• Title, Summary, Keyword: Step and touch voltage

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Study on Measurement Error Reduction Technique when Measuring Touch and Step Voltage of Grounding System (접지시스템의 접촉전압 및 보폭전압 측정오차 감소 기법에 관한 연구)

  • Kim, Dong-Woo;Lim, Young-Bea;Lee, Sang-Ick;Choi, Myeong-Il;Moon, Hyun-Wook
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.1
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    • pp.188-195
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    • 2015
  • This paper presents measurement error reduction technique of touch and step voltage of grounding system based on numerical analysis. When measuring touch and step voltage of grounding system, auxiliary current probes should be located at suitable places. However, the auxiliary probes can not be located at suitable places in such cases as there are buildings and pavements. Therefore, in this paper, we provided measurement error reduction technique of touch and step voltage of grounding system according to the positions of auxiliary probes and angle between auxiliary probes. Also, measurement error analyses of touch and step voltage of grounding system have been conducted using more than one current probe. Based on these analyses, recommended positions of auxiliary probes within allowable measurement errors were presented.

Study of Touch and Step Voltages with Grounding Grid Using Electrolytic Tank and Analysis Program

  • Gil, Hyoung-Jun;Kim, Hyang-Kon;Kill, Gyung-Suk
    • International Journal of Safety
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    • v.9 no.2
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    • pp.1-5
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    • 2010
  • In order to analyze the potential rise of ground surface of grounding grid installed in buildings, the grounding simulator has been designed and fabricated as substantial and economical measures. This paper describes the study of touch and step voltages with grounding grid where earth leakage current is injected. To assess risk voltage of grounding grid, the grounding simulator and CDEGS program were used to obtain measured data and theoretical results of this study. The grounding simulator was composed of an electrolytic tank, AC power supply, a movable potentiometer, and test grounding electrodes. The potential rise was measured by grounding simulator, and the touch and step voltages were computed by CDEGS program. As a consequence, the touch voltage and step voltage above the grounding grid were very low, but were significantly increased near the edge of grounding grid.

Comparative Measurement of Touch and Step Voltages in Ground Systems (접지시스템에서 접촉전압과 보폭전압의 비교측정)

  • Kim, Hwang-Kuk;Moon, Byung-Doo;Park, Dae-Won;Kil, Gyung-Suk;Han, Ju-Seop
    • Proceedings of the KSR Conference
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    • pp.311-315
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    • 2008
  • Ground systems set the reference voltage level of circuit and system, and suppress Ground Potential Rise (GPR) by flowing fault currents to ground safely. There are several parameters which evaluate the performance of ground systems as ground resistance, touch voltage and step voltage. The touch and step voltages are especially important to ensure safety of human body. In this paper, we measured the touch and step voltages by injection of power frequency and surge current. Also correlation between touch and step voltages is compared and analyzed for the same ground systems.

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Analysis of Touch Voltage and Step Voltage using a Potential Distribution Characteristic (전위분포특성을 이용한 접촉전압과 보폭전압의 분석)

  • Lee, Bok-Hee;Jung, Hyun-Uk;Choi, Jong-Hyuk;Cho, Sung-Cheol;Beak, Young-Hwan;Lee, Kyu-Sun;Ahn, Chang-Hwan
    • Proceedings of the KIEE Conference
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    • pp.1474-1475
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    • 2006
  • This paper describes touch and step voltage in the reinforced concrete and steel poles. Ground surface potential rises were measured as a function of the separation between pole and ground rod. Touch and step voltage are calculated on the basis of the distribution of ground surface potential rises. As a result, touch and step voltages strongly depend on the position of installation of ground rod.

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Measurement and Analysis of Risk Voltages by Various Current Sources in Grounding System (다양한 전류원에 대한 접지시스템의 위험전압 측정과 분석)

  • Kil, Gyung-Suk;Moon, Byoung-Doo;Kim, Hwang-Kuk;Park, Dae-Won;Gil, Hyoung-Jun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.1
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    • pp.113-118
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    • 2009
  • Grounding systems set the reference voltage level of electric circuits and suppress the Ground Potential Rise (GPR) by flowing fault currents to the ground safely. There are several parameters which evaluate the performance of grounding systems as ground resistance, touch voltage and step voltage. The touch and step voltages, which is called "risk voltage", are especially important to ensure the safety of human body. This paper dealt with the influence of current sources with the different frequency components on the touch and the step voltages. Three types of current sources as commercial frequency, square wave, and surge with the fast risetime of $50\;ns{\sim}500\;ns$ were used to analyze the risk voltages in a grounding system. The risk voltages showed remarkable difference in the same current amplitude depending on the current sources, and increased linearly with the current amplitude in the same current source. From the experimental results, it was confirmed that the risk voltages can be evaluated by a small current application in large-scale grounding systems and the possible largest risk voltage can be calculated by a surge current with the risetime of 200 ns or a current source with the same frequency component as the surge current.

