Design and development of megawatt wind turbines - Wind Power Generation and Wind Turbine Design - page 252

Products should be validated at the system level and at the component level. The
systems to components and back to systems approach should be used, as it
supports continuous cycles of improvement.
6.2.1 System level validation
Systems level validation is the key activity that closes the loop between design and
fi eld performance and facilitates the process of continuous improvement for WT
equipment. Validation also enables realistic noise and power curve specifi cation for
customer documents and project pro formas. In addition, turbine reliability improve-
ments and optimized structural designs result from measuring load conditions and
responses identifi ed from validation activity.
6.2.2 Component validation
Unexpected interaction of components is revealed during tests. Certifi cation
testing under environmental extremes permits observations not easily possible
in the fi eld. Components are the building blocks for the larger system - get the
components right, together with their interactions, and the system optimization
will follow.
6.2.3 Rotor blade static and fatigue testing
Rotor blade static and fatigue testing are used to validate design assumptions and
simulations used to predict the ultimate strength and 20-year life for the blade.
There are a number of wind blade test facilities around the world that can be used
to perform this type of testing, and plans for others have been announced to sup-
port the next generation of longer blades (i.e. >50 m in length). Of all the parts in
today's modern turbines, the blades are perhaps the most fi ckle of all, requiring
not only structural and aerodynamic design execution, but also the most critical
of manufacturing and process control to ensure material and structural quality.
Provisioning the cost and time for proper validation for blades is crucial before
new blades are introduced into serial production.
7 Closure
Modern WTs are large complex structures that have achieved mainstream accep-
tance with rapid market growth and product standards development. The inex-
haustible wind is a great fuel for electricity production, even with the challenges
of turbulence, gusting, directional change and storm extremes. These impart the
highest fatigue loadings to any manmade machine, and require turbine designers
to carefully account for all effects to blades, hub, shaft, drivetrain, electricity gen-
eration system, support structure and the power plant system considerations that
include interaction with the grid.
Value engineering or value analysis is the cornerstone process for identifying
which innovations should be pursued and help the MW WT designer to focus on
what matters most to their customers. It guides the OEM and ensures successful
new products. The fundamental physics for the economic extraction of kinetic