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  • Title/Summary/Keyword: Soil Resistivity

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Numerical Analysis of the Interference of the Buried Pipeline due to the Stray Current from the Parallel Electric Railway (전기철도와 평행한 매설배관에서 누설전류에 의한 간섭현상의 수치해석적 연구)

  • Jung, Chan-Oong;Choi, Kyu-Hyoung
    • Journal of the Korean Institute of Gas
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    • v.12 no.4
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    • pp.8-13
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    • 2008
  • The stray current interference problem could induce the corrosion of near-by structure and rail itself. Many efforts has been concentrated on the reduction of the interference. In this work the influences of separation distance, soil resistivity, pipe coating resistance, leak resistance of rail were studied using the numerical analysis methods. These analysis could be used to estimate the sensitivity of each variables in the study of the mitigation method and their numerical analysis.

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Technical Trends of Domestic and Overseas on Electro-physical Properties Measurement (전기물성 측정의 국내외 기술 동향)

  • Park, Sam-Gyu;Cho, Seong-Jun;Lee, Tae-Jong;Lee, Seong-Kon;Lee, Sang-Kyu
    • 한국지구물리탐사학회:학술대회논문집
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    • 2007.06a
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    • pp.285-290
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    • 2007
  • Electrical and electromagnetic methods were widely applied to survey of civil engineering, environment site assessments and maintenance of underground structures in Korea. Electro-physical properties measurements of soil and rock are necessary in order to quantitatively estimate the ground from these survey results. A few geotechnical researcher groups have been simplified measurement system of the electro-physical properties, which was intermittently operating by the necessity. Recent strong concern about CO2 underground storage and development of gas hydrate projects have urged many advanced countries. The electro-physical properties estimation of the deep object stratum is very importance for basic information of these research. So, advanced countries have a high-end measurement system with high temperature(200 degrees) and pressure(300 MPa), also they have been a lot of experience and know-how on the electro-physical properties measurement.

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Evaluation of the potential reduction and energy dispersion caused by ionization phenomena at the submerged ground rod (수중에 잠긴 접지전극주변에서 이온화에 의한 전위저감 및 에너지 방출의 평가)

  • An, Sang-Duk;Choi, Jong-Hyuk;Park, Geon-Hun;Yang, Soon-Man;Lee, Bok-Hee;Ahn, Chang-Hwan
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2008.10a
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    • pp.337-340
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    • 2008
  • When high surge voltage invaded into the ground rod contacted with ground water, the ionization phenomena are happened in the water. Although some researchers have surveyed the ionization phenomena in soil, they have just analyzed the variation of the ground resistance. The most important role of the ground rod is to elect human beings from potential rise and to dissipate energy to the earth safely. In this wort we presented the method evaluating the potential reduction and energy dispersion. Also we analyzed theses factors as a function of charging voltages at the water resistivity of 50Ωm using the Matlab Program. As a result the ground rod potential was reduced to 38 kV by ionization just below breakdown voltage. The energy more than half of the total injected energy was dispersed through the grounding electrode caused due to ionization.

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Evaluation of Errors Due to Earth Mutual Resistance in Measuring Ground Impedance of Vertically-driven Ground Electrode (수직 접지전극의 접지임피던스 측정에서 도전유도에 의한 오차 평가)

  • Choi, Jong-Hyuk;Choi, Young-Chul;Lee, Bok-Hee
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.9
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    • pp.1778-1783
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    • 2009
  • Ground impedance for the large grounding system is measured according to the IEEE Standard 81.2 which is based on the revised fall-of-potential method of installing auxiliary electrode at a right angle. When the auxiliary electrodes are located at an angle of 90, the ground impedance inevitably includes the error due to earth mutual resistance. In this paper, in order to accurately measure the ground impedance of vertically-driven ground electrodes, error rates due to earth mutual resistance are evaluated by ground resistance and ground impedance measuring devices and compared with calculated values. As a result, the measured results are in good agreement with the computed results considering soil layer with different resistivity. The error rates due to earth mutual resistance decrease with increasing the length of ground electrode in the case that the ratio of the distance between the ground rod to be measured and the auxiliary electrodes to the length of ground electrode(D/L) is same. The ground impedance should be measured at the minimum distance between the auxiliary electrodes that will have an estimated measurement accuracy due to earth mutual resistance.

A Study of Optimizing Cathodic Protection in Comparison of Design Methodologies

  • Choi, Young-Kwan;Choi, Sang-Yule;Shin, Myong-Chul
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.24 no.11
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    • pp.23-29
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    • 2010
  • The principal factor determining an optimum design method for cathodic protection is finding the protection current for preventing the corrosion of existing, already laid pipe. Some factors currently used to test designs include the sizes and lengths of pipes, soil resistivity, and the coating damage rate. We believe this method and current formulae are not optimum due to the uncertainty of determining the coating damage rate and the corrosion protection current's density. This paper analyzes the amount of protection current obtained by performing a temporary current test using data describing existing laid pipe. We then propose determining the corrosion protection current by using the temporary current test after modifying the formula. In addition, we suggest a way to choose optimized cathodic protection and the process of design by executing the design and taking account of such factors as a site condition of 34km-long non-protected water supply pipe lines (stages I and II) in region, climate, interferences, and durability.

Design and A Safety Analysis and Assessment of a Grounding System according to International Standards (국제 표준(IEC)에 의한 접지 설계 및 이에 대한 안전성 분석·평가)

  • Kim, Doo-Ung;Cho, Man-Hyung;Kim, Han-Soo;Shin, Dae-Sung;Ryu, Ki-Hwan;Kim, Chul-Hwan
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.10
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    • pp.54-59
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    • 2015
  • In this paper, we evaluate safety of grounding system which is designed according to IEC standards. Safety assessment of construction site and grounding system of building is needed before construction for the safety of human in building. Until now, in case of domestic field, design of grounding system is proceeded based on methods which are proposed in IEEE Std. 80. In other words, it is not in the situation that grounding system is designed based on IEC standards. Therefore, we propose a method which designs grounding system and evaluates safety of it according to IEC standards. We measure ground resistance of construction site using measuring equipment of ground resistance. Using this value, soil structure and ground resistivity are obtained through program analysis. CDEGS program of SES company is used for simulation analysis.

