• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.1A
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• pp.27-33
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• 2010

This study addresses a methodology to use small wind turbines for dual purposes, improving aerodynamic performance of flexible bridges and wind energy harvesting. A way to proper placement of small wind turbines on flexible bridges were proposed according on the analogy of conventional aerodynamic appendages. From the wind tunnel tests, it was found that the wind turbine attached like fairing was effective to reduce the vortex-induced vibration of bridge and the optimal spanwise interval of the wind turbine was 3-4.5 time of turbine diameter. Moreover the aerodynamic coefficients of the bridge were improved after installation of the wind turbines. Present results showed the general availability of wind turbine for improvement of aerodynamic performance and energy supply of flexible bridges although the capacity of wind power generation was strongly dependent on wind characteristics of the bridge site.

• Journal of Wind Energy
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• v.14 no.3
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• pp.54-60
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• 2023

In order to reveal the levelized cost of energy (LCOE) of Korean and foreign wind turbines, a study was conducted for Korean onshore wind farms. Actual CapEx and OpEx data were obtained from audit reports for 26 onshore wind farms corresponding to 53.87 percent of the total onshore wind farms in Korea in the Data Analysis, Retrieval Transfer (DART) system. In addition, capacity factor (CF) data were calculated from data provided by Statistics Korea. Random numbers were generated from distributions that were fitted by the datasets, which were used as input data to perform a Monte Carlo simulation (MCS). The levelized fixed cost (LFC) and the levelized variable cost (LVC) were calculated from distributions of the CapEx, the OpEx and the CF. As a result, the LCOEs of the analyzed total Korean wind farms, and Korean and foreign wind turbines were 147, 148, and 146 USD/MWh, respectively. The averaged LCOE of Korea was estimated to be 4 USD/MWh lower than that of Japan, while it was much higher than German and global averages.

• Solar Energy
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• v.6 no.2
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• pp.86-92
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• 1986

This paper presents the aerodynamic performances of horizontal axis wind turbines with non-twisted but taperd blades. Five configurations of blades, namely, one straight blade and four tapered blades with taper ratio of ranging from 0.1 to 0.7 have been simulated. The aerodynamic performances of the wind turbines have been determined over blade incidence angle of ranging from $2^{\circ}$ to $6^{\circ}$ and keeping same solidity and radius of them. The results are presented comparing straight blade from four tapered blades for maximum power coefficient and tip looses against variation of taper ratio. It also shows that the wind turbine with taper ratio of 0.5 has the highest maximum power coefficient than others. And wind turbines with taper ratio below 0.2 have lower values of maximum power coefficients than straight one. The tip loss of straight blade is the largest and reduces Slightly with the decrementation of taper ratio.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.3
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• pp.397-404
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• 2023

This paper designs a wind turbine test site based on international regulations for the certification of wind turbine prototypes. The maximum height of the meteorological mast installed at the test site is 140m, and power facilities capable of testing up to three wind turbines of 5MW or more are installed. The weather resources measured at the mast can be recorded and analyzed using a monitoring system. Wind turbine manufacturers can use this test site during the certification period, and the installed wind turbines can be used for continuous power generation projects. Therefore, this test site can provide fundamental data for measuring the long-term performance and durability of wind turbines, which can be used to improve models or develop new wind turbines.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.9
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• pp.1560-1565
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• 2010

The renewable resource are getting more attentions with increased concerns on the depletion of fossil fuels and several environmental issues like emission problem. Wind power is a representative option among several renewable sources and the generation capacity using wind power is being increased. However, the wind generation is so volatile on its output characteristic, so it is required to assess the grid impact of wind power generation by measuring the fluctuation effect more precisely. This paper proposes the method for measuring the generation output according to IEC 61400-21(Measurement and assessment of power quality characteristics of grid connected wind turbines) to assess the power quality of wind turbine generation. In addition, it shows an application case to a small-scale wind power generator. In the case study, it suggests a structure design of the proposed measurement instrument both on hardware and software aspects, which is composed of a remote monitoring & data analysis program and an FPGA based real-time signal processing device.

