• Title/Summary/Keyword: Electric Potential Rise

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A Rise in Electric Potential of Telecommunication Line for Electric Power System by Lightning Surges (뇌서지에 의한 전력통신선로의 전위상승)

  • Lee, Bok-Hee;Chang, Sug-Hun
    • Proceedings of the KIEE Conference
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    • 1997.07e
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    • pp.1718-1720
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    • 1997
  • This paper deals with n rise in electric potential of telecommunication line for electric power system by lightning surges. When $1.2/50{\mu}s$ and $8/20{\mu}s$ impulse voltage and current were applied on telecommunication cable, the voltage waveforms at the end terminal and equipment were measured. The telecommunication lines, which consist of 60 conductors and 3.5km in length, have some surge protectors such as preposition lightning arrester and TVSS. In each case, the rise in electric potential was measured for differential mode and common mode, respectively. Also, the rise in ground potential and the induced voltages were measured and analyzed. As a result, a significant rise in ground potential was observed for lightning surge. It can cause failure or malfunction of telecommunication systems.

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Calculation of Electric Potential Rise of Horizontal Grounding Electrode Caused by Lightning Stroke Currents (뇌격전류에 의한 수평접지극의 전위상승 계산)

  • Lee, Bok-Hee;Cho, Sung-Chul
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.27 no.12
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    • pp.81-86
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    • 2013
  • An electric potential rise of the grounding electrode developed by the lightning stroke currents should be calculated for the purpose of effective protection of electrical and electronic equipment. In this paper, the electromagnetic model was applied to calculate the harmonic impedance of grounding electrode. Also the empirical equation related to the permittivity and resistivity of soil was used. The lightning current waveforms, which are expressed by the Heidler's equation, were used in order to calculate accurately transient electric potential rises. The transient voltage was obtained by using the simulated harmonic impedance and the lightning current in frequency domain. Finally, the transient voltages of horizontal grounding electrode(10m) under lightning stroke currents were calculated by IFFT(Inverse Fast Fourier Transform).

A Simulation Modeling for Rail Potential and Leakage Current Analysis in DC Traction System (직류 전기철도에서의 레일전위 및 누설전류 해석을 위한 시뮬레이션 모델링)

  • Yoon, Yim-Joong;Lee, Jong-Woo
    • Proceedings of the KSR Conference
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    • 2008.11b
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    • pp.196-201
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    • 2008
  • In DC traction systems, a part of feedback current returning through rails becomes leakage current, illumination on a metal laid underground results from the leakage current to ground. To prevent the leakage current on rails, feedback rails almost have insulated with the ground. Insulation between rails and the ground causes that the earth method changes a isolated method in DC traction systems. the rail potential rise results in the isolated method. the rail potential rise causes an electric shock when a person touches the ground and rolling stock. To decrease the rail potential rise and leakage current, there are methods for reducing the feedback resistance and current of rails, increasing the leakage resistance, decreasing the distance between substations. But it are necessary to forecast and analyze the rail potential and amplitude of leakage current. In this paper, we modeled DC traction systems and feedback circuit to simulate the rail potential and amplitude of leakage current using PSCAD/EMTDC that is power analysis program, forecasted the rail potential and amplitude of leakage current about changing various parameters in the electric circuit. By using the simulation model, we easily will forecast the rail potential and amplitude of leakage current in case of a level of basic design and maintenance in electric railway systems, valuably use basic data in case of system selection.

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Measurements of the Ground Resistance using the Test Current Transition Method in Powered Grounding Systems (측정전류전이법을 이용한 운전중인 접지시스템의 접지저항 측정)

  • Lee, Bok-Hui;Eom, Ju-Hong;Kim, Seong-Won
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.51 no.8
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    • pp.347-353
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    • 2002
  • This paper presents an accurate method for measuring the ground resistance in powered grounding system. Most of substations and electric power equipments are interconnected to an extensive grounding network of overhead ground wires, neutral conductors of transmission lines, cable shields, and etc. The parasitic effects due to circulating ground currents and ground potential rise make a significant error in measuring the ground resistance. The test current transition method was proposed to reduce the effects of stray ground currents, ground potential rise and harmonic components in measurements of the ground resistance for powered grounding systems. The instrumental error of the test current transition method is decreased as the ratio of the test current signal to noise(S/N) increases. It was found from the test results that the proposed measuring method of the ground resistance is more accurate than the conventional fall-of-potential method or low-pass filter method, and the measuring error was less than 3[%]when S/N is 10.

