A shielding theory for upward lightning

Shindo, Takatoshi; Aihara, Yoshinori

doi:10.1109/61.180352

Cited by 6 publications

(6 citation statements)

References 14 publications

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“…As already mentioned in Section V-B, altitudes typical for winter and summer clouds are 1 km and 1 4 km, respectively [18]. The (6) manifests that the estimated current value I should be inversely proportional to the assumed channel length "L".…”

Section: B Effect Of the Altitude Of The Thundercloudmentioning

confidence: 91%

“…Shindo et al surmised the altitude of a typical thundercloud charge in the winter season to be 1,000 m above ground taking the shielding effect rendered by independent steel towers locating windward several hundred meters apart from each other into consideration [18]. During the summer season, however, the thundercloud itself is located as high as 1 to 4 km above ground in most cases.…”

Section: B Altitude Of the Thundercloudmentioning

confidence: 99%

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Study of the Winter Lightning Ground Flash Density Investigated by the Lightning Location Systems

Udo¹

2006

IEEE Trans. Power Delivery

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A network of lightning location systems covering the entire Japanese Archipelago has been operational since the late 1980s. However, the operational records appear to be distorted relative to winter lightning flash densities. The maximum flash density registered was 0.3 ashes km 2 per one winter season, a mere one-tenth of the corresponding figure for severe summer lightning anywhere along the archipelago. On the other hand, the fault frequencies of overhead transmission lines constructed in the severe winter lightning districts are comparable with those of severe summer lightning districts. The author submits to resolve the apparent disparity by introducing two analytical parameters, namely 1) the propagation velocity of the return strokes of the winter lightning, and 2) the seasonal difference in the altitude of the lightning charge in the cloud. Consequently, the author proposes a certain seasonal modification of the threshold level applicable to the operation of lightning location systems.Index Terms-Altitude of cloud, flash density, lightning location systems, propagation velocity of return stroke, threshold level, winter lightning.

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Section: B Effect Of the Altitude Of The Thundercloudmentioning

confidence: 91%

Section: B Altitude Of the Thundercloudmentioning

confidence: 99%

Study of the Winter Lightning Ground Flash Density Investigated by the Lightning Location Systems

Udo¹

2006

IEEE Trans. Power Delivery

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“…Several attempts were made in USA and Japan to conduct laser-triggered guided lightning discharge (LTGLD). New Mexico researchers demonstrated laser triggered guided lightning discharge in laboratory and are working on long range propagation barrier facing long duration problem, cloud charge distribution over clouds in horizontal patches [18], or as a vertical line [115]. Recent reports show the kilometer long range remains no more a problem [116].…”

Section: Lightning Protection and Controlmentioning

confidence: 99%

Lightning Interactions with Humans and Lifelines

Kalair

Abas²,

Khan³

2013

JLR

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Lightning is one of the fascinating phenomena exhibiting tremendous natural power. It is source of awe, curiosity, enticement, inspiration as well as fear. On average, 50 lightning strikes occur on earth in one second. Fortunately not all of them kill people, albeit 10% people fall prey to lightning annually, out of which hardly 20 to 25% die. Lightning injures victims by heat, shockwave, intense brightness, radio waves, and secondary slip or fall mechanisms. Lightning injury is different from the normal electric shock as it involves transient flashover unlike the electrical contact freeze, wherein alternating (AC) and direct currents (DC) pass through the conductive interior body. Vacuity in knowledge is the driving force behind discoveries and inventions. Lightning experts had hardly developed any concurrence on lightning physics, and the observation of dark lightning complicated the Gordian knot. Lightning preventive, alerting and control devices help reduce fatality rates by the bolts out of blue skies. Lightning was considered to be the second cause of death making natural disasters after flashfloods but preventive measures have slithered it down to the third place in developed countries. Lightning prevention rule recommends 'when the thunder roars, go indoors'. This work describes lightning characteristics, damage thresholds to humans, machines, energy infrastructures, airplanes, wind turbines, light railway tractions, underground cables and pipelines. Power and energy lifelines such as transmission lines, oil tankers and gas or petroleum pipelines are susceptible to lightning strikes. Artificial rocket and laser triggered lightning protection and control techniques help to divert the lightning attacks. Interaction of lightning with power and energy infrastructures disrupts these lifelines. However, lightning itself is viewed as an extraterrestrial energy source. Lightning energy harvesting is an interesting application which has been investigated quantitatively.

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“…The shielding angel for the horizontal lightning leader is about 0.67 times that for the vertical lightning leader. There are many previous suggested values of the air terminal shielding angle such as 45 o or 60 o [10]. As shown in Fig.…”

Section: Shielding Anglementioning

confidence: 99%

“…The slant lightning leader is the main reason for bypassing the shielding wires and the upper phase conductors and strikes the lower phase conductor. The electrogeometric model (EGM) is a technique used for estimating the protection zone of air terminal [6][7][8][9][10][11][12]. The EGM was first introduced by Whitehead in the late 1960s [6] and is based on field studies of natural lightning.…”

Section: Introductionmentioning

confidence: 99%

Study of Air Terminals Shielding Due to Lightning Leader Slant

Nayel

2009

JES. Journal of Engineering Sciences

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A shielding theory for upward lightning

Cited by 6 publications

References 14 publications

Study of the Winter Lightning Ground Flash Density Investigated by the Lightning Location Systems

Study of the Winter Lightning Ground Flash Density Investigated by the Lightning Location Systems

Lightning Interactions with Humans and Lifelines

Study of Air Terminals Shielding Due to Lightning Leader Slant

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