• New & Renewable Energy
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• v.9 no.4
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• pp.13-18
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• 2013

Wind turbines should generally be installed at a certain distance from a road to ensure passengers' safety. In Korea, there is no clear guidance as the Ministry of Environment first proposed a road setback distance of 400 m in the Onshore Wind Farm Siting Guidelines draft proposed in July 2012, and then modified it to 1.5 times the height of the wind turbine in October of the same year. This study analyzed the dynamic range of onshore wind resource potential according to how the road setback distance is set using the Korea Wind Atlas with 100m spatial resolution made by the Korea Institute of Energy Research, the transportation network of the Ministry of Construction and Transportation, and the forest road network of the Korea Forestry Service. Owing to the geographical characteristics of Korea, where mountainous terrain accounts for 70% of the total territory, the wind resource potential within 1 km from forest roads are estimated to be 14.3 GW, 14% of Korea's total wind resource potential. In addition, the construction distance of new road for transporting wind turbines from the existing road to a wind farm site is estimated as less than 2 km. Given the limited wind resource potential and geographical constraints, an assessment system that can maximize wind resource utilization and ensure road safety at the same time, and which takes into account the regional characteristics instead of applying the fixed road setback distance across-the-road, is required.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.4
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• pp.201-212
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• 2016

A Wind resource assessment and optimal micrositing of wind turbines were implemented for the development of an onshore wind farm of 30 MW capacity on Gadeok Island in Busan, Republic of Korea. The wind data measured by the automatic weather system (AWS) that was installed and operated in the candidate area were used, and a reliability investigation was conducted through a data quality check. The AWS data were measured for one year, and were corrected for the long term of 30 years by using the modern era retrospective analysis for research and application (MERRA) reanalysis data and a measure- correlate-predict (MCP) technique; the corrected data were used for the optimal micrositing of the wind turbines. The micrositing of the 3 MW wind turbines was conducted under 25 conditions, then the best-optimized layout was analyzed with a various wake model. When the optimization was complete, the estimated park efficiency and capacity factor were from 97.6 to 98.7 and from 37.9 to 38.3, respectively. Furthermore, the annual energy production (AEP), including wake losses, was estimated to be from 99,598.4 MWh to 100,732.9 MWh, and the area was confirmed as a highly economical location for development of a wind farm.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.211-212
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• 2008

As a result of environmental concerns, the production of electricity through renewable energy resources is rapidly increasing. Wind energy is among the fastest growing renewable energy resources now being integrated in the power system, and the penetration rate of wind generation has been gradually increased. For power flow analysis of the recent systems, thus, steady-state modeling of wind turbines and their application are of great importance. This paper presents the procedure we applied for implementation of a steady-state wind turbine model in power flow.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1389-1391
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• 2003

The development of wind turbine power generation has grown during the past ten years. An important question, when installing wind turbines with the generator connected directly to the grid, is holt much the voltage quality will be affected by the uneven power production and by the connection of the wind turbine to the grid. This paper presents the voltage fluctuation of grid-connected WTG(wind turbine generators) by MATLAB/Simulink.

• Journal of Ocean Engineering and Technology
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• v.28 no.4
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• pp.288-293
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• 2014

The IEC standard for onshore or offshore wind turbines requires additional dummy simulations (at least 5 s) for the transient responses due to initial conditions. An increase in the dummy time causes a considerable increase in the computational cost considering multiple design spirals with several thousand design load analysis cases. A time of 30 s is typically used in practical simulations for a wind turbine design with a fixed platform. However, 30 s may be insufficient for floating offshore wind turbines (FOWT) because the platforms have lower natural frequencies, and the transient responses will last much longer. In this paper, an initial condition application algorithm is implemented for WindHydro, and the appropriate dummy simulation time is investigated based on a series of dynamic simulations of a FOWT. As a result, it is found that more than 300 s is required for the platform to have stationary motion after the initial transient responses for the FOWT under the conditions considered.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.9
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• pp.922-929
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• 2014

Wind turbines are in the limelight in the alternative energy industry. However, they face frequent and various problems during operation. We focused on the supervising of the blades of a wind turbine. In this paper, we present the design of a maintenance robot that takes the size of wind turbine blades into consideration, so the general form of the robot is a square with four wires fixed to its vertices and to the nacelle. After the robot is placed near the nacelle, it moves along the blades. We also designed an attitude control algorithm for the robot to maintain its balance. Our control algorithm for the robot consists of roll and pitch attitude controllers and a height controller. Each controller was designed independently and then superposed together. We used simulations to verify our control algorithm.

