• Title/Summary/Keyword: Rod-ground system

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Theoretical analysis and measurement of Ground impedance of Ground rods (봉상전극 접지임피던스의 측정과 이론적 분석)

  • Lee, Bok-Hee;Lee, Tae-Hyung;Lee, Su-Bong;Eom, Ju-Hong
    • Proceedings of the KIEE Conference
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    • 2004.07c
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    • pp.1876-1878
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    • 2004
  • A systematic approach of measurement, modeling and analysis of grounding system impedance is presented. The measurement and analysis system of ground impedance is based on a computer aided technique. The ground impedances of the ground rod are considerably dependent on the frequency. The ground impedance is mainly resistive in the frequency range of 3-20 kHz. At higher frequencies, the reactive components of the ground impedances are no longer negligible and the inductance of the ground rod was found to be the core factor deciding the ground impedance. As a consequence, the equivalent circuit model based on the measured data was proposed, and the calculated results were in approximately agreement with the measured data.

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A Study on the Application Methods of Chemicals for Reducing Grounding Resistance of the Bar-Shaped Electrode on the Power Distribution System (배전계통에서 봉형접지극의 접지저항 향상을 위한 접지저항저감제 사용방법에 관한 연구)

  • Park, Jung-Shin;Na, Chae-Dong
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.24 no.1
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    • pp.136-144
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    • 2010
  • The bar-shaped electrode is very popular for earth construction in Korea. Copper ground rod, Deep-buried ground rod and conductive concrete ground rod are major types of the bar-shaped electrode and generally applied on the distribution system. But in most case, to obtain the targeted ground resistance is difficult, because ground resistance is very different by soil condition. Therefore, a chemicals for reducing ground resistance is applied. In this paper, the initial and the variation of ground resistance according to the applied methods and types of chemicals over one year are compared with copper ground rod applied with water and the experimental results show that the new methods with chemicals reduced not only the initial ground resistance but also the variation of ground resistance over year.

Transient Impedance of the Ground Grid and Deeply-driven Ground Rod (그리드접지와 심매설 접지전극의 과도임피던스)

  • Lee, Bok-Hee;Lee, Su-Bong;Lee, Tae-Hyung;Jung, Hyun-Uk;Jeong, Dong-Cheol;Gil, Hyoung-Jun
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2005.05a
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    • pp.240-243
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    • 2005
  • This paper presents the transient behaviors of grounding system impedance against lighting impulse currents. The dynamic characteristics of the deeply driven ground rod and grounding grid subjected to the impulse current with various rise time were investigated. It was found that the transient ground impedance strongly depends on the configuration and size of grounding electrodes and the shapes of impulse currents, and the inductance of grounding electrodes has a significant affect on the transient ground impedance of grounding system in the short time domain.

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Ground impedance of deeply driven rod in high frequency domain (고주파수 영역에서 심매설 접지전극의 접지임피던스)

  • Lee, Bok-Hee;Lee, Tae-Hyung;Lee, Su-Bong;Jeong, Hyun-Wook;Jeong, Dong-Cheol
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2004.11a
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    • pp.247-250
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    • 2004
  • A ground resistance is a good index of performance in a grounding system, but it does not reflect the performance in transient states. Recently long vertical ground rods in urban areas are often installed. But because of the inductance of long ground rods the ground impedance at high frequency might be greater than its resistance at low frequency. In this paper, a ground impedance of deeply driven ground rod has been measured in the frequency range from 10 kHz to 50 MHz. As a result, the ground impedances of a deeply driven ground rods are almost constant at the frequency range less than 100 kHz. However at high frequency the ground impedance showed the strong frequency dependance.

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The Hammer Energy Delivered to the Drilling Rod in the SPT 1 (표준관입시험시 롯드에 전달되는 해머의 낙하에너지 평가 1)

  • 조성민;정종홍;김동수;이우진
    • Proceedings of the Korean Geotechical Society Conference
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    • 2001.03a
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    • pp.469-476
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    • 2001
  • The Ν-value in the standard penetration test(SPT) is affected by the magnitude of the rod penetration energy transmitted from the falling hammer as well as the geotechnical characteristics of the ground. Understanding of the striking energy efficiency in the SPT equipment is getting important for that reason. The energy efficiencies of the doughnut hammer with the hydraulic lift system and the automatic trip hammer system were investigated through field tests using the instrumented rod and wave-signal acquisition systems including the pile driving analyzer(PDA) . The rod energy ratio, ΕR$\_$r/ was defined as the ratio of the energy delivered to the drilling rod to the potential free-fall energy of the hammer. It appears that the type of the hammer and lift/drop system had a strong influence on the energy transfer mechanism and ΕR$\_$r/ also varies according to the energy instrumentation system and the analysis methods.

