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- Load calculations
The calculation of the loads of each major component of a wind turbine
is one of the core tasks in the design process. The load calculation is
a highly iterative and complex procedure. Based on the rules and regulations
selected (for example GL guidelines and/or IEC guidelines), all possible
situations that can occur in the 20 years lifetime of a wind turbine are
simulated and the results are carefully evaluated. This needs a fairly complex
computer internal turbine model comprising of all load carrying turbine
components from the rotor blades through the hub, the shaft, the gear box
and the generator, all main bearings down to the tower and its foundation.
Also realistic assumptions of the control scheme of the wind turbine need
to be made.
Usually not all information is available during the preliminary design
phase of a wind turbine. The experience of the WINDnovation engineers
allows to define a reasonable design initialization by collecting the
data available and completing it by data taken from experience. These
assumptions lead to a first set of loads that can be used for a preliminary
dimensioning of the components and are invaluable for discussions with
possible suppliers of these components. In an iterative process, the real
data of the components selected will be used to refine the calculation
model leading to more precise load data. This loop will be repeated in
combination with a fine tuning of the turbine controller in order to reduce
the load level until an optimized turbine design has been found.
WINDnovation uses the internationally recognized software package BLADED
(from Garrad Hassan of Bristol, England) to perform these calculations.
The software package is highly accepted by all certification authorities.
Especially when performing load calculations for innovative or non-standard
turbines, the WINDnovation engineers seek a dialog with the certification
authorities in an early design stage to define the relevant load cases and
to define the appropriate way to handle these load cases. To agree on the
calculation procedure before doing the calculation job saves WINDnovation's
customers time-consuming repetitions of jobs and leads to an overall
efficient certification of the wind turbine and its components.
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