Backup mandate Research Council: RObust NAcelle Transfer functions under different turbulence conditions (RONAT)

Belgium is the fourth-largest producer of offshore wind energy worldwide. As Flanders is not a producer of large wind turbines, operation and maintenance is one of the main fields where Flanders can generate innovation and economic benefit. Such benefit must come from making optimal use of available data.

Every wind turbine in a wind farm is equipped with a nacelle anemometer, which measures the wind speed downstream of the rotor. For the purpose of control and performance measurement, it is the wind speed upstream of the rotor that needs to be known. Therefore, it is essential to be able to relate the downstream and upstream wind speeds. Such a relationship is called a nacelle
transfer function (NTF). The objective of this application is to develop an extended framework for NTFs. The classical NTF concept for mean wind speeds will be generalised to include unsteady flows and to define a novel turbulence nacelle transfer function. This latter function extends the concept of an NTF to relate downstream turbulence characteristics to their upstream counterparts.

This allows to achieve robust and reliable power curves all turbines in a farm, regardless of their position. This paves the way for innovative operation strategies that maximise power production. The extension
of the concept of NTFs to determine inflow turbulence makes it a promising tool for estimating loads and supplementing other measurement data to develop optimal predictive maintenance strategies.