• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 E
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• pp.1718-1720
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• 1997

This paper deals with n rise in electric potential of telecommunication line for electric power system by lightning surges. When $1.2/50{\mu}s$ and $8/20{\mu}s$ impulse voltage and current were applied on telecommunication cable, the voltage waveforms at the end terminal and equipment were measured. The telecommunication lines, which consist of 60 conductors and 3.5km in length, have some surge protectors such as preposition lightning arrester and TVSS. In each case, the rise in electric potential was measured for differential mode and common mode, respectively. Also, the rise in ground potential and the induced voltages were measured and analyzed. As a result, a significant rise in ground potential was observed for lightning surge. It can cause failure or malfunction of telecommunication systems.

• 조명전기설비학회논문지
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• 제19권3호
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• pp.51-56
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• 2005

접지의 성능을 결정하는 기본 요소인 접지저항을 측정하는 것은 성능평가를 위한 중요한 기술이 된다. 접지저항의 정확한 측정을 위하여는 측정 환경상 고려하여야 할 주요한 변수들이 있는데 실제의 측정 현장에서 이러한 변수들을 알고 측정하기는 곤란한 것이 현실이다. 본 논문에서는 3점전위강하법상의 전류전극에 이르기까지 나타나는 전위차 특성 곡선에 대하여 측정 환경 변수의 특성을 내포하고 있는 변이율이라는 개념을 도입하여 미지의 측정 환경 변수중에서도 가능한 접지저항의 참값에 근접한 측정을 지향하는 방법을 제의한 것이다. 이 이론은 이미 기검증된 논문들의 결과 내용을 분석함으로써 귀납적인 결론을 유도한 것이다.

• 대한토목학회논문집
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• 제34권6호
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• pp.1831-1836
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• 2014

공학적 측면에서 확률론적 액상화 재해 작성법이 점차 요구됨에 따라, 본 연구에서는 실제 액상화 피해 현장의 액상화 가능 지수(Liquefaction Potential Index, LPI)를 이용한 로지스틱 회귀분석으로 액상화 피해 확률을 예측하였다. 또한 이 분석을 바탕으로 광역지역의 액상화 재해도 기법을 제시하였다. 사례 연구로서 미국 세인트루이스 지역 홍수평야의 표준관입시험(273 곳) 결과를 대상으로 LPI를 산정하였고 최대지반가속도를 코크리깅의 이차변수로 적용하여 보간하였다. 연구결과, 일부 구역에서 연약지반과 얕은 지하수위로 인해 LPI 값이 5이상으로 나타나, 액상화로 인한 지반 피해 확률이 0.5 이상으로 예측되었다.

• 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.

• 한국안전학회지
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• 제7권4호
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• pp.55-61
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• 1992

An engineer designing a tunnel in an urban area should be to predict the magnitude and distribution of ground movements which are important to Investigate the potential damage to the existing structures around tunnel. The present study examines available theories and emprical equations, and tries to investigate quantativily ground movements around tunnel with tunnel progressing. Approcaches to the problem of ground movements associated with twin tunnel was and elasto - plastic finite element method. Typical section in Seoul Subway were selected in numerical study. The analysis and study was done with respect. to surface, subsurface and crown settlements with varying ground conditions, tunnel geommetry and construction conditions.

• 조명전기설비학회논문지
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• 제18권4호
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• pp.181-187
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• 2004

3상 4선식 배전계통을 채용하는 우리나라는 비선형 부하의 증가로 중성선에는 많은 중성선 고조파 전류가 관측되고 있다. 또한 접지 임피던스는 고조파가 있는 중성선 전류에 영향 끼친다고 알려져 있다. 전위 강하법에 따라 현장에서 실측한 고조파 전류와 전압을 측정하고, Pattern Search 기법으로 고조파 해석용 접지 임피던스를 모델링 하였다. 여기서 구한 임피던스 모델은 현장 시험에 의한 임피던스 모델과 비교하여 유사한 결과를 얻었고, 접지 시스템의 고조파 및 과도 응답 특성을 평가하는데 활용될 것으로 사료된다.

