Spatiotemporal Correlations in the Power Output of Wind Farms: On the Impact of Atmospheric Stability

Energies

Adam Lavely¹  Sven Schmitz¹  Leonardo P. Chamorro²  Nicolas Tobin² 

[1] Department of Aerospace Engineering, Pennsylvania State University, University Park, PA 16802, USA;Department of Mechanical Science and Engineering, University of Illinois, Urbana, IL 61801, USA;

关键词: atmospheric stability;    coherence;    turbulence;    wind farm;   

DOI  :  10.3390/en12081486

来源: DOAJ

【 摘 要 】

The dependence of temporal correlations in the power output of wind-turbine pairs on atmospheric stability is explored using theoretical arguments and wind-farm large-eddy simulations. For this purpose, a range of five distinct stability regimes, ranging from weakly stable to moderately convective, were investigated with the same aligned wind-farm layout used among simulations. The coherence spectrum between turbine pairs in each simulation was compared to theoretical predictions. We found with high statistical significance (p < 0.01) that higher levels of atmospheric instability lead to higher coherence between turbines, with wake motions reducing correlations up to 40%. This is attributed to higher dominance of atmospheric motions over wakes in strongly unstable flows. Good agreement resulted with the use of an empirical model for wake-added turbulence to predict the variation of turbine power coherence with ambient turbulence intensity (R${}^2$ = 0.82), though other empirical relations may be applicable. It was shown that improperly accounting for turbine–turbine correlations can substantially impact power variance estimates on the order of a factor of 4.

【 授权许可】

Unknown