• 한국해양공학회지
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• 제30권6호
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• pp.526-534
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• 2016

This study had the goal of designing onboard structures for a pre-pilot mining test (PPMT), which is required for the commercialization of the deep-sea mining industry. This PPMT is planned to validate the performance of a hydraulic lifting system and verify the concept of operating through a moon-pool in the east sea, Korea. All of the onboard equipment and facility were designed by KRISO. Because the test was performed at the first development, it is difficult to determine what risk will occur in the facility. Therefore, risk-based design is required in the facility for the PPMT, which includes the facility layout, failure mode and effect analysis (FMEA), and risk reduction plan. All of the expected performances of the lifting system itself and the onboard facilities were qualitatively validated using the risk-based design.

• 한국해양공학회지
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• 제26권2호
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• pp.48-57
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• 2012

This paper deals with numerical analyses in the context of estimations of hydrodynamic motions and dynamic loads for a floating type offshore platform using some exclusive simulation code such as code for the simulation of a floating type of offshore crane based on multi-body dynamics, along with the commercial code AQWA. Verifications of numerical models are carried out by comparing the RAO results from the simulation code. In the verification analyses, hydrodynamic motions are examined in the frequency domain for the floating type offshore platform according to the mooring lines. Both the hydrodynamic motions and dynamic loads are estimated for floating type offshore platforms equipped with the catenary type and taut mooring lines. A review and comparison are carried out for the numerically estimated results. The structural safety of the connection parts in an offshore structure such as a floating type offshore platform is one of the most important design criteria in view of fatigue life. The dynamic loads in the connecting area between a floating type offshore platform and its mooring lines are estimated in detail according to variations in the mechanical properties of the mooring lines. The dynamic tension load on the mooring lines is also estimated.

• Structural Engineering and Mechanics
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• 제51권5호
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• pp.755-771
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• 2014

Environmental changes, especially global climate change, are creating new challenges to the development of the Arctic regions, which have substantial energy resources. And attention to offshore structures has increased with oil and gas development. The structural impact response of an explosion-resistant profiled blast walls normally changes when it operates in low temperatures. The main objectives of this study are to investigate the structural response of blast walls in low temperature and suggest useful guidelines for understanding the characteristics of the structural impact response of blast walls subjected to hydrocarbon explosions in Arctic conditions. The target temperatures were based on the average summer temperature ($-20^{\circ}C$), the average winter temperature ($-40^{\circ}C$) and the coldest temperature recorded (approximately $-68^{\circ}C$) in the Arctic. The nonlinear finite element analysis was performed to design an explosion-resistant profiled blast wall for use in Arctic conditions based on the behaviour of material properties at low temperatures established by performing a tensile test. The conclusions and implications of the findings are discussed.

• 한국초전도ㆍ저온공학회논문지
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• 제20권4호
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• pp.60-64
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• 2018

As the offshore wind farms increase, interest in the efficient power system configuration of submarine cables is increasing. Currently, transmission system of the offshore wind farm uses almost AC system. High temperature superconducting (HTS) power cable of the high capacity has long been considered as an enabling technology for power transmission. The HTS cable is a feasible way to increase the transmission capacity of electric power and to provide a substantial reduction in transmission losses and a resultant effect of low CO2 emission. The HTS cable reduces its size and laying sectional area in comparison with a conventional XLPE or OF cable. This is an advantage to reduce its construction cost. In this paper, we discuss the economic feasibility of the 22.9 kV HTS power cable and the conventional AC power cables for an offshore wind farm connections. The 22.9 kV HTS power cable cost for the offshore wind farm connections was calculated based on the capital expenditure and operating expense. The economic feasibility of the HTS power cable and the AC power cables were compared for the offshore wind farm connections. In the case of the offshore wind farm with a capacity of 100 MW and a distance of 3 km to the coast, cost of the 22.9 kV HTS power cable for the offshore wind farm connections was higher than 22.9 kV AC power cable and lower than 70 kV AC power transmission cable.

• 한국해양공학회지
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• 제32권6호
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• pp.411-418
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• 2018

This paper introduces a new method of ice load generation in the time domain for the station-keeping performance evaluation of Arctic offshore structures. This method is based on the ice load spectrum and mean ice load. Recently, there has been increasing interest in Arctic offshore technology for the exploration and exploitation of the Arctic region because of the better accessibility to the Arctic ocean provided by the global warming effect. It is essential to consider the ice load during the development of an Arctic offshore structure. In particular, when designing a station-keeping system for an Arctic offshore structure, a consideration of the ice load acting on the vessel in the time domain is essential to ensure its safety and security. Several methods have been developed to consider the ice load in the time domain. However, most of the developed methods are computationally heavy because they consider every ice floe in the sea ice field to calculate the ice load acting on the vessel. In this study, a new approach to generate the ice load in the time domain with computational efficiency was suggested, and its feasibility was examined. The ice load spectrum and mean ice load were acquired from a numerical analysis with GPU-event mechanics (GEM) software, and the ice load with the varying heading of a vessel was reconstructed to show the feasibility of the proposed method.

