Simple Formulas for Impulse Characteristics of Vertical and Horizontal Ground Electrodes.

Although the underlying phenomena when grounding electrodes discharge lightning currents are very complex, it is possible to derive simple formulas of impulse characteristics that allow for important engineering estimates. The interest in simple formulas was recently renewed, resulting in many contributions in the literature. In this paper, a parametric analysis is performed by a simulation of time-domain responses, with parameters in broad ranges. From this study, new formulas of impulse characteristics have been derived, including the expressions for ranges of parameters when grounding electrodes exhibit dominant inductive, resistive, or ionization effects. New formulas are compared with the existing ones, with experimental results, and their accuracy has been investigated. [ABSTRACT FROM AUTHOR]