A Comparative Analysis of Step and Touch Voltages Depending on Two Test Voltage Waveforms

  • Jung, Kwang-Seok;Cha, Sang-Wook;Park, Dae-Won;Kil, Gyung-Suk;Oh, Jae-Geun
    • Transactions on Electrical and Electronic Materials
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    • v.12 no.4
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    • pp.152-155
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    • 2011
  • This paper presents a comparative analysis on step and the touch voltages generated by either a sine and a ring wave voltage generator; this analysis was done as a basic study in order to develop a small and lightweight ground meter. A ring wave generator using pulsed power technology was fabricated; an experimental grounding system specified in Institute of Electrical and Electronics Engineers standards 80 and 81 was installed. The step and the touch voltages, which were measured using comparable a sine and a ring waves in terms of magnitude and frequency, were equal. Using pulsed power technology, the weight of the fabricated ring wave generator could be reduced to one-fifth of that of a sine wave generator. Consequently, if a ground meter adopts the ring wave instead of a sine wave, it will be possible to reduce the weight of a ground meter and improve the efficiency of measurement.

Design and Application of a Ground Risk Voltage Measurement System (대지 위험전압 측정기의 설계 및 적용)

  • Jang, Un-Yong;Cha, Hyeon-Kyu;Cha, Sang-Wook;Park, Dae-Won;Kil, Gyung-Suk
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.24 no.3
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    • pp.250-255
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    • 2011
  • This paper dealt with the design, fabrication and application of a risk voltage measurement system (RVMS) which analyzes the step and touch voltages in electrical grounding systems. The RVMS supply 300 V and 1.4 A in ranges from 40 Hz to 1 kHz as the test power source. A DAQ module having resolution of 400 kS/s and 16 bit is equipped with 7 inputs for measuring voltage and current. Also, a noise elimination algorithm of digital filter was applied to reduce the measurement error caused by external noises as a commercial frequency current. The performance of the RVMS was evaluated by measurement of the step and touch voltage according to the IEEE standard 80 and 81 in a grounding system with a 10 m counterpoise. The result showed that the RVMS analyzes the risk voltage with the error below 5%.

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.

A Method for Evaluating Electric Shock Hazards Based on Human Body Current (인체전류를 기반으로 하는 감전의 위험성 평가방법)

  • Lee, Bok-Hee;Yoo, Yang-Woo;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.108-114
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    • 2011
  • In order to mitigate the possible hazards from electric shock due to the touch and step voltages, the high resistivity material such as gravel is often spread on the earth's surface in substations. When the grounding electrode is installed in two-layer soil structures, the surface layer soil resistivity is different with the resistivity of the soil contacted with the grounding electrodes. The design of large-sized grounding systems is fundamentally based on assuring safety from dangerous voltages within a grounding grid area. The performance of the grounding system is evaluated by tolerable touch and step voltages. Since the floor surface conditions near equipment to be grounded are changed after a grounding system has been constructed, it may be difficult to determine the tolerable touch and step voltage criteria. In this paper, to propose an accurate and convenient method for evaluating the protective performance of grounding systems, the propriety of the method for evaluating the current flowing through the human body around on a counterpoise buried in two-layer soils is presented. As a result, it is reasonable that the grounding system performance would be evaluated by measuring and analyzing the current flowing through the human body based on dangerous voltages such as the touch or step voltages and the contact resistance between the ground surface and feet.

An Analysis of the Ground Surface Potential Rise and Hazardous Voltages Caused by Impulse Currents (임펄스전류에 의한 대지표면전위상승 및 위험전압의 분석)

  • Lee, Bok-Hee;Lee, Kyu-Sun;Choi, Jong-Hyuk;Seong, Chang-Hoon
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.25 no.4
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    • pp.117-123
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    • 2011
  • Lightning and switching surges propagating through the grounding conductors lead to transient overvoltages, and electronic circuits in information technology systems are very susceptible to damage or malfunction from the electrical surges. Surge damages or malfunctions of electrical and electronic equipment may be caused by potential rises. To solve these problems, it is very important to evaluate the ground surface potential rises and hazardous voltages such as touch and step voltages at or near the grounding systems energized by electrical surges. In this paper, the performance of grounding systems against the surge current containing high frequency components on the basis of the actual-sized tests is presented. The ground surface potential rises and hazardous voltages depending on impulse currents for vertical or horizontal grounding electrodes are measured and analyzed. Also the touch and step voltages caused by the impulse currents are investigated. As a result, the ground surface potential rises, the touch and step voltages near the grounding electrodes are raised and the conventional grounding impedances are increased as the front time of the injected impulse currents is getting faster.