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

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.

Design of Grounding Grid According to IEEE Standards

2018 ◽  
pp. 158-186
Keyword(s):  
System Design ◽  
Design Procedure ◽  
Grounding System ◽  
Grounding Resistance ◽  
Computerized Analysis ◽  
Grounding Grid ◽  
Homogeneous Soil ◽  
Ieee Standards

This chapter contains the following points: design procedure of grounding system according to IEEE 80, methods for calculating the grounding grid resistance (Dwight's formula, Laurent and Niemann, Sverak's equation, Schwarz's Formula, Dawalibi, Mukhedkar's Formula, Chow and Salama's Formula, Nahman's Formula and Heppe's Method). It contains also the design of charts of grid earthing system and application of step and mesh potential in safe grounding system design. This chapter draws attention also to the following points: Grounding resistance of grounding system in non-homogeneous soil, calculations of maximum step and mesh voltages, estimation of minimum buried grid conductor length and finally computerized analysis in grounding design.

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.

The effects of surface absorbed monolayer microdiffraction patterns

1988 ◽  
Vol 46 ◽  
pp. 680-681
Author(s):  
M. Pan ◽  
J.M. Cowley
Keyword(s):  
Surface Potential ◽  
Electron Probe ◽  
Potential Distribution ◽  
Crystal Surface ◽  
Normal Direction ◽  
Surface Image ◽  
Extended Surface ◽  
Gas Molecules ◽  
Surface Nature ◽  
Electron Microdiffraction

Electron microdiffraction patterns, obtained when a small electron probe with diameter of 10-15 Å is directed to run parallel to and outside a flat crystal surface, are sensitive to the surface nature of the crystals. Dynamical diffraction calculations have shown that most of the experimental observations for a flat (100) face of a MgO crystal, such as the streaking of the central spot in the surface normal direction and (100)-type forbidden reflections etc., could be explained satisfactorily by assuming a modified image potential field outside the crystal surface. However the origin of this extended surface potential remains uncertain. A theoretical analysis by Howie et al suggests that the surface image potential should have a form different from above-mentioned image potential and also be smaller by several orders of magnitude. Nevertheless the surface potential distribution may in practice be modified in various ways, such as by the adsorption of a monolayer of gas molecules.

Modeling on Effects of Charging Time and Recombination on Surface Potential Decay Crossover of LDPE

2016 ◽  
Vol 136 (2) ◽  
pp. 86-92 ◽  
Author(s):  
Daomin Min ◽  
Shengtao Li ◽  
Guochang Li ◽  
George Chen
Keyword(s):  
Surface Potential ◽  
Charging Time ◽  
Potential Decay

Direct Measurement of Charge Reversal on Lipid Bilayers using Heterodyne-Detected Second Harmonic Generation Spectroscopy

2019 ◽  
Author(s):  
HanByul Chang ◽  
Paul Ohno ◽  
Yangdongling Liu ◽  
Franz Geiger
Keyword(s):  
Lipid Bilayers ◽  
Surface Potential ◽  
Second Harmonic ◽  
Fluid Phase ◽  
Cationic Polyelectrolyte ◽  
Charge Reversal ◽  
Buried Interfaces ◽  
Phase Transition Temperatures ◽  
Complementary Techniques ◽  
Order Susceptibility

We report the detection of charge reversal induced by the adsorption of a cationic polyelectrolyte, poly(allylamine) hydrochloride (PAH), to buried supported lipid bilayers (SLBs), used as idealized model biological membranes. We observe changes in the surface potential in isolation from other contributors to the total SHG response by extracting the phase-shifted potential-dependent third-order susceptibility from the overall SHG signal. We demonstrate the utility of this technique in detecting both the sign of the surface potential and the point of charge reversal at buried interfaces without any prior information or complementary techniques<i>.</i>Furthermore, isolation of the second-order susceptibility contribution from the overall SHG response allows us to directly monitor changes in the Stern Layer. Finally, we characterize the Stern and Diffuse Layers over single-component SLBs formed from three different zwitterionic lipids of different gel-to-fluid phase transition temperatures (T<sub>m</sub>s). We determine whether the surface potential changes with the physical phase state (gel, transitioning, or fluid) of the SLB and incorporate 20 percent of negatively charged lipids to the zwitterionic SLB to investigate how the surface potential changes with surface charge.

Sign in / Sign up

Export Citation Format

Share Document