Research on the application of flexible direct-current transmission technology in the system planning integrated with large scale of offshore wind farms

2021 ◽  
Author(s):  
H. Cai ◽  
G. Wang ◽  
Z. Xie ◽  
J. Huang ◽  
J. Zhang ◽  
...  
Keyword(s):  
Direct Current ◽  
Large Scale ◽  
Wind Farms ◽  
Offshore Wind ◽  
System Planning ◽  
Offshore Wind Farms ◽  
Current Transmission

Collector System Layout Optimization Framework for Large-Scale Offshore Wind Farms

2016 ◽  
Vol 7 (4) ◽  
pp. 1398-1407 ◽  
Author(s):  
Yingying Chen ◽  
Zhao Yang Dong ◽  
Ke Meng ◽  
Feng ji Luo ◽  
Zhao Xu ◽  
...  
Keyword(s):  
Large Scale ◽  
Wind Farms ◽  
Layout Optimization ◽  
Offshore Wind ◽  
Offshore Wind Farms ◽  
Optimization Framework ◽  
Collector System ◽  
System Layout

Wind wake effects of large offshore wind farms, an underrated impact on the marine ecosystem?

2020 ◽  
Author(s):  
Corinna Schrum ◽  
Naveed Akhtar ◽  
Nils Christiansen ◽  
Jeff Carpenter ◽  
Ute Daewel ◽  
...  
Keyword(s):  
Boundary Layer ◽  
North Sea ◽  
Large Scale ◽  
Spatial Scales ◽  
Wind Farms ◽  
Offshore Wind ◽  
Offshore Wind Farms ◽  
The North ◽  
The North Sea ◽  
Ocean Hydrodynamics

<p>The North Sea is a world-wide hot-spot in offshore wind energy production and installed capacity is rapidly increasing. Current and potential future developments raise concerns about the implications for the environment and ecosystem. Offshore wind farms change the physical environment across scales in various ways, which have the potential to modify biogeochemical fluxes and ecosystem structure. The foundations of wind farms cause oceanic wakes and sediment fluxes into the water column. Oceanic wakes have spatial scales of about O(1km) and structure local ecosystems within and in the vicinity of wind farms. Spatially larger effects can be expected from wind deficits and atmospheric boundary layer turbulence arising from wind farms. Wind disturbances extend often over muliple tenths of kilometer and are detectable as large scale wind wakes. Moreover, boundary layer disturbances have the potential to change the local weather conditions and foster e.g. local cloud development. The atmospheric changes in turn changes ocean circulation and turbulence on the same large spatial scales and modulate ocean nutrient fluxes. The latter directly influences biological productivity and food web structure. These cascading effects from atmosphere to ocean hydrodynamics, biogeochemistry and foodwebs are likely underrated while assessing potential and risks of offshore wind.</p><p>We present latest evidence for local to regional environmental impacts, with a focus on wind wakes and discuss results from observations, remote sensing and modelling.  Using a suite of coupled atmosphere, ocean hydrodynamic and biogeochemistry models, we quantify the impact of large-scale offshore wind farms in the North Sea. The local and regional meteorological effects are studied using the regional climate model COSMO-CLM and the coupled ocean hydrodynamics-ecosystem model ECOSMO is used to study the consequent effects on ocean hydrodynamics and ocean productivity. Both models operate at a horizontal resolution of 2km.</p>

scholarly journals The Explicit Wake Parametrisation V1.0: a wind farm parametrisation in the mesoscale model WRF

2015 ◽  
Vol 8 (4) ◽  
pp. 3481-3522 ◽  
Author(s):  
P. J. H. Volker ◽  
J. Badger ◽  
A. N. Hahmann ◽  
S. Ott
Keyword(s):  
Large Scale ◽  
Wind Farm ◽  
Mesoscale Model ◽  
Wind Farms ◽  
Simulation Models ◽  
Offshore Wind ◽  
Offshore Wind Farms ◽  
Eddy Simulation ◽  
Large Eddy

Abstract. We describe the theoretical basis, implementation and validation of a new parametrisation that accounts for the effect of large offshore wind farms on the atmosphere and can be used in mesoscale and large-scale atmospheric models. This new parametrisation, referred to as the Explicit Wake Parametrisation (EWP), uses classical wake theory to describe the unresolved wake expansion. The EWP scheme is validated against filtered in situ measurements from two meteorological masts situated a few kilometres away from the Danish offshore wind farm Horns Rev I. The simulated velocity deficit in the wake of the wind farm compares well to that observed in the measurements and the velocity profile is qualitatively similar to that simulated with large eddy simulation models and from wind tunnel studies. At the same time, the validation process highlights the challenges in verifying such models with real observations.