• Advances in Energy Research
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• v.5 no.2
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• pp.147-177
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• 2017

This study aims to evaluate and prioritize ten different sites in Iran's Khorasan provinces for the construction of wind farm. After studying the geography of the sites, nine criteria; including wind power, topography, wind direction, population, distance from power grid, level of air pollution, land cost per square meter, rate of natural disasters, and distance from road network-are selected for the analysis. Prioritization is performed using data envelopment analysis (DEA). The developed DEA model is validated through value engineering based on the results of brainstorming sessions. The results show that the order of priority of ten assessed candidate sites for installing wind turbines is Khaf, Afriz, Ghadamgah, Fadashk, Sarakhs, Bojnoord, Nehbandan, Esfarayen, Davarzan, and Roudab. Additionally, the outcomes extracted from the value engineering method identify the city of Khaf as the best candidate site. Six different wind turbines (7.5 to 5,000 kW) are considered in this location to generate electricity. Regarding an approach to produce and store hydrogen from wind farm installed in the location, the AREVA M5000 wind turbine can produce approximately $337ton-H_2$ over a year. It is an enormous amount that can be used in transportation and other industries.

• Journal of Wind Energy
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• v.14 no.1
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• pp.14-20
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• 2023

In this study, using the commercial software Bladed developed by DNV for integrated load calculation of wind turbines, the generation of seismic waves according to soil type based on Korea's domestic regulations, and load calculation considering earthquake conditions were performed according to the IEC standard, and load in the main coordinate system of the fixed offshore wind turbine was calculated. By comparing the calculated load with the design load of the fixed offshore wind turbine, the effect of earthquake loads according to soil type on the main components of fixed offshore wind turbines was evaluated. As a result of the evaluation, when an earthquake load on a wind turbine is considered, the effect of the earthquake load is related to the natural frequency of the major components and the magnitude of the adjacent acceleration in the earthquake response spectrum, and the earthquake load differs according to soil type and may exceed the design load.

• International Journal of Aerospace System Engineering
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• v.11 no.1
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• pp.1-3
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• 2024

Around the world, fossil fuel energy is being replaced with renewable energy due to environmental problems and sharp price increases. Many countries are making a change in the direction of moving toward eco-friendliness by reducing carbon emissions. Among renewable energies, the wind energy is eco-friendly because it produces electricity by wind power without carbon emissions, and it attracts attention worldwide as a great alternative to the exhausted fuel energy. To improve the efficiency of wind turbines, large and extra-large wind turbines have been developed all over the world by increasing install and diameter. These wind turbines have difficulty in transport after manufacture because of their size and height. Since the height of wind turbine blades is higher than the existing tunnel height, it is impossible to transport them. In this study, therefore, a 5 MW class large blade was separated for transport easiness as wind power generators became larger globally. Aerodynamic design and analysis was carried out for the blade. After performing structural design and analysis with the model designed, the stress concentration of the analyzed model and the various factors for consideration when separating were considered to conduct the study of selecting the optimal blade separation positions.

• KEPCO Journal on Electric Power and Energy
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• v.2 no.4
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• pp.631-638
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• 2016

Offshore wind power can be an alternative for onshore wind power which suffers from not only civil complaints regarding to landscape damage and noise but also wind power siting due to lack of onshore site candidates. Compared to onshore wind power, offshore wind power is free from these problems considering that generally the sites are far enough from the coast. And more electricity is generated in offshore wind turbines due to abundant offshore wind resources. However high installation costs of offshore turbines could deteriorate the economical efficiency. The main cause of the high installation costs comes from a long-term lease of the heavy marine equipment and the consequential high rental cost. In this paper, the conceptual design of the support structure for offshore wind turbines will be suggested for the installation of them with less heavy marine equipment.

• Ocean Systems Engineering
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• v.8 no.3
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• pp.281-312
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• 2018

Characteristics of a turbulence wind model control the magnitude and frequency distribution of wind loading on floating offshore wind turbines (FOWTs), and an in-depth understanding of how wind spectral characteristics affect the responses, and ultimately the design cost of system components, is in shortage in the offshore wind industry. Wind spectrum models as well as turbulence intensity curves recommended by the International Electrotechnical Commission (IEC) have characteristics derived from land-based sites, and have been widely adopted in offshore wind projects (in the absence of site-specific offshore data) without sufficient assessment of design implications. In this paper, effects of wind spectra and turbulence intensities on the strength or extreme responses of a 5 MW floating offshore wind turbine are investigated. The impact of different wind spectral parameters on the extreme blade loads, nacelle accelerations, towertop motions, towerbase loads, platform motions and accelerations, and mooring line tensions are presented and discussed. Results highlight the need to consider the appropriateness of a wind spectral model implemented in the strength design of FOWT structures.