• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.8
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• pp.83-89
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• 2015

This study suggests the methodology to decide the number and adequate capacity of substation transformer in a large-scale offshore wind farm (OWF). The recent trend in transformer capacity of offshore substation is analyzed in many European offshore wind farm sites prior to entering the studies. In order to carry out the economic evaluation for the transformer capacity we present the cost models which consist of investment, operation, and expected energy not supplied (EENS) cost as well as the probabilistic wind power model of wind energy that combines the wind speed with wind turbine output characteristics for a exact calculation of energy loss cost. Economic assessment includes sensitivity analysis of parameters which could impact the 400-MW OWF: average wind speed, availability, discount rate, energy cost, and life-cycle.

• 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.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.494-503
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• 2010

This paper reviews research trend in suction bucket foundation. Wind energy farm has been considered as an efficient alternative to fuel energy as world markets attempt to discover renewable resources. Recently, Korean government initiated the research projects investigating installation method of offshore wind energy foundation and design guideline as well as verifying feasibility of offshore wind farm. In fact, the installation of monopile and gravity type foundation has been sucessfully carried out in European and other advanced countries, and design guideline of those foundations are well established; however, various types of foundation would be necessary in the near future as offshore wind farm demands abundant wind resources in deep sea. In this paper, bucket foundation is spot lighted as a powerful and economic alternative applicable to deep sea condition.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1351-1354
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• 2002

Wind farm which are composed with wind turbine generators can be a good alternatives to solve environmental problem and solutions to cope with energy crisis for using wind energy. Until now, these wind turbine generators have been being studied on the viewpoint of only active power control for reducing the burden of main grid. In this control scheme, we might demand a reactive power compensator in order to make reparation for the reactive power produced from wind turbine generator itself. Therefore, if the reactive power as well as active power of wind turbine generator were controlled according to the demand of reactive power, the installation of a additional reactive power compensator could be reduced. This paper presents the control method of a active and reactive power for wind turbine generators by means of SVPWM(Space Vector Pulse Width Modulation) inverting method and describes a operational coordination of wind turbine generators. The proposed power control algorithm can simply produce the output power of wind turbine generator needed in wind farm, which can reduce the power of main grid more and exclude a supplementary reactive power compensator. We assumed that wind farm are composed with two kinds of wind turbine generators, AC/DC/AC and induction generator types.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.11
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• pp.89-95
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• 2013

In resent years, Offshore Wind Farm (OWF) is being actively developed. Typically, OWF has a better wind resource than onshore one, but also have a very high investment cost and maintenance cost. Furthermore, due to a difficulty of geographical access, OWF can be affected by the failure for a longer time. As the result, OWF has a higher loss cost. Therefore, a reliability evaluation should be performed more carefully at OWF planning stage. In this paper, a methodology for the reliability evaluation on inner grid is suggested. Inner grid connects wind turbines via submarine cables and transfers power to offshore substation. According to location of the faulted cable under layouts of inner grid, the transfer ability of inner grid is influenced. In order to indicate the transfer ability of inner grid, several indices are introduced such as PNDR, EEND and EENDC. To demonstrate the methodology described in this paper, diversity case studies were performed.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.2
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• pp.186-192
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• 2014

In this paper, we analysed vessel traffic volume and patterns of traffic flow for ships using areas where included wind farm site and adjacent waters of Daejeong Offshore Wind Farm, and estimated traffic volume by classified navigational routes according to suggestion of rational routeing measures on the basis of classified patterns after installation of offshore wind facilities. Also, we assessed vessel traffic safety for each designed routeing measures on the basis of estimated traffic volume and proposed requisite countermeasures for the safe navigation of ships. With a result of analysing patterns of traffic flow, the current traffic flow was classified by 8 patterns and the annual traffic volume was predicted to 8,975 ships. On the basis of these, expected the vessel traffic volume according to designed four routeing mesaures after installation of wind farm. As result of assessing vessel traffic safety by using powered-vessel collision model of SSPA on the basis of the estimated traffic volume, the value of collision probability was less than safe criteria $10^{-4}$. Thereby we made sure usability of the designed routeing measures for the safe navigation of ships.

• Journal of Wind Energy
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• v.9 no.4
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• pp.40-46
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• 2018

In this study, a three-dimensional Navier-Stokes simulation around Wido Island was performed to analyze the wake effect behind an island. A 10 m/s wind speed and pressure boundary conditions were assigned for the inflow and outflow boundary conditions, respectively. Wido Island was modeled using GIS data. A prevailing wind from the north-northwest direction was determined based on QuikSCAT satellite data. A computational domain of $40km{\times}20km{\times}5km$ covering Wido Island was applied for numerical analysis. Sixty points were specified to extract the wind speed data. A wind speed profile inside the atmospheric boundary layer was compared with a wind profile using a simple power law. It turns out that the wake effect decreases the mean wind speed by 5% more or less, which corresponds to a 14% decrease in wind energy. Thus, the installation of a meteorological mast or development of a wind farm behind Wido Island is not highly recommended.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.8
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• pp.60-66
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• 2013

The wind-speeds among geographically close wind-farms have high correlations seasonally. This paper presents a novel wind-speed sampling method which sincerely reflects the correlation among wind-speeds of different wind-farms. In the proposed method, the wind-speed samples are generated through the statistical data analysis of the measured past wind-speed data and are adequate to be applied to generation adequacy assessment based on random sampling. In the proposed method, the specific probability distribution need not to be assumed and sufficiently accurate wind-speed samples can be generated based only on the measured past data. The proposed method is applied to the two wind-farm problem to show its applicability.

• New & Renewable Energy
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• v.16 no.2
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• pp.20-27
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• 2020

According to "The Renewable Energy 3020 Implementation Plan", offshore wind power accounts for 12 GW of the total new capacity of 48.7 GW. Like the south-west 2.5 GW offshore wind farm case, government-led development has had difficulty in securing the residents' acceptability. This study contributes to the study of local acceptance by analyzing the perceptions of Maldo residents. To this end, in-depth interviews were conducted with the head of a village and fishing village chief, and the entire contents of the interview were revised and analyzed. The cognitive structure of the stakeholders could be confirmed using semantic network analysis, which analyzes the network structure among words. Based on the analysis results, focusing on the identity frames related to the compensation process from previous national projects, gain vs. loss frames act as the dominant frame in terms of profits from offshore wind turbines. To invigorate offshore wind farms, the policy implications as follows. First, a negotiation organization should be organized to deal with strategic opposition by fishes. Second, installing offshore wind farms on a public water body will result in demands for compensation from various actors, and a licensed fishing territory as an offshore wind farm installation site should be considered.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.7
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• pp.80-86
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• 2015

As wind farm outputs depend on natural wind resources that vary over space and time, spatial correlation analysis is needed to estimate power outputs of wind generation resources. As a result, geographic information such as latitude and longitude plays a key role to estimate power outputs of spatially distributed wind farms. In this paper, we introduce spatial correlation analysis to estimate the power outputs produced by wind farms that are geographically distributed. We present spatial correlation analysis of empirical power output data for the JEJU Island and ERCOT ISO (Texas) wind farms and propose the Correlation Decay Distance (CoDecDist) model based on geographic correlation analysis to enhance the estimation of wind power outputs.