scholarly journals INVESTIGATIONS ON SCOUR DEVELOPMENT AT TRIPOD FOUNDATIONS FOR OFFSHORE WIND TURBINES: MODELING AND APPLICATION

2012 ◽  
Vol 1 (33) ◽  
pp. 90 ◽  
Author(s):  
Arne Stahlmann ◽  
Torsten Schlurmann
Keyword(s):  
Large Scale ◽  
Mechanical Stability ◽  
Transport Model ◽  
Structural Parameters ◽  
Complex Structure ◽  
Wind Farms ◽  
Point Of View ◽  
Offshore Wind ◽  
Offshore Wind Farms ◽  
Physical Model Tests

Regarding offshore constructions, there is still a lack in knowledge of scour progression for complex structures like foundations for offshore wind energy converters at present, which is however necessary for its dimensioning. As an example of such complex structure types, tripod foundations are constructed in German offshore wind farms at present. In order to describe physical processes and influencing factors on scour progression from a scientific point of view, comprehensive investigations on the scouring phenomena for tripod foundations have been carried out and will be partly presented here. The overall investigation method consists of a combination of 1:40 small and 1:12 large scale physical model tests in wave flumes, numerical simulations using CFD methods and in-situ measured scour data. For the numerical modeling part, a sediment transport model formulation has been implemented into OpenFOAM software code. The results show a general variability of scour depending on the load boundary conditions and structural parameters. Scours occur both at the foundation piles and directly under the structure, which in this form could not be predicted using standard approaches, but which has to be taken into account when regarding the soil mechanical stability and the final dimensioning of the foundations.

scholarly journals High Voltage DC Transmission Systems for Offshore Wind Farms with Different Topologies

2019 ◽  
Vol 8 (11) ◽  
pp. 2354-2363
Keyword(s):  
High Voltage ◽  
Large Scale ◽  
Wind Farms ◽  
Offshore Wind ◽  
Voltage Source ◽  
Future Research ◽  
Voltage Source Converter ◽  
Offshore Wind Farms ◽  
Multi Level ◽  
Level Converter

Theoretical review of various topologies of high voltage DC links in application to off shore wind forms has been studied and analysed. In addition to that, various types of high voltage DC links such as back to back, two terminal, multi-terminal systems has been covered under this study. The Line-Commutated Converters, Voltage Source Converter, Modular Multi-Level Converter as well as some of advanced hybrid high voltage DC topologies in application to off shore wind forms has been reviewed. This study covers complication arising from large-scale wind power generation. The review paper also points out the scope of future research in high voltage DC converters.

New Approach for Offshore Pile Decommissioning With Hydraulic Presses and Floating Panels

2020 ◽  
Author(s):  
Patrick Lehn ◽  
Nils Hinzmann ◽  
Jörg Gattermann
Keyword(s):  
Large Scale ◽  
Competent Authority ◽  
Wind Farms ◽  
Renewable Energies ◽  
Offshore Wind ◽  
Offshore Wind Farms ◽  
Pullout Resistance ◽  
Offshore Wind Turbines ◽  
Technical Solutions ◽  
Large Scale Tests

Abstract Renewable Energies become more and more important in industries and society all over the world. In Germany, offshore wind farms generated 49 % of the renewable energies in 2018. Monopiles are the preferred system for the foundation of offshore wind turbines in water depths up to 40 m. They are authorized by the competent authority for 25 years. When reaching the end of lifetime, the structure inclusive the foundation must be decommissioned. The decommissioning of monopiles will be challenging in the future and can lead to unexpected costs and risks for the owners. Removing the monopiles in it’s entirely ensures the opportunity to reuse the space for new offshore wind farms. The Institute of Geomechanics and Geotechnics of the Technische Universität Braunschweig (IGG-TUBS) obtained the funding for the research program on technical solutions with large-scale tests for decommissioning of offshore monopiles named DeCoMP. Several decommissioning methods such as vibratory extraction, internal dredging, external jet drilling, decommissioning with overpressure and the use of buoyancy force are investigated. The proposed paper will present technical opportunities and issues for extracting the pile with hydraulic presses in combination with a steel framework. Hydraulic presses brace the steel framework with the monopile. Further hydraulic presses, positioned at a certain distance to the pile on the framework, use the seabed as abutments to push out the monopile. In addition, results of a feasibility study to remove monopiles with floatation panels are presented in this paper. This method is based on floating panels, which are attached to the monopile above the mud line. These panels are inflated with air pressure to reach the required amount of buoyancy to overcome the pullout resistance. The decommissioning solutions are compared to point out possible combinations.

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