• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.5
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• pp.551-560
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• 2020

Recently, the offshore wind power generator market is expected to grow significantly because of increased energy demand, reduced dependence on fossil fuel-based power generation, and environmental regulations. Consequently, wind power generation is increasing worldwide, and several attempts have been made to utilize offshore wind power. Norway's Petroleum Safety Authority (PSA) requires a leg-structure design with a collision energy of 35 MJ owing to the event of a collision under operation conditions. In this study, the results of the numerical analysis of a wind turbine installation vessel subjected to ship collision were set such that the maximum collision energy that the leg could sustain was calculated and compared with the PSA requirements. The current leg design plan does not satisfy the required value of 35 MJ, and it is necessary to increase the section modulus by more than 200 % to satisfy the regulations, which is unfeasible in realistic leg design. Therefore, a collision energy standard based on a reasonable collision scenario should be established.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.5
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• pp.1003-1012
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• 2022

The horizontal force transfer to the turbine and substructure of a wind power generation system is a very important factor in maintaining the safety of the system, but it is inevitably vulnerable to large-scale coastal disasters such as earthquakes and typhoons. Wind power generation systems built on the coast or far offshore are very disadvantageous in terms of economic feasibility due to an increase in initial investment cost because a more robust design is required when installed in areas vulnerable to coastal disasters. In this study, the GIS method was used to select the optimal site for a wind farm from the viewpoint of reducing the risk of coastal disasters. The current status of earthquakes in the West and South Seas of Korea, and the path and intensity of typhoons affecting or passing through the West and South Seas were also analyzed. Accordingly, the optimal offshore wind farm site with the lowest risk of coastal disasters has been selected and will be used as basic research data for offshore wind power projects in the region in the future.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.58.1-58.1
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• 2011

In this paper, the purpose is a study on structural analysis for offshore wind turbine using commercial code. Because offshore wind turbine is subjected to great wind and wave force, it is necessary to analyse the dynamics and minimize the response of wind turbine. The offshore wind turbine tower is modelled as a single degree of freedom and multi degree of freedom structure. It is assumed that the blades, nacelle are composed of concentrated masses.

• Journal of Wind Energy
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• v.14 no.4
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• pp.75-86
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• 2023

We observed five species and 163 individuals of birds in the Demonstration Offshore Wind Farm in the southern part of the West Sea in Korea, and 33 species and 4,023 individuals from Gusipo to Dongho Beach. The most dominant bird in both areas was the black-tailed gull, Larus crassirostris. The flight height of birds for collision risk (wind turbine and bird) was divided into two groups. First, the safe height was from sea level to 20 m (< 20 m), with no effect from the action of revolving blades. Second, the danger height was more than 20 m from sea level (> 20 m), with a collision risk from the action of revolving blades. Birds flying a safe height (< 20 m) were 83.9% (271 individuals) and danger height (> 20 m) were 16.1% (52 individuals). Also, 11.7% of birds (35 individuals) used the inside of the Demonstration Offshore Wind Farm as a habitat for foraging and resting, and 88.3% birds used the outside. We suggest that the risk of collision with the wind farm was low due to the relatively low flight height of birds and distance between wind turbines (> 800 m).

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.281-286
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• 2006

본 연구의 목적은 차세대 대체에너지로 각광받는 풍력발전 중에서 육상발전보다 여러 가지 이점이 있는 한국형 해상풍력터빈 블레이드의 최적형상설계를 위한 알고리즘을 구현하는 것이다. 블레이드 단면 익형의 양력과 항력 분포는 XFOIL을 이용하여 예측하였다. 첫 번째 수준의 설계변수인 각각의 블레이드 지름과 축 회전수에서 익형의 공력변수들과 최소에너지손실 조건을 이용하여 두 번째 설계변수인 각 블레이드 단면에서의 시위길이와 피치각 분포를 최적화하였다. 그리고 성능결과를 바탕으로 반응면을 구성하고, 확률적 방법을 이용하여 타당성 있는 설계공간까지 첫 번째 설계변수를 이동시키고 구배최적화 기법을 통해 각각의 제약함수를 만족하면서 목적함수를 죄대로 하는 최적블레이드 형상을 구현하였다. 설계된 최적형상에 대해 탈설계점 해석을 수행하여 성능을 구하였다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.610-613
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• 2011

