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Conference programme 

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Poster session

Lead Session Chair:
Stephan Barth, Managing Director, ForWind - Center for Wind Energy Research, Germany
Arno Brand ECN, The Netherlands

(1) ECN, Petten, The Netherlands (2) 3E, Brussels, Belgium (3) Senvion, Hamburg, Germany (4) RWE Innogy, Hamburg, Germany (5) Imperial College London, London, United Kingdom (6) ForWind Oldenburg, Oldenburg, Germany

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Presenter's biography

Biographies are supplied directly by presenters at OFFSHORE 2015 and are published here unedited

Arno Brand is a research scientist in the unit Wind Energy of the Energy Research Centre of the Netherlands ECN. He has a M.S. degree in applied physics and a Ph.D. degree in mechanical engineering, both from Delft University of Technology.

Dr. Brand has been employed in wind energy since 1991. Up to 1999 he was mainly involved in wind turbine rotor aerodynamics. In 1998 he got involved in wind energy meteorology. Currently he works on modelling and control of clusters of wind farms.


Tuning offshore wind performance


The challenge in designing and operating large offshore wind farms is in cost effectiveness. Various approaches are under development to date, but in this presentation the focus is on the solutions of the ClusterDesign consortium. In the ClusterDesign consortium six partners in four countries work together in order to improve the capabilities to design and operate large offshore wind clusters.


Their philosophy is:
• To accurately predict energy production and fatigue-life consumption, designers must take into account the interaction between wake losses and electrical losses.
• To take the maximum out of a wind farm, operators need to find a balance between energy production and fatigue-life consumption.
• Designer and operators must take grid requirements into account.
To this end the consortium developed and improved specific models and strategies, and integrated these in a Wind Cluster Controller and a ClusterDesign ToolBox. This includes work on wind models, a mechanical load model, an electrical collection and grid connection model, and wind farm control strategies.

Main body of abstract

ForWind Oldenburg and ECN developed the FLaP-Ainslie and FarmFlow wind farm flow models further with the objective to use model output in load calculations, by extending these models with the ability to predict turbulence and shear.
To complement or replace measurements, ForWind Oldenburg applied the meteorological model WRF to determine the inflow conditions for the wake flow simulations. In addition, by using WRF, they created a Wind And Stability Atlas of the North Sea, containing pre-cooked inflow conditions.
As to wake effects between wind farms, ECN demonstrated that FarmFlow accurately models clusters of wind farms too. This functionality allows designers and operators to take the effect of adjacent wind farms into account without having to rely on extra software.
Senvion developed a new model for offshore wind turbine load prediction, which is built on the capability of the FLaP-Ainslie and FarmFlow models to predict the turbulence and the horizontal and vertical shear at the turbine positions.
Imperial improved the Delecto model for the evaluation of the electrical system of wind farms and the connection to the onshore grid. The improvements ensure an efficient connection within wind clusters, meeting grid code requirements and supply system service requests, while taking into account the interaction of wake losses and electrical losses.
Their models allow wind farm designers to develop alternative design solutions to meeting grid code requirements, and to evaluate the reliability performance and corresponding wind curtailment associated with alternative topologies with different levels of redundancy and flexibility.


RWE Innogy identified control concepts that at the same time can reduce the load on offshore wind turbines, optimize the overall power output while minimizing mechanical loading, and allow the operation of offshore wind farms similar to conventional power plant. The concepts include ECN’s Active Wake Control and Imperial’s Optimal Reactive Power Distribution strategies. In the process they developed a simulation model of the Wind Cluster Controller.

Learning objectives
The Wind Cluster Controller of consortium partner RWE Innogy and the ClusterDesign ToolBox of consortium partner 3E combine the best of the models outlined above. These tools allow one to design and operate large offshore wind farms in a cost effective way by taking the design philosophy of the ClusterDesign consortium into account. But this is the subject of a separate presentation by R Donnelly et al.