A dissertation submitted in fulfillment of the requirements to the Faculty of Science, University of the Witwatersrand, Johannesburg, for the degree of Master of Science in the School of Electrical and Information Engineering, June 2019 / The objective of this study is to determine the quantity of charge transferred, in
Coulombs, during the continuing current phase of natural cloud-to-ground (CG)
lightning flashes over an area in Johannesburg, South Africa. Continuing current
is responsible for most thermal related lightning damages such as destruction of
property, electrical fires and physical human trauma. The mitigation of lightningrelated
risks can be better managed through improved measurement methods of
naturally occurring lightning. The application of a point-charge model used to
infer charge transfer from changing electric field measurements is detailed. A flatplate
antenna with an integrator is set up to record the changing electric fields
from lightning flashes. These measurements, along with high-speed video footage
to determine continuing current durations, are processed and charge transfer quantities
are inferred. From 34 negative lightning strokes with long continuing current
(i.e. > 40 ms), the quantity of charge transfer ranges from 0.3 C to 145.5 C and
has a mean quantity of 18.3 C. For the 5 recorded positive strokes, the quantity
of charge transfer ranges from 3.7 C to 66.6 C / NG (2020)
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/29157 |
| Date | January 2019 |
| Creators | Tasman, Jesse Dean, Tasman, Jesse Dean |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | Online resource (various pagings), application/pdf |
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