Grounding systems under lightning surges with soil ionization for high voltage substations by using two layer capacitors (TLC) model

Ghania, Samy M.

doi:10.1016/j.epsr.2019.105871

Cited by 14 publications

(6 citation statements)

References 16 publications

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“…The power frequency grounding simulation test is based on the similarity three theorems deduced by the Laplace equation [6].…”

Section: Power Frequency Grounding Complete Similar Modelmentioning

confidence: 99%

“…According to grounding grid prototype, a small grounding grid model is constructed, and the measurement data of small grounding grid is used to infer the parameters of grounding grid prototype. It can conveniently change the topological structure of grounding grid and accurately control the test parameters; therefore, grounding simulation tests have received extensive attention in grounding research field [6]. Around the 1940s, the modeling method based on similarity theory was widely used in natural science fields such as aviation, water transport, solid mechanics, electromagnetics and meteorology, providing a reliable and effective theoretical analysis method for engineering research.…”

Section: Introductionmentioning

confidence: 99%

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RETRACTED ARTICLE: Structure optimization and preparation of power system grounding grid based on similarity data analysis algorithm

Huang

Jeon

et al. 2022

Int J Adv Manuf Technol

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The grounding grid of power equipment is the most basic overvoltage protection device for the power system. Before the design and construction of the power grounding grid, the power system generally uses a scaled-down model to verify the characteristics of the grounding grid. As the types and structures of grounding materials become more and more complex, there are one or more similar items in the grounding simulation test that cannot be scaled down. This paper takes the similarity test of a new type of grounding material-flexible graphite composite grounding material as an example. Firstly, the complete similarity theory of grounding simulation test is deduced. Secondly, the source of similar distortion items is analyzed. Then, the distortion error of different similar items is analyzed. Finally, the distortion similarity test of the flexible graphite composite grounding material is taken as an example to verify the test error influence of the distortion similarity item of the grounding simulation. The research results of this paper can provide reference for grounding simulation test, and at the same time, it can be applied to similar tests in other fields.

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“…The power frequency grounding simulation test is based on the similarity three theorems deduced by the Laplace equation [6].…”

Section: Power Frequency Grounding Complete Similar Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

RETRACTED ARTICLE: Structure optimization and preparation of power system grounding grid based on similarity data analysis algorithm

Huang

Jeon

et al. 2022

Int J Adv Manuf Technol

View full text Add to dashboard Cite

show abstract

“…However, soil is a typical porous medium composed of soil particles, air voids between particles and liquid water (Hallikainen et al, 1985). The breakdown inside the air voids is what initiates the soil ionization (Ghania, 2019). Meanwhile, the porosity may determine the proportion of air and water in the soil.…”

Section: Introductionmentioning

confidence: 99%

Influences of Soil Water Content and Porosity on Lightning Electromagnetic Fields and Lightning-Induced Voltages on Overhead Lines

Liu

Jiang

Gao

et al. 2022

Front. Environ. Sci.

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This study is performed to analyze the effects of both soil water content and porosity, two of the influencing factors of the finite conductivity, on the propagation of lightning electromagnetic fields (LEMFs) and lightning-induced voltages (LIVs) on overhead lines. A two-dimensional finite difference time domain (FDTD) model together with an improved Archie’s soil model is adopted for the field calculation at close distances from the lightning channel. The obtained results confirm that the soil water content and porosity have notable impacts on the peak values of LEMFs, especially the horizontal electric field. Moreover, the soil water content and porosity are correlated when acting together. The peak values of the horizontal electric field are found to be markedly influenced by the porosity changes at high water content or the water content changes at low porosity. The LIVs on overhead lines in these two cases are also studied. There appear to be greater differences in the induced voltages as the water content changes at low porosity.

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“…Therefore, in MV networks, for the sake of providing better protection for the transformers against external overvoltage surges, as well as due to safety requirements, the transformer poles are grounded. Direct lightning imposes a very high current that, in grounded poles, goes toward the ground and may cause soil ionization as a result of a breakdown inside the air voids existing among the soil particles [23]. Soil ionization results in decreasing the earthing resistance [24], i.e., under the ionization condition, the resistance is varied by the current.…”

Section: Introductionmentioning

confidence: 99%

Optimized Protection of Pole-Mounted Distribution Transformers against Direct Lightning Strikes

2020

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Direct lightning strikes on overhead phase conductors result in high overvoltage stress on the medium voltage (MV) terminals of pole-mounted transformers, which may cause considerable damage. Therefore, introducing an efficient protection strategy would be a remedy for alleviating such undesirable damages. This paper investigates the optimized protection of MV transformers against direct lightning strikes on the phase conductors. To this end, first, the impacts of grounding densities (number of grounded intermediate poles between every two successive transformer poles) on the probability of overvoltage stress on transformer terminals are investigated. Then, the implications of guy wire, as a supporting device for ungrounded intermediate poles, on reducing the overvoltage stress on transformers, are studied. Finally, the role of a surge arrester in mitigating the overvoltage stress of non-surge-arrester-protected transformer poles is scrutinized. The investigations are conducted on a sample MV network with 82 wood poles comprising 17 pole-mounted transformers protected by spark gaps. To provide in-depth analysis, two different poles, namely creosote- and arsenic-impregnated poles, are considered under wet and dry weather conditions. A sensitivity analysis is performed on grounding distances and on a combination of guy wire and grounded intermediate poles while taking into account soil ionization. The results provide a clear picture for the system operator in deciding how many grounded intermediate poles might be required for a system to reach the desired probabilities of transformers experiencing overvoltage stress and how the surge arrester and guy wires contribute to mitigating undesirable overvoltage stress.

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Grounding systems under lightning surges with soil ionization for high voltage substations by using two layer capacitors (TLC) model

Cited by 14 publications

References 16 publications

RETRACTED ARTICLE: Structure optimization and preparation of power system grounding grid based on similarity data analysis algorithm

RETRACTED ARTICLE: Structure optimization and preparation of power system grounding grid based on similarity data analysis algorithm

Influences of Soil Water Content and Porosity on Lightning Electromagnetic Fields and Lightning-Induced Voltages on Overhead Lines

Optimized Protection of Pole-Mounted Distribution Transformers against Direct Lightning Strikes

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