Surrogate model for fast simulation of turbine loads in wind farms

Abstract

A surrogate model for turbine loading is presented which has been developed for predicting the fatigue loads on each turbine in a wind farm, taking full account of wake effects, for detailed site-specific load assessment and/or to predict the effects of wind farm control on the loads. The model has been implemented in the wind farm simulation code LongSim, where it can be used both for steady-state setpoint optimisation against a merit function which can include both power and turbine loads, and for dynamic time-domain simulations, for example to evaluate the effects of wind farm control on turbine loading. For this application, fatigue loads need to be evaluated much more rapidly than is possible with full aeroelastic turbine simulations. Surrogate models based on fatigue load interpolation from a database of pre-computed aeroelastic turbine simulations are unwieldy and likely to miss important wake effects. The key simplifying approximation of the new model is that the load contributions from different causes can be calculated separately and then combined. This makes it straightforward to account for all relevant effects, at the same time vastly reducing the number of aeroelastic simulations required to populate the model.