Application research on grounding resistance reduction in substation in high soil resistivity area and with limited grounding area

Author(s):  
Dongsheng Wang
Author(s):  
Ahmed Thabet ◽  
Youssef Mobarak

The earthing system is very important to safe human’s lives and protect power system from normal and abnormal faults. High soil resistivity regions is the main problem of installation the earthing systems in electric power substations to pass the current through the earth's surface. This paper has been overcome on high soil resistivity regions by penetrating conductive nanoparticles to have extremely low grounding resistance. Moreover, it has been succeeded to examine the methodology of the proposed Nano-Tech earthing systems in case of single rods, multiple rods and grids. Also, it has been defined optimal types and concentrations of nanoparticles for Nano-Tech grounding system to provide excellence protection for electrical substations with respect to built beneath of soil where substation is located. A comparative study has been discussed and analyzed the results of traditional and nanotechnology grounding systems.


2014 ◽  
Vol 615 ◽  
pp. 66-73
Author(s):  
Jun Jie Zheng ◽  
Bin Cao ◽  
Ming Liu ◽  
Chang Zheng Xia ◽  
Chang Geng Tu ◽  
...  

The composition of the tower's grounding system is always with several layers, for single-layer structure of the tower in high soil resistivity area, it is the use of partial replacement of soil to reduce the tower grounding resistance, also the analysis object is equivalent to the hierarchical model, Therefore, the study of layered soil structure tower grounding impulse characteristics is more representative. To study the impact properties of the layered structure of the soil grounding, In this paper, through the establishment a double-layer soil model structure, the impulse characteristics of the soil structure of grounding electrode is studied through simulation, resulting of the quantitative relationship between several high resistivity soils partially replacing low resistivity soil area size and impulse grounding resistance of elongation grounding. The results show that the impulse grounding resistance decreases as the replacement area of low resistivity soil increases and converges to a certain value, which indicates the impulse characteristics of extended grounding electrode in double-layer soil model increases with the expand of the upper level low resistivity zone and approaching that of single layer with low resistivity soil. The results have a reference value for use of local soil replacement method to reduce tower impulse grounding resistance in high soil resistivity areas and the determination of soil replacement plan.


2016 ◽  
Vol 680 ◽  
pp. 361-364 ◽  
Author(s):  
Jun Du ◽  
Cheng Tang ◽  
Bo Jia ◽  
De Zhang ◽  
Qiang Miao

The steel fiber/graphite conductive concrete is applied in power system grounding. In high soil resistivity regions, the common methods for reducing the grounding resistance are not practical. It is difficult for grounding resistance of substations to meet the requirements of working earthing and safety earthing. In order to solve this problem, a steel fiber/graphite conductive concrete is developed in this paper. Steel fiber and graphite are added as conductive fillers. The long-term stability of the steel fiber/graphite conductive concrete is studied. The experiment results show that steel fiber/graphite conductive concrete not only maintains excellent conductivity, but also has good mechanical strength and corrosion resistance in 300 days.


Author(s):  
Marina Kizhlo ◽  
Arvids Kanbergs ◽  
Mihails Kizhlo

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.


This chapter contains the factors affecting the soil resistivity and grounding resistance such as the soil moisture content, soil mineral content and soil temperature. It discusses the methods of measuring of soil resistivity and grounding resistance using Wenner method. Method to obtain the required samples for obtaining accurate site resistivity is presented. Soil resistivity measurement procedure is given in this chapter. The chapter contains three electrode method or fall-of-Potential method, dead earth method, and ground resistance testing existing systems using ‘Selective' Clamp-on-Measuring of high voltage transmission towers feet resistance. Methods of calculating the apparent soil resistivity of Multi-Layers, apparent soil resistivity of two layers and apparent soil resistivity of three layers are presented in this chapter.


Author(s):  
Shin-Der Chen ◽  
Li-Hsiung Chen ◽  
Chih-Kun Cheng ◽  
Jiann-Fuh Chen

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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