Modelling cluster wakes and wind farm blockage

Abstract

Abstract We present two new models for wind turbine interaction effects and a recipe for combining them. The first model is an extension of the Park model, which explicitly incorporates turbulence, both the ambient atmospheric turbulence and the turbulence generated in the wake itself. This Turbulence Optimized Park model is better equipped to describe wake recovery over long distances such as between wind farms, where the wake expansion slows down as the turbine-generated turbulence decays. The second model is a first version of a full engineering wind farm blockage model. In the same vein as the wake model it adds blockage contributions from the individual wind turbines to form an aggregated wind farm scale blockage effect that can be incorporated directly into the park power curve and annual energy calculations. The wake model and the blockage model describe downstream and upstream turbine interaction effects, respectively. They are coupled as the outputs of one model are the inputs to the other model and vice versa. We describe how this coupling is achieved through an iterative process. We give early stage examples of the validation of the two models and discuss how they might be further validated and improved in the future.