A simulation model for electromagnetic transients in lightning protection systems
ABSTRACT This paper deals with the evaluation of electromagnetic transients in a lightning protection system (LPS). A field approach is used, based on the numerical solution of a modified version of the thin-wire electric field integral equation in the frequency domain. Time profiles of interesting electromagnetic quantities are computed by using a discrete fast Fourier transform algorithm. The model takes into account coupling effects among aerial parts and ground electrodes in order to correctly estimate the quantities which can determine electromagnetic hazard inside the LPS; transient touch and step voltages can be easily evaluated also taking into account the human body presence on the soil surface. To this purpose, a crucial point is the accurate evaluation of the current distribution among the earthed branches of the LPS and this needs to correctly consider mutual electromagnetic interference among the aerial parts and the earth-termination system of the same LPS. A suitable approach to consider the lossy soil is employed. Validation of the proposed model is performed by comparing the results with those measured and computed available in technical literature. Simulation examples related to realistic LPS structures are presented and discussed to show the flexibility and the accuracy of the model in the range of practical applications inside the volume to be protected.
Recent Patents on Electrical Engineering 01/2011; 4(3):202-208.
Conference Proceeding: Application of an electromagnetic modeling method for railway grounding systems subjected to lightning strikes[show abstract] [hide abstract]
ABSTRACT: This document presents the work done for the Belgian railway operator Infrabel with respect to the modeling of grounding systems. Infrabel needed information on how to design the lightning protection systems of the recently deployed GSM-R installations. There exist many methods for simulating lightning strikes on grounding systems. One of these techniques, an electromagnetic method based on Moment Methods, is used to solve the problem. The theory behind the method is described and a novel technique is presented for simulating cylindrical cables without metal sheets. The method is applied to the grounding of the Infrabel GSM-R base station. The influence of the soil conductivity, the length of cables and grounding rods and the type of lightning strike on the effectiveness of the grounding system is researched.Harmonics and Quality of Power, 2008. ICHQP 2008. 13th International Conference on; 11/2008
Article: Finite difference time domain simulation of soil ionization in grounding systems under lightning surge conditions[show abstract] [hide abstract]
ABSTRACT: This paper proposes a Maxwell's equations finite difference time domain (FDTD) approach for electromagnetic transients in ground electrodes in order to take into account the non linear effects due to soil ionization. A time variable soil resistivity method is used in order to simulate the soil breakdown, without the formulation of an initial hypothesis about the geometrical shape of the ionized zone around the electrodes. The model has been validated by comparing the computed results with available data found in technical literature referred to concentrated earths. Some application examples referred to complex grounding systems are reported to show the computational capability of the proposed model. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)Applied Numerical Analysis & Computational Mathematics 02/2004; 1(1):90 - 103.