The Wave-Load Analysis of the Offshore Wind Power Installation Vessel Based on Frequency-Domain Methods

2011 ◽  
Vol 189-193 ◽  
pp. 1804-1808
Author(s):  
Ya Nan Zhao ◽  
Li Quan Wang ◽  
Hong Wang Du

The wave force spectrum expressed in terms of Morison's equation was deduced by ocean wave theory and spectral analysis theory, and the spectral analysis of wave force were analyzed with the finite element method which was applied to the leg of the offshore wind power installation vessel, the natural frequencies and the vibration model were accomplished with boundary conditions. The dynamic response of the leg were studied in different conditions, it can be concluded that the wave force of the leg is only related with geometric shape and working depth of truss legs.

2012 ◽  
Vol 36 (1) ◽  
pp. 69-80 ◽  
Author(s):  
John Olav Giæver Tande ◽  
Magnus Korpås ◽  
Kjetil Uhlen

At many locations with excellent wind conditions the wind farm development is hindered by grid issues. Conservative assumptions are often applied that unnecessarily limits the wind power installation. This paper shows that significantly more wind power can be allowed by taking proper account of the wind power characteristics and facilitating coordinated power system operation. A systematic approach is developed for assessing grid integration of wind farms subject to grid congestions. The method is applied to a case of connecting offshore wind farms to regional grid with hydro generation (380 MW) and loads (75–350 MW). The tie to the main grid is via a corridor with limited capacity (420 MW). With conservative assumptions (i.e. no changes in scheduled hydro generation or control of wind power output) the wind power installation is limited to 115 MW. The system operation is simulated on an hourly basis for multiple years taking into account the stochastic variations of wind speed and hydro inflow as well as the geographical distribution of wind farms. The simulation uses a control strategy for coordinated power system operation that maximises wind penetration. By using the developed methodology the wind power capacity can be increased from 115 MW to at least 600 MW with relatively little income reduction from energy sales compared to a case with unlimited grid capacity. It is concluded that coordinated operation allows for the integration of surprisingly large amounts of wind power. In order to realize the increase in transfer capability, it is essential to take account of the power system flexibility and the stochastic and dispersed nature of wind power. The presented methodology facilitates this and represents a rational approach for power system planning of wind farms.


2012 ◽  
Vol 479-481 ◽  
pp. 1059-1065 ◽  
Author(s):  
Yan Hua Yang ◽  
Shu Cheng Jin ◽  
Yong Tao Zhang

With the rapid rise of the marine industry, it is urgent need to develop the existing marine equipments. In order to meet the development of offshore wind power market and the construction of large-scale bridge over sea, marine machinery is melting towards large-scale, science, profession, intelligence, and multi-function. The study and development of the multifunction jack-up platform has a wide prospect, which integrating with piling, clear base, leveling, lifting, wind power installation, setting and providing life support for maritime and engineering. This article introduces our research status of existing multi-platform, illuminates the trends and application prospects, and puts forward a new multi-function jack-up platform for reference.


Wind Energy ◽  
2021 ◽  
Author(s):  
Yi‐Hui Wang ◽  
Ryan K. Walter ◽  
Crow White ◽  
Matthew D. Kehrli ◽  
Benjamin Ruttenberg

2021 ◽  
pp. 014459872199226
Author(s):  
Yu-chi Tian ◽  
Lei kou ◽  
Yun-dong Han ◽  
Xiaodong Yang ◽  
Ting-ting Hou ◽  
...  

With resource crisis and environmental crisis increasingly grim, many countries turn the focus to pollution-free and renewable wind energy resources, which are mainly used for offshore wind power generation, seawater desalination and heating, etc., on the premise that the characteristics of resources are fully grasped. In this study, the evaluation of offshore wind energy in offshore waters in China, as well as the advantages and disadvantages of existing studies were overviewed from four aspects: the spatial-temporal characteristics of wind energy, wind energy classification, the short-term forecast of wind energy and the long-term projection of wind energy, according to the research content and the future considerations about wind energy evaluation (evaluation of wind energy on islands and reefs, the impact of wind energy development on human health) were envisaged, in the hope of providing a scientific basis for the site selection and business operation ‘or military applications’ here (after business operation), etc. of wind energy development, ‘aritime navigation against environmental construction,’ here and also contributing to the sustainable development and health of human beings.


Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2058
Author(s):  
Zheren Zhang ◽  
Yingjie Tang ◽  
Zheng Xu

Offshore wind power has great development potential, for which the key factors are reliable and economical wind farms and integration systems. This paper proposes a medium-frequency wind farm and MMC-HVDC integration system. In the proposed scheme, the operating frequency of the offshore wind farm and its power collection system is increased from the conventional 50/60 Hz rate to the medium-frequency range, i.e., 100–400 Hz; the offshore wind power is transmitted to the onshore grid via the modular multilevel converter-based high-voltage direct current transmission (MMC-HVDC). First, this paper explains the principles of the proposed scheme in terms of the system topology and control strategy aspects. Then, the impacts of increasing the offshore system operating frequency on the main parameters of the offshore station are discussed. As the frequency increases, it is shown that the actual value of the electrical equipment, such as the transformers, the arm inductors, and the SM capacitors of the rectifier MMC, can be reduced, which means smaller platforms are required for the step-up transformer station and the converter station. Then, the system operation characteristics are analyzed, with the results showing that the power losses in the system increase slightly with the increase of the offshore AC system frequency. Based on time domain simulation results from power systems computer aided design/electromagnetic transients including DC (PSCAD/EMTDC), it is noted that the dynamic behavior of the system is not significantly affected with the increase of the offshore AC system frequency in most scenarios. In this way, the technical feasibility of the proposed offshore platform miniaturization technology is proven.


Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3759
Author(s):  
Kai Huang ◽  
Lie Xu ◽  
Guangchen Liu

A diode rectifier-modular multilevel converter AC/DC hub (DR-MMC Hub) is proposed to integrate offshore wind power to the onshore DC network and offshore production platforms (e.g., oil/gas and hydrogen production plants) with different DC voltage levels. The DR and MMCs are connected in parallel at the offshore AC collection network to integrate offshore wind power, and in series at the DC terminals of the offshore production platform and the onshore DC network. Compared with conventional parallel-connected DR-MMC HVDC systems, the proposed DR-MMC hub reduces the required MMC converter rating, leading to lower investment cost and power loss. System control of the DR-MMC AC/DC hub is designed based on the operation requirements of the offshore production platform, considering different control modes (power control or DC voltage control). System behaviors and requirements during AC and DC faults are investigated, and hybrid MMCs with half-bridge and full-bridge sub-modules (HBSMs and FBSMs) are used for safe operation during DC faults. Simulation results based on PSCAD/EMTDC validate the operation of the DR-MMC hub.


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