Vertical electric field inside the lightning channel and the channel-core conductivity during discharge – Comparison of different return stroke models

2014 ◽  
Vol 113 ◽  
pp. 30-40 ◽  
Author(s):  
Dragan Pavlovic ◽  
Jovan Cvetic ◽  
Fridolin Heidler ◽  
Radivoje Djuric
Keyword(s):  
Electric Field ◽  
Return Stroke ◽  
Lightning Channel ◽  
Vertical Electric Field ◽  
Stroke Models

scholarly journals Evaluation of Horizontal Electric Field from the Lightning Channel by Electromagnetic Field Equations of Moving Charges

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Yunfeng Zhang ◽  
Erchun Zhang ◽  
Jialiang Gu
Keyword(s):  
Electromagnetic Field ◽  
Electric Field ◽  
Finite Conductivity ◽  
Lightning Flash ◽  
Horizontal Distance ◽  
Field Equations ◽  
Long Distance ◽  
Return Stroke ◽  
Lightning Channel ◽  
Soil Conductivity

The horizontal electric field from the lightning return-stroke channel is evaluated by the electromagnetic field equations of moving charges in this paper. When a lightning flash strikes the ground, the charges move upward the lightning channel at the return-stroke speed, thereby producing the electromagnetic fields. According to the electromagnetic field equations of moving charges, the detained charges, uniformly moving charges, and decelerating (or accelerating) charges in each segment of the channel generate electrostatic fields, velocity fields, and radiation fields, respectively. The horizontal component of the sum is the horizontal electric field over the perfectly conducting ground. For the real soil with finite conductivity, the Wait formula is used here for the evaluation of the horizontal electric field over the realistic soil. The proposed method can avoid the oscillation of the fields in the long distance by the FDTD method and the singularity problem of the integral equation by the Sommerfeld integral method. The influences of the return-stroke speed, distance, and soil conductivity on the horizontal electric field are also analyzed by the proposed method. The conclusions can be drawn that the horizontal electric field decreases with the increasing of the return-stroke speed; the negative offset increases with the increasing of horizontal distance and with the decreasing of the soil conductivity, thereby forming the bipolar waveform. These conclusions will be practically valuable for the protection of lightning-induced overvoltage on the transmission lines.

Corona current concept in lightning return-stroke models of engineering type

2010 ◽  
Vol 59 (3-4) ◽  
pp. 177-188
Author(s):  
Grzegorz Masłowski
Keyword(s):  
Lightning Discharge ◽  
Current Source ◽  
Current Concept ◽  
Relaxation Model ◽  
Charge Motion ◽  
Return Stroke ◽  
Corona Current ◽  
Lightning Channel ◽  
Stroke Models

Corona current concept in lightning return-stroke models of engineering typeA role of radial corona current in a lightning discharge is discussed in the paper. It is shown that the corona current concept previously introduced by Cooray for lightning return stroke models of distributed-current-source (DCS) type, and later, by Maslowski and Rakov for lumped-current-source (LCS) type models enables to show duality between these two types of models. Further, it is demonstrated that the corona current is useful during consideration of dynamics of the lightning-channel corona sheath. As an example of application of presented approach a relaxation model of charge motion in the corona sheath is analysed together with plots which show the rate of expansion and shrinkage of the lightning corona sheath on both microsecond and millisecond time scales.

Effects of Lightning Current and Ground Conductivity on the Values of Vertical Electric Fields

2013 ◽  
Vol 64 (4) ◽  
Author(s):  
M. Izadi ◽  
M. Z. A. Ab Kadir ◽  
M. Hajikhani ◽  
N. Rameli
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Lightning Current ◽  
Lightning Channel ◽  
Vertical Electric Field ◽  
The Relationship ◽  
Ground Conductivity

In this paper, the relationship between current front time and front time of vertical electric field due to lightning channel at non perfect ground is considered. Results showed that the peak of simulated vertical electric fields under non perfect ground conductivity condition is decreased compared to the corresponding field at perfect ground while the front time of field is increased at non perfect case compared to the perfect one. Likewise, the effect of ground conductivity on the peak and front time of simulated vertical electric field is considered and the results are discussed accordingly.

The Effect of Direct Lightning Shielding Rod on Lightning Electromagnetic Fields Aboveground

Frequenz ◽  
2017 ◽  
Vol 71 (5-6) ◽  
Author(s):  
Ya-Peng Fu ◽  
Cheng Gao ◽  
Bo Yang
Keyword(s):  
Electric Field ◽  
Electromagnetic Fields ◽  
Fdtd Method ◽  
Shielding Effect ◽  
Azimuthal Magnetic Field ◽  
Lightning Channel ◽  
Vertical Electric Field ◽  
New Type ◽  
Difference Time ◽  
Ground Conductivity

AbstractA practical new type direct lightning shielding rod is designed to reduce the electromagnetic radiation produced by lightning stroking to Franklin lightning rod in the paper. The Finite-Difference Time-Domain (FDTD) method is adopted for analyzing. It is the shielding layer that affects the electromagnetic fields and the insulating medium make no difference. All the electromagnetic fields amplitude obtained decrease for the shielding layer existing, regardless of any condition, but the extent is different. That is, the effect on the horizontal electric field is most noticeable, the vertical electric field comes second, minimum the azimuthal magnetic field. All the field components are affected by shielding layer height and the distance between shielding layer and lightning channel, but not significantly by the shielding layer grounding depth. The shielding effect is more obvious with lower ground conductivity, but the ground relative permittivity makes no difference.

scholarly journals Focused Patterning of Electrospun Nanofibers Using a Dielectric Guide Structure

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1505
Author(s):  
Byeongjun Lee ◽  
Younghyeon Song ◽  
Chan Park ◽  
Jungmin Kim ◽  
Jeongbeom Kang ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Finite Elements ◽  
Electric Field ◽  
Electrospun Nanofibers ◽  
Electrospun Fibers ◽  
Continuous Line ◽  
Key Factors ◽  
Key Technology ◽  
Vertical Electric Field ◽  
Dielectric Guide

The patterning of electrospun fibers is a key technology applicable to various fields. This study reports a novel focused patterning method for electrospun nanofibers that uses a cylindrical dielectric guide. The finite elements method (FEM) was used to analyze the electric field focusing phenomenon and ground its explanation in established theory. The horizontal and vertical electric field strengths in the simulation are shown to be key factors in determining the spatial distribution of nanofibers. The experimental results demonstrate a relationship between the size of the cylindrical dielectric guide and that of the electrospun area accumulated in the collector. By concentrating the electric field, we were able to fabricate a pattern of less than 6 mm. The demonstration of continuous line and square patterning shows that the electrospun area can be well controlled. This novel patterning method can be used in a variety of applications, such as sensors, biomedical devices, batteries, and composites.

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