Overview of Method for Reducing Grounding Resistance of Substation Grounding System

Correlation Analysis between Grounding Resistance and Diurnal Variations of Upper Soil Resistivity during March 2010 in Balozhi, LatviaThe accurate measurement of soil resistivity and grounding system resistance is fundamental to electrical safety. However, geological and meteorological factors can have a considerable effect on the accuracy of conventional measurements and the validity of the measurement methods. This paper examines some aspects of grounding measurements and grounding system performance in the context of both geological and meteorological effects.We are reporting the results of grounding measurements using the 3-point method with ground resistivity tester type M416. The measurements were conducted during selected period from 2010 March 1 to March 31 in Balozhi, Latvia. We also noted that the resistivity of the upper layer significantly varied from a point to another, reflecting difference in water content in the upper soil layer due to local topography and other parameters.

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Grounding System Cost Analysis Using Optimization Algorithms

Energies ◽

10.3390/en11123484 ◽

2018 ◽

Vol 11 (12) ◽

pp. 3484 ◽

Cited By ~ 4

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.

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A modeling analysis of grounding resistance and sea surface potential on the jacket foundation offshore wind turbines

E3S Web of Conferences ◽

10.1051/e3sconf/20187201004 ◽

2018 ◽

Vol 72 ◽

pp. 01004

Author(s):

Shiqi Tao ◽

Xiaoqing Zhang ◽

Yaowu Wang

Keyword(s):

Surface Potential ◽

Wind Turbines ◽

Three Dimensional ◽

Influential Factors ◽

Sea Surface ◽

Offshore Wind ◽

Grounding System ◽

Grounding Resistance ◽

Offshore Wind Turbines ◽

Modeling Analysis

Offshore wind turbines (WTs) are frequently exposed to the risk from lightning, storm, and waves. As a kind of fixed foundations, jacket foundation can effectively reduce the correlatively risk and loss. In order to provide more information about the lightning protection of jacket foundation, a simulation model has been built by simplifying the hollow steel tubes into a series of solid steel cylinders. And some conclusions on the grounding resistance of jacket foundation have been summarized in this paper by using the GSSAS (Grounding System Safe Analysis Software). According to the simulation results, the actual influential factors of grounding resistance, including the depth of seawater, the thickness of clay layer and the resistivity of gravel layer, have been analysed and compared. It is found that the grounding resistance is influenced most severely by the depth of seawater. In addition, the values of sea surface potential have been calculated by the software GSSAS and the three-dimensional diagrams of potential distribution have been mapped out.

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Time-Domain Analysis and Experimental Verification of Portable Grounding System’s TGR

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.705.259 ◽

2014 ◽

Vol 705 ◽

pp. 259-262

Author(s):

Xin Bo Qu ◽

Bi Hua Zhou ◽

Ya Peng Fu ◽

Li Juan Yang ◽

Nan Zhang

Keyword(s):

Time Domain ◽

Time Domain Analysis ◽

Frozen Soil ◽

Lightning Protection ◽

Grounding System ◽

Grounding Resistance ◽

Long Time ◽

New Type ◽

Set Up ◽

Difference Time

The portable grounding system plays an important role in the lightning protection system of mobile equipments. But the traditional earth electrodes composed of vertical rods wouldn’t work well or would take a long time to set up in some conditions such as frozen soil, hard clay and so on. In this paper, a new type of portable grounding system which can be quickly spread and folded has been designed. To analyze the TGR’s (Transient Grounding Resistance) time-domain characteristics, the grounding systems have been modeled and simulated with FDTD (Finite Difference Time Domain). The influence rule of electrodes’ number and down-lead’s position to TGR has been studied with numerical analysis and validated with experiments. The results show that the new grounding system works well even on cement floor.

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Measuring electrode arrangement for grounding resistance measurement of grounding system in vertical-layered soil

PowerCon 2000. 2000 International Conference on Power System Technology. Proceedings (Cat. No.00EX409) ◽

10.1109/icpst.2000.898187 ◽

2002 ◽

Author(s):

Rong Zeng ◽

Jinliang He ◽

Yanqing Gao ◽

Weimin Sun ◽

Qi Su

Keyword(s):

Layered Soil ◽

Resistance Measurement ◽

Measuring Electrode ◽

Grounding System ◽

Grounding Resistance ◽

Electrode Arrangement ◽

Grounding Resistance Measurement

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An Experimental Study on the Electrical Properties of Fly Ash in the Grounding System

International Journal of Emerging Electric Power Systems ◽

10.2202/1553-779x.1284 ◽

2006 ◽

Vol 7 (2) ◽

Cited By ~ 2

Author(s):

Shin-Der Chen ◽

Li-Hsiung Chen ◽

Chih-Kun Cheng ◽

Jiann-Fuh Chen

Keyword(s):

