• Title/Summary/Keyword: Grounding Method

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An Analysis of Transient Characteristics on Grounding Systems in the Radio Relay Station (무선중계소 접지계의 과도특성 해석)

  • Wang Kim
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.30A no.9
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    • pp.1-5
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    • 1993
  • The surge impedance of grounding systems must be accurately computed for a safe grounding design. Specifically, the case of radio relay station in a mountaintop region is required special design method using transient analyses. To approach these design objectives, this paper presents an algorithm to compute the surge impedance of two or more grounding systems using the Laplace Transform technique and deals with the analysis of the transient characteristics on grounding systems. Also, simulation results are compared with the measured data to prove the validity of the algorithm.

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Impulse Impedance of a Rod type Grounding Electrode (봉형접지전극의 임펄스임피던스 도출)

  • Kim, Wang
    • Proceedings of the KIEE Conference
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    • 1993.07b
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    • pp.578-580
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    • 1993
  • The impulse impedence of grounding system must be accurately evaluated for a safe grounding design. However, a calculation nettled of the impulse impendence of a horizontal grounding electrode has not been established yet. This paper presents a method to compute the impulse impedance of a rod type grounding electrode and deals with the analysis of the transient characteristics on the electrodes.

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Numerical Calculation for Grounding Impedance of a Horizontal Ground Electrode Based on the Electromagnetic Field Theory (전자계 이론을 기반으로 한 수평접지전극의 접지임피던스 수치계산)

  • Lee, Bok-Hee;Cho, Sung-Chul
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.28 no.2
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    • pp.76-83
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    • 2014
  • This paper deals with the numerical method of calculating the frequency-dependent impedances of grounding electrodes. The proposed electromagnetic field approach is based on the solutions to Maxwell's equations obtained from the method of moment in the frequency domain. In order to evaluate the quality of the proposed simulation method, the frequency-dependent impedances of horizontally-buried ground electrodes were presented. The program for calculating the current distributions and impedances of grounding electrodes was implemented in MATLAB. The grounding impedances of two 10m and 50m long horizontal ground electrodes were measured and simulated in the frequency range from 100Hz to 10MHz for easy analysis and comparison. Also the simulated results were compared with those calculated from a sophisticated computer program CDEGS (HIFREQ module). As a result, the resultant results of frequency-dependent impedances obtained by using the numerical simulation method proposed in this work are in good agreement with experimental data. The validity of the approach techniques was confirmed.

An Experimental Study on Ground Resistivity and Grounding Resistance of Water Environment (수상환경의 대지저항률 및 접지저항 측정의 실험적 연구)

  • Choi, Young-Kwan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.4
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    • pp.2343-2348
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    • 2014
  • Main ground net of power plant is formed to protect human body from increase in potential gradient caused by grounding current during ground fault. Calculations during ground design are generally performed according to IEEE Std-80-2000 (Kepco Design Standard 2602). However, it is difficult to apply this Standard to water environment, and a grounding technology is required to secure grounding resistance of floating photovoltaic system. Therefore the aim of this paper is to investigate and analyze ground resistivity on the water surface and underwater of reservoir using Wenner 4-pin method, a general method of measuring ground resistivity. Also, grounding resistance of floating photovoltaic systems currently in operation was measured and analyzed using the voltage drop method suggested in the international standard (IEEE Std-81) to propose a grounding method for stable grounding of floating photovoltaic system. The resistivity at 1m below the surface of water ($126.3969[{\Omega}{\cdot}m]$) is mostly higher than resistivity at the river bed ($97.5713[{\Omega}{\cdot}m]$). Also the proposed grounding anchor method was determined as the most effective method of securing stable grounding resistance in floating photovoltaic systems and is expected to be utilized as a ground method for future floating photovoltaic generation systems.

A Modeling Optimization for Numerical Analysis of GPR in Multi-Grounding Systems (다중 접지계 GPR 수치 해석을 위한 최적 모델링 기법)

  • Lee, Jae-Bok;Chang, Sug-Hun;Myung, Sung-Ho;Cho, Yeon-Gyu
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.17 no.11 s.114
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    • pp.1120-1131
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    • 2006
  • This paper describes the numerical analysis techniques using the Combined Integration/Matrix Method to calculate ground potential rise which can be occurred in the various grounding systems. Combined Integration/Matrix Method is used to reduce the error and computation time with the analytical integration equation and the proper segmentaion of earth embedded conductor. To do it, optimal segmentaion method for the buried conductors is presented through error analysis which is capable of applying the practical scaled various grounding systems. The optimum length of segmented element is much co-related with the buried depth of grounding electrode and the maximum length of buried electrode. As a result, less 3 precent errors was obtained by proposed model. The proposed model is applied to verify an effect of multi-grounding problems which was aroused much controversy with separated or common grounding between the high power grounding system and low power grounding system such as signal and telecommunication grounding.

