8.2 France guarantees measurements of rotor imbalance and measures the blade angles of wind turbines.

Measurements of rotor imbalance

8.2 France guarantees measurements of rotor imbalance and measures the blade angles of wind turbines.

The references in the sector recommend a maximum offset to be taken into account of +/- 0.3° on each blade, or a maximum relative tolerable deviation of 0.6° between 2 blades.

To date, 8.2 France has measured 172 rotors for blade angle deviations. The last 3 years have shown that around 30% of rotors are affected by aerodynamic imbalance: relative angle deviations (between the blades of a single rotor) of more than 0.6%.

Thanks to the software co-developed by 4Op, the 8.2 France teams will help you optimize the yield of your wind farm, particularly with regard to the consequences of imbalance phenomena, so as to master the impacts that it generates on the mechanics and life span of the wind turbines.

This “aerodynamic imbalance” has an influence on the mechanical load applied to the head of the rotor, transmitted to the kinematic chain and the entire tower, and this has a direct impact on the durability of the machines.

To measure imbalance, 8.2 France carries out low frequency vibration measurements on housings with accelerometers. These measurements show that the vibrations are reduced considerably after re-adjustment of the blade angles (suppression of the aerodynamic imbalance), up to -90% in certain recent cases.

Mass balancing of the rotor makes it possible to further reduce these vibrations, particularly in the case of unequal distribution of the rotor mass (blades that are poorly paired, or replacement or full repair of a blade, etc.).

Measurements of rotor imbalance
The reduction in parasite vibrations is the direct consequence of the decrease in mechanical load which is responsible for the fatigue of all the components, in the kinematic chain (bearings, multipliers…) as well as the structures (housing chassis, yaw brakes, yaw gears, tower), thus making it possible to preserve their life span.

8.2 France follows the recommendations of the Germanischer Lloyd, and guarantees follow-up of the evolution and vibration effects on your equipment.

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