Final report for WP4.3: Enhancement of design methods ... - Upwind

DLC 6.2a considers a turbine idling in 50-year storm conditions during grid loss, meaning the yaw system
is inactive, resulting in significant yaw misalignments. Thus, wind direction shall be considered misaligned
to the rotor axis between 30 deg and 180 deg (in 30 deg steps). The remaining load case setup equals
DLC 6.1a despite for the support structure orientation and the wind-wave misalignment. The support orientation
shall be determined by the support orientation for DLC 6.1a that resulted in maximum loads. Accordingly,
wind-wave misalignment shall account for those site-specific values that resulted in maximum
loads for DLC 6.1a.
Again, during load case computation, the influence of the aerodynamic wake model should be taken care
of.
DLC 2.2: Safety system fault
- Vin < V < Vout ; Hs(V) ; Tp(V)
- NTM model for turbulent wind
- Wind bin width 2m/s
- One Hs, Tp-combination per wind bin
- Wind misalignment +8 deg or -8 deg
- 6 to 10 seeds per wind bin
- Wind and waves in line
- Two support structure orientations (0°; 45°)
The setup is comparable to DLC 1.2 in the step one fatigue analysis. For reason of preliminary jacket design,
safety system fault computations may be limited to one significant pitch fault at high wind speeds
(near cut-out). It is conservatively proposed to assume all blades turn to fine (with a reasonable average
pitch rate such as 5 deg/s) until the safety system is activated again by reaching the safety system overspeed
limit.
DLC 1.6: Power production in 50-year sea state
- 0.8 Vr; Vr; 1.2 Vr; Vout
- NTM model for turbulent wind
- 50 year sea state with embedded Hmax,50 wave
- Wind misalignment +8 deg or -8 deg
- 6 to 10 seeds per wind speed
- Wind and waves in line
- Two support structure orientations (0°; 45°)
DLC 1.6 represents power production in turbulent wind conditions and a 50-year sea state. For conservative
reason of preliminary jacket design, an embedded wave with a maximum 1-year wave height (Hmax,1)
may be assumed. Furthermore, a minimum of 6 wind seeds shall be computed in combination with wind
misalignment and seeds for sea states as described for DLC 1.2.
DLC 2.3 (DLC 1.5 in GL standard [31]): Generator cut-out
- Vr ± 2m/s and Vout ; Hs(V) ; Tp(V)
- EOG1
- Rotor start position 0 – 90 deg (30 deg steps)
- Generator cut-out at 3 time instants
- Wind misalignment +8 deg or -8 deg
- Wind and waves in line
- Two support structure orientations (0°; 45°)
DLC 2.3 represents a load situation of a turbine in power production during a one-year gust (EOG1) that
looses the generator torque due to a generator cut-out from the grid. The grid loss shall be considered at
the three time instants, lowest wind speed, highest gust acceleration, maximum wind speed (see GL 2005
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