An approximation to the Heidler Function with an analytical integral for engineering applications using lightning currents
Date
2015
Authors
Terespolsky, Brett Ryan
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Abstract
The work presented contributes to research in lightning protection simulations and focuses
on approximating the Heidler function with an analytical integral and hence a
frequency domain representation. The integral of lightning current models is required
in the analysis of lightning events including the induced effects and frequency analyses
of lightning strikes. Previous work in this area has produced very specific forms of the
Heidler function that are used to represent lightning current waveshapes. This work
however focuses on a generic solution with parameters that can be modified to produce
any lightning current waveshape that is required. In the research presented, such an
approximation is obtained. This function has an analytical solution to the integral and
hence can be completely represented in the frequency domain. This allows for a true
representation of Maxwell’s equations for Electromagnetic (EM) fields and for an analytical
frequency domain analysis. It has parameters that can be changed to obtain
different waveshapes (10/350, 0.25/100, etc.). The characteristics of the approximation
are compared with those of the Heidler function to ascertain whether or not the function
is applicable for use with the lightning protection standard (IEC 62305-1). It is shown
that the approximation does represent the same characteristics as those of the Heidler
function and hence can be used in IEC 62305-1 standardised applications. This represents
a valuable contribution to engineers working in the field of lightning protection,
specifically simulation models.
Description
A dissertation submitted to the Faculty of Engineering and the Built
Environment, University of the Witwatersrand, Johannesburg, in fulfilment of
the requirements for the degree of Master of Science in Engineering
in the
Lightning and EMC Research Group
School of Electrical and Information Engineering
September 2015
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Citation
Terespolsky, Brett Ryan (2015) An approximation to the Heidler Function with an analytical integral for engineering applications using lightning currents, University of the Witwatersrand, Johannesburg, <http://hdl.handle.net/10539/22605>