• 지구물리
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• 제6권3호
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• pp.179-188
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• 2003

전기설비의 접지는 시설과 인명피해를 방지하기 위한 시설로서 고압전선의 지락사고시 대용량의 전류를 대지속으로 흘려보냄으로서 주변대지의 전위상승을 억제하는데 있다 이와 같은 위험전위는 접지계의 대지구조의 성분 및 균질성 지락전류의 크기 및 지속시간 인체의 전기적 특성 등과 같이 변수가 많아 해석이 매우 어렵다 최근 고장 전류 유입시 대지전위분포를 최대한 균일하게 하기위하여 접지저항을 낮추는 GPR(ground Potential Rise) 저감 방향으로 접지시스템 설계가 이루어졌으며 지상공간의 전위변동의 최소화 균등화함으로써 보안 및 기능 접지를 동시에 만족하는 접지시스템의 해석과 설계가 이루어지고 있다 본 연구에서는 전기비저항 탐사를 통해 밝혀진 지하의 대지비저항 분포를 통해 접지 설계를 수행한 사례를 보여준다

• Earthquakes and Structures
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• 제10권6호
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• pp.1315-1330
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• 2016

This study investigates ground motion parameters and their damage potential for building type structures. It focuses on low and mid-rise reinforced concrete buildings that are important portion of the existing building stock under seismic risk in many countries. Correlations of 19 parameters of 466 earthquake records with nonlinear displacement demands of 1056 Single Degree of Freedom (SDOF) systems are investigated. Properties of SDOF systems are established to represent RC building construction practice. The correlation of damage and ground motion characteristics is examined with respect to number of story and site classes. Equations for average nonlinear displacement demands of considered RC buildings are given for some of the ground motion parameters. Velocity related parameters are generally found to have better results than the acceleration, displacement and frequency related ones. Correlation of the parameters may be expected to decrease with increasing intensity of seismic event. Velocity Spectrum Intensity and Peak Ground Velocity have been found to have the highest correlation values for almost all site classes and number of story groups. Common parameter of Peak Ground Acceleration has lower correlation with damage when compared to them and some other parameters like Effective Design Acceleration and Characteristic Intensity.

• 해양환경안전학회지
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• 제19권3호
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• pp.264-269
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• 2013

This paper is to investigate propagation path characteristics of GPS potential jamming signal. To do this, the spherical ground diffraction model is applied to the potential jamming scenario referred to the GPS jamming events occurred in recent years. The fundamental theory on the propagation path loss is discussed and a specific model is applied to several vehicles types which have own heights of antennas in order to compare their propagation path loss values at same 2-D location. The transmitting powers are appropriately given as the ordinary GPS jamming events. And then the received powers in dBW are obtained with given transmitting powers and the estimated total loss. The result of received jamming power at various locations due to the given scenario was distinct. For example, propagation loss values were estimated as -147 ~ -142dBW and -167 ~ -162dBW in $10^6W$ and $10^4W$, respectively. This computation result of the loss can be seriously considered with the tolerable jammer power against L1- C/A GPS receiver under any real jamming situations.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2001년도 봄 학술발표회 논문집
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• pp.299-306
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• 2001

Crushed Stone Pile(CSP) is one of the ground improvement methods available to loose sand and clayey ground by forming compacted CSP in the weak soil layer. The effects of this method are enhancement of ground bearing capacity, reduction of settlement and prevention of lateral ground movement in cohesive layer, reduction of liquefaction potential in sandy ground. This study performs model tests in 1.0m${\times}$1.0m${\times}$1.0m and 1.5m${\times}$1.5m${\times}$l.2m model tank to observe bearing capacity of CSP treated ground. The area replacement ratio of CSP composite ground varies 20%, 30% and 40% with square grid pattern. After the composite ground was consolidated under pressure of 0.5kg/$\textrm{cm}^2$ and 1.0kg/$\textrm{cm}^2$, load tests were carried out. The results show that ultimate bearing capacity increases with area replacement ratio and the preconsolidation pressure of ground.