• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.239-240
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• 2015

This paper presents the transient state characteristic and single phase ground fault occurred by deterioration of surge arrester when offshore wind turbine is struck by lightning strike. The wind turbine and submarine cable data are based on the 2.5GW offshore wind farm planned in South Korea Southwest Seashore. During lightning strikes, additional ground fault can lead to damage of the generation components. So, the sensitive analyses are conducted in order to investigate the effects of lightning strike on offshore wind farm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.1094-1095
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• 2015

The costs of installation, loss, and energy not supplied energy for submarine cable of offshore wind power plant (OWPP) are very high because the level of technology is still in the early stage as well as because of the marine environments. Therefore, reducing the total costs of a grid network for OWPPs is very important for financial feasibility. In particular, it is needed to minimize the project cost for optimizing the grid design and offshore substation location of a OWPP. The suggested method can reduce the total system cost and make it lower compared with existing methods.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1655-1657
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• 1994

To measure treeing, visual measurement with an optical microscope has been used to explain breakdown mechanism by treeing in materials. The conventional direct visual method of tree deterioration observation is difficult to measure in short time processing, and impossible to analyze the deteriorated area by treeing, direction of tree growth, tree patterns etc. In this paper, we have developed a tree-measuring system using image processing for the tree growth, the area of deterioration, and other progresses of treeing. As experimental result, image processing is an effective alternative to direct visual observation method.

• 한국전자통신학회논문지
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• 제5권2호
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• pp.109-118
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• 2010

여수지역에는 옛날부터 통신관련 역사유적과 유물이 봉수대, 솟대, 등대, 거문도 최초 해저케이블 설치 등으로 통신의 역사적 가치가 존재하고 있다. 그러므로 관광문화 산업과 연계하여 통신박물관이나 과학관을 설립하여 통신의 중요성을 인식시키고 교육장으로 활용하여 지역민과 국민들에게 공헌할 수 있도록 건립을 추진하고자 한다.

• 한국전자통신학회논문지
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• 제6권5호
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• pp.603-610
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• 2011

여수지역에는 옛날부터 통신관련 역사유적과 유물이 봉수대, 솟대, 등대, 거문도 최초 해저케이블 설치 등으로 통신의 역사적 가치가 존재했었다. 옛 고문서에 나타나 있는 이지역의 통신 역사성을 확인하여 통신에 의한 여수지역의 발달을 이해하고 통신역사성의 자원을 확인할 필요가 있다.

• 한국군사과학기술학회지
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• 제5권2호
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• pp.50-61
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• 2002

In this study, 3-dimensional virtual visualization was performed for a rapid and accurate analysis of sea bottom topography, The visualization was done through the extracted data using the developed program and the generated data using the gridding method. The data extraction program was developed with AutoLISP programming language and this program was able to extract the needed sample bathymetry data from the electronic sea chart systematically as well as effectively. The gridded bathymetry data were generated by the interpolation or extrapolation method from the spatially-irregular sample data. As the result of realization for the 3-dimensional virtual visualization, it was shown a proper feasibility in the analysis of the sea bottom topography to determine the route of submarine cable burial.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제51권2호
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• pp.74-79
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• 2002

We have been analyzed the interference problems already in steady state, especially AC corrosion when the gas pipeline is burred with power cable in the same submarine tunnel. In the next stage, we analyze the induced voltage in a fault condition of 154[kV] underground T/L. This paper presents the results of them which are limitation of safety voltage. meodeling of power cables, gas pipeline and grounding systems, analysis of induced voltage in a fault condition, and protection of Power line system.

• 한국산학기술학회논문지
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• 제20권6호
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• pp.472-482
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• 2019

본 논문은 수중용 TAS윈치 전개/회수 성능 안정화 방안에 대한 내용을 서술하고 있다. TAS윈치는 함미에 장착되어 자함과 이격되어 운용되는 센서, 예인케이블 및 꼬리로프의 전개/회수 기능을 수행하고, TAS에 대한 전원공급 경로, 수중환경 정보 및 수신된 음향신호 송/수신을 위한 데이터 전송 경로 제공 역할을 수행한다. TAS윈치 시험평가 과정에서 간헐적으로 TAS 전개 중 멈춤현상 및 회전속도 변동현상이 식별되었다. TAS 전개/회수에 필요한 토크를 제공하는 구성요소인 윈치모터에 대한 고장분석 결과, 구성품 중 회전자의 정렬 틀어짐으로 인한 편심현상에 따른 자기장 왜곡이 발생한 것을 확인하였다. 자기장 왜곡 발생 방지를 위해 윈치모터 회전자 및 슬립링 등 윈치모터 구성품의 고정성 향상 방안을 제안하였다. 제안된 방안에 대한 신뢰성 확보를 위해 LBTS 환경에서 TAS윈치 운용환경을 모사하여 TAS윈치 전개/회수 성능을 검증하였다. 최종적으로 TAS윈치 전개/회수 성능 뿐만 아니라 해상에서 TAS윈치를 운용할 경우 요구되는 함 속력 및 타각별 TAS 지속 운용능력과 같은 여러 가지 항목에 대한 해상 시험평가를 수행함으로써 설계 요구조건 만족 및 제안 방안에 대한 타당성을 검증하였다.

• Smart Structures and Systems
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• 제15권2호
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• pp.299-314
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• 2015

Submersed rock-berm structures are frequently used for protection of underwater lifelines such as pipelines and power cables. During the service life, the rock-berm structure can experience several accidental loads such as anchor collision. The consequences can be severe with a certain level of frequency; hence, the structural responses should be carefully understood for implementing a proper structural health monitoring method. However, no study has been made to quantify the structural responses because it is hard to deal with the individual behavior of each rock. Therefore, this study presents a collision analysis of the submersed rock-berm structure using a finite element software package by facilitating the smoothed-particle hydrodynamics (SPH) method. The analysis results were compared with those obtained from the Lagrange method. Moreover, two types of anchors (stock anchor and stockless anchor), three collision points and two different drop velocities (terminal velocity of each anchor and 5 m/s) were selected to investigate the changes in the responses. Finally, the effect of these parameters (analysis method, anchor type, collision point and drop velocity) on the analysis results was studied. Accordingly, the effectiveness of the SPH method is verified, a safe rock-berm height (over 1 m) is proposed, and a gauge point (0.5 m above the seabed) is suggested for a structural health monitoring implementation.

• Ocean Science Journal
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• 제41권4호
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• pp.227-234
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• 2006

Year-to-year variation of bottom cold waters around the Korea Strait was investigated based on bottom temperatures measured by submarine telephone cable between Pusan, Korea and Hamada, Japan from 1982 to 1992. The characteristics of bottom temperatures could be divided into three different groups: the Korean side, the middle, and the Japanese side. Temperature drops in summer appeared in all the three regions implying the intrusion of cold waters into the Korea Strait. Significant decreases in the Korean side were observed in 1983, 1986, 1990, 1991, and 1992 when bottom temperatures were high in the middle. In contrast, bottom temperatures significantly decreased in the middle in 1985, 1988, and 1989 when the temperature drops in the Korean side were relatively small. This tendency for a negative relationship was also shown in the second mode of an EOF analysis. In the years when bottom temperatures significantly decrease din the Korean side, the cold water along the east coast of Korea expanded offshore and its temperature was low. On the contrary, cold water in the southern region of the Ulleung Basin developed in the years when bottom temperatures decreased considerably in the middle.