Electromagnetic Field Due to Lightning Strikes to Mountainous Ground

Document Type : Research Article

Authors

1 PhD. Student, Department of Electrical and Computer Engineering, Amirkabir University of Technology, Tehran, Iran

2 Professor, Department of Electrical and Computer Engineering, Amirkabir University of Technology, Tehran, Iran

Abstract

The produced electric and magnetic fields due to lightning strikes to mountainous ground are determined in this paper. For the sake of simplicity a cone-shaped ground with finite conductivity is assumed to represent a natural nonflat ground. By this assumption, we deal with an axillary symmetrical structure so we use the cylindrical 2D-FDTD to save the simulation memory and time, dramatically. The return stroke channel is modeled using the antenna theory model with fixed inductive loading (ATIL-F) which is appropriately incorporated into the FDTD algorithm. We have derived the updating equations of 2D-FDTD for distributed resistance and inductance in ATIL-F model. Both the first and the subsequent return strokes are considered and their related radiated electromagnetic fields are determined and compared with each other. The fields are calculated at an intermediate horizontal distance from the cone-axis.
The calculated results show that the presence of the cone-shape ground introduces an enhancement in electric and magnetic fields, for both first and subsequent return strokes. Since sharper lossy cone means larger current density in the ground, the increment in the amplitude of the fields is inversely proportional to the cone-angle. A hump is observed in electromagnetic field waveforms because of the current reflection form joint point of the cone-shape ground and the flat ground beneath it. It is more specific in the subsequent-stroke fields. simulation results for different cone-height are presented. It shows that for small values of height, the results approaches to those of the flat ground.

Keywords

References

[1] V. A. Rakov, F. Rachidi, "Overview of recent progress in lightning research and lightning protection", IEEE Transaction of Electromagnetic Compatibility, vol. 51, no. 3, pp. 428-442, August 2009.
[2] F. Rachidi, et al, “Influence of a lossy ground on lightning-induced voltages on overhead lines,” IEEE Transaction on Electromagnetic Compatibility, vol. 38, no. 3, pp. 250-264, 1996.
[3] A. Shoory, R. Moini, S. H. H. Sadeghi, and V. A. Rakov, “Analysis of lightning-radiated electromagnetic fields in the vicinity of lossy grounds,” IEEE Transaction on Electromagnetic Compatibility, vol. 47, no. 1, pp.131-145, Fab. 2005.
[4] M. Khosravi-Farsani, R. Moini, S. H. H. Sadeghi, and F. Rachidi, “On the validity of approximate formulas for the evaluation of the lightning electromagnetic fields in the presence of a lossy ground,” IEEE Transaction on Electromagnetic Compatibility, vol. 55, no. 2, April 2013.
[5] F. H. Silveira, S. Visacro, R. Alipio, and A. De Conti, “Lightning-induced voltages over lossy ground: the effect of frequency dependence of electrical parameters of soil,” IEEE Transactions on Electromagnetic Compatibility, vol. 56, no. 5, pp. 1129-1136, October 2014.
[6] F. Delfino, R. Procopio, M. Rossi, A. Shoory, and F. Rachidi, “The effect of a horizontally stratified ground on lightning electromagnetic fields,” International Symposium on EMC, 2010.
[7] V.A. Rakov, “Transient response of a tall object to lightning,” IEEE Transactions on Electromagnetic Compatibility, vol. 43, no. 4, pp. 654-661, November 2001.
[8] F. Rachidi, V.A. Rakov, C.A. Nucci, and J.L. Bermudez, “Effect of vertically-extended strike object on the distribution of current along the lightning channel,” Journal of Geophysical Research, vol. 107, no. D23, 2002.
[9] S. Bonyadi-Ram, R. Moini, and S. H. H. Sadeghi, and V. Rakov, “On the representation of lightning return stroke as a lossy monopole antenna with inductive loading,” IEEE Transaction on Electromagnetic Compatibility, vol. 50, no. 1, pp. 118-127, February 2008.
[10] A. Taflove and S. C. Hagness, Computation Electrodynamics: The Finite Difference Time Domain Method, 3rd ed. Artech House, 2005.
[11] Y. Baba and V. A. Rakov, “Electromagnetic models of lightning return stroke,” Journal of Geophysics Research, vol. 112, no. D04102, 2007.
[12] Y. Baba and V. A. Rakov, “Application of Electromagnetic models of the lightning return stroke,” IEEE Transactions on Power Delivery, vol. 23, no. 2, pp. 800-811, April 2008.
[13] R. Moini, B. Kordi, G. Z. Rafi, and V. Rakov, “A new lightning return stroke model based on antenna theory,” Journal of Geophysics Research, vol. 105, no. D24, December 2000.
[14] V. A. Rakov, “Lightning return stroke speed: A review of experimental data,” in Proc. 27th Int. Conf. Lightning Protection, Soc. de l’Electr., et des Technol. de l’Inf. et de la Commun., Avignon, France, September 2004.
[15] F. Heidler, “Analytische blitzstromfunktion zur LEMP-Berchnung," Proc. 18th Int. Conf. Lightning Protection, Munich, Sept. 1985, paper 1.9, pp. 63-66.
[16] F. Rachidi, et al., “Current and electromagnetic field associated with lightning-return strokes to tall towers,” IEEE Transaction on Electromagnetic Compatibility, vol. 43, no. 3, pp. 356-367, August 2001.
[17] W. Yu and R. Mittra, “A conformal finite difference time domain technique for modeling curved dielectric surfaces,” IEEE Microwave and Wireless Components, vol. 11, no. 1, January 2001.
[18] G. Mur, “Absorbing boundary conditions for the finite-difference approximation of the time-domain electromagnetic field equations,” IEEE Transaction on Electromagnetic Compatibility, vol. 23, no. 4, pp. 377-382, November 1981.
[19] B. Kordi, et al., “Application of the antenna theory model to a tall tower struck by lightning,” Journal of Geophysical Research, vol. 108, no. D17, 2003.
[20] V. Cooray, “Horizontal electric field above-and underground produced by lightning flashes,”IEEE Transaction on Electromagnetic Compatibility, vol. 52, no. 4, pp.936-943, Nov. 2010.
AUT Journal of Electrical Engineering
Volume 47, Issue 2 - Serial Number 2
December 2015
Pages 27-37

Files

Share

How to cite

Statistics