http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
조용승(Yong-Seung Cho),이봉(Feng Li),유재덕(Jae-Duk Yoo),김동성(Dong-Sung Kim),김기복(Ki-Bok Kim),이복희(Bok-Hee Lee) 한국조명·전기설비학회 2010 한국조명·전기설비학회 학술대회논문집 Vol.2010 No.9월
This paper presents the ground surface potential rises caused by a counterpoise buried in two-layered soils. To propose fundamental data relevant to the risk reduction of electric shock of human beings, the ground surface potential rises near the counterpoise were computed by CDEGS program. Touch and step voltages are calculated on the basis of the distribution of the ground surface potential rises. As a result, touch and step voltages, ground surface potential rises depend on the soil resistivity of installation point of counterpoise in the two-layered soil structure.
조용승(Yong-Seung Cho),양순만(Soon-Man Yang),유양우(Yang-Woo Yoo),이강수(Kang-Soo Lee),이복희(Bok-Hee Lee) 한국조명·전기설비학회 2011 한국조명·전기설비학회 학술대회논문집 Vol.2011 No.5월
In these days, Grounding system of large buildings are constructed by the combination of foundation structures and grounding grids. Because the distances between the grounding grid and auxiliary electrodes are not enough in down areas, it is very difficult to measure the ground resistance of large-scaled system. In some cases, auxiliary electrodes are located in grounding grid. It is very wrong to precisely measure the ground resistance. For this reason, this paper presents the method of measuring the ground resistance by using the vertically-placed auxiliary electrodes. The potential distribution curves between the grounding grid being measured and the current auxiliary electrode for different-sized grounding grid are calculated. The location of the potential auxiliary electrodes to measure the ground resistance with the measurement accuracy less than 5% is determined.
임펄스전류에 의한 수직 접지전극 주변에서 전위간섭 영향 분석
조용승(Yong-Seung Cho),이복희(Bok-Hee Lee) 한국조명·전기설비학회 2011 한국조명·전기설비학회 학술대회논문집 Vol.2011 No.11
When the ground current is injected into the adjacent ground electrode, the potential interference is caused between grounding electrodes. Ground potential interferences have been largely studied with power frequency fault currents. Many attempts to find a frequency-dependent grounding impedance report that the grounding impedance at high frequency is very different with the ground resistance. In this paper, the potential interference effects in the vicinity of vertical ground rod of 4 m long are measured according to the front time of the injected impulse current. The ground potential rises around the test ground rod of 4 m were measured and discussed. As a result, the ground potential rises and potential interference factor are decreased with decreasing the conventional grounding impedance. It was found that the lowering of conventional grounding impedance is critical to reduce the ground potential interference effects.
접지전류의 주파수에 따른 수직 접지전극 주변에서 전위간섭 영향 분석
이복희(Bok-Hee Lee),조용승(Yong-Seung Cho),최종혁(Jong-Hyuk Choi),양순만(Soon-Man Yang) 한국조명·전기설비학회 2011 조명·전기설비학회논문지 Vol.25 No.12
When the ground current is injected into the adjacent ground electrode, the potential interference is caused between ground electrodes. the ground potential interferences have been largely studied with power frequency fault currents. Many attempts to find the frequency-dependent grounding impedance report that the high frequency grounding impedance is very different with the ground resistance. This paper presents experimental data on the frequency-dependent potential interference effects in the vicinity of ground rod. The ground potential rises around the test ground rod of 4 or 6[m] were measured and discussed. As a result, the ground potential rises and potential interference factor are decreased with decreasing the grounding impedance. It was found that the lowering of grounding impedance is critical to reduce the ground potential interference effects.
유재덕(Jae-Duk Yoo),조용승(Yong-Seung Cho),이복희(Bok-Hee Lee) 한국조명·전기설비학회 2010 조명·전기설비학회논문지 Vol.24 No.12
This paper deal with an analysis of the ground surface potential profiles using a hemispherical scaled-model. 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 ground surface potential profile around the grounding electrodes according to the configuration of grounding electrodes. In this work, a hemispherical vessel with a diameter of 1,100 [㎜] was employed to simulate uniform soil and CDEGS program was employed to compare the measured and simulated results. As a result, the ground surface potential around the grounding electrode was significantly raised and the ground surface potential at the just upper point of ground electrode particularly was higher than other points. The ground surface potential of counterpoise was higher than other grounding electrodes such as mesh and grounding rods and the ground surface potential strongly depends on the frequency responses of grounding electrodes. Also the results measured with the small-sized model were in reasonably agreement with the data obtained from simulation.
