Impact of wind-speed ramps on turbines: from fluid-dynamic to aeroelastic simulation, via observed joint statistics

This report documents DTU contributions to Carbon Trust’s Offshore Wind Accelerator (OWA) project, entitled “OWA Impact of Gusts on Loads and Power Production”; it was subcontracted through the Fraser-Nash Consultancy (‘FNC’). The focus of DTU’s work—and the original design of the project—is detection of wind speed ramps and statistical characterization of their relevant metrics, and their effects on a wind farm. The latter is done through a model chain including large-eddy simulation coupled to constrained Mann-model turbulence simulation and the aeroelastic code Flex5; the simulated wind farm and models’ configurations were chosen to compare with the Rødsand 2 (R2) windfarm. FNC analysed limited SCADA and mast data from R2, whereas DTU’s work used data from Høvsøre; this is because the R2 mast data was from heights below hub and did not cover 1 year—thus making it unusable for ramp statistics affecting the current generation of wind turbines. In terms of the OWA project, this report covers work package 2 (‘event detection’) and WP3 (‘modelling’).