• New & Renewable Energy
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• v.3 no.3
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• pp.45-53
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• 2007

This paper demonstrates a computational method in predicting aerodynamic noise generated from wind turbines. Low frequency noise due to displacement of fluid and leading fluctuation, according to the blade passing motion, is modelled on monopole and dipole sources. They are predicted by Farassat 1A equation. Airfoil self noise and turbulence ingestion noise are modelled upon quadrupole sources and are predicted by semi-empirical formulas composed on the groundwork of Brooks et al. and Lowson. Aerodynamic flow in the vicinity of the blade should be obtained first, while noise source modelling need them as numerical inputs. Vortex Lattice Method(VLM) is used to compute aerodynamic conditions near blade. In the use of program X-foil [M.Drela] boundary layer characteristics are calculated to obtain airfoil self noise. Wind turbine blades are divided into spanwise unit panels, and each panel is considered as an independent source. Retarded time is considered, not only in low frequency noise but also In turbulence ingestion noise and airfoil self noise prediction. Numerical modelling is validated with measurement from NREL [AOC15/50 Turbine) and ETSU [Markham's VS45] wind turbine noise measurements.

• Journal of Wind Energy
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• v.13 no.4
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• pp.80-89
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• 2022

In this paper, a study was conducted to evaluate the safety of pitch reducers for 8 MW class wind turbines. The housing and carrier of the pitch reducer were subjected to structural analysis for the ultimate load by load duration distribution (LDD). As a result of the finite element analysis of the housing parts, the part with the highest stress was the output housing, and the equivalent stress was 522.4 MPa and the safety factor was 1.14. As a result of finite analysis of the carrier, the highest stress occurred at 80.5 MPa in the first carrier, and the safety factor was 10.3. In addition, extreme strength and life analysis by LDD load were performed for gears and bearings included in each stage. The strength analysis of the planetary gear train was conducted based on ISO 6336, and the stability evaluation of the bearings through life analysis based on ISO 281 found all to be safe.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.4
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• pp.13-19
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• 2014

To develop a wind farm in a mountainous terrain like Korea, it is generally more advantageous to install wind turbines along a mountain ridge where has relatively better wind resource because that is open in all directions and free from shielding by the surrounding topography. In this study, the SRTM (Shuttle Radar Topography Mission) v4.1 3 arc-second resolution digital elevation database and the geomorphometric characterization software LandSerf v2.3 are used to extract ridge lines for assessing a wind farm siting in mountainous terrain. The effectiveness of wind farm siting along a ridge line is confirmed that the most of wind turbines in the Gangwon, Taegisan, and Maebongsan wind farms in Korea's mountainous terrain are placed along the primary and secondary ridge lines where wind resource is relatively outstanding.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.30 no.4
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• pp.191-199
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• 2018

In this paper, wind data at 20 locations are collected and analyzed in order to review optimal candidate site for offshore wind farm around Korean marginal seas. Observed wind data is fitted to Rayleigh and Weibull distribution and annual energy production is estimated according to wind frequency. As the model of wind turbine generator, seven kinds of output of 1.5~5 MW were selected and their performance curves were used. As a result, Repower-5 MW turbines showed high energy production at wind speeds of 7.15 m/s or higher, but G128-4.5 MW turbines were found to be favorable at lower wind speeds. In the case of Marado, Geojedo and Pohang, where the rate of occurrence of wind speeds over 10 m/s was high, the capacity factor of REpower's 5 MW offshore wind turbine was 56.49%, 50.92% and 50.08%, respectively.