• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.244-246
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• 2002

In this paper, We studied about effects of human safety due to leakage current on the point of cable connection for outdoor electrical facility in the submerged condition and conducted its evaluation in the testing field. In this case, the reason of leakage on the point of cable connection is caused by formation of electrical pass between the grounded outdoor electrical facility and the enclosure of electrical facility which is connected to grounding system.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.247-249
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• 2002

In this paper, We studied, about effects of human safety due to leakage current on the point of cable connection for outdoor electrical facility in the submerged condition and conducted its evaluation in the testing field. In this case, the reason of leakage on the point of cable connection is caused by formation of electrical pass between the grounded outdoor electrical facility and the other outdoor electrical facility which is disconnected to grounding system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.4
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• pp.56-61
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• 2009

This paper presents the ground surface potential profiles and hazard voltages around the metallic structure connected to a small-sized model ground electrode. Because it is very difficult to draw valid conclusions concerning a general grounding problem from actual field data, scale model tests can be used to determine the touch and stop voltages and surface potential profiles around ground electrode. In this work, a hemispherical vessel with a diameter of 1,100[mm] was employed to simulate uniform soil. As a result, the ground surface potential around the ground electrode was significantly raised In particular the ground surface potential at the just upper point of ground rod was higher than other points. When the buried depth of ground rod is increased, the ground surface potential and step voltage were lowered but the touch voltage was elevated.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1489_1490
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• 2009

Ground impedance is changed according to frequency of the current injected into the grounding system. Because the lightning surge gives a broad frequency spectrum from some ten Hz to a few MHz, frequency dependance of ground impedance must be evaluated. In this paper, we have constructed 10m, 30m, 50m counterpoise and evaluated frequency dependance of ground impedance. Also we have evaluated frequency dependance of ground impedance according to current injection point. As a result, long counterpoises have low ground resistance, but ground impedances of those are significantly increased in the range of high frequency. In the case that currents are injected into the center of counterpoise, the ground impedance is most lower than any other injection point. Also, additory ground rod of 1.8m long affect ground impedance decrease.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.10
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• pp.68-73
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• 2006

As in the measurement of ground resistance by using the 3 point fall-of-potential method, it is known that the distance of current electrode should be at the point of showing the plateu on the potential curve. But the problem is that it my be practically impossible to meet the condition in actual sites. For solving such a situation, this paper provides the least distance of current electrode according to the analysis for the test-field measurement showing that it is feasible to measure the ground resistance in the two in current electrode distance as the length of driven-rod type electrode and the some district length of mesh electrode.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.7
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• pp.966-973
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• 2011

Power distribution onboard vessel is typically configured as ungrounded system due to the ability to continuously supply electric power even when an earth fault occurs. The impedance connections between 3 phase power lines and hull cause the line-to-hull voltages to become unstable and increased in case the impedances are unbalanced, bringing the situation susceptible to electric shock and deterioration of insulation material. Also the line-to-hull voltage can reach to a certain maximum value in the steady state depending on the distributed capacitances and grounding resistances between lines and hull. This study suggests how to find and calculate the maximum line-to-hull voltage in view of magnitude and phase angle based on the vector diagram.

• Proceedings of the KIEE Conference
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• 2007.11b
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• pp.282-284
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• 2007

최근 가로등에 의한 감전사가 사회적 관심을 끌고 있다. 가로등은 감전사고의 위험성이 높은 도로시설물로 철저한 감전사고 예방대책이 요구되지만 누전 차단기에 의존하는 기존의 대책으로는 사고예방에 한계가 있다. 본 연구에서는 기존의 중성점 접지 방식을 개선하고자 가로등 전용 변압기를 설치하여 침수 우려 시 중성점 접지를 개방하고 순간적인 접지스위칭을 실시함으로써 접지시스템과 비 접지시스템의 장점을 모두 유지할 수 있게 함으로써 원활한 시스템운전을 보장하면서도 감전사고를 획기적으로 줄일 수 있는 방안을 제시하였다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.10
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• pp.1811-1816
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• 2011

This paper describes switching surge analysis for reclosing decision in 345kV combined transmission line with GIL. Reclosing operation should be decided based on the detailed technical analysis in combined transmission line because this line includes power cable section which is week on insulation. Insulation of power cable can be breakdown at the week point in case of reclosing moment. Therefore the detailed analysis has to be carried out by considering several conditions such as charging rate, inserting resistance, arrester, length ratio of power cable section, grounding resistance, etc. Analysis is performed by EMTP/ATP.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.140-144
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• 1988

This paper describes requirements for cogenerating in parallel with utility. Cogenerating is the simultaneous generation of energy in two or more forms, usally electricity and heat. Cogeneration is most energy efficient when generating in paralled will the electric utility, but requires proper control and protection. When onsite generation and utility systems are operated in parallel, there are many factors. such as operation mode. point of connection, grounding, synchronizalion. protective relaying, metering, and the like, that must be considered to provide safe and efficient operation.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1741-1743
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• 2001

This paper presents the induced ground potential rise distributions on several ground electrodes buried nearby. These experiments were conducted with the impulse currents as a function of the ground electrodes types and distances from the current injection point. The ground potential is significantly induced in the vicinity of ground electrodes, and the induced ground potential rises can caused unwanted erratic operation of electronic device.