scholarly journals Calculation of Grounding Grids Parameter at Arbitrary Geometry

2017 ◽  
Vol 2 (2) ◽  
pp. 11
Author(s):  
Carlos L. B. Silva ◽  
Thyago G. Pires ◽  
Wesley P. Calixto ◽  
Diogo N. Oliveira ◽  
Luis A. P. Souza ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Computer Program ◽  
Arbitrary Geometry ◽  
Resistance Surface ◽  
Ground Resistance ◽  
Step Voltage ◽  
Grounding Grid ◽  
Grounding Grids ◽  
Homogeneous Soil ◽  
Touch Voltage

This paper deals with the computation of ground resistance, surface voltage, touch voltage and step voltage, to mesh with horizontal wires arranged in different angles. The computer program implemented used in the mathematical modeling is based on the method proposed by Heppe, which allows obtaining the grounding parameters for homogeneous soil and soil stratified in two layers. The results obtained with the proposed method will be compared with other methods in literature. Also will be presented the results of a grounding grid using wires at various angles.

Step and Touch Voltages and Grounding Potential Rise (IEEE and IEC)

2018 ◽  
pp. 187-247
Keyword(s):  
Reduction Factor ◽  
Scaling Factor ◽  
Three Dimensions ◽  
Voltage Profile ◽  
Soil Resistivity ◽  
Step Voltage ◽  
Grounding Grids ◽  
Ieee Standards ◽  
Touch Voltage ◽  
Ground Potential

This chapter contains safety criteria according to IEEE Standards, step and touch voltage criteria, reduction factor, simplified equations for mesh and step voltage, application of step and mesh potential in safe earthing system design, safety criteria, IEC 479-1 STD, permissible touch and step voltage according to IEC 479-1, Optimum Compression Ratio (OCR), test and verify, approximated analysis to calculate voltage profile using apparent soil resistivity, Scaling factor, test and verify the approximated method—Ground Potential Rise (GPR) of faulty substations having equal and unequal spacing grounding grids conductors. This chapter draws attention also to the following points: Infinite Series Potential (I.S.M.) expressions in three dimensions and calculations of three dimensions potential rise.

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

2020 ◽  
Vol 20 (2) ◽  
pp. 870
Author(s):  
Zulkurnain Adul Malek ◽  
Mohammad Shahrin Affendy Yaman ◽  
Muhammad Adnan
Keyword(s):  
Single Layer ◽  
Current Amplitude ◽  
Transient Performance ◽  
Grounding System ◽  
Step Voltage ◽  
Lightning Current ◽  
Grounding Grid ◽  
Lightning Impulse ◽  
Touch Voltage ◽  
Impulse Current

<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>

scholarly journals Effect of Non-Homogeneous Soil Characteristics on Substation Grounding-Grid Performances: A Review

2021 ◽  
Vol 11 (16) ◽  
pp. 7468
Author(s):  
Navinesshani Permal ◽  
Miszaina Osman ◽  
Azrul Mohd Ariffin ◽  
Mohd Zainal Abidin Ab Kadir
Keyword(s):  
Soil Structure ◽  
System Analysis ◽  
Soil Characteristics ◽  
Design Parameters ◽  
Soil Conditions ◽  
Grounding System ◽  
Ground Resistance ◽  
Grounding Grid ◽  
Design Changes ◽  
Homogeneous Soil

Designing an effective grounding system for AC substations needs predetermination of ground resistance and ground potential distribution caused by fault current’s presence in the ground. Therefore, it is necessary to have a suitable grounding grid structure in the soil properties in which the grid is buried. Though the soil composition where the grounding grid is located is typically non-homogeneous, the soil is often presumed to be homogeneous due to the complexities of grounding system analysis in non-homogeneous soil. This assumption will lead to inaccuracies in the computation of ground resistance and ground potentials. Although extensive research has been done on non-homogeneous soil structure, comprehensive literature on grounding system performance in non-homogeneous soil is yet to be reviewed. Thus, this paper reviews the effect of non-homogeneous soil on the grounding system, with different soil characteristics in horizontal and vertical two-layer soil structure and the horizontal three-layer soil structure. In addition, the effect of design parameters on the grounding performance in non-homogeneous soil conditions for non-transient fault conditions is also studied. The significance of this study is that it provides a comprehensive review of grounding performance as grounding design changes and their effects as soil layers and their corresponding features change. This knowledge will be useful in developing safe grounding designs in non-homogeneous soil.