Frequency Dependence of Impedance of the Grounding Grid (접지그리드의 접지임피던스의 주파수 의존성)

  • 이복희;이동문;엄주홍;김교운
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.17 no.5
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    • pp.22-28
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    • 2003
  • This paper describes the frequency dependence of the grounding impedance. In order to propose the evaluation method of the transient response of powered grounding systems, the grounding impedances were measured with varying the frequency of incoming currents by way of the variable frequency inverter and band pass filter. The magnitude and phase of the grounding impedance were analyzed in the frequency range of 20 [Hz]∼2.1[kHz]. The grounding impedance were increased with increasing the frequency of the test current. The grounding impedance at the frequency of 2[kHz] in the actual 22.9[kV] substation grounding system was approximately 3 times as large as the 60[Hz] grounding impedance. It was found that the frequency dependence of the grounding impedance is mainly subject to the inductive reactance of the grounding conductors. As a result, it is critical to determine the shape and size of grounding grid reducing the resultant inductance in grounding systems for lightning surge protection.

Effective Impulse Impedances of Deeply Driven Grounding Electrodes

  • Lee, Bok-Hee;Jeong, Dong-Cheol;Lee, Su-Bong;Chang, Keun-Chul
    • KIEE International Transactions on Electrophysics and Applications
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    • v.4C no.5
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    • pp.207-214
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    • 2004
  • This paper presents the characteristics of transient and effective impulse impedances for deeply driven grounding electrodes used in soil with high resistivity or in downtown areas. The laboratory test associated with the time domain performance of grounding piles subjected to a lightning stroke current has been carried out using an actual-sized model grounding system. The ground impedances of the deeply driven ground rods and grounding pile under impulse currents showed inductive characteristics, and the effective impulse ground impedance owing to the inductive component is higher than the power frequency ground impedance. Both power frequency ground impedance and effective impulse ground impedance decrease upon increasing the length of the model grounding electrodes. Furthermore, the effective impulse ground impedances of the deeply driven grounding electrodes are significantly amplified in impulse currents with a rapid rise time. The reduction of the power frequency ground impedance is decisive to improve the impulse impedance characteristics of grounding systems.

An Improved Method for Mesh Grounding System Using Spaced Arrangement of Grounding Conductor (접지도체의 간격배치에 따른 개선된 접지설비 모델)

  • Song, Young-Joo;Choi, Hong-Kyoo
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.19 no.3
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    • pp.57-65
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    • 2005
  • No matter how well the equally spaced grounding grid is designed, there we questions keep rising, such as leakage of current from comer conductor, high voltage of touch voltage in comers of grid than in center, and high material cost for grounding grid. The best-fitted design for unequally spaced grounding grid is a part that must be considered. Explain advantages of unequally spaced grounding grid and lead formula by dividing the number of grid division, j, into 20, instead of 7. Then, present Dij, which is optimum rate for unequally spaced grounding grid and verify safety and economy of the unequally spaced grounding grid by computer simulation with a poly-nominal function form.

Analysis Technique of Risk Voltage around Grounding Electrode by New Touch and Step Voltage Measurement Methods (새로운 접촉 및 보폭전압 측정법에 의한 접지전극 주위의 위험전압 분석기법)

  • Gil, Hyoung-Jun;Kim, Hyang-Kon
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.26 no.6
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    • pp.81-86
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    • 2012
  • This paper describes the analysis technique of risk voltage around grounding electrode by new touch and step voltage measurement methods. We have analyzed three techniques for risk voltage measurement, such as footprint-electrode method, test-probe method, and simulated-personnel method. We have selected test-probe method considering applicability of site. In order to reduce error related to the location of the auxiliary electrode, we propose a new approach to perform risk voltage measurement with minimum errors and short auxiliary electrode distances. Field tests were carried out at a grounding grid. It can be concluded that the proposed method will be satisfactory for risk voltage measurement.

An Improved Method for Mesh Grounding System Using Unequally Spaced Arrangement (접지도체의 간격배치에 따른 개선된 접지설비 모델)

  • Choi, Hong-Kyoo;Song, Young-Joo
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2004.11a
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    • pp.259-265
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    • 2004
  • No matter how well the equally spaced grounding grid is designed, there are questions keep rising, such as leakage of current from comer conductor, high voltage of touch voltage in corners of grid than in center, and high material cost for grounding grid. The best-fitted design for unequally spaced grounding grid is a part that must be considered. Explain advantages of unequally spaced grounding grid and lead formula by dividing the number of grid division, j, into 20, instead of 7. Then present $D_{ij}$, which is optimum rate for unequally spaced grounding grid and verify safety and economy of the unequally spaced grounding grid by computer simulation with a poly-nominal function form.

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