• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.11
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• pp.82-88
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• 2013

It is important to give lightning warning prior to a cloud-to-ground (CG) discharge within an Area of Concern (AOC) because most of lightning damage and victim are usually occurred by the first lightning in the AOC. The aim of this study is to find the optimal operation conditions of the automated lightning warning systems in order to make the best use of the available data. In this paper, the test-operated results of the automated lightning alert and risk management system (ALARM) based on detections of CG discharge and eletrostatic field and optimized at probability of lightning have been described. It was possible to obtain the following warning performance parameters: probability of detection (POD), false alarm ratio (FAR), probability of lightning (POL) and failure-to-warn rate (FTW). The data obtained from trial operation for 5months were not sufficient but the first analysis of domestic lightning warning was carried out. We have observed that the evaluated statistical results through trial operation depend on the various factors such as analysis methods and criteria, topographical conditions, etc. Also we suggest some methods for improvement of POL and POD including the finding of the optimal electric field threshold level to be used, based on the high values of FAR and FTW found in this work.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.11
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• pp.532-537
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• 2006

Lightning induced faults accounts for more than 66% at the transmission lines of KEPCO. The lightning causes damages to power system equipments including transmission line, the blackout of electricity and the electro-magnetic interference. Because of this reason, we need the real time lightning information for the optimal operation of power system. And, it is required to obtain and accumulate the lightning current parameters for the insulation design. In 2005, KEPRI constructed a lightning detection network, the KLDNet (i.e. Kepco Lightning Detection & Information System) and launched a lightning information service for KEPCO customers. It is intended to provide data service on the operation of transmission lines and collect lightning-related data, which is the most important factor regulating power system design and operation. The new system will replace LPATS, the old detection system, which has been operating since 1995 and is rapidly failing in terms of both detection performance and location accuracy. The purpose of this paper is to explain the work performed and the results of that work in performing a site survey of several locations. The purpose of the site survey is to find locations acceptable for the installation of a lightning location receiver in support of a Lightning detection system(LDS). A restriction was placed on the surveyed locations, as they must belong to the Korea Electric Power Company. This requirement was made to facilitate the communication needs of the LDS network. Total of 15 sites were evaluated as possible LDS sensor sites. Some of the sites were rejected for physical reasons and therefore no electrical testing was performed. Of the 15 sites, total of 10 sites were considered acceptable and 5 sites were rejected for various reason. In this paper, we would like to explain the site survey and detection efficiency for LDS.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1482-1504
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• 2007

An electrical railway system uses high voltage system for train traction and low voltage system for train control. Railway systems are broadly distributed across mountains, sea sides and cities. Electrical accidents provoke the death and injury of a human being and the damage of the equipment by the overcurrent due to the catenary dropping and by the overvoltage due to lightning. Grounding systems are adopted for the protections of the system from the overcurrent and the overvoltage. Isolation grounding for each system can be easily installed. However, the closed circuits between grounding systems can be occurred. The currents flow through the closed circuits cause the abnormal operation of the system. To overcome the problem of the isolation grounding, the equipotential bonding is usually adopted. The equipotential bonding should have very small grounding resistance. In this paper, we showed the transition from the isolation grounding system to the common grounding system and presented the comparison and the analysis of two grounding systems by simulation. In addition, we proposed the direction for a new grounding system of electric railway.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.8
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• pp.33-44
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• 2000

The lightning with high voltage and current can enter the basestations for mobile communication through their antenna. The device which can protect the basestation against the lightning, is surge arrestor. In this paper, the concept, kind, operating mechanism, design and fabrication of surge arrestor were studied. Based on the studied data, variable surge arrestors were designed for the current mobile communication service like a cellular, GSM and PCS and the next generation mobile communication like a IMT-2000. Computer simulation for the prediction of their characteristics and inner structure optimization for the improvement of their electrical characteristics were carried with high frequency 3D structure simulator. Quarter wave short stub surge arrestors for IMT-2000 were fabricated with their final design and then the measurement of electrical characteristics and the lightning test were executed. As a results of measurement, we obtained below 1.05 of VSWR, -0.035 dB of insertion loss, -150 dBc of intermodulation and 7∼ll V of residual voltage.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.693-696
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• 2005

Parallel and cross of the electrical power and telecommunication network is become accelerated, because telecommunication equipments are constructed according to road for efficient maintenance of domestic telecommunication network. The electrical power network can generate an electrostatic induction, and is itself transmission medium from electrical transient phenomenon such as lighting. So, transient phenomenon of lightning surge is induced to telecommunication network, and then it is damaged by connecting between electrical ground of electrical power network and telecommunication network. In this study, we found that cut-off of return path current by separate distance between electrical ground of electrical power network and telecommunication network, and cut-off of electrostatic induction voltage by grounding unused leads of both terminals of the electrical and telecommunication network have good effect as the protection methods of telecommunications network from electrical transient phenomena.

• Journal of the Korean Institute of Gas
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• v.24 no.4
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• pp.48-55
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• 2020

The installation of lightning protection system has recently been increasing, but the amount of damage has still been increasing. In this study, survey (interview) and field conditions were conducted to identify the installation and safety standards of the lightning protection system. it was analyzed that the safety management system is non-existent at the stage of the design, manufacturing and construction of the site lightning protection system, and that the safety inspection of the lightning protection facility is not properly managed. It has been shown that lightning protection systems, that can solve these problems, need to be re-established according to the reality so that safety inspection can be carried out in accordance with safety standards such as management of safety certification products, operation of survey institutions, design, manufacturing, and construction of safety standards at a national level.

