The Effect of Frequency Dependence of Soil Electrical Parameters on the Lightning Performance of Grounding Systems

Akbari, Mohsen; Sheshyekani, Keyhan; Alemi, Mohamad Reza

doi:10.1109/temc.2012.2222416

Cited by 106 publications

(38 citation statements)

References 16 publications

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“…such as stratified and mixed path (e.g., [6]- [15]), frequencydependent ground parameters (e.g., [16] and [17]), and more recently orography were also studied (e.g., [18]- [22]). …”

mentioning

confidence: 99%

On Lightning Electromagnetic Field Propagation Along an Irregular Terrain

Azadifar

Rachidi

et al. 2016

IEEE Trans. Electromagn. Compat.

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Abstract-In this paper, we present a theoretical analysis of the propagation effects of lightning electromagnetic fields over a mountainous terrain. The analysis is supported by experimental observations consisting of simultaneous records of lightning currents and electric fields associated with upward negative lightning flashes to the instrumented Säntis tower in Switzerland. The propagation of lightning electromagnetic fields along the mountainous region around the Säntis tower is simulated using a full-wave approach based on the finite-difference time-domain method and using the two-dimensional topographic map along the direct path between the tower and the field measurement station located at about 15 km from the tower. We show that, considering the real irregular terrain between the Säntis tower and the field measurement station, both the waveshape and amplitude of the simulated electric fields associated with return strokes and fast initial continuous current pulses are in excellent agreement with the measured waveforms. On the other hand, the assumption of a flat ground results in a significant underestimation of the peak electric field. Finally, we discuss the sensitivity of the obtained results to the assumed values for the return stroke speed and the ground conductivity, the adopted return stroke model, as well as the presence of the building on which the sensors were located.

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“…such as stratified and mixed path (e.g., [6]- [15]), frequencydependent ground parameters (e.g., [16] and [17]), and more recently orography were also studied (e.g., [18]- [22]). …”

mentioning

confidence: 99%

On Lightning Electromagnetic Field Propagation Along an Irregular Terrain

Azadifar

Rachidi

et al. 2016

IEEE Trans. Electromagn. Compat.

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“…Later, from the application of the new methodology to determine this frequency dependence (described in [5]), expressions for predicting it based on field measurements were developed [6]. Using these expressions, the impact of this effect on the lightning response of different arrangements of electrodes was assessed by simulation, considering horizontal and vertical grounding electrodes [7], [8] and small [8] and large [9] grids. The theoretical background of this effect is addressed in a recent work [17], which develops a new causal model to predict the frequency dependence of soil parameters from the measured low-frequency resistivity, taking uncertainties and the dispersion of soil behavior into account.…”

Section: Frequency Dependence Of Soil Resistivity and Permittivitymentioning

confidence: 99%

The Impact of the Frequency Dependence of Soil Parameters on the Lightning Performance of Transmission Lines

Visacro

Silveira

2015

IEEE Trans. Electromagn. Compat.

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This study assesses the lightning performance of 230-and 138-kV transmission lines under the assumptions of constant and frequency-dependent soil parameters. An electromagnetic model was used to simulate the response of tower-footing electrodes and overvoltages across insulators due to direct lightning strikes to the line, considering representative lightning current waveforms. Backflashover rates were determined using the Disruptive Effect Model. It was found that the decrease of soil resistivity and permittivity, resulting from the frequencydependence effect, is responsible for significant decrease of the expected outage rate of the tested lines, in the range of 13-32% for usual distributions of soil resistivity along the lines.Index Terms-Backflashover rate, frequency dependence of electric parameters of soil, lightning, transmission lines.

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“…To this aim, transient voltage of the grounding systems (defined as the voltage of point of the injected current to a point at infinite) should be first correctly computed. Hence, to compute this quantity a number of numerical approaches in time domain, frequency domain, and mixed time‐frequency domain have been proposed . In only‐ionized soils, time domain approaches are usually preferable, whereas in only‐dispersive soils, the frequency‐domain techniques are more appealing .…”

Section: Introductionmentioning

confidence: 99%

“…Hence, to compute this quantity a number of numerical approaches in time domain, frequency domain, and mixed time‐frequency domain have been proposed . In only‐ionized soils, time domain approaches are usually preferable, whereas in only‐dispersive soils, the frequency‐domain techniques are more appealing . To consider two effects simultaneously, frequency domain approaches in combining with circuit theory have been proposed.…”

Section: Introductionmentioning

confidence: 99%

Comprehensive formulae for effective length of multiple grounding electrodes considering different aspects of soils: Simplified multiconductor transmission line‐intelligent water drop approach

Sajjadi

Aghajani

Ostadzadeh

2020

Int J Numerical Modelling

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In this paper, an approximate modeling approach called simplified multiconductor transmission line model (simplified MTL) is proposed for transient analyses of multiple grounding electrodes. Since this approach is in the frequency domain, the effect of soil dispersion (frequency variation of soil electrical parameters) is easily incorporated. In addition, the soil ionization effect is treated as gradually increasing radius of the electrode. With the use of this approach, predicting formulae for effective length of multiple grounding electrodes considering both ionization and dispersion are proposed for the first time. Finally, combining the extracted formulae with the apparent resistivity in two‐layer soils, effective length in such soils is easily predicted.

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The Effect of Frequency Dependence of Soil Electrical Parameters on the Lightning Performance of Grounding Systems

Cited by 106 publications

References 16 publications

On Lightning Electromagnetic Field Propagation Along an Irregular Terrain

On Lightning Electromagnetic Field Propagation Along an Irregular Terrain

The Impact of the Frequency Dependence of Soil Parameters on the Lightning Performance of Transmission Lines

Comprehensive formulae for effective length of multiple grounding electrodes considering different aspects of soils: Simplified multiconductor transmission line‐intelligent water drop approach

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