Analysis of the foundation movement on wind turbines

Visualization of the foundation movement at two opposite points

Foundations of wind turbines are exposed to considerable loads that they cannot always withstand over the long term. In recent years there have occasionally been cases that required more or less extensive foundation renovation. At the beginning, however, there is always the determination of the actual situation. Direct investigation methods are associated with considerable effort. It is much easier to use an indirect method, namely the analysis of the movement between the foundation component and the foundation.

Concrete and the foundation component are normally in form-locking relationship. The easiest way to check whether this is actually the case is to measure the maximum possible movement between the two at an accessible point. Displacement sensors are used here.

The measurement data can be digitized using mobile measurement technology or an online system. With GfM's mobile system, the PeakStore5, the data can be recorded in multiple channels. GfM's online condition monitoring system, the Peakanalyzer, is ideal for permanent monitoring.

Starting and shutting down a wind turbine can be used to provoke movement between the foundation and the built-in part. Experience has shown that sufficiently high and therefore representative loads occur, which generate corresponding movements between the foundation and the foundation component. However, using the normal operation of the system is much more tolerable for all system components. This works if a correspondingly long measurement period is provided, for example with a permanently installed system.

To evaluate the measurement data, the distance between the measurement point and the load application point of the foundation component in the foundation is relevant. The elastic elongation of the steel must be regarded as non-critical. Movements beyond this count as a possible damage indicator. You can find recommendations from experts.

In addition, the asymmetry of the movement on the opposite sides can be interpreted as an indication of damage. The picture shows an example.

GfM offers the analysis of the foundation movement as a complete service. Alternatively, GfM supplies the systems for these measurements.