Reproduction of Electromagnetic Field Waveforms of Subsequent Return Strokes Hitting Tokyo Skytree over Lossy Ground

Saito, Mikihisa; Miki, Takafumi; Shindo, Takatoshi; Motoyama, Hideki; Ishii, Masaru; Sonehara, Takeo; Taguchi, Hiroshi; Tajima, Akira; Fujisawa, Akinobu

doi:10.1541/ieejpes.135.472

Cited by 14 publications

(16 citation statements)

References 4 publications

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“…Measurements of current for lightning events producing electric field signatures with EZCs were rarely reported. For strokes terminated on the Tokyo Skytree that produced EZC electric field waveforms at multiple stations, the measured currents were similar to the typical return stroke current waveforms measured at tall objects and the modeling showed that channel geometry was an important factor in producing the EZC in electric field waveforms (Araki et al, ; Saito, Miki, Shindo, Motoyama, Ishii, ; Saito, Miki, Shindo, Motoyama, Ishii, Sonehara, et al, ). Pavanello et al () also reported typical return‐stroke current waveform for an EZC event striking the CN tower.…”

Section: Can Traditional Return‐stroke Models Reproduce Early Zero‐crmentioning

confidence: 62%

A Modeling Study of Narrow Electric Field Signatures Produced by Lightning Strikes to Tall Towers

et al. 2018

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The lumped voltage source model proposed by Baba and Rakov (2005b, https://doi.org/10.1029/2004JD005202) for studying the interaction of lightning with tall objects was used to examine the origin of earlier zero crossings observed in electric field signatures produced by lightning strikes to towers. Different return stroke models of transmission line type were used, and model parameters were varied in wide ranges. Lightning channel was assumed to be straight and vertical. It was found that the observed narrow field signatures cannot be reproduced by traditional models and require a narrower input current waveform or/and its faster decay with height. Contribution to the total electric field peak from a tower whose height exceeds 100 m or so is greater than that from the lightning channel. At distances of 2 to 50 km, the electric field signature due to the tower current was found to be bipolar, while that due to the lightning channel current was unipolar. The narrow bipolar electric field waveforms produced by lightning striking the 257‐m tower in Florida were reproduced using two approaches. In the first one, we employed as input a typical channel base current waveform and the transmission line with exponential current decay with height model with a very small decay height constant. In the second approach, we used a narrow pulse followed by a steady‐level tail as the input current waveform and the transmission line with linear current decay with height model. In both approaches, the computed electric field waveforms matched well the corresponding measured waveforms, at least for the initial half‐cycle and opposite polarity overshoot.

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Section: Can Traditional Return‐stroke Models Reproduce Early Zero‐crmentioning

confidence: 62%

A Modeling Study of Narrow Electric Field Signatures Produced by Lightning Strikes to Tall Towers

et al. 2018

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“…The short‐circuit current I sc was used to determine the current injected into the tower and into the lightning channel, I sc Z ch / ( Z ch + Z t ) = (1 − ρ top ) I sc /2 (Baba & Rakov, ). (b) Waveforms of model‐predicted current in the tower at a height of about 500 m above ground and corresponding waveforms measured at 497 m for events observed on 18 May 2012 and on 6 August 2013 (Saito et al, ).…”

Section: Analysis and Resultsmentioning

confidence: 99%

“…Waveforms of vertical electric field computed for different values of ground conductivity at three distances, (a) 27, (b) 57, and (c) 101 km, and the corresponding measured ones for events observed on 18 May 2012 (left‐column panels) and on 6 August 2013 (right‐column panels) (Saito et al, ). All the waveforms are shown on a 10‐μs time scale.…”

Section: Analysis and Resultsmentioning

confidence: 99%

“…Hence, it is important to study the interaction of lightning with towers and associated electromagnetic fields (e.g., Baba & Rakov, ; Rakov, ). Several research groups have reported directly measured lightning currents and associated electric fields (e.g., Pavanello et al, ; Pichler et al, ; Saito et al, ; Zhu et al, ). Modeling attempts with varying degree of success were reported by Pavanello et al (), Kordi et al (), Saito et al (), Zhu and Rakov (), and Zhu et al ().…”

Section: Introductionmentioning

confidence: 99%

“…Several research groups have reported directly measured lightning currents and associated electric fields (e.g., Pavanello et al, ; Pichler et al, ; Saito et al, ; Zhu et al, ). Modeling attempts with varying degree of success were reported by Pavanello et al (), Kordi et al (), Saito et al (), Zhu and Rakov (), and Zhu et al (). As of today, no one formulated the problem in the framework of 3‐D finite difference time domain (FDTD) method.…”

Section: Introductionmentioning

confidence: 99%

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3‐D Finite Difference Time Domain Simulation of Lightning Strikes to the 634‐m Tokyo Skytree

Shohei

Nasu

Baba

et al. 2018

Geophysical Research Letters

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Waveforms of vertical electric field observed at distances of 27, 57, and 101 km from the 634‐m tall Tokyo Skytree (Japan) struck by lightning have been reproduced using the 3‐D finite difference time domain method. Optically observed 3‐D lightning channels and currents directly measured in the tower were used. Distribution of current along the lightning channel was represented using the transmission line model, assuming a constant propagation speed v = 0.5c. Simulations with commonly assumed vertical channel did not allow us to reproduce the observed early (within 5 μs or so) field zero crossing when the 1‐D speed was set to be constant and equal to the 3‐D speed (v = 0.5c) used for the actual‐channel‐geometry case. It was, however, possible to achieve a good match for a vertical channel when the vertical component of 3‐D speed was evaluated for each nonvertical channel segment and used in the corresponding range of heights.

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Lightning striking characteristics to tall structures

Shindo

2018

IEEJ Transactions Elec Engng

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Recently, very tall structures with heights more than several hundred meters have been constructed all over the world and observation of lightning has been made. The striking characteristics obtained from these observations are reviewed, and conventional and new shielding models are discussed. In addition, future themes of studies to be carried out are proposed. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

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Reproduction of Electromagnetic Field Waveforms of Subsequent Return Strokes Hitting Tokyo Skytree over Lossy Ground

Cited by 14 publications

References 4 publications

A Modeling Study of Narrow Electric Field Signatures Produced by Lightning Strikes to Tall Towers

A Modeling Study of Narrow Electric Field Signatures Produced by Lightning Strikes to Tall Towers

3‐D Finite Difference Time Domain Simulation of Lightning Strikes to the 634‐m Tokyo Skytree

Lightning striking characteristics to tall structures

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