Assessment of Step and Touch Voltages for Different Multilayer Soil Models of Complex Grounding Grid

Nikolovski, Srete; Knežević, Goran; Baus, Zoran

doi:10.11591/ijece.v6i4.10637

Cited by 7 publications

(6 citation statements)

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“…In case of uniform soil, when the depth of a grounding grid increases, the ground resistance decreases but for non-uniform soil or multilayer soil, this is not always true, even if the change of grounding grid depth is confined within one layer. Generally, the grounding resistance values are greatly dependent on the layer in which the grounding grid is located [24][25][26][27]. When it is located in a layer has low resistivity, the grounding resistance is low, while when it is located in a layer has high resistivity, the grounding resistance is high.…”

Section: Effect Of Soil Profile To the Maximum Transient Gpr Touch Voltage And Step Voltagementioning

confidence: 99%

Effects of Soil Profile on the Transient Performance of Substation Grounding System

Malek

Yaman

Adnan

2020

IJEECS

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<table width="593" border="1" cellspacing="0" cellpadding="0"><tbody><tr><td valign="top" width="387"><p>Lightning transient characteristic of the grounding grid is fundamental for optimum performance of lightning protection of a substation. In order to design an appropriate grounding system for such substation, it is important to study its transient characteristics because the high impulse current is significantly different compared to power frequency current. In this paper, substation grounding grid model was developed using CDEGS software to analyze the grid transient performance in terms of ground potential rise (GPR), touch voltage and step voltage when the grounding system is struck by a lightning impulse current. Several parameters, such as lightning current amplitude, feed point and the number of sub-grids, were altered to study their relationship with the transient performance. The maximum transient GPR, touch voltage, and step voltage increase as the lightning current amplitude increase. The maximum transient GPR and step voltage are the highest at the corner of the grounding grid while the maximum touch voltage is the highest at the centre of the grounding grid. In addition, the maximum transient GPR and step voltage decrease when the number of sub-grid increases. In contrast, the touch voltage slightly increases as the number of sub-grid increases. The maximum transient GPR, and step voltage are the highest at the 2-layer and the lowest at the uniform soil or single-layer soil.</p></td></tr></tbody></table>

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Section: Effect Of Soil Profile To the Maximum Transient Gpr Touch Voltage And Step Voltagementioning

confidence: 99%

Effects of Soil Profile on the Transient Performance of Substation Grounding System

Malek

Yaman

Adnan

2020

IJEECS

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“…Having such a procedure not only means a considerable economic saving given the cost of direct measurement on the ground but also a considerable simplification when the step potentials must be estimated in urban areas where direct measurement is often difficult. From decades, many authors have spent great efforts to propose calculation methods for step potentials, from the exclusive use of approximate analytical formulas [4,5] to using complex numerical techniques [6], while they were measured in the field by using various strategies [7,8]. However, none of the methods known to the authors of this paper is as simple and quick to apply as the one proposed here [9].…”

Section: Introductionmentioning

confidence: 99%

Estimation of an Upper Bound to the Value of the Step Potentials in Two-Layered Soils from Grounding Resistance Measurements

Moreno

Simón²,

Faleiro

et al. 2020

Materials

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Due to the constant updating of regulatory standards on safety issues in electrical installations, limits are established for the maximum step potential that an installation can hold in a ground fault situation. In this paper, an upper bound to the maximum value of the step potentials arising in the soil surface when a fault takes place in a grounded electrical installation is estimated by means of a simple procedure. The direct measurement of the grounding electrode resistance together with some information about the soil resistivity and the knowledge of characteristic parameters of the electrode are used for the calculation of that upper bound. The procedure is tested at numerical simulation level by using different electrodes in several different scenarios corresponding to two-layered soils with different resistivity ratios. The dependency of the calculated upper bound with the electrode burial depth is also studied. Finally, a real case study is presented, and the results of the field measurements are shown as an example of the validity of the procedure.

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“…The soil characteristics in which the grid will be buried must be reviewed and evaluated when planning an efficient and safe grounding grid system. The substation grounding grid configuration is vital in ensuring the grounding system's safety, which is highly dependent on the soil characteristics in which the grounding system will be installed (IEEE 80, 2013;Gursu & Cevdet, 2019;Moradi, 2020;Nikolovski et al, 2016;Pavel et al, 2020;Sing et al, 2013;Vyas & Jamnani, 2012). Soil resistivity varies greatly depending on the earth's geological structure (Coelho et al, 2018;Nassereddine et al, 2010;Ma & Dawalibi, 2009;Tung & Lim, 2017;Vycital et al, 2017;Yang & Zou, 2020).…”

Section: Introductionmentioning

confidence: 99%

Assessment of the Grid Safety Values for Substation Grounding Grid Design Parameters in Vertical Two-Layer Soil Structure

Permal¹,

Osman²,

Ariffin³

et al. 2022

JST

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Typically, the impact of the structure of vertically layered soil on the grounding behavior is not considered while designing a substation grounding system. Therefore, it will result in poor grounding designs due to computed inaccurate grid safety values. Besides, no comparative analysis of the grounding design parameters’ impact on the grounding grid systems’ behavior and protection level between vertical and horizontal two-layer soil structures is presently available. Computing and analyzing the grounding behavior of apparent soil resistivity installed in a vertical two-layer soil structure is more challenging than in a horizontal two-layer soil. There are many other parameters to consider, such as the distance ‘a’ between the test electrodes and the angle ‘β’ between the perpendicular line to the soil boundary and the location of the test electrodes. One of the important findings of the assessment shows that the influence of vertically layered soil on grid impedance, step, and touch voltages of a grounding system is insignificant compared to a homogeneous and horizontally layered soil structure. The current flow is affected by an entire grounding grid placed in a specified layer of soil with a specific resistivity for horizontally layered soil. In contrast, soil boundaries separate a grounding grid with various resistivities for vertically layered soil. The outcome of this work is crucial in helping the engineers to understand the behavior of grounding systems in diverse soil conditions and tropical climates.

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Assessment of Step and Touch Voltages for Different Multilayer Soil Models of Complex Grounding Grid

Cited by 7 publications

References 0 publications

Effects of Soil Profile on the Transient Performance of Substation Grounding System

Effects of Soil Profile on the Transient Performance of Substation Grounding System

Estimation of an Upper Bound to the Value of the Step Potentials in Two-Layered Soils from Grounding Resistance Measurements

Assessment of the Grid Safety Values for Substation Grounding Grid Design Parameters in Vertical Two-Layer Soil Structure

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