• Journal of Wind Energy
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• v.9 no.4
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• pp.32-39
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• 2018

In this study, the annual power production of a wind farm according to obstacles and wind data was predicted for the Garyeok-do wind farm in the Saemangeum area. The Saemangeum Garyeok-do wind farm was built in December 2014 by the Korea Rural Community Corporation. Currently, two 1.5 MW wind turbines manufactured by Hyundai Heavy Industries are installed and operated. Automatic weather station data from 2015 to 2017 was used as wind data to predict the annual power production of the wind farm for three consecutive years. For prediction, a commercial computational fluid dynamics tool known to be suitable for wind energy prediction in complex terrain was used. Predictions were made for three cases with or without considering obstacles and wind direction errors. The study found that by considering both obstacles and wind direction errors, prediction errors could be substantially reduced. The prediction errors were within 2.5 % or less for all three years.

• Journal of Electrical Engineering and Technology
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• v.7 no.2
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• pp.157-162
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• 2012

Wind energy is created in mega-sized wind farms situated kilometers off shore. In fact, two possibilities are considered for the transmission system between the offshore wind farm and the onshore grid: high-voltage direct current and high-voltage alternating current. From this point of view, the current paper aims to compare both systems for a 2 GW wind farm situated 80 km from the Point of Common Coupling on an economic basis using a discounted cash flow analysis. A tool is developed in Microsoft Excel to allow for quick insight in the variation of input parameters.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.8
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• pp.1063-1069
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• 2011

This paper presents aerodynamic power outputs of wind turbine of 6 MW wind farm composed of 3 sets of 2 MW wind turbine according to the separation distance by using CFD. Layout design including offshore wind farm and onshore wind farm is key factor for the initial investment cost, annual energy production and maintenance cost. For each wind turbine rotor, not actuator disc model with momentum source but full 3-dimensional model is used for CFD and it has a great technical meaning. The results of this study can be applied to the offshore wind farm layout design effectively.

• Journal of Wind Energy
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• v.13 no.1
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• pp.5-14
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• 2022

Currently, the Korean government is driving the construction of large-scale floating offshore wind farms to increase domestic renewable energy generation and decrease carbon emissions. In offshore wind farms, maintenance approaches can be limited more often than onshore wind farms by marine weather conditions (wave height, etc.). Therefore, maintenance planning optimization is more important to minimize maintenance costs and power generation loss by downtime. Additionally, the power generation of a wind farm is affected by wind speed as well as wind direction because of the wake effect, so it is possible that power generation loss by downtime is also dependent on combinations of weather conditions (wind speed and direction) and the location of wind turbines for maintenance. In this study, the effects of the wind conditions and the locations of tripped wind turbines on power generation loss were explored for a hypothetical floating offshore wind farm. In order to calculate the power generation of a wind farm, a wake effect calculator was developed based on Jensen's formula. Then, a simple methodology of determining maintenance priorities that minimize power generation loss was proposed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.3
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• pp.399-404
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• 2015

This paper presents the DC voltage control method in DC link of High Voltage Direct Current(HVDC) for an offshore wind farm in Low Voltage Ride Through(LVRT) situation. Wind generators in an offshore wind farm are connected to onshore network via HVDC transmission. Due to LVRT control of grid side inverter in HVDC, power imbalancing in DC link is generated and this consequentially causes rising of DC voltage. A de-loading scheme is one of the method to protect the wind power system DC link capacitors from over voltage. But the flaw of this method is slow control response time and that it needs long recovery time to pre-fault condition after fault clear. Thus, this paper proposes improved de-loading method and we analyze control performance for DC voltage in LVRT control of HVDC for an offshore wind farm.

