• Journal of the Korean Solar Energy Society
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• v.33 no.5
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• pp.41-50
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• 2013

Economic feasibility study using weighted average variable Jeju System Marginal Price, SMP, was conducted for Gasiri wind farm of Jeju Island. To predict the variable Jeju SMP, generator share ratio for SMP was calculated from the real time wind power production and the power demand data for years. Also, sensitivity analysis on Net Present Value, NPV, and Benefit/Cost Ratio, B/C ratio, were performed to clarify which factors are more important in assessing economic feasibility. The result shows that the Gasiri wind farm has a minimum of 110 billion won and a maximum of 132 billion won difference between fixed and variable SMP. Also, Capacity Factor, C.F., had the highest sensitivity for NPV, followed by SMP. Accordingly, when economic analysis for a potential wind farm site is carried out, the variable SMP as well as C.F. should be considered for more accurate assessment of the wind farm.

• KIPS Transactions on Computer and Communication Systems
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• v.1 no.3
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• pp.161-170
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• 2012

In recent years, many researchers and developers have been interested in renewable energy all over the world. Particularly, the development of wind power is being processed actively due to its high economic efficiency. A few years ago, Korean government has started the research for building a large-scale offshore wind farm in domestic west-southern area. Current domestic SCADA technology level for operating wind farm is very low compared with foreign SCADA technology level. In this paper, we found IT issues and solutions for developing SCADA system. Based on these solutions, we designed SCADA system for a large-scale offshore wind farm.

• Journal of Wind Energy
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• v.14 no.2
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• pp.14-25
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• 2023

This study focuses on proposing measures for the reasonable development of offshore wind farms using the case of Norway, which was the first nation in the world to build a floating offshore wind farm of 80 MW or more. Norwegian authorities conducted a strategic environment assessment in 2012 to select offshore wind farm sites, discovered 15 potential sites, and finally decided on two designated sites in 2020. Based on various survey data such as seabirds, marine environment, and fishing activities, scientific-based spatial analysis was conducted to select additional offshore wind farm sites in line with future development plans. In addition, a government-led steering committee and advisory group have established marine spatial plans since 2002. Therefore, it will be possible to listen to and coordinate the opinions of stakeholders by using the steering committee and advisory group for offshore wind power development. By examining the case of Norway, we suggest the following policy points that can achieve carbon neutrality and develop sustainable offshore wind farms: 1. Establish a government-led steering committee and advisory group that can select potential sites for offshore wind farms by coordinating the opinions of stakeholders 2. Induce efficient and sequential offshore wind farm development by using various survey data and scientific-based spatial analysis.

• New & Renewable Energy
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• v.7 no.2
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• pp.51-58
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• 2011

Saemankeum is well known for its high speed wind, and it is known that the blueprint of a future city around Saemankeum, including new industrial complex, has been planned. As a result, large-scale offshore wind farm, on the basis of the measurement of wind resource for a long time, can be considered, so that generated electricity can be used to meet the energy demand near the wind farm. Wind speed in Kokunsando of Saemankeum is measured and analyzed with its statistical distribution and wind directions. The probability of wind power resource over Kokunsando of Saemangeum is reviewed with the measured data in one island of Kokunsando. According to measured data, the shape and scale factor of Weibull distribution of wind speed are obtained, and then power density is analyzed as well. Through this study, it is clear that the Saemangeum area has a fluent and abundant wind power source to develop the wind farm in Korea.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.59.2-59.2
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• 2011

Although there are many activities on the construction of wind farm to produce amount of power from the wind, in practice power productions are not as much as its expected capabilities. This is because a lack of both the prediction of wind resources and the aerodynamic analysis on turbines with far wake effects. In far wake region, there are velocity deficits and increases of the turbulence intensity which lead to the power losses of the next turbine and the increases of dynamic loadings which could reduce system's life. The analysis on power losses and the increases of fatigue loadings in the wind farm is needed to prevent these unwanted consequences. Therefore, in this study velocity deficits have been predicted and aerodynamic analysis on turbines in the far wake is carried out from these velocity profiles. Ainslie's eddy viscosity wake model is adopted to determine a wake velocity and aerodynamic analysis on wind turbines is predicted by the numerical methods such as blade element momentum theory(BEMT) and vortex lattice method(VLM). The results show that velocity recovery is more rapid in the wake region with higher turbulence intensity. Since the velocity deficit is larger when the turbine has higher thrust coefficient, there is a huge aerodynamic power loss at the downstream turbine.