• Journal of Korean Society of Transportation
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• v.18 no.1
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• pp.7-15
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• 2000

물류에서는 재화 또는 정보의 흐름이 매우 중요하다. 그 동안 우리나라에서는 물류시스템을 물리적인 시설로 간주 시설의 공급에만 관심을 기울여 왔다. 그 결과 물류활동을 지원할 수 있을 만한 정보시스템의 구축이 충분히 이루어지지 못하였다. 본 연구에서는 화물운송을 위주로 한 화물유통체계의 합리화 방안을 모색하기 위하여 교통부분과 밀접한 연계를 갖는 첨단화물운송체계의 도입효과를 논의하고 Life-Cycle Cost의 개념을 이용하여 첨단화물운송체계의 시스템 대안을 평가하였다. 분석결과 노변 통신시스템을 이용한 시스템의 구성이 중장기적으로 유리한 것으로 평가되었다. 이는 통신비의 부담이 시설의 유지보수비의 부담보다 크기 때문이다. 그러나 노변통신시스템시설은 표준화 등의 문제로 아직 적용에 문제점들이 많으며 낙뢰 등 비용산정에 포함되지 못한 유지보수의 추가비용이 발생할 소지가 크다. 그러므로 교통시설의 특징에 따라 두 접근방식을 혼용하는 방안이 검토되어야 한다.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.4 no.2
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• pp.82-90
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• 1993

전자파에 의한 산란현상의 해석은 지금까지 주로 시간조화함수의 형태를 지닌 전원에 의한 정 상상태의 산란에 관하여 이루어졌다. 그러나 레이다나 피파괴 검사, 전송선로 점검 등의 응용에서는 주로 펄스형태의 전자파를 사용하며, 따라서 시간에 따라 변화하는 함수형태의 전원에 의한 전자파의 산란해 석이 중요한 문제로 등장하였다. 또한 통신선로에서 외부의 잡음에 대한 혼신 등을 해석하거나, 낙뢰가 송 전선로에 미치는 영향을 해석하는 데에도 펄스신호의 산란해석이 필수적이다. 일반적인 함수의 형태를 지닌 전원에 의한 산란현상을 해석하기 위해서는 전원함수를 Fourier 변환하 여 주파수 영역의 스펙트럼을 구하고, 주파수영역에서의 산란해를 이용하여 Fourier 역변환을 하여 시간 영역의 해를 구할 수 있다. 주파수 영역에서의 산란판의 해를 Fourier 역변환 하기 위해서는 적분을 행하여야 하며, 일반적으로 적분과정에서 매우 복잡한 계산이 필요하고, 산란체의 구조가 복잡하여 해석 적인 해를 구할수 없는 경우에는 해석적으로 시간영역의 해를 구하는 것이 불가능하다. 시변 함수에 의 한 산란파를 구하기 위한 수치해석적 방법으로는 모멘트방법이나 유한요소법(Finite Element Method), 경계요소법(Boundary Element Method), 유한차분법(Finite Difference Method)등이 있으며, 해석적 해 를구할 수 없는 경우에 적용할 수 있는 반면에 많은 계산량이 요구된다.

• 한국공간정보시스템학회:학술대회논문집
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• 2007.06a
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• pp.413-423
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• 2007

우리나라의 자연재해는 기상학적 자연현상에 의해 주로 발생되고 있으며 그 발생원인은 태풍, 호우, 폭풍, 폭풍우, 재설, 폭풍성 우박, 해일 및 기타(낙뢰, 돌풍, 설해, 결빙, 지진 등을 포함)로 구분되며 이중 발생빈도가 가장 높은 것은 강우에 의한 재해로 전체 재해발생 원인 중 약 80%로 대부분을 차지하고 있다. 특히 사면붕괴와 관련된 자연재해(산사태, 옹벽붕괴, 매몰 등)는 최근 국지성 집중호우를 포함하여 호우의 집중 강도가 높아지는 등 기상학적 원인에 의해 매년 발생하고 있다. 따라서 우리나라에서 발생되는 자연재해와 관련한 사면붕괴의 특성을 강우특성에 따라 조사 분석할 필요가 있으며 이에 적합한 대책들이 더욱 필요하다. 이 연구에서는 산사태 유발인자와 강우조건을 고려하여 산사태 잠재가능성을 평가하고 산사태 취약지역을 분석하여 지역적인 강우특성을 고려한 산사태 가능성을 평가하였다.

• Proceedings of the KIEE Conference
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• 2008.09a
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• pp.95-97
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• 2008

현대 산업에서 정밀기기와 정보기기의 사용이 증가되면서 전력품질의 중요성이 강조되고 있다. 또한 건축물 뇌 보호 관련 규정이 KS C IEC 62305로 개정피면서 선택사항에 불과했던 내부 뇌 보호 시스템 서지보호기(SPD)의 설치가 의무화 되었다. 그런대 사용자들이 실제 이용하고 있는 서지보호기를 현장에 적용하였을 때 많은 문제점이 드러났다. 첫째, 서지보호기를 설치 후 제대로 작동 하는지 동작 상태를 파악할 수 없고 단지 낙뢰가 몇 번 유입되었는지의 카운터 기능의 시각적 판단만 가능하다. 또한 시간이 지나면서 서지보호기의 특성 변화 파악이 불가능하다. 설치 후 제 성능은 얼마나 발휘하는 가를 알 수 없고 LAMP에 의해 SPD의 소손 여부만을 판단할 수 있어 SPD의 교체시기를 알 수 없다. 이런 문제점을 해결하기 위해서는 서지보호기에 유입되는 서지크기, 유입경로 및 횟수를 통한 서지의호소자의 성능에 대한 대책 마련을 가능케 하여 바람직한 서지보호 및 적용이 가능토록 하고자 한다.