Wind turbine structures
FEMM′s high sensitivity is able to predict cracks in wind mill
structures/components long before cracks happen. The FEMM has been
developed for the O&G offshore market and for condition monitoring
of subsea steel structures, however, it can be applied to any steel
structure offshore and onshore where the sensors can be fit in.
It is regarded that there are several locations both in the nacelle,
the tower and the substructure that are feasible for applying FEMM
for fatigue monitoring. Focus has in first instance been the
monitoring of substructures for offshore wind mills, e.g. jacket
structures. The monitoring is proposed to be at the subsea part and
close to the seabed. The potential cost savings by applying condition
monitoring are regarded to be significant both related to Capex and
The construction cost savings are regarded to be significant as design
fatigue factor can be reduced by a factor of 3 and thus allows for
significant reduction of steel dimensions.
About 25% of the costs of offshore wind energy are related to the
operations and maintenance and are important starting points in the
reduction of costs. The availability of wind turbines can be increased
further by effective maintenance that can reduce down time, which leads
directly to an increased production and a lower cost of energy.
To obtain these goals it is regarded as most relevant to focus on
measuring, monitoring and predicting degradation of the components in
due time in order to perform planned maintenance, and avoiding unplanned
maintenance as much as possible.
Most likely it is known which turbines are bearing the heaviest loads
in a wind park and which the least, based on this the condition monitoring
can be adjusted accordingly and it is regarded not needed to fit every
turbine with instruments to produce accurate estimates of the loads and
the consequences for the farm as a whole.