• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.7-8
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• 2012

본 논문에서는 3레벨 NPC(Neutral Point Clamped)와 Active NPC 인버터의 스위치 손실 분배 기법에 따른 출력전력 분석을 하였다. 기존 3레벨 NPC 인버터의 경우 특정 불균형한 스위치 발열 때문에 전력밀도를 높이 설계할 수 없다. 따라서 본 논문에서는 ANPC inverter의 손실 분배기법을 적용하여 시뮬레이션으로 검증하였다.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.249-250
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• 2012

해상 풍력 발전은 가장 유망한 재생 에너지원의 하나이며, 육상 풍력 발전보다 풍력이 강력하고 일정하여 장시간 고출력 발생이 가능하다. 또한 소음, 공간적 한계, 경관훼손 등 기존 육상 풍력 발전의 단점을 보완하고 초대형 단지조성이 가능한 장점이 있다. 초대형 해상풍력단지에는 일반적으로 MW급의 해상풍력발전기가 사용된다. 본 논문에서는 MW급의 해상 풍력발전기에 ANPC(Active Neutral-Point-Clamped) Multi-Level VSC(Voltage Source Converter)를 적용하여 Back-to-Back으로 구성한 시스템을 제안하고 계통연계형 풍력 발전 시스템을 모의한 시뮬레이션을 통하여 제안된 시스템의 성능을 검증한다.

• Journal of the Korean Solar Energy Society
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• v.29 no.6
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• pp.69-74
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• 2009

Monitoring system is an absolutely-required system for assessing a performance and fatigue load of the wind turbine in an on-shore wind energy experimental research complex. It was implemented for the purpose of monitoring the wind information measured from a meteorological tower at the monitoring house, and of utilizing the measured data(fatigue data and electric analyzing data of wind turbine)for the performance assessment, by using the LabVIEW program. Then, by adding the performance assessment-related data acquired from the wind turbine during the performance assessment and the data recorder for synchronizing the data of meteorological tower, the system(BusDAQ) was implemented. Because it transmitted the data by converting the output 'RS-232' of data logger which measures the wind condition into CAN protocol, the data error rate was minimized. Also, This paper is introduced to make the best use of the developed monitoring system and to explain about construct of the system and detailed data communication of its system.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.3
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• pp.381-394
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• 2019

The marine industry contributes a large proportion of the air pollutant emissions along coastal regions, and this air pollution has been strongly linked to cardiovascular diseases and other illnesses. To alleviate the problem, many ports have installed alternative maritime power (AMP) facilities that enable onboard marine auxiliary engines with generators (gensets) to be shut down while a ship is at berth. This study compared the emissions from conventional gensets with those from AMP facilities, focusing on four emission types: greenhouse gases (GHG), sulphur oxides (SOX), nitrogen oxides (NOX), and particulate matter (PM). Both direct (combustion / operation) and indirect (upstream) emissions were considered together for the emission comparison. The results showed that AMP has lower emissions than conventional onboard gensets, and this benefit is highly dependent on the electricity generation mix onshore. On average, GHG emissions could be reduced by about 18.3 %, while the other emissions (SOX, NOX, and PM) would decrease more dramatically (88.4 %, 90.1 %, and 91.5 %, respectively). Additionally, future benefits of the AMP would increase due to the expansion of renewable energies. Thus, this study supports the potential of AMP as a promising solution for environmental concerns at ports worldwide.

• Journal of the Korean Solar Energy Society
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• v.30 no.3
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• pp.65-70
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• 2010

As for the present wind power industry, most of the computerization for monitoring and control is based on the traditional development methodology, but it is necessary to improve SCADA system since it has a phenomenon of backlog accumulation in the applicable aspect of back-data as well as in the operational aspect in the future. Especially for a system like offshore wind power where a superintendent cannot reside, it is desirable to operate a remote control system. Therefore, it is essential to establish a monitoring system with appropriate control and monitoring inevitably premised on the integrity and independence of data. As a result, a study was carried out on the modeling of offshore wind power data-centered database. In this paper, a logical data modeling method was proposed and designed to establish the database of offshore wind power. In order for designing the logical data modeling of an offshore wind power system, this study carried out an analysis of design elements for the database of offshore wind power and described considerations and problems as well. Through a comparative analysis of the final database of the newly-designed off-shore wind power system against the existing SCADA System, this study proposed a new direction to bring about progress toward a smart wind power system, showing a possibility of a service-oriented smart wind power system, such as future prediction, hindrance-cause examination and fault analyses, through the database integrating various control signals, geographical information and data about surrounding environments.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.215-216
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• 2014