Influence of Driven Rods on Performance of Grounding Grids in Stratified Soils

2003 ◽  
Author(s):  
S. A. El-Drieny ◽  
I. A. Metwally ◽  
M. M. El-Saadawi
Keyword(s):  
Experimental Study ◽  
Soil Structure ◽  
Great Influence ◽  
Ground Resistance ◽  
Triple Layer ◽  
Grounding Grid ◽  
Scale Models ◽  
Grounding Grids ◽  
Mathematical Equations

The variation in soil structure has a great influence on the grounding grid performance. This influence can be measured in terms of ground resistance, touch and step potentials. This paper presents a comprehensive experimental study for the influence of adding driven rods on the performance of grounding grids. The study is applied on three constructed scale models. The models have been performed to simulate a single-, double- and triple-layer soils. A comparison between results obtained experimentally and that computed by mathematical equations is introduced.

scholarly journals Diagnosis for Conductor Breaks of Grounding Grids Based on the Wire Loop Method of the Transient Electromagnetic Method

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Shengbao Yu ◽  
Guanliang Dong ◽  
Nannan Liu ◽  
Xiyang Liu ◽  
Chang Xu ◽  
...  
Keyword(s):  
Topological Structure ◽  
Electromagnetic Response ◽  
Height Difference ◽  
Measuring Point ◽  
Wire Loop ◽  
Loop Method ◽  
Transient Electromagnetic ◽  
Grounding Grid ◽  
Grounding Grids ◽  
The Wire

The wire loop method of the transient electromagnetic (TEM) method is used to nondestructively detect conductor breaks of grounding grid. For this purpose, grounding grids serve as an underground wire loop, and the measuring points are arranged on the ground. At each measuring point, a receiving loop is employed to detect the electromagnetic response generated by transmitting the current of the transmitting loop. Conductor breaks can be diagnosed by analyzing the slices of the electromagnetic response. We study the effect of loop size and height difference through the simulation of an intact 2×2 grounding grid, confirming that it is easier to obtain the topological structure using a small transmitting loop and a small height difference. Furthermore, simulations of an intact 4×4 grounding grid and grids with different locations of conductor breaks are also conducted with a small transmitting loop. It is easy to distinguish the topological structure of the grounding grid and the locations of conductor breaks. Finally, the detection method is applied experimentally. The experimental results confirm that the proposed method is an effective technique for conductor break diagnosis.

scholarly journals Grounding System Cost Analysis Using Optimization Algorithms

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3484 ◽  
Author(s):  
Jau-Woei Perng ◽  
Yi-Chang Kuo ◽  
Shih-Pin Lu
Keyword(s):  
Human Body ◽  
Rbf Neural Network ◽  
Grounding System ◽  
Grounding Resistance ◽  
Grounding Grid ◽  
Engineering Costs ◽  
System Data ◽  
And Performance ◽  
Touch Voltage ◽  
Resistance Value

In this study, the concept of grounding systems is related to the voltage tolerance of the human body (human body voltage tolerance safety value). The maximum touch voltage target and grounding resistance values are calculated in order to compute the grounding resistance on the basis of system data. Typically, the grounding resistance value is inversely proportional to the laying depth of the grounding grid and the number of grounded copper rods. In other words, to improve the performance of the grounding system, either the layering depth of the grounding grid or the number of grounded copper rods should be increased, or both of them should be simultaneously increased. Better grounding resistance values result in increased engineering costs. There are numerous solutions for the grounding target value. Grounding systems are designed to find the combination of the layering depth of the grounding grid and the number of grounded copper rods by considering both cost and performance. In this study, we used a fuzzy algorithm on the genetic algorithm (GA), multi-objective particle swarm optimization (MOPSO) algorithm, Bees, IEEE Std. 80-2000, and Schwarz’s equation based on a power company’s substation grounding system data to optimize the grounding resistance performance and reduce system costs. The MOPSO algorithm returned optimal results. The radial basis function (RBF) neural network curve is obtained by the MOPSO algorithm with three variables (i.e., number of grounded copper rods, grounding resistance value, and grounding grid laying depth), and the simulation results of the electrical transient analysis program (ETAP) system are verified. This could be a future reference for substation designers and architects.