• Journal of Power Electronics
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• v.12 no.3
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• pp.495-502
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• 2012

This paper presents an improved grid voltage control strategy for wind farms with doubly-fed induction generators (DFIGs) connected to distribution networks based on an analysis of the operation limits of DFIG systems. A modified reactive power limit calculation method in different operation states is proposed and a reactive power control strategy during grid voltage dips/rises is further discussed. A control strategy for compensating unbalanced grid voltage, based on DFIG systems, by injecting negative sequence current into the grid through the grid side converter (GSC) is proposed. In addition, the negative current limit of the GSC is discussed. The distribution principle of the negative sequence current among the different DFIG systems in a wind farm is also introduced. The validity of the proposed voltage control strategy is demonstrated by Matlab/Simulink simulations. It is shown that the stability of a wind farm and the power grid can be improved with the proposed strategy.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.10
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• pp.1265-1270
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• 2018

One of the ways to improve the stability of power facilities used in power systems is to use power surge arresters and to protect against transient overvoltages and surges in normal operation. Also it is important to reduce the impact of lightning strikes because lightning can create overvoltage in the grid of the wind turbine and affect power quality. So This paper analyzes the effects of overvoltage and adjacent turbines due to single strike and multi strike to ground impedance changes when the surge arrester is deteriorated in a wind power farm.

• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.2134-2141
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• 2014

This paper addresses on a wind power system with BESS(Battery Energy Storage System). The concerned system consists of four parts: the wind speed production model, the wind turbine model, configure capacity of the battery energy storage, battery model and control of the BESS. First of all, we produce wind speed by 4-component composite wind speed model. Secondly, the maximum available wind power is determined by analyzing the produced wind speed and the characteristic curve of wind power. Thirdly, we configure capacity of the BESS according to wind speed and characteristic curve of wind speed-power. Then, we propose a control strategy to track the power reference. Finally, some simulations have been demonstrated to visualize the feasibility of the proposed methodology.

• Current Photovoltaic Research
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• v.9 no.1
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• pp.17-21
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• 2021

In this study, the effect of water level and temperature on the power generation was investigated in a water tank with an aquavoltaic PV module to perform feasibility research for the development of salt farm aquavoltaic system. The silicon solar cell attached to the bottom of each water tank is a 1-cell mini module, and the underwater effects of the crystal phase (19.0~19.9% of single- & 17.9~19.9% of poly-crystalline) of the PV module were investigated, and power generation characteristics for water level (0~10 cm) and temperature (10~40℃) were analyzed. The deterioration coefficients according to the water level and temperature of each single- and poly-crystalline module were investigated at very similar levels such as, -2.01 %/cm and -2.02 %/cm, -0.50 %/℃ and -0.48 %/℃, respectively. Therefore, in salt farm aquavoltaic system, water levels need to maintain as low as possible, and heat-induced degradation is similar to those shown in general land, and no factors have been found to be affected by the underwater environment depending on the determination.

• Journal of Biosystems Engineering
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• v.15 no.1
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• pp.52-60
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• 1990

The main purpose of this report is to analyse the utilization results of farm machinery, farm mechanization rate and influences on the farm household economy. These results are summarized as follows : 1) The annual working days of major farm machinery are from 34.3 to 68.8 days for power tillers and tractors ; 7.9 to 8.5 days for rice transplanters ; 3.6 to 6.9 days for binders ; and, from 18.6 to 20.6 days for combines. Also income and expenditures of the farm management reveals al surplus in major farm machinery except for binders. 2) The popularization rate of major farm machinery is currently low, reaching the level of the early 1970's in Japan and the level of the early 1980's in Taiwan for rice transplanters and harvesters respectively. 3) The farm mechanization rate is 81.7% in plowing & levelling, 66.3% in rice transplanting, 87.5% in pest and disease control, 62.1% in harvesting and 12.5% in drying. However the farm mechanization rate of rice transplanting, harvesting and drying still remains at a low level. 4) The composition rates of farm machinery and implements are 10.2% in farm management expenditures (23.6% in Japan) and 13.2% in fixed capitals (29.4% in Japan) which still reflect a low level, and below that of the 1970's in Japan. From these analysis results, farm mechanization contributes to the improvement of farm management. Nevertheless, the popularization status and mechanization rate are still at a low level in korea. Therefore, it is deemed desirable to furthure promote effective utilization methods and guide farmers in higher safety utilization and management technology.