Wind turbine defense to escape high wind events
Embodiments of the invention provide a number of passive and active defense designs and methods that enable a wind turbine to escape high wind events. The disclosure includes descriptions of multiple designs and methods for lowering the elevated portion of a wind turbine. Other embodiments of the invention concern ways to connect the elevated portion of a wind turbine to the tower. Numerous counterweight systems are also disclosed which enable the lowering of the elevated portion of the wind turbine.
1. An apparatus for wind turbine defense during a high wind event, comprising:
a support tower extending upward from a ground plane beneath the support tower and declined away from an axis perpendicular to the ground plane at a declination angle;
an elevated portion; and
a coupling mechanism coupling the elevated portion to the support tower in a manner permitting movement of the elevated portion along a support tower length, wherein the elevated portion of a wind turbine moves downward along the support tower from a working height to a stowed height during the high wind event.
2. The apparatus of claim 1 , the coupling mechanism further comprising:
a track secured to the support tower;
the elevated portion being coupled to the track for movement of elevated portion along the track.
3. The apparatus of claim 1 , the coupling mechanism further comprising:
a track secured to the support tower; and
a trolley secured to the elevated portion for rolling movement along the track.
4. The apparatus of claim 1 , wherein the declination angle is greater than 0° and less than or equal to 45°.
5. The apparatus of claim 1 , wherein the declination angle is oriented toward at least one of a historical wind direction and a recent time-averaged wind direction.
6. The apparatus of claim 1 , further comprising:
a bearing rotationally coupling the support tower to the ground plane about a tower yaw axis.
7. The apparatus of claim 6 , wherein the elevated portion is cantilevered outward from the support tower in a downwind direction, and wherein aerodynamic forces on the elevated portion passively control an angular orientation of the support tower about the tower yaw axis.
8. The apparatus of claim 6 , further comprising:
a flag member coupled to at least one of the elevated portion and the support tower, wherein aerodynamic forces on the flag member passively control the angular orientation of the support tower about the tower yaw axis.
9. The apparatus of claim 6 , further comprising:
an actuation mechanism controlling an angular orientation of the support tower about the tower yaw axis.
10. The apparatus of claim 1 , wherein the wind turbine comprises a horizontal axis wind turbine.
11. The apparatus of claim 1 , the elevated portion comprising any of:
a rotor;
a gear box; and
a shroud.
12. The apparatus of claim 1 , further comprising:
a mechanism for transmitting any of power and communication signals to the elevated portion, the mechanism comprising any of:
one or more rails along the support tower;
one or more flexible cables configured in a service loop;
one or more flexible cables within a flexible conduit; and
one or more spring-loaded contacts.
13. The apparatus of claim 1 , further comprising:
a counterweight offsetting at least a fraction of an elevated portion mass.
14. The apparatus of claim 13 , wherein a counterweight mass exceeds the elevated portion mass.
15. The apparatus of claim 13 , further comprising:
a damping system reducing amplitude of oscillating movement of the elevated portion along the support tower length.
16. The apparatus of claim 13 , wherein the elevated portion mass exceeds a counterweight mass.
17. The apparatus of claim 13 , further comprising:
a braking mechanism maintaining the elevated portion at a working height during operating wind speeds and automatically releasing the elevated portion for movement toward a stowed height during the high wind event.
18. The apparatus of claim 13 , wherein the counterweight is aerodynamic in any of placement and shape.
19. A method for constructing a wind turbine tower providing wind turbine defense during a high wind event, comprising:
constructing a support tower extending upward from a ground plane beneath the support tower and declined away from an axis perpendicular to the ground plane at a declination angle; and
said support tower configured for receiving an elevated portion via a coupling mechanism in a manner permitting movement of the elevated portion along a support tower length between a working height and a stowed height during the high wind event.
20. The method of claim 19 , further comprising:
providing a mechanism for transmitting any of power and communication signals to the elevated portion, the mechanism comprising any of:
one or more rails along the support tower;
one or more flexible cables configured in a service loop;
one or more flexible cables within a flexible conduit; and
one or more spring-loaded contacts.
21. The method of claim 19 , further comprising:
providing a counterweight offsetting at least a fraction of an elevated portion mass.
22. The method of claim 19 , further comprising:
providing a bearing rotationally coupling the support tower to the ground plane about a tower yaw axis.
23. The method of claim 22 , wherein the elevated portion is cantilevered outward from the support tower in a downwind direction, and wherein aerodynamic forces on the elevated portion passively control an angular orientation of the support tower about the tower yaw axis.