This paper proposes a control algorithm for permanent magnet synchronous generator with a back-to-back three-level neutral-point clamped voltage source converter in a medium-voltage offshore wind power system under unbalanced grid conditions. The proposed control algorithm particularly compensates for the unbalanced grid voltage at the point of common coupling in a collector bus of offshore wind power system. This control algorithm has been formulated based on the symmetrical components in positive and negative rotating synchronous reference frames under generalized unbalanced operating conditions. Instantaneous active and reactive power are described in terms of symmetrical components of measured grid input voltages and currents. Negative sequential component of ac input current is injected to the point of common coupling in the proposed control strategy. The amplitude of negative sequential component is calculated to minimize the negative sequential component of grid voltage under the limitation of current capability in a voltage source converter. The proposed control algorithm makes it possible to provide a balanced voltage at the point of common coupling resulting in the generated power of high quality from offshore wind power system under unbalanced network conditions.

• Korea Trade Review
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• v.43 no.6
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• pp.93-112
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• 2018

Lately, various nations including the U.S. and China aim to decrease air pollutants in port areas. As the number of vessels as ports increases, the volume of cargo and air pollutants emitted from vessels are also increasing. Therefore, the social responsibility of port construction, shipping companies and terminal operators is becoming important. Alternate Maritime Power(AMP) is an anti-pollution measure which helps in reducing air pollution generated from diesel generators by using shore electric power. This study compares the AMP tariff and Bunk Fuel tariff at berth in order to determine how to operate an efficient offshore power supply facility in Gwangyang Port.

• Journal of Ocean Engineering and Technology
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• v.22 no.6
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• pp.88-94
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• 2008

The concentration of atmospheric carbon dioxide (CO2), which is one of the major greenhouse gases, continues to rise with the increase in fossil fuel consumption. In order to mitigate global warming the amount of CO2 discharge to the atmosphere must be reduced. Carbon dioxide capture and storage (CCS) technology is now regarded as one of the most promising options. To complete the carbon cycle in a CCS system, a huge amount of captured CO2 from major point sources such as power plantsshould be transported for storage into the marine or ground geological structures. Since 2005, we have developed technologies for marine geological storage of CO2,including possible storage site surveys and basic design of CO2 transport and storage process. In this paper, the design parameters which will be useful to construct on-shore and off-shore CO2 transport systems are deduced and analyzed. To carry out this parametric study, we suggested variations in thedesign parameters such as flow rate, diameter, temperature and pressure, based on a hypothetical scenario. We also studied the fluid flow behavior and thermal characteristics in a pipeline transport system.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.3
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• pp.240-245
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• 2014

As the seriousness of the global environment pollution is gaining our attention recently, researches on application of greenhouse gas emission of ship are being carried globally. However domestic study on greenhouse gas emission from ship was not carried out in various fields. In this study, quantitative data which was presented by greenhouse gas emission of training ship HANBADA and greenhouse gas emission was calculated by Tier 1 method based on total fuel consumption and amount of shore power. Actual voyage data for 1year in 2012 was used to analysis the greenhouse gas emission. This study showed how many weight of gases were exhausted per 1 gross tonnage and per 1trainee in the training ship. There is a need of further research to reduce pollutant and to respond to international environment regulation consistently.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2003.05a
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• pp.141-146
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• 2003

Time seres of suspended sediment concentration, surface elevation and velocity were measured and analysed to investigate the role of waves and the predominance of infra-gravity wave component for sediment suspension phenomena in the surf zone. For the investigation in detail, we adopted the cross spectral analysis method between sediment concentration and the characteristic values of wave, and ensemble average analysis method about long-period wave component, which is dominant to sediment suspension in the measurement point. The obtained results are summarized as follows: 1) The relationship between sediment concentration and the characteristic values of wave is stronger for the long-period standing wave components(about 60s and 30s) than the long wave components(about 100s), which have the most energetic power, 2) and also, it is cleared that sediment concentration is increased in the case of the phase, the velocity components of the first mode long-period standing wave(60sec) were accelerated toward on-shore direction, that is, the water surface in offshore side is higher than on-shore side.