• Title/Summary/Keyword: Grounding grid

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The study on the spaced grounding conductor (접지도체 간격에 관한 연구)

  • Choi, Hong-Kyoo;Choi, Byoung-Sook;Song, Young-Joo
    • Proceedings of the KIEE Conference
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    • 2004.05b
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    • pp.140-147
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    • 2004
  • 등간격 접지Grid의 설계에서는 대부분의 전류가 외곽접지도체로 누설되어 Grid 구석 접촉전압이 중심 접촉전압 보다 높아지는 문제점이 있다. 비등간격 접지Grid의 설계는 이러한 문제점을 극복할 수 있으나 적절한 비등간격 접지Grid의 설계방법이나 간격결정 방법은 논의되고 있지 않다. 따라서, 본 논문에서는 비등간격 접지Grid의 장점, 수식, 최적의 간격비율을 제시한다.

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Transient Ground Impedances According to Shapes of Grounding Electrodes (접지전극의 형상에 따른 과도접지임피던스)

  • Lee, Bok-Hee;Lee, Su-Bong;Lee, Tae-Hyung;Jung, Hyun-Uk;Jeong, Dong-Cheol
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.20 no.1
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    • pp.65-70
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    • 2006
  • This paper presents the transient behaviors of grounding system impedance against lightning impulse currents. The dynamic characteristics of the deeply driven ground rod and grounding grid subjected to the impulse current were investigated. 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 Also, the deeply-driven ground rod was effective to reduce the transient ground impedance in time domain of miceroseconds.

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.

Improvement of Transient Grounding Performance with Auxiliary Grounding Grid (보조접지망에 의한 과도접지성능의 개선)

  • Choi, Jong-Kee;Jung, Gil-Jo;Kim, Seon-Gu
    • Proceedings of the KIEE Conference
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    • 1998.11c
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    • pp.932-934
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    • 1998
  • In an electric substation, there are many sources of surge such as switching operations or lightning strokes. A grounding system submitted to such surge current presents very different behaviour from the observed under low frequency current. Especially, it has been reported that significant overvoltage occurs at the current feed-in point, and this may cause damages to other grounded components in the substation area. This paper describes the basic mechanism of improvement of grouding performance in transient state with auxiliary grounding grids.

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An Improved Model for Grounding System Using Examination of Dangerous Voltage (위험전압 검토에 따른 개선된 접지설비 모델)

  • Shin, Bog-Sung;Hong, Soon-Seuk
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.22 no.4
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    • pp.68-77
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    • 2008
  • When we design the grounding grid, dangerous voltage IEEE Std. 80 method has been commonly used in the domestic area. However there is not appropriative examination of ground design environment. So in this paper, we examined of IEEE Std. 80 touch voltage method's marginal utility and we induced corrective factor for those problems by comparison between IEEE Std. 80 touch voltage value and simulation experimentation value. Moreover, Logistic model's corrective factor we proved the maximum accidental error has reduced less than 10[%].

A Study on the Potential Interference Analysis in the Isolated Grounding System by Field Tests (현장시험에 의한 독립접지 시스템의 전위간섭 해석에 관한 연구)

  • Kim, Kyung-Chul;Choi, Jong-Kee;Paik, Seung-Hyun;Park, Sang-Young;Kim, Jong-Uk
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.18 no.6
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    • pp.145-151
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    • 2004
  • The purpose of isolated grounding system is to protect own electrical facilities from the other grounding systems in order to avoid the potential interference between ground grid areas. But the physically close distances involved could lead to potential interference problems. The simplified equation for determining potential interferences based on the measured data under the case study grounding system is proposed in this paper. The results obtained with the equation to verify the accuracy have been compared with the results obtained from the CDEGS program.

