Lightning Impulse Performances of Grounding Grids for Substations Considering Soil Ionization

Purpose The purpose of this paper is to propose a fast, accurate and efficient algorithm for assessment of transient behavior of grounding grids buried in horizontal multilayered earth model considering soil ionization effect. Design/methodology/approach The purpose of this paper is to develop a numerical simulation method to calculate the lightning impulse response of the grounding grid buried in a horizontal multilayered earth model. The mathematical model about the hybrid method based on PI basic function belonging to time domain is proposed in the paper; the mode can precisely calculate the lightning current distribution and lightning impulse response to grounding grids buried in horizontal multilayered soil model considering soil ionization effect. To increase computing efficiency, quasi-static complex image method (QSCIM) and its time-domain Green’s function closed form are introduced in the model. Findings The hybrid model is rather stable, with the respect to the number of elements used and with excellent convergence rate. In addition, because this mathematical model belongs to the time domain algorithm, it is very powerful for the simulation of soil ionization caused by high amplitude lightning current. Research limitations/implications To increase computing efficiency, QSCIM and its time domain Green's function closed form are introduced in the model. Practical implications The mathematical model about the hybrid method based on PI basic function can precisely calculate the lightning current distribution and lightning impulse response to grounding grids buried in horizontal multilayered soil model considering the soil ionization effect. Social implications Considering the soil ionization effect, the simulation calculation of lightning impulse response of substation grounding grid buried in the actual horizontal multilayered earth can effectively support the scientific and efficient design of lightning protection performance of substation grounding grid. Originality/value The hybrid model in time domain is originally developed by the authors and used to precisely calculate the lightning current distribution and lightning impulse response to grounding grids buried in horizontal multilayered soil model considering soil ionization effect. It is simple and very efficient and can easily be extended to arbitrary grounding configurations.

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A Transmission Line Modeling (TLM) Algorithm to Evaluate Grounding Grids Including Soil Ionization

2020 IEEE International Conference on Environment and Electrical Engineering and 2020 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe) ◽

10.1109/eeeic/icpseurope49358.2020.9160774 ◽

2020 ◽

Author(s):

Daniel S. Gazzana ◽

Alex B. Tronchoni ◽

Arturo S. Bretas ◽

Lucas T. C. Pulz ◽

Renato G. Ferraz ◽

...

Keyword(s):

Transmission Line ◽

Transmission Line Modeling ◽

Grounding Grids ◽

Soil Ionization

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Transient impedance of grounding system with impulse superimposed sinewave

ENP Engineering Science Journal ◽

10.53907/enpesj.v1i1.7 ◽

2021 ◽

Vol 1 (1) ◽

pp. 8-12

Author(s):

Sherif Ghoneim ◽

Ahdab Elmorshedy ◽

Rabah Amer

Keyword(s):

System Configuration ◽

System Operation ◽

Grounding System ◽

Several Variables ◽

Wire Conductor ◽

Lightning Impulse ◽

In Series ◽

Grid Side ◽

Soil Ionization ◽

Impulse Current

Investigating the transient performance of grounding systems subject to lightning (impulse or impulse superimposed sinewave) is valuable for protecting the power system and maintaining the system operation. In this work, the grounding system's impedance is computed when an impulse superimposed sinewave is applied to the grounding grid's proposed lumped circuit and grounding system can be simulated as an inductance in series with resistance, and all of them are in parallel with capacitance based on Thione's assumption. Several variables were investigated to study their effects on the grounding system's behavior. The variables were the soil resistivity, soil permittivity, main wire length, grid conductor radius, grid side length, grid configurationand its mesh number. The grounding system configuration varied between square and rectangular shapes, which connects to the protecting rod via the main wire conductor. A 3.69 kA peak of impulse current was applied to avoid soil ionization. The results indicated the performance of the grounding system when subjecting to impulse current.

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Soil ionization in different types of grounding grids simulated by FDTD method

2009 SBMO/IEEE MTT-S International Microwave and Optoelectronics Conference (IMOC) ◽

10.1109/imoc.2009.5427615 ◽

2009 ◽

Cited By ~ 1

Author(s):

Thais L. T. dos Santos ◽

Rodrigo M. S. de Oliveira ◽

Carlos Leonidas da S. S. Sobrinho ◽

Jose F. Almeida

Keyword(s):

Fdtd Method ◽

Different Types ◽

Grounding Grids ◽

Soil Ionization

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Grounding System Modeling and Evaluation Using Integrated Circuit Based Fast Relaxed Vector Fitting Approach, Considering Soil Ionization

Applied Sciences ◽

10.3390/app10165632 ◽

2020 ◽

Vol 10 (16) ◽

pp. 5632

Author(s):

Maziyar Fakhraei ◽

Mehrdad Mahmoudian ◽

Eduardo Manuel Godinho Rodrigues

Keyword(s):

Integrated Circuit ◽

System Modeling ◽

Model Verification ◽

Lightning Strikes ◽

Grounding System ◽

Vector Fitting ◽

Grounding Grids ◽

Electro Magnetic ◽

Soil Ionization ◽

System Frequency

Since high voltage transmission line towers or wind turbines structures are installed in high-altitude areas, it is essential to achieve a high overvoltage protection system against direct and indirect lightning strikes collisions. The lightning current must be discharged quickly into the protective earth, to prevent the dangerous over-voltages formation and define a reference voltage node. This paper presents a novel model to assess the behavior of the grounding system, based on Pocklington integral equations under lightning magnetic fields and variations in soil ionization, in which an explicit circuit-based vector fitting RLC admittance branches are proposed. The frequency-dependent behavior of grounding system frequency response and soil ionization effect is modeled in time domain, straightly to implement into the electro-magnetic transient program (EMTP). The model verification contains horizontal, vertical, and their combinations of grounding grids to represent the complete investigations under lightning strikes. The harmonic impedance mathematical formulations and principles are derived based on a rational function, that could be applicable on ground potential rise (GPR) investigation.

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