Aarhus University Seal / Aarhus Universitets segl

Mass detection on stationary wind turbine blade

More energy

out of the wind

Using sensors Professor Rune Brincker can record vibrations in wind turbines and thereby learn more about the conditions that affect energy conversion.

The researchers are carrying out experiments with sandbags on the blades to investigate the effect of a change in mass

Small sensors on wind turbine blades reveal how to reduce downtime and produce more produce more power from the same amount of wind.

By recording vibrations in wind turbine blades, researchers can acquire previously unavailable data about wind turbine performance and thereby new knowledge about how to optimise wind power. The researchers have entered into an agreement with Vestas Wind Systems A/S, the world’s largest manufacturer of wind turbines. In the years ahead, they will further develop a sensor-based measuring method that can be used for purposes such as monitoring operating conditions and wear and tear, as well as predicting durability.

“Our fundamental ambition is to gain more detailed knowledge about what goes on in the blades when the wind blows and the turbine produces electricity. We want to know more about the factors that have an impact on wind turbine durability and the turbine’s ability to boost its output of wind energy. We hope to be able to use the sensor technology to learn about the vibrations and gain a better understanding of what’s required to maximise power production for the same cost,” says Professor Rune Brincker.

Vibrations reveal damage
Vibrations occur all the time in all constructions. They originate from sources such as ordinary seismic activity in the ground surface and from wind. By following the development in the vibration patterns, the researchers can provide precise characteristics of the main properties, such as mass and rigidity, and thereby determine the start of structural damage.

“Today we actually have to over-dimension our wind turbines to ensure that they can withstand years of wear and tear. But it’s a strategy the wind turbine manufacturers have used for want of a better solution. Using the sensors, we can not only learn something new about the structure’s wear and tear, but we can also predict damage long before it becomes visible or is symptomatic. This means that we can carry out maintenance and repair with higher accuracy and thereby save on materials,” says Professor Brincker.

So far the researchers have documented that sensor-based monitoring of wind turbines can provide material savings of 20 percent in the tower’s expensive steel construction alone.

No more ice on the blades
The same method has proved to be useful for detecting ice on wind turbine blades, and this solves a major problem – especially in the Nordic countries where layers of ice impair the wind turbine’s aerodynamic properties and cause a risk of dangerous ice throw.

In low temperature conditions, wind turbines stand still for approximately 10 percent of the year because of ice. This percentage is significantly higher in arctic or mountain regions.

The researchers will use computer-based models to study how to reduce the number of sensors on the wind turbine and thereby make the technology cheaper.