Performance Comparison of Signal Reference Grid and Insulated/Isolated Ground Using HIFREQ Simulator (기준신호용 그리드와 절연/독립접지방식의 비교)

  • Paik, Seung-Hyun;Kim, Kyung-Chul;Choi, Jong-Ki
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.18 no.5
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    • pp.69-73
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    • 2004
  • This paper deals with the transient performance of zero signal reference grid(ZSRG) and insulated/isolated ground(IG) in case of lightning strike or surge currents in buildings. Using HIFREQ, which is a commercial code for electromagnetic field analysis, the difference of transient performances of ZSRG and IG type grounding structure have been presented based on the numerical calculations. It is expected that the quantitative and numerical calculation based analysis, which is adopted in this paper, will attribute to the selection of optimal grounding method in the intelligent buildings.

Impulse Ground Impedances of a Deeply Driven Ground Rod Combined with Different Shape Grounding Electrodes (형상이 다른 접지전극에 접속된 심매설 봉상 접지전극의 임펄스접지임피던스 특성)

  • Lee, Bok-Hee;Lee, Su-Bong;Chang, Keun-Chul
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.19 no.2
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    • pp.63-68
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    • 2005
  • This paper describes the characteristics of effective impulse ground impedance of deeply driven ground rods combined with grounding grid or counterpoises with needles. The potential rises of the test ground electrodes were measured as a function of the rise time of applied impulse currents and the effective impulse ground impedances were calculated The impulse ground impedances of deeply driven ground rods strongly depend on the rise time of impulse currents and significantly reduced by the connection of grounding grids in parallel.

A study on the Interpretation Technique of Fall-Of-Potential Curve for Grounding Performance Evaluation of a Large Grounding Electrode Network (대규모 접지전극 망의 접지성능 평가를 위한 겉보기저항곡선의 해석에 관한 연구)

  • Choi, Jong-Kee;Ryu, Hee-Young;Lee, Dongil;Jung, Gil-Jo;Kim, Kyung-Chul
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.19 no.2
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    • pp.49-54
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    • 2005
  • Measuring ground resistance is a typical way of performance evaluation of a grounding electrode. Among various ground resistance measurement methods, FOP (Fall-Of-Potential) method has been widely used, especially in case of a relatively large grounding electrode such as a substation grounding mesh grid Since FOP measurement line has to be increased as the size of grounding electrode increases, however, it is often that securing long enough FOP-line is practically impossible. In this paper, a sophisticated interpretation method of FOP measurement ma which is applicable to large grounding electrode networks, is presented.

Modeling and Implementation of Safety Test Device for Grounding System Based on IEC 60364 (IEC 60364의 접지방식에 기반한 안전성 평가 시험장치의 모델링 및 구현에 관한 연구)

  • Kim, Soon-Sik;Han, Byeong-Gill;Lee, Hu-Dong;Ferreira, Marito;Rho, Dae-Seok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.6
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    • pp.599-609
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    • 2021
  • A novel grounding system, which is presented in IEC 60364, has been adopted since 2021. A safety evaluation for the human body on the grounding system is required due to the various characteristics of the touch voltage and current passing when the human body experiences an electric shock. The Korea Electrical Safety Corporation (KESCO) and Korea Electric Association (KEA) have been conducting a safety technical education on the grounding system. On the other hand, it is difficult to instruct the electrical safety manager because of a lack of safety evaluations for the test equipment on the grounding system. Therefore, this paper modeled and implemented a test device for a safety evaluation depending on the grounding system of IEC 60364. Namely, this paper presents the modeling of the test device for a safety evaluation using PSCAD/EMTDC S/W, which is composed of an AC grid section, s test device section on the grounding system, and a sub-device section. This paper implemented a test device for safety evaluation, which consisted of an AC grid section, TT grounding system section, TN-S grounding system section, and monitoring section. From the simulation and test results with the safety characteristics of the human body in the TT and TN-S grounding system, when the fault impedances are 0[Ω], 10[Ω], and 100[Ω], the currents passing through the human body in the TT grounding system are 104[mA], 87.4[mA], and 35.5[mA], respectively. The corresponding currents in the TN-S grounding system are 54.9[mA], 4.1[mA], and 0.4[mA], respectively. Based on the results, the protection performance for an electric shock to the human body in the TN-S system is better than the TT system. This can be improved when the existing grounding system is changed from the TT system to the TN-S system.