본 논문에서는 해상풍력발전기와 선박의 충돌시 타워와 기초보강재의 거동에 대하여 연구하였다. 풍력발전기는 5MW급 풍력발전기를 나셀, 타워, 보강재, 바닥판, 기초로 나누어서 모델링 하였다. 나셀은 집중질량으로 타워의 상부에 위치하였고 타워, 보강재, 바닥판은 탄소성거동을 한다고 가정하여 Shell 요소로 모델링 하였다. 선박은 풍력발전기와 마찬가지로 탄소성거동을 한다고 가정하였고 실제모델에 대해 풍력발전기와의 정면충돌로 고려하였으며, 충돌속도는 2.0m/sec로 가정하였다. 선박과 풍력발전기의 충돌 해석은 비선형 해석 프로그램인 ABAQUS/Explicit을 이용하여 수행하였으며, 이를 통하여 선박충돌시 타워와 보강재의 거동을 분석하였다. 해석결과 타워에서 대부분의 에너지를 소산하는 것으로 나타났다.

• Journal of Korea Port Economic Association
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• v.28 no.3
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• pp.27-44
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• 2012

The offshore wind farm is increasingly attractive as one of future energy sources all over the world. In addition, the capacity of an offshore wind turbine gets larger and its physical characteristics are big and heavy. In this regard, a special port is necessary to assemble, store, and transport the offshore wind systems, supporting to form the offshore wind farms. Thus, this study aims to provide a policy maker which evaluation factors can significantly affect to the optimal site selection of a offshore wind port. For this, Fuzzy-AHP method is applied to capture the relative weights. The results of this study can be summarized as follows. Five criteria in level I was defined such as the accumulation factor, the regional factor, the economic factor, the location factor, and the consortium factor. Of these, the accumulation factor(37.4%), the location factor(34.2%), and the economic factor( 24.5%) were analyzed by major factors. In level II, three assessment items of each factor were selected so that total fifteen items were formed. To sum up, the site selection of offshore wind port should consider the density of the wind industry, cargo volume of securing the economic operation of terminals, the development degree of offshore wind related industry, and the proximity to the offshore wind farms. In other words, the construction of offshore wind port should be paid attention to considering not only the proximity to offshore wind farms but also the preference of turbine manufacturing companies.

• Korean Chemical Engineering Research
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• v.53 no.2
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• pp.156-163
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• 2015

This paper presents a new framework for design and economic evaluation of wind energy-based electricity supply system. We propose a network optimization (mixed-integer linear programming) model to design the underlying energy supply system. In this model we include practical constraints such as land limitations of onshore wind farms and different costs of offshore wind farms to minimize the total annual cost. Based upon the model, we also analyze the sensitivity of the total annual cost on the change of key parameters such as available land for offshore wind farms, required area of a wind turbine and the unit price of wind turbines. We illustrate the applicability of the suggested model by applying to the problem of design of a wind turbines-based electricity supply problem in Jeju. As a result of this study, we identified the major cost-drivers and the regional cost distribution of the proposed system. We also comparatively analyzed the economic performance of on/off shore wind farms in wind energy-based electricity supply system of Jeju.

• Journal of Wind Energy
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• v.13 no.4
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• pp.26-41
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• 2022

Three similarities (i.e., geometrical similarity, kinematic similarity and dynamic similarity) between a prototype and model must be satisfied to perform an experiment for a floating offshore wind turbine (FOWT). For dynamic similarity, most of the model tests in ocean engineering basins are performed based on the Froude number, so the scale effect for the wind turbine of an FOWT occurs by different Reynolds numbers between the prototype and model. In this study, various model test techniques for overcoming the scale effect of the wind turbine part of the FOWT are investigated. Firstly, model test techniques using simple approaches are reviewed, and the advantages and disadvantages of the simple approaches are summarized. Secondly, the model test techniques in recent projects that apply improved approaches are introduced including advantages and disadvantages. Finally, new approaches applying digitalization are reviewed, and the characteristics of the new approaches are introduced.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.290-294
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• 2008

Offshore wind farms will contribute significantly to the renewable generation of electricity for the world. The economic development of wind farms depends, however, on development of efficient solutions to a number of technical issues, one of these being the foundations for the offshore turbines. We review here the results of recent research for wind turbine foundations. Also it is a short overview of some of the challenges facing the growth of offshore wind energy foundation technology.