A model to calculate fatigue damage caused by partial waking during wind farm optimization

Abstract

Abstract. Wind turbines in wind farms often operate in waked or partially waked conditions, which can greatly increase the fatigue damage. Some fatigue considerations may be included, but currently a full fidelity analysis of the increased damage a turbine experiences in a wind farm is not considered in wind farm layout optimization because existing models are too computationally expensive. In this paper, we present a model to calculate fatigue damage caused by partial waking on a wind turbine that is computationally efficient and can be included in wind farm layout optimization. The model relies on analytic velocity, turbulence, and load models commonly used in farm research and design, and it captures some of the effects of turbulence on the fatigue loading. Compared to high-fidelity simulation data, our model accurately predicts the damage trends of various waking conditions. We also perform example wind farm layout optimizations with our presented model in which we maximize the annual energy production (AEP) of a wind farm while constraining the damage of the turbines in the farm. The results of our optimization show that the turbine damage can be significantly reduced, more than 10 %, with only a small sacrifice of around 0.07 % to the AEP, or the damage can be reduced by 20 % with an AEP sacrifice of 0.6 %.

Loads assessment of a fixed‐bottom offshore wind farm with wake steering

“…This could be due to partial waking and whether the wake impinges more on the rising or falling blade, given the clockwise rotor rotation. 36 For the yawed results, the same trends as the non-yawed are observed, but with larger absolute values due to the additional yaw moments from wake steering yaw offset. Additional yaw moments due to wake steering at the zero-degree inflow angle…”

“…Additionally, for negative inflow angles above , the downstream turbine mean moments are higher than the zero‐degree inflow results. This could be due to partial waking and whether the wake impinges more on the rising or falling blade, given the clockwise rotor rotation 36 . For the yawed results, the same trends as the non‐yawed are observed, but with larger absolute values due to the additional yaw moments from wake steering yaw offset.…”

Wind Turbine Loads in the Near Wake

“…Due to the afore mentioned accuracy to reproduce the flow statistics in the wake, AL-LES simulation are recently used to propose models for the wake added turbulence intensity (see e.g. [7] and [8]).…”

Implications of complex terrain topography on the performance of a real wind farm

“…Over the past years, the analysis of the blade loads and the fatigue life of the turbine has been mainly studied focusing on the aeroelasticity of the blades [26,27], on the wake interaction [28,29] and on the effect of imposed yaw misalignment to optimize the power production of the array of turbines [30,31,32,33]. However, to our knowledge, few studies have investigated the effect of complex terrain topography on the wind turbines fatigue loads due to the lack of available field data and the difficulty of reproducing realistic conditions both from a numerical and experimental point of view.…”