Analysis of Electromagnetic Fields Inside a Reinforced Concrete Building With Layered Reinforcing Bar due to Direct and Indirect Lightning Strikes Using the FDTD Method

On the representation of thin wires inside lossy dielectric materials for FDTD‐based LEMP simulations

“…To protect sensitive electronic devices inside a building from lightning threats, there is a requirement to design effective lightning protection systems on the basis of the concept of LPZs by taking into account the characteristics of lightning electromagnetic fields [1]. Thus, the shielding effectiveness of reinforcing bars against electromagnetic fields has been studied numerically and experimentally [20][21][22][23][24][25][26][27]. In practice, reinforcing bars are placed inside concrete, and it is well known that concrete has some shielding effects against electromagnetic fields.…”

“…In a previous study [20], using FDTD-based surge simulations, we studied the shielding effectiveness of concrete against LEMPs in a five-story reinforced-concrete building model for both direct and indirect lightning strikes, where the concrete was modeled by lossy dielectric materials, and the shielding effectiveness of the lossy dielectric was obtained on the fifth, third, and first floors in terms of the peak values of the electric and magnetic fields. The study showed that the lossy dielectrics have little influence on the magnetic fields, while they have a significant effect on the electric fields, and the shielding effects against the electric fields are highly dependent on the particular floor being considered.…”

“…To apply the FDTD method to surge analyses, several techniques for representing thin wires [9][10][11], surge arresters [12,13], arcing-horn flashover models [14], and so on have been developed, making the method an effective tool for the study of electromagnetic transient phenomena in power stations, substations, transmission lines, distribution lines, and buildings [15,16]. For direct or nearby lightning strikes, the FDTD method has been used to study electromagnetic fields and voltages induced on electrical wires inside buildings and the effect of building structures [17][18][19][20].…”

“…In previous studies [20][21][22][23][24][25][26][27], it was demonstrated through numerical and experimental analyses that the reinforcing bars of buildings have a significant effect on the behavior of LEMPs inside buildings. In surge analyses, the modeling of thin wires, such as electrical wires, is important for obtaining accurate results, and some techniques to simulate an arbitrary radius of thin wires in a lossless medium, such as overhead phase conductors [9] or wires in a lossy medium such as earth electrodes [10], have been developed for FDTD-based surge simulations.…”

Effects of Cement Paste Enhanced with Iron-Based Magnetic Particles on an Embedded Small Resonator Antenna

“…It is known that common building materials, such as concrete, gypsum and plaster, have high shielding effectiveness (SE) values. Direct measurements 5,6 , and analysis using finite-difference time-domain (FDTD) 7 , and method of moments (MOM) 8 techniques show that building materials have more than 80 dB to 100 dB of SE. One way to improve the performance of concrete is by adding magnetic and/or conductive particles into the cement mix.…”