Dynamic Flow Modelling for Model-Predictive Wind Farm Control

Maarten J Van Den Broek,Jan-Willem Van Wingerden

doi:10.1088/1742-6596/1618/2/022023

Maarten J Van Den Broek, Jan-Willem Van Wingerden

Open Access

https://doi.org/10.1088/1742-6596/1618/2/022023

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Abstract

We aim to improve wind farm control for power output by building on the results from WFSim for the development of a dynamic wind farm model. This model will be part of a closed-loop, economic model-predictive control approach for wind farms. It is constructed from first principles using open-source tools to be suitable for adjoint-based optimisation of turbine yaw angles.In a steady-state inflow configuration with two turbines, the new control model matches power expectations from high fidelity simulations in SOWFA to within 15 %. Under time-varying wind directions, it shows time delays in wake direction as inflow changes propagate through the farm with the wind speed, although the dynamics still differ from the SOWFA reference. The model runs flow simulations for a wind farm with a 3 x 3 array of turbines at a real-time order of magnitude on a regular laptop computer.The new control model shows dynamic flow behaviour as wake changes propagate through the wind farm. Some further adjustments are necessary to accurately model three-dimensional flow in two dimensions. With more validation of the wake dynamics, it will be suitable for application in a new closed-loop wind farm controller.

Highlights

Large, densely spaced wind farms suffer from aerodynamic interaction between wind turbines
In a steady-state inflow configuration with two turbines, the new control model matches power expectations from high fidelity simulations in SOWFA to within 15 %. It shows time delays in wake direction as inflow changes propagate through the farm with the wind speed, the dynamics still differ from the SOWFA reference
FLORIS Results from FLORIS are used to illustrate the difference between dynamic flow modelling and steady-state models currently used for wind farm control

Summary

Introduction

Densely spaced wind farms suffer from aerodynamic interaction between wind turbines. Wind turbines may be operated under yaw misalignment to redirect the downstream wake This reduces power output for the misaligned turbine but model studies [1, 2] and wind-tunnel experiments [3] have shown improved power production for the park as a whole, as well as a reduced structural loading on downstream turbines. Field experiments confirm these findings for specific wind directions [4], without a significant gain in annual energy production [5]

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