Fly Ash ◽

Power Systems ◽

Power Plants ◽

Bottom Ash ◽

Waste Utilization ◽

Mineral Admixture ◽

Attractive Alternative ◽

Grounding System ◽

Grounding Resistance ◽

Resistance Reduction

A good grounding system is the fundamental insurance to keep the safe operation of power systems. The grounding resistance reduction additive-fly ash is proposed in this study. Fly ash is the byproduct of coal-fired power plants. A pulverized coal boiler generates approximately 80% fly ash and only 20% bottom ash. Furthermore, the study of these materials will assume greater importance. Waste utilization is an attractive alternative to disposal in that disposal cost and potential pollution problems are reduced. Extensively used as an additive in Portland cement or as a mineral admixture in concrete in recent years, we have found that fly ash has a low resistivity, and so can be used as an agent for reducing resistance to grounding. Also, an effort is made to investigate the effect of water-to-cement(W/C) and temperature on the resistivity of the test specimens. The grounding resistance reduction agent was determined by considering various proportions of water, cement and salt. Experimental results demonstrate that the proposed approach can effectively reduce the grounding resistance.

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Research of Mountain Area Wind Farm Grounding Scheme

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.584-586.2695 ◽

2014 ◽

Vol 584-586 ◽

pp. 2695-2699

Author(s):

Wen Bo Yu ◽

Xiao Lin Luo ◽

Bing Chen ◽

Wen Xiang Wang

Keyword(s):

Wind Turbine ◽

Wind Farm ◽

Green Energy ◽

Mountain Area ◽

Grounding System ◽

Grounding Resistance ◽

Ground Resistance ◽

Lightning Accident ◽

Wind Resource ◽

Impulse Current

Wind power has become one of the most potential and vital green energy sources. Location of the wind farm has a better wind resource，and it is also relatively open. Lightning accident in the wind farm happened occasionally, in order to avoid the situation, which impulse current damages the wind turbine, in the accident, lightning protection grounding system of wind turbine is essential .In this paper, according to the experience of Dongshan wind farm project , the method of how to design the wind turbines and booster station grounding grid as required, the calculation of ground resistance and specific measures to reduce grounding resistance of wind turbine grounding device are discussed.

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Impact of First Tower Earthing Resistance on Fast Front Back-Flashover in a 66 kV Transmission System

Energies ◽

10.3390/en13184663 ◽

2020 ◽

Vol 13 (18) ◽

pp. 4663

Author(s):

Abdullah H. Moselhy ◽

Abdelaziz M. Abdel-Aziz ◽

Mahmoud Gilany ◽

Ahmed Emam

Keyword(s):

Transmission Tower ◽

Lightning Stroke ◽

Worst Case ◽

Grounding System ◽

Grounding Resistance ◽

Tower Structure ◽

Proper Design ◽

Substation Equipment ◽

The Cost ◽

Transient Overvoltage

Lightning stroke on a transmission tower structure is one of the major reasons that results in high voltages at the tower arms due to the excessive lightning current flowing through the transmission tower to earth. The Surge voltage seen at the tower cross arm on the first tower close to a substation is the worst case. If this voltage is higher than the withstand level of the insulator string, the insulation of substation equipment will be exposed to transient over-voltage called fast front back-flashover (FFBF). The peak of this transient overvoltage is affected by the value of the system’s earthing resistance. This paper studies the effect of reducing the grounding resistance of both the surge arrestor (SA) and the first transmission line tower adjacent to a 66 kV substation on FFBF. Three case studies using PSCAD/EMTDC software are presented to simulate the variation of the potential sire at the substation equipment with different resistance values for the first tower and SA earthing resistance. The paper also addresses the economic protection system for solving the problem of transient overvoltage. The study proves that the proper design of the first tower grounding system enhances the safety of the system and reduces the cost for the grounding system to the minimum.

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A New Derivation of TGR with Naked Antenna in Lossy Medium

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.380-384.4098 ◽

2013 ◽

Vol 380-384 ◽

pp. 4098-4102

Author(s):

Xin Bo Qu ◽

Bi Hua Zhou ◽

Zheng Wan ◽

Wei Shi ◽

Xiao Gang Xie

Keyword(s):

Fourier Transform ◽

Frequency Domain ◽

Integral Equations ◽

Time Domain ◽

Inverse Fourier Transform ◽

Input Resistance ◽

Grounding System ◽

Grounding Resistance ◽

Lossy Medium

A new derivation of Transient Grounding Resistance (TGR) has been proposed in this paper. Take grounding system as naked antenna in lossy medium, and then get the input resistance of naked antenna in a given frequency based on Helen current integral equations. With inverse Fourier transform, the resistance calculation equations can be translated from frequency domain to time domain. The result can be applied to design a new grounding system and to calculate its TGR .

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