hopes these can either support or disprove an idea that ground resistivity affects stroke current magnitude.
Minutes prepared by
Tom McDermott
July 18, 2001