Models of Lightning Channel Impedance

1981 ◽  
Author(s):  
Rayner K. Rosich ◽  
Martin D. Rymes ◽  
Frederick J. Eriksen
Keyword(s):  
Lightning Channel

scholarly journals Computation of Energy Absorption and Residual Voltage in a Fourth Rail LRT Station Arresters in EMTP-RV: A Comparative Study

2021 ◽  
Author(s):  
Farah Asyikin Abd Rahman ◽  
Mohd Zainal Abidin Ab Kadir ◽  
Ungku Anisa Ungku Amirulddin ◽  
Miszaina Osman
Keyword(s):  
Electromagnetic Transients ◽  
Lightning Strike ◽  
Voltage Gradient ◽  
Urban Transit ◽  
Residual Voltage ◽  
Voltage Ratio ◽  
Lightning Channel ◽  
Breakdown Region ◽  
Current Region ◽  
Performance Results

AbstractThis paper presents a study on the performance of a fourth rail direct current (DC) urban transit affected by an indirect lightning strike. The indirect lightning strike was replicated and represented by a lightning-induced overvoltage by means of the Rusck model, with the sum of two Heidler functions as its lightning channel base current input, on a perfect conducting ground. This study aims to determine whether an indirect lightning strike has any influence with regard to the performance of the LRT Kelana Jaya line, a fourth rail DC urban transit station arrester. The simulations were carried out using the Electromagnetic Transients Program–Restructured Version (EMTP–RV), which includes the comparison performance results between the 3EB4-010 arrester and PDTA09 arrester when induced by a 90 kA (9/200 µs). The results demonstrated that the PDTA09 arrester showed better coordination with the insulated rail bracket of the fourth rail. It allowed a lower residual voltage and a more dynamic response, eventually resulting in better voltage gradient in the pre-breakdown region and decreased residual voltage ratio in the high current region.

Simulations of electric field at the initiation altitudes of sprites and halos generated by the thundercloud charge structure and lightning channels of causative return strokes

2021 ◽  
Author(s):  
Petr Kaspar ◽  
Ivana Kolmasova ◽  
Ondrej Santolik ◽  
Martin Popek ◽  
Pavel Spurny ◽  
...  
Keyword(s):  
Electromagnetic Field ◽  
Electric Field ◽  
Boundary Conditions ◽  
Free Space ◽  
Nonlinear Effects ◽  
Charge Structure ◽  
Transient Luminous Events ◽  
Lightning Channel ◽  
Free Parameters

<p><span>Sprites and halos are transient luminous events occurring above thunderclouds. They can be observed simultaneously or they can also appear individually. Circumstances leading to initiation of these events are still not completely understood. In order to clarify the role of lightning channels of causative lightning return strokes and the corresponding thundercloud charge structure, we have developed a new model of electric field amplitudes at halo/sprite altitudes. It consists of electrostatic and inductive components of the electromagnetic field generated by the lightning channel in free space at a height of 15 km. Above this altitude we solve Maxwell’s equations self-consistently including the nonlinear effects of heating and ionization/attachment of the electrons. At the same time, we investigate the role of a development of the thundercloud charge structure and related induced charges above the thundercloud. We show how these charges lead to the different distributions of the electric field at the initiation heights of the halos and sprites. We adjust free parameters of the model using observations of halos and sprites at the Nydek TLE observatory and using measurements of luminosity curves of the corresponding return strokes measured by an array of fast photometers. The latter measurements are also used to set the boundary conditions of the model.</span></p>

scholarly journals The wave form of atmospherics at night

1940 ◽  
Vol 176 (965) ◽  
pp. 180-202 ◽  
Keyword(s):  
Wave Form ◽  
Time Interval ◽  
Time Separation ◽  
The Earth ◽  
Lightning Channel ◽  
Reflexion Coefficient ◽  
Primary Pulse

