Excellent reply! Do you have a URL to get copies? I said 'significant', not 'spectral bandwidth of energy'
I assumed these frequencies were of interest, because coupling is increased, breakdown is more likely to occur, and I thought the goal was to make a connection system with broadband characteristics. And, as we both know, inductance can certainly ruin the high frequency end of a system. Your point is well taken about how to refer to lightning energy. It's almost like once it is brought into existance, it doesn't go away, one just moves it about. And, the best we can hope for is to keep it out of our systems while all that's happening. Robert > Robert Macy wrote: >> Assuming most of lightning >> energy is significant between 1MHz to 100MHz, calculate each conductor's >> characteristics at 10MHz and at 100MHz using 2D finite element analysis. >> >> > This is at variance with real lightning and the simulated lightning > generators for equipment test. > > Lightning Physics and Effects (Rakov &Uman) states that electromagnetic > signal levels from lightning peak in the 5 to 10 kHz region, then fall > inversely with frequency up to 10 MHz and then fall inversely with the > square root of frequency to 10 GHz. > > Actual simulated lightning generators, such as the 1.2/50 and 10/1000 > obviously have an even more restricted spectrum. Strandler (Protection > of Electronic circuits from overvoltages) shows the spectrum of several > lightning test pulses. The --6 decibel spectrum fall-off points are > variously 300 Hz 10/1000, 5 kHz 1.2/50, 30 kHz 8/20 and 200 kHz for the > 100 kHz ring wave. Non-lightning waveshapes like EFT and HEMP have a > much broader frequency spectrum. > > Also please be careful when talking about lightning energy - this can > lead to dreadful statements like "The lightning protection system > diverts the lightning energy to earth". It doesn't, current gets > diverted to ground and the amount of energy in the earth depends on the > earth potential rise - something the lightning doesn't have control over. > > Mick > UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <emcp...@socal.rr.com> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
