• Nuclear Engineering and Technology
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• v.53 no.7
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• pp.2377-2386
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• 2021

To model the atmospheric dispersion of radionuclides released from nuclear accident is very important for nuclear emergency. But the uncertainty of model parameters, such as source term and meteorological data, may significantly affect the prediction accuracy. Data assimilation (DA) is usually used to improve the model prediction with the measurements. The paper proposed a parameter bias transformation method combined with Lagrangian puff model to perform DA. The method uses the transformation of coordinates to approximate the effect of parameters bias. The uncertainty of four model parameters is considered in the paper: release rate, wind speed, wind direction and plume height. And particle swarm optimization is used for searching the optimal parameters. Twin experiment and Kincaid experiment are used to evaluate the performance of the proposed method. The results show that the proposed method can effectively increase the reliability of model prediction and estimate the parameters. It has the advantage of clear concept and simple calculation. It will be useful for improving the result of atmospheric dispersion model at the early stage of nuclear emergency.

• Proceedings of the KIEE Conference
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• 1986.07a
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• pp.65-68
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• 1986

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.648-658
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• 2018

Regarding the fact that wind power forecast accuracy is gradually improved as time is approaching, this paper proposes a two-stage rolling dispatch approach based on model predictive control (MPC), which contains an intra-day rolling optimal scheme and a real-time rolling base point tracing scheme. The scheduled output of the intra-day rolling scheme is set as the reference output, and the real-time rolling scheme is based on MPC which includes the leading rolling optimization and lagging feedback correction strategy. On the basis of the latest measured thermal unit output feedback, the closed-loop optimization is formed to correct the power deviation timely, making the unit output smoother, thus reducing the costs of power adjustment and promoting wind power accommodation. We adopt chance constraint to describe forecasts uncertainty. Then for reflecting the increasing prediction precision as well as the power dispatcher's rising expected satisfaction degree with reliable system operation, we set the confidence level of reserve constraints at different timescales as the incremental vector. The expectation of up/down reserve shortage is proposed to assess the adequacy of the upward/downward reserve. The studies executed on the modified IEEE RTS system demonstrate the effectiveness of the proposed approach.

• Journal of the Korean Solar Energy Society
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• v.35 no.2
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• pp.33-41
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• 2015

A feasibility study to estimate annual energy production of an offshore wind farm was performed using MERRA reanalysis data. Two well known commercial codes commonly used to wind farm design and power prediction were used. Three years of MERRA data were used to predict annual energy predictions of the offshore wind farm close to Copenhagen from 2011 to 2013. The availability of the wind farm was calculated from the power output data available online. It was found from the study that the MERRA reanalysis data with commercial codes could be used to fairly accurately predict the annual energy production from offshore wind farms when a meteorological mast is not available.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.5
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• pp.351-360
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• 2016

Rapid population growth with high living standards and high electronics use for personal comfort has raised the electricity demand exponentially. To fulfill this elevated demand, conventional energy sources are shifting towards low production cost and long term usable alternative energy sources. Hybrid renewable energy systems (HRES) are becoming popular as stand-alone power systems for providing electricity in remote areas due to advancement in renewable energy technologies and subsequent rise in prices of petroleum products. Wind and solar power are considered feasible replacement to fossil fuels as the prediction of the fuel shortage in the near future, forced all operators involved in energy production to explore this new and clean source of power. Presented paper proposes fuzzy logic based Energy Management System (EMS) for Wind Turbine (WT), Photo Voltaic (PV) and Diesel Generator (DG) hybrid micro-grid configuration. Battery backup system is introduced for worst environmental conditions or high load demands. Dump load along with dump load controller is implemented for over voltage and over speed protection. Fuzzy logic based supervisory control system performs the power flow control between different scenarios such as battery charging, battery backup, dump load activation and DG backup in most intellectual way.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.5
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• pp.326-333
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• 2009

Design life-time of a wind turbine is required to be at least 20 years. In the meantime, the wind turbine will experience a lot of load cases such as extreme loads and fatigue loads which will include several typhoons per year and extreme gusts with 50 years recurrence period as well as endless turbulence flow. Therefore, IEC61400-1 specifies design load cases to be considered in the wind turbine design and requires the wind turbine to withstand the load cases in various operational situations. This paper investigates the ultimate loads which the wind turbine will experience for 20 years and their characteristics based on the IEC61400-1 using an aero-elastic software, GH-Bladed. And the performance characteristics of a wind turbine such as electrical power generation and annual energy yield are also investigated.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2880-2885
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• 2008

Design lifttime of a wind turbine is required to be at least 20 years. In the meantime, the wind turbine will experience a lot of load cases such as extreme loads and fatigue loads which will include several typhoons per year and extreme gusts with 50 years recurrence period as well as endless turbulence flow. Therefore, IEC61400-1 specifies design load cases to be considered in the wind turbine design and requires the wind turbine to withstand the load cases in various operational situations. This paper investigates the ultimate loads which the wind turbine will experience for 20 years and their characteristics based on the IEC61400-1 using an aero-elastic software, GH-Blade. And the performance characteristics of a wind turbine such as electrical power generation and annual energy yield are also investigated.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.3
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• pp.547-554
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• 2018

Wind energy is widely recognized as one of the cheapest forms of clean and renewable energy. In fact, in several countries, wind energy has achieved cost parity with fossil fuel-based sources of electricity generation for new electricity generation plants. Offshore wind energy development promises to be a significant domestic renewable energy source for the target of korea government 3020 plan. A pivotal activity during the development phase of a wind project is wind resource assessment. Several approaches can be categorized as three basic scales or stages of wind resource assessment: preliminary area identification, area wind resource evaluation, and micrositing. This study is to estimate the wind power capacity of chonnam province offshore area using three basic stages based on the six meteorological mast data. WindPRO was used, one of a well-known wind energy prediction programs and based on more than 25 years of experiences in development of software tools for wind energy project development. The design results of offshore wind power generation capacity is calculated as total 2.52GW with six wind farms in chonnam offshore area.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.184.1-184.1
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• 2010

Floating wind turbines have been suggested as a feasible solution for going further offshore into deeper waters. However, floating platforms cause additional unsteady motions induced by wind and wave conditions, so that it is difficult to predict annual energy output of wind turbines by using conventional power prediction method. That is because sectional inflow condition on a rotor plane is varied by unsteady motion of floating platforms. Therefore, aerodynamic simulation using Vortex Lattice Method(VLM) were used to investigate the influence of motion on the aerodynamic performance of a floating offshore wind turbine. Simulation with individual motion of offshore platform were compared to the case of onshore platform and carried out according to the wave height and the wave angular frequency.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.165-166
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• 2015

본 논문에서는 제주풍력단지에 대한 측정 데이터(measured wind power outputs)를 기반으로 제주 실측 풍력데이터를 이용하여 공간적인 상관관계 분석을 수행하고, 상관관계 감쇠거리(CDD; Correlation Decay Distance)를 적용하여 새로운 풍력발전단지에 대한 공간모델 적용 시 기존 풍력발전단지의 포함여부(set 또는 subset)를 결정하는 기준(Threshold)으로 활용하고자 한다. 이를 통해 풍력발전출력 예측에 공간모델을 적용하고, 정확도를 향상시키는 방안을 연구하고자한다.