• Transactions of the KSME C: Technology and Education
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• v.3 no.1
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• pp.29-36
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• 2015

Some major companies representing Korea's ship building actively take part in building Oil & Gas offshore which produces both oil and gas from the ocean. Merchant ships become enlarge and high-powered electric as well as increasing number of Oil & Gas offshore. Thus, maritime university cadets are pushed to participate in onboard training on 440V to 6,660V high voltage ships. Although they have difficulty and danger from onboard training course on high voltage ships, their curriculum is still focusing on the training on low voltage ships. Therefore, this study is to suggest the upcoming education measures based on the questionnaire survey and analysis from the Maritime cadets who had experienced in high voltage ships.

• Journal of Korea Ship Safrty Technology Authority
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• s.34
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• pp.18-32
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• 2013

최근 선저 부착 생물에 관한 문제가 환경오염으로 확대되고 그에 따른 여러 가지의 선체 방오 방법 중 특히 주석(Sn)의 화합물질의 화학반응으로 따개비 등의 오염 요소를 방지하는 기존 방법이 수은, 구리 등의 유독성 화합물에 의해 임포섹스 유발과 그에 따른 2차 오염 확산의 요인이 되어 2012년 7월부터는 유기주석화합물(TBT) 도료를 사용한 신규 선박은 규제되는 등 그 심각성이 대두하고 있다. TBT는 매우 미량의 농도에서도 다양한 생물학적 저해영향을 일으키는 것이 알려져 이를 대체하기 위한 여러 화학물질이 개발됐다. 본 논문에서는 이러한 추세에 따라서, 유독성 화합물의 독성을 벗어나 저 전류의 고주파 고전압 펄스 에너지를 이용한 새로운 환경조성을 통해서 부착성 패류의 선저 부착에 대한 특성을 연구하였으며, 특히 환경오염 및 해양오염에 영향이 적은 방오시스템을 개발하고자 하였다. 또한 본 연구에서 적용된 고전압 펄스 시스템을 이용하여 선체의 부식정도를 저감 가능한 시스템을 구현을 위한 기초 실험과 현재 이슈화 되고 있는 선박평형수의 살균장치에 적용하는 파생연구들을 통하여 해양오염방지 요소들을 겨냥하여 후속연구를 위한 토대를 마련하고자 하였다.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.189-190
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• 2012

본 논문에서는 선박의 DC 배전시스템과 같은 고압 대용량 전력변환시스템에 적합한 멀티레벨 시스템을 분석한다. 3레벨 NPC(Neutral Point Clamped) 구조의 멀티레벨 컨버터는 입력 전류의 고조파를 줄일 수 있고 시스템의 용량을 증가시킬 수 있다는 장점 때문에 고전압이 필요한 응용분야에 가장 많이 사용되고 있다. 하지만 이 구조는 각 전력 반도체 스위칭 소자의 전력 손실이 불균일한 단점이 있다. 따라서 이러한 단점을 제거하기 위해 ANPC(Asctive NPC) 구조의 컨버터가 제안되었다. ANPC 방식은 각 소자의 손실 분포를 균일하게 하여 효율적으로 개선할 수 있다. 본 논문에서는 ANPC 컨버터를 구성하는 각 스위칭 소자의 손실을 분석하고 시뮬레이션을 통하여 검증하였다.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.145-146
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• 2012

Recently the problem of the fouling organisms, especially Sn-compounds is expanded to environmental problems from the chemical reaction with imposex and secondary contamination. One of the existing antifouling system, antifouling paints, is regulated from 2012, July because of seriousness about toxic substances such as TBT, mercury, copper and so on. TBT is known that causes a variety of biological inhibition in various chemicals even a very small amount of concentration. So it has been developed to replace it. In this paper, we try to develope a new system with the environmental background and the research of the adhesion characteristics of fouling organisms using a low current, high frequency high voltage pulse power, not toxic compounds.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.487-495
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• 2021

The voltages mainly used in ships are 450 [V], 6.6 [kV], and 11 [kV], and an earthed system is applied to ensure the stability of the power distribution system. In general, low-voltage ships using 450 [V] apply an unearthed system, while high-voltage ships using 6.6 [kV] or 11 [kV] use a high-resistance earthed system. When an earth fault occurs in a ship's power distribution system, the voltage of the healthy phase increases to the line-to-line voltage or higher, which causes an excessive impact on the insulation of the cable. Thus, analyzing this behavior is very important. In this paper, we investigate the characteristics of the line-to-earth voltage variation according to earth faults and a recognition procedure of a faulty phase using the symmetrical coordinate method for a high-resistance earthed system and unearthed system. A mathematical model of the line-to-earth voltage was derived through the symmetric coordinate method, and the ship voltage for simulations was selected as 6.6 [kV] and 450 [V]. A MATLAB simulation proved that this method can determine the highest increase of the line-to-earth voltage, which leads by 120° on the faulty phase, and it accurately judges the faulty phase in both earthed systems.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.6
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• pp.1591-1601
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• 2016

In recent years most of large-sized merchant ships have been equipped with a high-voltage system. The ships demanding a lot of electric power adopt the high voltage such as 3.3kV, 6.6kV, 11kV. Gradually as the high voltage system is increased in the ships, engineering officers are more opportunities to operate the high voltage system. So the high voltage training for engineering officers was established in the STCW 1978 as amended by the Manila Amendments in 2010. According to this convention when the engineering officers want to board the high voltage ships on and after January 1 in 2017, they must take the high voltage training. This paper, firstly, analyzes the content of high voltage training in STCW convention and IMO model course. In addition, it reviews the parts need to be considered in the content of the high voltage training. Finally this paper proposes the contents of training model divided into theory and practice.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.7
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• pp.854-867
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• 2014

In the circumstance that high oil price state is continued over the world, the investment in crude oil development by oil major is a trend of increasing. Recently the number of delivered drill-ship for 5 years has been sharply increased all over the world and about twice than that of past 30 years. As addition to the increase of the drill-ship demand, the operation of drill-ships which is delivered recently is about 3,000 meters, ultra deep sea, on average and the work area is expending. Accordingly the drilling system including the size and length of pipe for drilling has been bigger and bigger and the power supply equipment for operation system also has large capacity. Unlike merchant vessel, high power and high voltage of diesel generators are required for drill-ship for which the demand for V-type 320 bore of diesel generator has increased. It is on the raised that the importance of lubrication oil cleaning for diesel generator on drill-ship which has longer time for construction, and also long term low load operation is unavoidable during commissioning of equipments. Recently it was reported that engine crankpin was damaged due to the hard contact caused by the abnormal wear down(Cam wear) on crankpin and bearing. The same pattern of wear down was found through the inspection on series vessels and the other vessel under commissioning. The purpose of this paper is to analyze of the wear mechanism based on the observation and theories and objective research from actual cases and to prepare the counter measures to avoid foreseeable damage when the lubricating oil is not properly cleaned.