2.5a_Pedersen: The influence of wind farm control on optimal wind farm layout

Design of an optimal wind farm topology is dependent on the chosen wind farm control strategy. The objective of this paper is to investigate the influence of optimal wind farm control on the optimal wind farm layout as seen from a production perspective.

An increased proportion of the turbines to be installed in the future are foreseen to be sited in large wind farms. Establishment of large wind farms requires enormous investments, putting steadily greater emphasis on optimal topology layout in order to obtain the lowest possible cost of wind energy. This theme was addressed in^1,2, describing the TOPFARM platform for assessing the optimal balance between capital costs, operation and maintenance (O&M) costs, fatigue degradation of turbine components, and power production. However, wind farm control aspects were not considered.

In this paper we focus on power production only, but includes wind farm control in an optimal wind farm topology optimization. Restricting the objective function to power production is a significant simplification compared to approach taken in^1,2, because 1) wind turbines can be described in terms of C_t and C_p curves; 2) a stationary description of the wake affected wind farm flow field suffices; and 3) no cost models are needed.

The modeling will be based on a simplified version of the TOPFARM platform, in which only production is considered, and a newly developed platform for design optimal open-loop wind farm control³. The flow within the wind power plant, including all essential interactions between the wind turbines, is modelled using a very fast linearized CFD RANS solver. The wind turbines are modelled as actuator discs, and four design variables per turbine - two geometric (i.e. coordinates of the wind turbine position) and two variables specifying the individual wind turbine control settings (i.e. collective pitch and tip speed ratio) - are defined for the optimization problem

Based on the new ’combined’ platform, the paper will demonstrate the effect of including wind farm control aspects on optimal wind farm layout.

Figure 1: Optimal control schedule conditioned on topology, ambient mean wind speed and mean wind direction.

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[a] Technical University of Denmark, Department of Wind Energy, Frederiksborgvej 399, 4000 Roskilde, Denmark

[1] P.-E. Réthoré, P. Fuglsang, G.C. Larsen, T. Buhl, T.J. Larsen, H.Aa. Madsen (2013). TOPFARM: Multi-fidelity optimization of   wind farms. Wind Energy, vol. 17, pp. 1797–1816.

[2] G.C. Larsen, P.-E. Réthoré (2013). TOPFARM – A Tool for Wind Farm Optimization. Energy Procedia, vol. 35, pp. 317–324.

[3] J.A. Vitulli, G.C. Larsen, M.M. Pedersen, S. Ott and M. Friis-Møller (2019). Optimal open-loop wind farm control. To appear in

Journal of Physics: Conference Series.