Optimizing the Unrestricted Wind Turbine Placements with Different Turbine Hub Heights

Abstract

Wind farm layout optimization is an effective means to mitigate the wind power losses caused by the wake interventions between wind turbines. Most of the research on this field is conducted on the basis of fixed wind turbine hub height, while it has been proved that different hub height turbines may contribute to the reduction of wake power losses and increase the wind farm energy production. To demonstrate this effect, the results of simple two-wind-turbine model are reported by fixing the first wind turbine hub height while varying the second one. Then the optimization results for a wind farm are reported under different wind conditions. The optimization with differing hub heights is carried out using the unrestricted coordinate method in this paper. Different optimization methods are applied for the wind farm optimization study to investigate their effectiveness by comparison. It shows that the selection of the identical wind turbine hub height yields the least power production with the most intensive wake effect. The value of optimum wind turbine hub height is dependent on several factors including the surface roughness length, spacing between the two wind turbines and the blowing wind direction. The simultaneous optimization method is more effective for the complex wind conditions than for the simple constant wind condition.