Dynamic flow model for real-time application in wind farm control

Conference Paper (2017)
Author(s)

A. Rott (University of Oldenburg)

S. Boersma (TU Delft - Team Jan-Willem van Wingerden)

J.W. Van Wingerden (TU Delft - Team Jan-Willem van Wingerden)

Martin Kuhn (University of Oldenburg)

Research Group
Team Jan-Willem van Wingerden
Copyright
© 2017 A. Rott, S. Boersma, J.W. van Wingerden, Martin Kühn
DOI related publication
https://doi.org/10.1088/1742-6596/854/1/012039
More Info
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Publication Year
2017
Language
English
Copyright
© 2017 A. Rott, S. Boersma, J.W. van Wingerden, Martin Kühn
Research Group
Team Jan-Willem van Wingerden
Volume number
854-1
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Abstract

For short-term power predictions and estimations of the available power during curtailment of a wind farm, it is necessary to consider the flow dynamics and aerodynamic interactions of the turbines. In this paper, a control-oriented dynamic two-dimensional wind farm model is introduced that aims to incorporate real-time measurements such as flow velocities at turbine locations to estimate the ambient wind farm flow. The model is intended to derive flow predictions for real-time applications. Since fully resolved computational fluid dynamics are too CPU-intensive for such a task, the dynamic model presented in this paper relies on an approximation of the flow equations in a two-dimensional framework. A semi-Lagrangian advection scheme and a step-wise flow solver together offer fast calculation speed, which scales linearly with the number of grid points. In order to emulate effects of realistic three-dimensional wind farm flow, a relaxation of the two-dimensional continuity equation is presented. Furthermore, with little extra computational expense, additional dynamic state variables for various possible applications can be propagated along the wind flow. For instance, a dynamic confidence parameter can provide estimations of the accuracy of flow predictions, while a turbulence parameter adds the possibility to estimate wake induced loads on downstream turbines. In order to demonstrate the performance and validity of the new model it is compared with other models. At first a two turbine reference case is compared with a steady-state model and secondly with results obtained by the dynamic wind farm flow model WFSim. Finally a small wind farm is simulated in order to show the computational scaling of the model.