Results mirror ground-based measurements

Initial situation: Many turbines are struggling with imbalances

Many wind turbines have to face imbalances that over time can cause damages and high costs. To detect further imbalances, the first thing to do is to rule out relative pitch angle errors.

 

At the request of a customer an :ALIGN system was installed on an Enercon E-82-E2 2MW in Germany to detect relative pitch angle deviations and furthermore measuring causes for aerodynamic imbalances continuously.

 

Continuous measurement of the relative pitch angle

:ALIGN uses sensores directly attached on the blades that are wireless and redundant, to measure the accelerations in all three directions occurring there during the operation of the wind turbine. The measurments of the sensors take place synchronized and multiple times daily over defined time intervals (bursts) to record several rotor revolutions and different operating states. From the measured accelerations, the rotational speed of the rotor and the alignment of its blades to each other are calculated via corresponding algorithms. In the following chapter, the results of this project are presented in more detail.

 

Successful measurement through :ALIGN

In the course of the measurement through :ALIGN significant pitch angle deviations were detected. (see figure 1 calender week 36 to 45). A subsequent independent on-site measurement of the pitch angle deviations using photogrammetry came to a comparable result (see figure 2, left side).

Correction of the pitch angle deviations in calender week 46

After the on-site measurement and correction of the relative pitch angles in calender week 46, the deviations of the relative pitch angles are constantly clearly reduced and coincide very well with the values of the independent measurement (see figure 2).

Comparison of :ALIGN results with photogrammetry results

The following table shows the comparison of the results before and after the correction.

 

Conclusion

The implementation of :ALIGN on an Enercon E-82-E2 2MW wind turbine in Germany enabled reliably measurements and mirrored the photogrammetry results. Clear pitch angle deviations were detected and successfully corrected in calender week 46. This highlights the efficiency of :ALIGN in identifying and correcting the aerodynamic imbalances.