A Study on Separation Distance Calculation Model for Limitation of Earth Potential Rise nearby Tower Footings (송전철탑 부근의 대지전위 억제를 위한 이적거리 산정모델 연구)

  • Choi, Jong-Kee;Lee, Dong-Il
    • Proceedings of the KIEE Conference
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    • 2007.11a
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    • pp.212-213
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    • 2007
  • In case of a line-to-ground fault at transmission lines, a portion of fault current will flow into the earth through the footings of the faulted tower causing electrical potential rise nearby the faulted tower footings. In this situation, any buried pipelines or structures nearby the faulted tower can be exposed to the electrical stress by earth potential rise. Although many research works has been conducted on this phenomena, there has been no clear answer of the required separation distance between tower footings and neary buried pipeline because of its dependancy on the soil electrical charactersics of the concerned area and the faulted system. In this paper, an analytical formula to calculate the requried sepeartion distance from the faulted tower has been derived.

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Analyses of Earth Surface Potentials Depending on Soil Structures (대지구조에 따른 대지표면전위의 분석)

  • Lee, Bok-Hee;Baek, Young-Hwan;Jung, Hyun-Wook
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.10
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    • pp.1796-1801
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    • 2007
  • This paper presents electric potential rise on the surface of the earth due to ground currents. It is the aim of this paper to propose fundamental data relevant to the earth surface potentials depending on the soil structures. The earth potential rise, touch and step voltages in the immediate vicinity of the ground rod of a distribution pole were measured and analyzed. The results described in this paper are based on laboratory measurements which were intended to simulate conditions existing in actual installations. As a result, the earth surface potential rise, touch and step voltages strongly depend on the soil structure. The highest earth surface potential occurred in the vicinity of the top of ground rod. When the ground rod was installed in the distance range of $1{\sim}1.5\;m$ from distribution pole, the highest touch voltages appeared near the place of 1 m on the straight line connecting the distribution pole to ground rod.

Potential Ruse as a function of the Buried Depth for Structure (구조체의 매설깊이에 따른 전위상승)

  • Gil, Hyoung-Jun;Kim, Dong-Ook;Kim, Dong-Woo;Lee, Ki-Yeon;Kim, Hyang-Kon
    • Proceedings of the KIEE Conference
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    • 2006.07e
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    • pp.27-28
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    • 2006
  • This paper deals with an approach to the reduction of potential rise according to the buried depth of structure. In order to analyze the surface potential rise of structure, an electrolytic tank which simulates the semi-infinite earth has been used. The potential rise has been measured and analyzed for types of structure using an electrolytic tank experimental apparatus in real time. The structure models were designed through reducing real buildings and fabricated with two types on a scale of one-one hundred sixty When a test current flowed through structure models, the potential rise of outline frame type(structure model A) was more high than that of electric cage type(structure model B). The distributions of surface potential rise are dependent on the buried depth of structure model.

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Analysis of Conductive Interference nearby High Voltage Power Lines under Fault Condition (송전선로 지락시 철탑 인근의 대지전위간섭 해석모델)

  • Choi, J.K.;Lee, W.K.;Ryu, H.Y.;Shin, B.H.;Son, K.M.;Kim, T.Y.;Hwang, G.C.
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.466-467
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    • 2008
  • In case of a line-to-ground fault at transmission lines, a portion of fault current will flow into the earth through the footings of the faulted tower causing electrical potential rise nearby the faulted tower footings. In this situation, any buried pipelines or structures nearby the faulted tower can be exposed to the electrical stress by earth potential rise. Although many research works has been conducted on this phenomena, there has been no clear answer of the required separation distance between tower footings and neary buried pipeline because of its dependancy on the soil electrical charactersics of the concerned area and the faulted system.

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Grounding Characteristic Analysis of Plate Electrodes

  • Kim, Sung-Sam;Kim, Ju-Chan;Koh, Hee-Seog
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.21 no.4
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    • pp.53-60
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    • 2007
  • In this study, an experiment on the efficient construction method of plate electrodes, the influence of electric potential interference in plate electrodes, and building foundations were explored. The experimental result of the electric potential measurement was taken on the basis of the direction of movement and the condition in which the plate electrodes are laid underground in building foundations. It shows that the construction method of laying the plate electrodes vertically exhibits a more efficient reduction of electric potential in a diagonal direction and on an X axis than laying plates horizontally. For plate electrode construction in an area that has uniform conditions, the parallel joint construction method is more effective than a single construction to reduce earth electrical potential and ground resistance. In addition, a straight arrangement performs well in ground efficiency, compared to the parallel arrangement.

Ground Surface Potential Distribution near Ground Rod Associated with Soil Structures (대지구조에 따른 접지봉 주번의 대지표면전위분포)

  • Lee, Bok-Hee;Jung, Hyun-Uk;Baek, Young-Hwan
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.21 no.1
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    • pp.142-147
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    • 2007
  • This paper presents the distributions of ground surface potential rises as functions of soil structure and buried depth of ground rod. To propose fundamental data relevant to the reduction of electric shock of human beings due to ground surface rise, the ground surface potential rises near the ground rod were computed and measured. Ground surface potential rises near ground rod strongly depend on the soil structure, and an increase of the buried depth of ground rod results in a decrease of the ground surface potentials. The maximum ground surface potential appeared at the just above point of ground rod. Also, the measured results were in reasonably agreement with the data computered by grounding analysis program.