• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1453-1454
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• 2007

A street light is an electrical equipment to improve the traffic safety and the security for people in night. However, many accidents due to electric shock have happened in recent, people were interested in the safety of electrical facilities. And people want to know the danger by touch and step voltages. When the electric power lines fall down on the ground, the fault current flows to ground rod and the potential near the ground rod is increased to induce the high touch and step voltages. In this paper, we installed different ground rods with a street light and investigated the electrical potential according to ground methods and the types of ground rod. Finally, we examined the electrical facilities with the experimental result and present the improved technical data for the safety from electric shock

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.10a
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• pp.337-340
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• 2008

When high surge voltage invaded into the ground rod contacted with ground water, the ionization phenomena are happened in the water. Although some researchers have surveyed the ionization phenomena in soil, they have just analyzed the variation of the ground resistance. The most important role of the ground rod is to elect human beings from potential rise and to dissipate energy to the earth safely. In this wort we presented the method evaluating the potential reduction and energy dispersion. Also we analyzed theses factors as a function of charging voltages at the water resistivity of $50\;{\Omega}{\cdot}m$ using the Matlab Program. As a result the ground rod potential was reduced to 38 kV by ionization just below breakdown voltage. The energy more than half of the total injected energy was dispersed through the grounding electrode caused due to ionization.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.290-292
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• 2003

The intake tower of D-dam located in a mountainous area positioned in the left side of the dam and its structure installed alone on the water surface then, can become target of direct lightening. To protect the intake tower from the direct lightening and indirect-lightening, lightening rod installed in the top area of the intake tower and ground pole laid under the surrounding ground. however, because the surrounding ground almost consists of a rock, it is very difficult to obtain the grounding resistance. It is main object to examine the construction plan of the optimum lightening rod equipment and ground pole with measuring the earth specific resistance of the around of the intake tower which is the scheduled area to lay the ground pole with the Wenner's 4-electric pole method and the Schlumberger's method. and using the analysis tool, ESII.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.351-354
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• 2006

This paper deals with the potential interferences between ground rod and counterpoise. The ground potential rise and coefficient of potential interference were measured by using the hemispherical water tank grounding simulator and calculated from CDEGS program as functions of the configuration and size of grounding electrodes and the distance between grounding electrodes. The ground potential un and potential interference coefficient strongly depend on the distance between grounding electrodes, the arrangement and size of grounding electrodes.

• 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.

• 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.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.7
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• pp.41-48
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• 2009

Grounding impedance depends on the frequency of current flowing into a grounding system lightning in particular has a broad frequency spectrum from some tens of Hz to a few MHz. So the grounding impedance related to transient currents such as lightning should be measured. In this paper, the grounding impedances of vertically-driven ground rods of 10, 30 and 48[m] long are measured and analyzed as functions of the frequency of injected current and the feeding point. As a result, the longer the ground rod is, the lower the steady-state ground resistance is. However the grounding impedance of a vertically-driven ground rod at a high frequency is significantly increased. It is not always true that low grounding impedance follows from a low steady-state ground resistance. It is important to evaluate the high frequency performance of grounding systems for protection against lightning.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.155-157
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• 1997

This paper presents the results of an experimental investigation of ground impedance in the low frequency region regarding the transiant state on the soil and ground electrodes(rod, electric rod with needles, electric mesh). The grounding resistance playing an important part in substation grounding designs is measured. Especially, the reduction effect of ground impedance by using the electric rod with needles in the soils are presented.

• 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.

• 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.