• 수산경영론집
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• 제54권3호
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• pp.45-67
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• 2023

The purpose of this study is to construct a regional-sector-fishery-offshore and inshore fishery competitiveness index, examine the types and changes of competitiveness, and derive implications by processing data of the Survey on the Current Status of Offshore and Inshore Fishery from 2013 to 2020 for this study. The main results of this study can be summarized as follows. First, considering the competitiveness of offshore and inshore fishery by region and year, Jeonnam, Jeju, and Incheon were relatively competitive. Second, considering the competitiveness of inshore fishery by region and year, we found that Jeonnam, Chungnam, Jeonbuk, and Jeju were relatively competitive. Third, looking at the types of competitiveness based on the competitiveness index in the management sector of offshore and inshore fisheries by region and year, Ulsan, Jeonnam, and Gyeongbuk were relatively competitive between 2014 and 2020. Fourth, Jeonnam and Jeju were relatively competitive between 2014 and 2020 based on the competitiveness index in the fishing sector of offshore and inshore fisheries by region and year. Fifth, we found that Jeonnam, Jeju, and Chungnam were relatively strong in the competitiveness of offshore and inshore fishery, combining the offshore and inshore fishery indexes by region and year. The results of this study have some limitation on outlier treatment, grade assignment, and weight for aggregation, so research considering these needs to be done in the future. In conclusion, the results of this study which were derived objectively and scientifically in the era of the 4th industrial revolution, when evidence-based decision-making was becoming critical, are expected to help the central or local governments determine the priority of support projects or investments.

• 스마트미디어저널
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• 제1권1호
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• pp.48-52
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• 2012

해양플랜트에 대한 설계 엔지니어링 기술을 확보하는데 있어 신뢰성 있는 평가 수행이 중요한 위치를 차지하고 있다. 국내 해양플랜트 공정설계 및 기본설계기술의 자립화를 위해서는 신뢰성 평가 기반의 설계검증 기술개발이 필요하고, 이를 위해 신뢰성 있는 실증실험 데이터 확보가 중요한 요소이다. 따라서, 신뢰성 있는 데이터를 확보하기 위해서는 해양플랜트 환경모사 실증시험 시스템이 구축되어야 한다. 본 연구에서는 해양플랜트 공정모듈 환경모사 시스템 구성을 위한 환경제어 및 측정변수 분석과 도출된 변수를 기반으로 데이터 수집장치 및 제어시스템의 설계 계획안을 연구한다.

• 해양환경안전학회지
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• 제23권3호
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• pp.231-241
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• 2017

The purpose of this study was to analyze traffic safety assessments for fishing vessels near the southwest offshore wind farm. This study applied a collision model for safety assessment. It also involved a spatiotemporal analysis of vessels engaged in fishing to identify fishing hotspots around the offshore wind farm. This study used data from fishing vessel location transmission devices gathered over 1 year in 2014. As a result, in September, when the average number of vessels engaged in fishing is high, 62 ships were operating in fishing section 184-6 and 55 ships in section 184-6. In addition, in fishing sections 184-8 and 192-2, where an offshore wind farm was located, there were 55 and 38 ships operating, respectively. As the recovery period for a seaway near wind farm turbines is 55 years, it was determined that safety measures are required in order to reduce collision frequency while allowing fishing vessels to navigate through offshore wind farms. Meanwhile, the return period of Seaway B between the groups of generators considered was 184 years. A safety zone for offshore wind farms should be installed covering a distance of at least 0.3 NM from the boundary of turbines. Then, the collision return period was derived to be close to 100 years. Through this traffic safety assessment, it has been concluded that such measures would help prevent marine accidents.

• 한국해양공학회지
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• 제28권4호
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• pp.274-279
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• 2014

This paper investigates the line dynamic forces connecting tugs and a floater, where the planar motion of the floater is due to the weather criteria during the position keeping of the offshore structure by tugs. The analysis situation consists of the position keeping states for the seabed mooring line connection work of the offshore structure at the offshore site. Specifically, the decision about the tug power capacity for the position keeping is essential and depends on the weather criteria, line characteristics, length of line, etc. The planar motion of the structure is constrained by the interference of the installation vessel's operational range, behavior of the underwater fairlead, and other surrounding structures. In this paper, the tug line forces and planar motion of an offshore structure are summarized dependent on the tug line length and line material characteristics in the states fora given floater draft and weather criteria. The tug line dynamic forces and planar motion evaluated here will be used to determine the proper tug power and clearance of an offshore structure.

• 신재생에너지
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• 제6권1호
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• pp.20-28
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• 2010

Developing the offshore wind farm is essential to meet the national target of the renewable energy and to achieve the green growth in Korea. In this context, KEPRI is now carrying the feasibility study for introducing the offshore wind fam in Korea. Accordingly, it is required to formulate an appropriate strategy, this paper mainly discuss, for this goal. First of all, several preliminary sites for the offshore wind farm are selected based on the evaluation criteria presented herein. In addition, the domestic sub-technological level of key technology sectors associated with the offshore wind power is analyzed. It includes the industries related to wind turbine, grid integration, structural design and construction. Integrating these results, we propose a strategy in order to successfully develop the first offshore wind farm more than 100-MW class in the south-western sea area of Korea.