Frequency Dependence of Soil Parameters: Effect on the Lightning Response of Grounding Electrodes

• Published in: IEEE transactions on electromagnetic compatibility Vol. 55; no. 1; pp. 132 - 139
• Main Authors: Alipio, R., Visacro, S.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.02.2013; Institute of Electrical and Electronics Engineers
• Subjects: Applied sciences; Arcs, sparks, lightning; Conductivity; Connection and protection apparatus; Currents and their properties; Earth sciences; Earth, ocean, space; Electric discharges; Electrical engineering. Electrical power engineering; Electrodes; Exact sciences and technology; Frequency dependence; Frequency dependence of soil; General theory of currents; General theory of fields and particles; Grounding; Impedance; lightning response of grounding electrodes; Permittivity; Physics; Physics of gases, plasmas and electric discharges; Physics of plasmas and electric discharges; Soil; soil permittivity; soil resistivity; Soils; Surficial geology; The physics of elementary particles and fields; soil permittivity; Frequency dependence; Electromagnetism; Grounding; Frequency dependence of soil; Resistivity; impedance; dielectric constant; lightning response of grounding electrodes; Lightning discharge; soil resistivity; Lightning; Impulse; Earthing device
• ISSN: 0018-9375; 1558-187X
• DOI: 10.1109/TEMC.2012.2210227

Quantities related to the response of grounding electrodes subject to lightning currents are simulated under the assumption of constant and frequency-dependent soil resistivity and permittivity for 100-4000 Ω·m soils, using an accurate electromagnetic model. It was found that the frequency dependence of soil parameters is responsible for decreasing the grounding potential rise of electrodes and, thus, their impulse impedance and their impulse coefficient. This effect is more pronounced with increasing soil resistivity and for typical currents of subsequent strokes. The reduction of these quantities is negligible for soils of 300 Ω·m and below. It is considerable for soils above 500 Ω·m and is very significant above 1000 Ω·m. Reductions of around 23%, 30%, 40%, and 52% are found, respectively, for soils of 600, 1000, 2000, and 4000 Ω·m and typical subsequent stroke currents. Lower values, around 8%, 11%, 18%, and 28%, are found for first stroke currents.