Dependence of offshore wind turbine fatigue loads on atmospheric stratification

The Science of Making Torque from Wind 2014

Hansen, K.S.^1 ; Larsen, G.C.^1 ; Ott, S.^1

Department of Wind Energy, Technical University of Denmark, Nils Koppels Allé, B403-DTU, DK-2800 Kgs.Lyngby, Denmark^1

关键词: Atmospheric stratification;    Combined measurements;    Fatigue loads;    Inflow conditions;    Load sensor;    Mean wind speed;    Operational statistics;    Rated wind speed;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/524/1/012165/pdf
DOI  :  10.1088/1742-6596/524/1/012165

来源: IOP

【 摘 要 】

The stratification of the atmospheric boundary layer (ABL) is classified in terms of the M-O length and subsequently used to determine the relationship between ABL stability and the fatigue loads of a wind turbine located inside an offshore wind farm. Recorded equivalent fatigue loads, representing blade-bending and tower bottom bending, are combined with the operational statistics from the instrumented wind turbine as well as with meteorological statistics defining the inflow conditions. Only a part of all possible inflow conditions are covered through the approximately 8200 hours of combined measurements. The fatigue polar has been determined for an (almost) complete 360° inflow sector for both load sensors, representing mean wind speeds below and above rated wind speed, respectively, with the inflow conditions classified into three different stratification regimes: unstable, neutral and stable conditions. In general, impact of ABL stratification is clearly seen on wake affected inflow cases for both blade and tower fatigue loads. However, the character of this dependence varies significantly with the type of inflow conditions-e.g. single wake inflow or multiple wake inflow.