The development of a model needs to include a validation process to determine how accurate it is for its intended purpose. Equally, any control design requires the demonstration of its performance. In CL-Windcon, these processes will be performed by increasing level of practical complexity, from simulation to wind tunnel, and finally in real wind farm testing.

The demonstration of the control methods will be pursued using the control oriented models, with scaled testing in the wind tunnel and full scale testing, using an experimental wind farm.

The collected data during the experiments will be of public access at the end of the project, becoming a useful input for future model validations and research.

Computational simulation

The developed control methods will be checked using high fidelity wind farm simulation models which will be implemented or adapted to the control needs.

In a first step the wind-turbine-level control functionality will be verified. Furthermore, the integrated wind-turbine/wind-farm controllers will be also proved.

The different developed technologies (minimal loading wind turbine induction based control and wake redirection control) will first be verified individually and successively validated in combination.

Polimi wind tunnel tests

During the three-year project, scaled tests will be performed at POLIMI boundary layer wind tunnel. Two types of tests will be performed.

The first one will test a selection of the wind turbine controllers including power curtailment, active yaw misalignment, active wake mixing, and active load mitigation in waked conditions. It will also measure and characterize the effects on the wakes by using techniques such as hot-wire probes and PIV (Particle Image Velocimetry).

The second type will be focused in testing integrated wind-turbine/wind-farm controllers where a matrix up to 2×3 wind turbine models, provided by TUM, will be set in different configurations (i.e. distances, yaw misalignments, wake deflections) and a selection of the integrated control solutions will be tested. These include: wake deflection, wake detection followed by wake steering.

The experiments will consider multiple setups, characterized by different numbers of interfering wind turbines in different layouts. Both types of tests will be performed at the boundary layer test section of the POLIMI wind tunnel, a 14 x 4 x 35 (width x height x length) meter test section with wind speeds up to 16 m/s and turbulence intensity up to 10%.

Wind farm test

During the second and third year of the project, full-scale wake experiments will be performed at Enel Green Power’s Sedini wind farm on configurations of several wind turbines.

The experiment will obtain loads and farm inflow measurements at high resolution spatially and temporally, to characterize and validate dynamic open-loop wake-deficit and wake-deflection models. The software orchestrating the experiment will command changes in turbine set-points in response to measured flow conditions, so that wake propagation within the cluster can be actively modified. The range of set-points will be predefined and varied as a function of wind speed and wind direction, in the form of lookup tables, to cover the necessary modelling space with adequate number of occurrences. A wind farm control trial is also considered.

The site of the experiment is the Sedini wind farm located in the island of Sardinia, Italy. A selected sub-cluster of several wind turbines manufactured by General Electric, with nominal power of 1.5MW will be used.