준평등전계에서의 SF₆와 N₂가스의 뇌임펄스전압에 대한 절연파괴특성
이복희(Bok-Hee Lee),김동규(Dong-Kyu Kim),이봉(Feng Li),조용승(Yong-Seung Cho),양순만(Soon-Man Yang),신희경(Hee-Kyung Shin),김기복(Ki-Bok Kim) 한국조명·전기설비학회 2010 한국조명·전기설비학회 학술대회논문집 Vol.2010 No.5월
This paper presents breakdown characteristics of a quasi-uniform electric field gap in SF? and N₂ gas as a function of gas pressure. The 1.2/50 [㎲] impulse voltage is applied. The gas pressure having the breakdown voltage of 150 [㎸<SUB>p</SUB>] in N₂ was 3.3 times higher than in SF?. Also the breakdown voltages for the positive polarity are greater than those for the negative polarity.
이복희(Bok-Hee Lee),김동규(Dong-Kyu Kim),이봉(Feng Li),조용승(Yong-Seung Cho),양순만(Soon-Man Yang),신희경(Hee-Kyung Shin),김기복(Ki-Bok Kim) 대한전기학회 2010 대한전기학회 학술대회 논문집 Vol.2010 No.7
본 논문은 N₂가스 중 준평등전계에서 1.2/50 [㎲] 표준 뇌 임펄스전압을 인가할 때 전극간 간격에 따른 절연파괴특성을 나타내었다. 정극성 · 부극성의 1.2/50 [㎲] 표준 뇌임펄스전압을 인가전압으로 사용하였으며, 준평등전계를 모의하기 위해서 스테인레스스틸의 구-평판전극을 사용하였다. 전극간 간격을 7.5 [㎜], 14 [㎜], 20 [㎜], 30 [㎜]로 증가시키면서 동일한 가스압력인 0.5 [㎫]에서 절연파괴특성을 파악하기 위하여 절연파괴전압(BDV??)과 전구방전전류, 방전광 파형을 측정하고 절연파괴특성을 검토하였다. 실험결과 전극간 간격이 증가함에 따라 절연파괴전압이 높아졌으며, 전계가 불평등화 되면서 평균절연파괴 전계강도는 낮아졌다.
2층 대지모델에서 대지저항률의 비율에 따른 접촉전류에 의한 감전의 위험성 분석
이복희(Bok-Hee Lee),김태기(Tae-Ki Kim),조용승(Yong-Seung Cho),최종혁(Jong-Hyuk Choi) 한국조명·전기설비학회 2011 조명·전기설비학회논문지 Vol.25 No.6
The touch or step voltages which exist in the vicinity of a grounding electrode are closely related to the earth structure and resistivity and the ground current. The grounding design approach is required to determine the grounding electrode location where the hazardous voltages are minimized. In this paper, in order to propose a method of mitigating the electric shock hazards caused by the ground surface potential rise in the vicinity of a counterpoise, the hazards relevant to touch voltage were evaluated as a function of the soil resistivity ratio p₂/p₁ for several practical values of two-layer earth structures. The touch voltage and current on the ground surface just above the test electrode are calculated with CDEGS program. As a consequence, it was found that burying a grounding electrode in the soil with low resistivity is effective to reduce the electric shock hazards. In the case that the bottom layer soil where a counterpoise is buried has lower resistivity than the upper layer soil, when the upper layer soil resistivity is increased, the surface potential is slightly raised, but the current through the human body is reduced with increasing the upper layer soil resistivity because of the greater contact resistance between the earth surface and the feet. The electric shock hazard in the vicinity of grounding electrodes is closely related to soil structure and resistivity and are reduced with increasing the ration of the upper layer resistivity to the bottom layer resistivity in two-layer soil.
Cho, Yong Seung 慶北大學校 1988 論文集 Vol.45 No.-
4-차원상의 SU(2)-번들의 분류 번들은 Hopf-번들, SU(2)→S^7→S^4 이다. 본 논문에서는 이 분류 번들에 유한군 작용을 구성했다. 일반 4-차원 다양체가 같은 isotropy 고정점을 갖는다면, 디그리(degree)가 일인 함수를 정의하여 유도된 일반 번들에 유한군 작용을 구성했다. 그리고 그 예를 주었다.