Analysis of the Ground Impedance of Ground Grids Combined with the Carbon Ground Electrodes (탄소접지극이 병설된 접지그리드의 접지임피던스의 해석)

  • Lee, Bok-Hee;Um, Sang-Hyun;Kim, You-Ha;Lee, Kang-Soo;Jeon, Byung-Wook;Choi, Jong-Hyuk
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.27 no.3
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    • pp.36-42
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    • 2013
  • This paper deals with the frequency-dependent ground impedance of ground grids combined with the carbon ground electrodes. Ground grids are generally valid for multipurpose grounding systems as well as lightning protection systems. The carbon ground electrodes may be supplementarily used to reduce the high frequency ground impedance and to improve the transient response to surge currents. The frequency-dependent ground impedances of ground grids combined with or without the carbon ground electrodes were measured and their simulations with due regard to frequency-dependent soil resistivity were implemented by using EMTP program and Matlab modeling. As a consequence, the ground impedance of ground grids combined with the carbon ground electrodes is significantly reduced when the test current is injected at the terminal of the carbon ground electrode. The measured and simulated data for the test ground grids fairly agree with each other. It was found that the proposed method of simulating the frequency-dependent ground impedance is distinguished. The simulation techniques of predicting accurately the ground impedances without actual measurements can be used in the design of grounding systems based on ground grids and the carbon ground electrodes.

Analysis on Coring Earth Electrode in Progress of Time (코아링 접지전극의 경년변화 해석)

  • Oh, Seong-Bo;Kim, Se-Ho;Kim, Ho-Chan;Boo, Chang-Jin;Ahan, Jae-Hyun;Ko, Seoung-Min;Ko, Young-Soo
    • Proceedings of the KIEE Conference
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    • 2006.07e
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    • pp.89-90
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    • 2006
  • Recent earth systems not only make earth resistance decreased by installing earth electrode but also are demanded by earth construction for the protection of human life and equipments through total investigation about circumstances. Layer constructions in Jeju island consist of multi-layer of scoria, rocks and shale except clay layers on the surface, which needs the construction of the coring earth electrode suitable in the condition of the area. For this reason, we've used the coring earth electrode. But the coring earth electrode is expected to slow down the performance of this equipment according to the progress of time changing the effects. It is also applied for the stability of earth system construction and management after the construction work analyzing the condition of the earth system. Therefore, this is actually focused on the analysis on measuring the earth resistance and the soil resistivity that cover the range where the remarkable contrast can be expected to be seen in the layer structures.

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A Study on the Safety Grounding for Prevention of Electric Shock Hazard in Construction of Industrial Plant in Maritime Landfill Area (해상 매립 지역 산업 플랜트 건설 시 감전 재해 예방을 위한 안전 접지에 관한 연구)

  • Kim, Hong-Yong;Jang, Ung-Burm
    • Journal of the Society of Disaster Information
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    • v.13 no.3
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    • pp.305-312
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    • 2017
  • In our society, the advanced, advanced, and information industries have continued to grow and now live in the era of the fourth industrial revolution. As the industry develops, the load of the users has also increased so much that it is deepened by the energy shortage phenomenon and the construction of additional energy facilities is required. Therefore, energy plant construction work is being actively carried out in the coastal area. In particular, it is common to build a plant in the ground by filling the coast with soil in other regions, reflecting the fact that Korea is lacking in the country when constructing power plants, gas and petrochemical plants. Current domestic grounding designs are designed or constructed to suit only the use of grounding resistors based on the electrical equipment design technical standards. However, in the case of a plant facility constructed in the untested buried soil, when the lightning current and the abnormal current are inputted, the facility operator or the user due to the elevation of the ground potential is seriously exposed to the risk of electric shock disaster. In this paper, we analyze the ground resistivity of the landfilled soil and use a computer program (CDEGS) based on KS C IEC 61936-1, We analyze the contact voltage and stratification voltage and propose a grounding design optimized for plant installation.

Analysis of Transient Potential Rises of Horizontal Ground Electrodes Considering the Frequency-Dependent of Soil (토양의 주파수의존성을 고려한 정보통신설비용 수평접지전극의 과도전위상승 분석)

  • Ahn, Chang Hwan
    • Journal of the Institute of Electronics and Information Engineers
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    • v.53 no.2
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    • pp.147-153
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    • 2016
  • The lightning protection of information and communication facilities is very important factor to improve a reliability of the action of these equipment. Especially the transient potential rise of ground electrode being injected with the lightning current is to be a basic data of the dielectric strength for both power and communication facilities so that more accurate analysis should be required. The transient potential rise can be calculated from the ground impedance and the ground impedance is strongly dependent upon the shape of the ground electrode and the frequency-dependence of soil. The Debye's equation which is able to calculate the characteristics of dielectrics is used to analyze the frequency-dependent of soil. Also, the method to calculate the transient potential rise from the ground impedance is specified in this paper. In order to analyze the transient potential rise resulting from calculations with Debye's equation, TLM(transmission line method) and case of ρ(resistivity)-constant are simulated, respectively. The length of a horizontal ground electrode is 30 m and simulations were performed at 10, 100, 1000Ωm with the standard lightning current waveform. In result, the transient potential rise of horizontal ground electrode calculating with Debye's equation is lower than it of other models.