Measurements of grounding resistances for high impulse currents

Sekioka, Shozo; Hayashida, Hiroshi; Hara, Takehisa; Ametani, Akihiro

doi:10.1049/ip-gtd:19982009

Cited by 52 publications

(33 citation statements)

References 2 publications

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“…It is worth noting that above quantities are traditionally coined as "impedances" [2], [22], or as "resistances" [9], [14], [43], often with quite different definitions, for example: -where is current at the time of voltage peak in [16]; -where is voltage at the time of current peak in [9]; -where and are measured at in [56]. In addition the harmonic impedance is very useful in transient analysis [11], [28].…”

Section: Quantities That Characterize the Dynamic Behavior Of Grmentioning

confidence: 99%

“…More recent work is summarized in the books [9] and [10]. There is a lack of carefully documented experimental work of which noteworthy examples are [11]- [14]. Recently computerized analysis methods have been developed based on different approaches, for example, on circuit theory [15]- [19], transmission line theory [21]- [27], electromagnetic field theory [28]- [37], and hybrid methods [38]- [40].…”

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confidence: 99%

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Impulse Efficiency of Ground Electrodes

Grcev

2009

IEEE Trans. Power Delivery

156

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Abstract-The lightning current waveform has a major influence on the dynamic performance of ground electrodes. While high lightning current intensity improves the dynamic grounding performance due to ionization of the soil, very fast fronted pulses might worsen the performance in case of inductive behavior. The previous analysis has often been based on quasistatic approximation that is not applicable to very fast fronted pulses. To extend the analysis to fast fronted pulses in this paper, the full-wave analysis method based on the rigorous electromagnetic-field theory approach is used. In addition, realistic lightning current waveforms are applied, which reproduce the observed concave rising portion of typical recorded lightning current pulses. Based on the simulation results, new empirical formulas applicable for slow and very fast fronted lightning current pulses are proposed. The effects of the ionization of the soil are disregarded; therefore, the new formulas are applicable for a conservative estimate of the upper bound of the impulse impedance of ground electrodes.

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Section: Quantities That Characterize the Dynamic Behavior Of Grmentioning

confidence: 99%

mentioning

confidence: 99%

Impulse Efficiency of Ground Electrodes

Grcev

2009

IEEE Trans. Power Delivery

156

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“…with substitutions p = s,Ā p = 1 in the case of Equation (15). The quantityĀ p in Equations (17), (19), (21) and (23) represents accumulated transmission factor between the s-th and the p-th medium model layers, while quantitiesF p−1 ,F p ,F s−1 andF s represent associated reflection factors [11].…”

Section: System Of Linear Equations For Transversal Segment Currentsmentioning

confidence: 99%

“…It needs to be stated that contrary to the vast number of simulation oriented papers, there is a great deficiency of carefully documented papers concerned with experimental works on transient grounding grid behavior. Noteworthy exemptions to this rule are given in, e.g., [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Time-Harmonic Current Distribution on Conductor Grid in Horizontally Stratified Multilayer Medium

Sarajčev¹,

Vujević²,

Lovrić³

2011

PIER B

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Abstract-This paper presents a novel time-harmonic electromagnetic model for determining the current distribution on conductor grids in horizontally stratified multilayer medium. This model could be seen as a basis of the wider electromagnetic model for the frequency-domain transient analysis of conductor grids in multilayer medium. The total number of layers and the total number of conductors are completely arbitrary. The model is based on applying the finite element technique to an integral equation formulation. Each conductor is subdivided into segments with satisfying the thin-wire approximation. Complete electromagnetic coupling between segments is taken into account. The computation of Sommerfeld integrals is avoided through an effective approximation of the attenuation and phase shift effects. Computation procedure for the horizontally stratified multilayer medium is based on the successful application of numerical approximations of two kernel functions of the integral expression for the potential distribution within a single layer, which is caused by a point source of time-harmonic current. Extension from the point source to a segment of the earthing grid conductors is accomplished through integrating the potential contribution due to the line of time-harmonic current source along the segments axis.

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“…Several investigations related to the impulse characteristics of tower grounding and concentrated ground electrodes have been reported in the literature [1][2][3][4][5][6]. Of the parameters characterising the impulse behaviour of grounding systems, the impulse resistance is of most significance; it is dependent on electrode geometry, earth resistivity, peak value and rate of rise of impulse current.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of Impulse Characteristics of Transmission Line Tower Footings

Harid¹

2012

JLR

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Abstract:Understanding the impulse response of tower grounding systems is a key factor in the determination of the lightning performance of transmission lines and the safety voltages near high voltage towers. This paper reports the results of an experimental study on the impulse characteristics of full-scale transmission line tower footings. The ground potential distribution both at the ground surface and below ground was examined under impulse currents and variable-frequency AC currents. Prospective impulse step and touch voltages were determined by measurement of the ground surface potential distribution near the tower base. The behaviour of the impulse resistance of the tower footings under highmagnitude impulse currents was investigated. The non-linear characteristics of the impulse resistance with peak current are demonstrated for the entire tower base and for single tower footings. The soil ionisation inception is found to be dependent on the rate of rise of applied current. The dynamic impulse resistance was used to describe the dynamics of soil ionisation.

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Measurements of grounding resistances for high impulse currents

Cited by 52 publications

References 2 publications

Impulse Efficiency of Ground Electrodes

Impulse Efficiency of Ground Electrodes

Time-Harmonic Current Distribution on Conductor Grid in Horizontally Stratified Multilayer Medium

Experimental Investigation of Impulse Characteristics of Transmission Line Tower Footings

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