• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1027-1036
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• 2007

Since the opening of the Seoul Metro in 1974, the electric railway passengers have been increased rapidly and as the advanced equipments(OC,PSD) were introduced, additional power facilities were built in a limited area for the comfortable transportation environment. Present grounding system were built according to old Electric equipment standards and all the electric signal, communication and electronic equipments were built only for the purposes of protecting building structure, people and electronic equipments. Grounding system which was additionally built in the limited area caused problems with the building structure and it caused secondary damages when earth fault happens. One of the problems is grounding system of the building structure; grounding system does not work properly since grounding equipments are not separated from each other. So, existing grounding system needs to be improved and unified grounding system in the building should be established. The purposed of this study is to analyze all the grounding systems that had been built in different year and to establish unified grounding system of Seoul Metro.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2009년도 추계학술대회 논문집
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• pp.315-318
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• 2009

Electric shock is the accident caused by the current through a person or animal's body. That is characterized by the physiological effects. In this paper, we evaluate performance of protection against electric shocks for TT and TN grounding systems which are used by a low voltage consumer nowadays. The performance of protection against electric shocks for TT grounding system is very excellent in equipotential area of the third class grounding, but the performance is poor outside the equipotential area. The performance of protection against electric shocks for TN grounding system is excellent because the potential difference is less than 50V. Accordingly, the performance of protection for TN grounding system is good as compared with that for TT grounding System.

• 조명전기설비학회논문지
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• 제25권11호
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• pp.91-97
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• 2011

In Korea, characterized in most cases by limited area or high earth resistivity, it is likely to design narrow distances between grounding conductors, with a view to keeping ground resistance and touch voltage below the safety margin values. A new grounding method is suggested, making use of double meshes, to lower touch voltage in a confined area, since it is difficult to lay the plugs under the ground with narrow gaps between them on a limited site. For the presentation of a new model, the suggested grounding system has been analyzed and studied in ground resistance, touch voltage and step voltage, using IEEE Std. 80 calculations and computer simulations.

• 조명전기설비학회논문지
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• 제17권5호
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• pp.103-110
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• 2003

대지 저항률이 높은 암반, 사력층 지역에서의 접지 저항은 일반적인 봉형 접지 전극으로는 얻기가 거의 불가능 하며 원하는 저항값을 얻기 위해서는 깊이 매설한 접지 전극과 접지 저항 저감제를 충분하게 사용하는 코어링 접지 방식을 채택하여 시설하는 것이 적절하다고 판단된다. 본 연구는 둥가반경 개념을 이용하여 코어링 접지 전극의 반 경이 확장되는 것을 보였으며 이릎 토대로 낮은 접지 저항이 얻어지고, 제주지역과 같이 고저항 지대에서의 각 토 양의 대지 저항률을 추정함으로써 다른 고저항 지대에서의 접지공사시 개략적인 접지저항을 예측하여 기초 자료로 사용할 수 있도록 하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.509-511
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• 2004

Grounding rods as a discharge path are normally used to ensure the safety of human beings and facilities from the over-voltages and the over·current. Each grounding mode class 1, class 2, class 3, special class 4- has prescribed ground resistance values which are kept by the utilities. However, in the distribution system, it is very difficult for grounding rods to obtain the prescribed ground resistance values because of the limits of installation space. Therefore, in this paper, the grounding effects of the grounding copper bands which are recently developed to use efficiently in small area and the grounding rods are compared by testing the ground resistance values, ground potential rise(GPR), and step voltage in various cases.

• 전기학회논문지
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• 제61권9호
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• pp.1374-1379
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• 2012

Urban rail transit tends to global grounding system in order to control ground potential rise and potential differences between electric equipments. In addition, global grounding system can discharge the large capacity surge current to the ground safely. Since some railway electric equipments are installed all section of line, the global grounding system connected with the connecting grounding wire is more effectively. However, if the fault occurred in the connecting grounding wire area, some dangerous voltage is generated. So, the installation of additional grounding rod will be required. In this study, the global grounding system is simulated using CDEGS program to analyze the divergence spacing of additional ground rod depending on dangerous electric potential characteristics. Grounding net of the each station is modelled in depending on the size of the platform, and the spacing of the connecting grounding rod are compared 50m, 100m, 250m and 400m. Simulation results considering of earth resistivity and underground condition of the connecting grounding wire, spacing of the connecting grounding rod is that less than 250m to spacing of the ground rod was appropriately confirmed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.2064-2067
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• 2000

In our country, most region is composed of mountains and people have recently been displeased with the construction of the substations in their vicinity so the substations newly built are mainly constructed with GIS system in the small area that has high soil resistivity near mountain. Therefore, nowadays the design of substation grounding system has been difficult, and the additional considerations are needed. UC substation was also difficult to design the grounding system because of so small substation area and high soil resistivity. This paper shows the examples of reducing the grounding system resistance reasonably by using several ways. Designing the ground grid electrode in the access road, deep electric earth probe, changing the substation soil with the law level resistivity soil. This report deals with the computer simulation of the grounding system resistance about the ways illustrated above.

• 대한원격탐사학회지
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• 제34권1호
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• pp.17-24
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• 2018

Grounding line of a glacier or ice shelf where ice bottom meets the ocean is sensitive to changes in the polar environment. Recent rapid changes of grounding lines have been observed especially in southwestern Antarctica due to global warming. In this study, ERS-1/2 and Sentinel-1A Synthetic Aperture Radar (SAR) image were interferometrically acquired in 1996 and 2015, respectively, to monitor the movement of the grounding line in the western part of Ronne Ice Shelf near the Antarctic peninsula. Double-Differential Interferometric SAR (DDInSAR) technique was applied to remove gravitational flow signal to detect grounding line from the interferometric phase due to the vertical displacement of the tide. The result showed that ERS-1/2 grounding lines are almost consistent with those from Rignot et al. (2011) which used the similar dataset, confirming the credibility of the data processing. The comparison of ERS-1/2 and Sentinle-1A DDInSAR images showed a grounding line retreat of $1.0{\pm}0.1km$ from 1996 to 2015. It is also proved that the grounding lines based on the 2004 MODIS Mosaic of Antarctica (MOA) images and digital elevation model searching for ice plain near coastal area (Scambos et al., 2017), is not accurate enough especially where there is a ice plain with no tidal motion.

• 전기학회논문지P
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• 제62권3호
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• pp.139-144
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• 2013

In Korea, where most of the sites are narrow in space and their earth resistivity is relatively high, the spaces between grounding conductors are likely to be designed narrow in order to lower ground resistance and dangerous voltage below to the permitted safety values. In addition, ground nets are in the shape of square or rectangle depending on the location and size of the facilities and ground contact area, and inner conductors are laid out in grids like the pattern of nets. Nevertheless, with the existing designs, the marginal voltage for safety gets higher as the area is extended further outside, in comparison with that of inner mesh grounding, thus causing much difficulty maintaining them equipotential, and there exist limits in the burial, grounding grid design considering the dangerous voltage of muti-layered model in the constrained sites, was studied.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 E
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• pp.2352-2354
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• 1999

The purpose of substation grounding system is to provide reference potential with power system and protect field workers from electrical shock resulted from unsymetrical power system faults. For this purpose, grounding grid should be designed to maintain max, touch voltage under safety criteria in fault conditions. It is difficult, however, to design a safe grounding grid at very resistive or narrow area. This paper describes an example of substation grounding grid design procedures in such areas with very severe design conditions. By using grounding conductors, which is located close to earth surface, earth surface potential could be controlled effectively, so that maximum touch voltages is to be maintained under safety criteria.