The wave form of all atmospherics received at night from sources within 2000 km. can be accurately described as a ground pulse followed by a series of sky pulses produced by successive reflexions between the ionosphere and the earth, thirty such reflexions being frequently recorded. The time separation between the peaks of these pulses is determined by the distance travelled and the height of the layer. The primary pulse emitted by the source is usually a single complete oscillation of period ranging from 50 to 400//sec. A t distances greater than 500 km. the ground pulse and the first sky pulse merge owing to the shortness of the time interval between them . Differences of amplitude, form and phase between pulses can arise from differences in angle of emission from the parent lightning channel. The height of the reflecting layer can be determined within ± 1 km. It ranged from 85-5 to 90-5 km. during two winter months, with a mean of 88-0 km. The distances of the sources as found by analysis of the pulse series were corroborated by independent location with cathode-ray direction-finders. The reflexion coefficient of the layer for the pulses of longer period exceeded 0-80. The velocity of the ground pulse where it can be tested is within 0.7 % of that of light.

scholarly journals Artificial Lightning Strike Tests and Coupled Electrical–Thermal Analysis on Roofing Glazed Tiles of Ancient Buildings

2021 ◽  
Author(s):  
Jingxiao Li ◽  
Zhiling Fang ◽  
Lin Fu ◽  
Shangchen Fu ◽  
Lihua Shi ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Thermal Stress ◽  
High Temperature ◽  
Heat Effect ◽  
Element Model ◽  
Joule Heat ◽  
The Body ◽  
Lightning Strike ◽  
Lightning Current ◽  
Lightning Channel

Abstract Lightning strike is one of the natural disasters to the roof components of ancient buildings. To investigate the causes and damage effects of lightning strikes on the roofing glazed tiles of ancient buildings, artificial lightning strike tests were carried out on glazed tiles. Based on the experiment results, a coupled electrical–thermal finite element model of mortar-containing glazed tiles was established and the Joule heat effect of lightning current was further investigated. The results show that when the lightning channel is attached to the surface of the enamel and body with a low electrical conductivity, the lightning current is mainly released in the form of surface flashover, and a minor damage is induced along the flashover path; when the lightning channel is attached to the mortar with a high electrical conductivity, the lightning current is injected into the mortar, resulting in significant tile damage. The spatial distributions of the temperature present clear gradient characteristics. The high-temperature area appears in the mortar while the high–thermal–stress area appears in the body connected to the grounding rail. As the peak of the lightning current increases, both the high-temperature and high–thermal–stress areas of the glazed tiles expand. The combination of the experiments and the numerical analysis results demonstrate that the damage mechanism of lightning Joule heat effect to glazed tiles may include two aspects. One is the internal explosive force generated from the sharp vaporization and expansion of the moisture inside the tiles due to rapid temperature increase, and the other is the thermal stress caused by the uneven temperature distribution.

scholarly journals Lightning Channel-Base Current Identification as Solution of a Volterralike Integral Equation

2008 ◽  
Vol 2 (1) ◽  
pp. 160-165 ◽  
Author(s):  
Federico Delfino ◽  
Renato Procopio ◽  
Mansueto Rossi
Keyword(s):  
Integral Equation ◽  
Numerical Simulations ◽  
Time Domain ◽  
Measurement Noise ◽  
Induction Field ◽  
Base Current ◽  
Lightning Channel ◽  
Regularization Techniques ◽  
Ill Conditioning ◽  
The Time Domain

In this paper, a novel procedure to reconstruct the lightning channel-base current starting from the measurement of the induction field generated by it is presented. The procedure is based on a suitable mathematical manipulation of the equation expressing the induction field in the time domain, in order to transform it into a Volterra-like integral equation. Such kind of equations can be easily numerically solved without resorting to any sort of regularization techniques as they are not affected by the typical ill-conditioning of the inverse problems. The developed algorithm has been validated by means of several numerical simulations, which have shown its effectiveness also in presence of measurement noise on the induction field values.

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