Surface Potential and Resistance of Grounding Grid Systems in Homogeneous Soil

2007 ◽  
Vol 35 (10) ◽  
pp. 1093-1109 ◽  
Author(s):  
M. Abdel-Salam ◽  
A. Ahmed ◽  
M. Nayel ◽  
Aboelsood Zidan
Keyword(s):  
Surface Potential ◽  
Grid Systems ◽  
Grounding Grid ◽  
Homogeneous Soil

Impacts of Diverting Potential Difference on Armored Cables in Substations

2014 ◽  
Vol 986-987 ◽  
pp. 931-935
Author(s):  
Li Chen
Keyword(s):  
Dielectric Breakdown ◽  
Simulation Software ◽  
Potential Difference ◽  
Insulation Material ◽  
Grid Simulation ◽  
Transient Electromagnetic ◽  
Grounding Grid ◽  
Large Current ◽  
Electrical Tree ◽  
Grounding Grids

To reduce the interference on communication equipments caused by transient electromagnetic field of switching operation, the shields of cables are connected to grounding grid on both sides in the substations grounding designs. However, when the substation is stroke by lightning or shorted, the huge potential difference called diverting potential difference between the cable core and the shield is generated, which can easily destroy insulation of cables, even producing electrical tree or dielectric breakdown in insulation material. Moreover, the large current flowing through the shield of cables will cause personnel accidents and equipment damages. In this paper, the electric model of cables is established using grounding grid simulation software—CEDGS. The way diverting potential difference changes influenced by grounding grids, soil and other parameters is analyzed. Measures to reduce diverting potential difference are proposed for providing a theoretical basis of construction in practice.

Mathematical modeling of aeration efficiency and dissolved oxygen provided by stepped cascade aeration

2011 ◽  
Vol 63 (1) ◽  
pp. 1-9 ◽  
Author(s):  
A. Khalifa ◽  
S. Bayoumi ◽  
O. El Monayeri
Keyword(s):  
Mathematical Modeling ◽  
Dissolved Oxygen ◽  
Computer Program ◽  
Environmental Engineering ◽  
Pollutant Load ◽  
Aeration Efficiency ◽  
Cascade Structure ◽  
Stepped Cascade ◽  
Different Levels

Mathematical modeling has been a vital tool in the field of environmental engineering. Various models have been developed to simulate the level of aeration efficiency (AE) provided by different aerating structures to raise levels of dissolved oxygen (DO) in streams; one of which is the stepped cascade structure. Three models developed by Gameson et al. WRL, and Nakasone, in addition to Qual2k, a computer program for stream modeling, have been used in this research; values of AEs obtained have been compared to those computed using DO measured from a built model at a WWTP. A stepped cascade structure was installed with different heights to aerate five flowrates with different levels of COD. An adjustment has been made to the Nakasone model to test the effect of pollutant load on the amount of aeration that could be reached. Values of AEs computed using the Gameson model were 30%, 39.5%, and 40% for cascade heights (Hd) 45, 60, and 75 cm respectively for the five flowrates (q) that ranged from 21–66 m3/hr. Values of AEs from WRL model were 32.8%, 42%, and 43% consequently. Values of AEs from Nakasone model ranged from 4.6–7.5%, 6–10%, and 7.6–12% respectively. For the adjusted Nakasone model, values of AEs ranged from 3.2–4.9%, 3.3–5.3%, and 4.1–6.7% respectively. Finally, the AEs computed using the values of downstream DO generated by Qual2k ranged from 4–18%, 2–15%, and 2.5–5.1% correspondingly. Around 80% of the downstream DO values computed using the Nakasone and adjusted Nakasone model were closer to those measured in the field, thus more reliable in cascade design.

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