Minutes of
Task Force on Nonstandard Lightning Voltages and
Task Force on Parameters of Lightning Strokes
7:00 p.m., Monday, 17 July 2000
Seattle, WA
The joint meeting of the two task forces was attended by four people. Prit
Chowdhuri summarized the work of the task forces as follows:
-
The Task Force on Nonstandard Lightning Voltages has recommended a second
waveshape for lightning voltages, i.e., 0.1/10-us wave, in addition to the present
standard 1.2/50-us wave"
- The TF members have written reports on the following:
- statistics on the first return stroke,
- statistics on the subsequent strokes,
- relationship between return-stroke current and velocity,
- statistics of the charge in the stepped leader,
- summary of physical models of air breakdown under lightning voltages
and the volt-time characteristics under nonstandard lightning voltages,
- modeling of transmission-line towers under fast transients,
- summary of critical electrical constants for computation of line shielding
failure, and
- comprehensive bibliography on lightning-stroke parameters.
Unfortunately, these documents have not been critically discussed by the general
memberships of the two task forces.
Prit brought up his previous suggestion that two papers be written jointly by the
two task forces. The first paper will be a bibliography of lightning stroke parameters. A
similar paper was written by the TF on Nonstandard Lightning Voltages. The second
paper will deal with the following:
- statistics of different stroke parameters,
- measurement techniques, and their shortcomings,
- proposals for better measurement techniques, if any,
- effects of lightning stroke parameters on the generation of transient voltages by (i)
direct strokes, and (ii) indirect strokes,
- response of power apparatus and systems to the generated voltages as dictated by
the lightning-stroke parameters, and
- finally, recommendations.
Again, no input has been received from the general membership.
Bill Chisholm commented that some of the documents submitted by the TF
members did not critically analyze the available data. The task forces should point out the
deficiencies of the available data, and suggest how better data can be obtained.
Bill Chisholm pointed out that several other groups need the data which we are
supposed to provide. Therefore, he suggested that we proceed with the second paper even
if we have not completed all our tasks. It is a continuing process.
The meeting was adjourned at 9:00 p.m.
Submitted by
P. Chowdhuri
19 July 2000
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