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Measurement Method of the Frequency Dependent Characteristics of Ground Impedance (접지임피던스의 주파수 의존성 측정기법)

  • Eom Ju-Hong;Lee Bok-Hee
    • 한국정보통신설비학회:학술대회논문집
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    • 2004.08a
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    • pp.211-214
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    • 2004
  • The measurement system of ground impedance is based on a computer aided technique. The magnitude and phase of ground impedance were determined by the novel measurement and analysis using the revised fall-of-potential method. The ground impedances of the ground rod of 30 m long are considerably dependent on the frequency. The ground impedance is mainly resistive in the frequency range of 3-20 kHz. At higher frequencies, the reactive components of the ground impedances are no longer negligible and the inductance of the ground rod was found to be the core factor deciding the ground impedance.

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The Effects of Soil Model in the Grounding System Design (침상 접지전극봉의 접지효과 분석)

  • Lee, Hyung-Soo;Shim, Keon-Bo;Ahn, Chung-Hoon;Kim, Kyu-Sam
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2004.05a
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    • pp.451-455
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    • 2004
  • Although DC ground resistance is a good index of performance for a grounding system, it does not reflect the grounding performance during the transient states. Besides, impulse ground impedance, which is defined by a ratio of the peak value of transient ground potential rise to the peak value of impulse current, cannot be an absolute performance index due to its dependence on impulse current shape. In this paper, a grounding performance of needle-typed ground rod has been compared with simple ground rod.

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Study for shielded enclosure and rod grounding electrode (쉴딩차폐와 봉상접지에 관한 연구)

  • Kim, Ju-Chan;Kim, Sung-Sam;Choi, Jong-Gyu;Lee, Chung-Sik;Koh, Hee-Seog
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2006.05a
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    • pp.414-417
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    • 2006
  • Especially, the case which the facilities have been shielded in the building. In this case there must be suitable grounding system, and this case must be considered sufficiently to the one part of the design at the design. in addition there must be an electric leakage defense system and The case to be a criterion signal ground system. Rod type grounding electrodes is applied much and we studied the relation that rod type grounding method and shielding room as newly grounding object. in this paper, shield room is the object(target) to be established newly additionally, we try to describe about the flow of a grounding technology concept change and a ground facilities.

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Examinations on the Reasonable Measuring Methods of the Soil Resistivity for Design of Grounding System (접지시스템의 설계를 위한 대지저항률의 합리적인 측정방법 고찰)

  • Lee, Bok-Hee;Kim, Ki-Bok;Lee, Seung-Hoon;Choi, Jong-Hyuk
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.25 no.6
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    • pp.35-41
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    • 2011
  • In order to design effectively the grounding system, it is very important to determine the optimum soil resistivity at the desired location of the connection to earth. This paper deals with the reasonable methods of measuring the soil resistivity where grounding electrodes are buried. The soil resistivity at three test sites with different resistivity of soil were measured as functions of the spacing between the test probes in the Wenner's four-point method and the length of test ground rod in the three-point method. In the case of the three-point method, the length of test ground rod of 2-10[m] in length was appropriate in two-layered soil structure. In the length range of 2-10[m], the results measured by the three-point method using the test ground rod with the length corresponding to the spacing between the test probes of the Wenner's four-point method are in good agreement with the data obtained from the Wenner's four-point method.

Grounding Characteristics Analysis of the Rod-Type Grounding Electrodes used for Electric Distribution Systems (배전계통에 사용되는 봉형 접지전극의 접지 특성 분석)

  • Kim, Kyung-Chul;Jung, Ji-Won
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.25 no.6
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    • pp.49-56
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    • 2011
  • Grounding system insures a reference potential point for electric devices and also provides a low impedance path for fault currents or transient currents in the earth. The ground impedance as function of frequency is necessary for determining its performance since fault currents could contain a wide range of frequencies. In this paper, the grounding resistance, grounding impedance and transient grounding impedance are measured by using 3-point fall-of-potential method in order to analyse grounding characteristics of the copper and concrete rod grounding electrodes. An equivalent transfer function model of the ground impedance and transient grounding impedance are identified from the measured values by using ARMA method and evaluated by comparing the conventional grounding impedance.