• Journal of the Korean Solar Energy Society
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• v.35 no.2
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• pp.1-10
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• 2015

Promising onshore wind farm sites in Gangwon province of Korea were investigated in this study. Gangwon province was divided into twenty five simulation regions and a commercial program based on Reynolds averaged Navier-Stokes equation was used to find out wind resource maps of the regions. The national wind atlas with a period 2007-2009 developed by Korea institute of energy research was used as climatologies. The wind resource maps were combined to construct a wind resource map of Gangwon province with a horizontal spatial resolution of 100m. In addition to the wind resource, national environmental zoning map, distance from substation, residence and automobile road, Beakdudaegan mountain range, terrain slope, airport and military reservation district were considered to find out promising wind farm sites. A commercial wind farm design program was used to find out developable wind farm capacities in promising wind farm site with and without excluding environmental protection regions. The total wind farm capacities with and without excluding the protection regions were estimated to be 46MW and 598MW, respectively, when a 2MW commercial wind turbine was employed.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.10 no.1
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• pp.40-45
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• 2011

As increasing the importance of renewable energy recently, the scale of a wind power plant is increasing to the number of GW scale and specially, it is trend to move from onshore to offshore to use the higher quantity and quality of wind. Consequently to meet the trend, it is largely considered the importance of communication protocol to control and monitor remotely. But, because the communication protocol between the control center and a wind turbine has been independently developed by each wind turbine vendor, it is absence of the compatibility and extensibility when the heterogeneous wind turbines are installed in the wind farm. The IEC 61400-25 is the specifying standard for these problems in Europe. In this paper, we will show the state of these problems and present a new structure of communication based on the IEC 61400-25 to get the compatibility and extensibility between a control center and wind turbines.

• Wind and Structures
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• v.20 no.1
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• pp.1-13
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• 2015

This study applied long-term wind speed data from Penghu and Dongjidao weather stations to simulate the wind energy production for eight onshore and one offshore wind farms at Penghu Island, Taiwan by a commercial software package, Wind Atlas Application Program (WAsP). In addition, the RET Screen software suite was also applied to analyze economic characteristics of these nine wind farms (WFs). The results show that the capacity factors (CFs) of the nine wind farms mentioned above are in the range of 44.5% to 49.1%. In addition, utilizing 1.8-MW wind turbines (WTs) for all onshore WFs was the most feasible selection among the four potential types of WTs (600, 900, 1,800 and 3,600 kW) considered. 3-MW WTs selected for the offshore WF can produce the most wind energy and the smallest wake loss among the three possible types of WTs (1, 2 and 3MW). As a consequence of implementing these WFs, the emission of about 680,977 tons carbon dioxide ($tCO_2$) into the local atmosphere in Penghu Island annually could be avoided. Finally, based on the payback periods achieved, the order of implementation of the considered WFs can be identified more clearly. Longmen WF should be the first priority, and the next one should be SiyuWF and so on. Besides, this study provides much useful information for WF planning on Penghu Island.

• Journal of Environmental Impact Assessment
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• v.33 no.4
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• pp.164-174
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• 2024

Recently, many offshore wind farm project plans and environmental impact assessments have been conducted in Korea. However, despite having different characteristics from onshore wind farm, there is a lack of alternative setting and evaluation methods suitable for this. Accordingly, this study attempted to derive implications for the alternative setting and evaluation method suitable for the domestic situation through overseas guideline and case analysis. Through the result of the analysis, it was possible to examine the process of the alternative setting and evaluation method for offshore wind farm, and through this, detailed considerations and methodology were found. Even overseas, the methodology for alternative setting and evaluation has not yet been clear, and the methodology used for onshore wind farm has been improved and developed. In Korea, it is necessary to prepare a system for setting and evaluating alternatives to such offshore wind farm projects, and research in various fields is required to carry out them reasonably and efficiently. For the successful promotion of domestic offshore wind farm projects, it is thought that continuous efforts to increase environmental and social acceptance are necessary along with the promotion of related research reflecting the implications derived from overseas cases.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.486-493
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• 2010

Recently, it has been a worldwide issue to develop offshore wind farm based on the past technical experiences of onshore wind turbine installation. In Korea, the government has the wind-energy to be a new-sustainable field of development to bring green-growth in near future and put political and fiscal efforts to support the academic and industrial technical development. Especially, there are much advancement for the fields of turbine, blade, bearing, grid connection, ETC. Correspondingly, technical needs do exist for the offshore foundation installation techniques in geotechnical point of view. Within few years, 2~5MW offshore wind turbines will be constructed at about 30m water depth and it is known that monopiles of D=4~6m are suitable types of foundation. In order to construct offshore wind-turbine foundation, technical developments for drilling machine, design manual, monitoring&maintenance technique are required. This paper presents technical issues with related to offshore wind farm and large diameter monopile in the point of renewable energy development.