Search

EP-4737710-A1 - WIND TURBINE, CONTROL SYSTEM, AND METHOD OF OPERATING A WIND TURBINE UNDER POTENTIAL ICING CONDITIONS TO PREVENT VIBRATIONS

EP4737710A1EP 4737710 A1EP4737710 A1EP 4737710A1EP-4737710-A1

Abstract

Wind turbine, control system, and method of operating a wind turbine (1) under potential icing conditions to reduce vibrations during idling or standstill operation, comprising: determining a potential icing condition for one or more blades (2,3,4), establishing a danger zone (10) where the falling of ice is to be avoided, identifying a risk of falling ice within the danger zone (10, wherein if a risk of falling ice in the danger zone (10) is identified, the method comprises: a) setting a pitch angle (P) of a first rotor blade (2) close to 0°, wherein a one or more further blades (3,4) comprise a pitch angle (P) differing by at least 30° from the first rotor blade (2); and b) adjusting the rotor yaw orientation (W) away from the danger zone (10).

Inventors

  • Holm-Joergensen, Kristian
  • GARCIA ANDUJAR, JUAN CARLOS

Assignees

  • Siemens Gamesa Renewable Energy Innovation & Technology S.L.

Dates

Publication Date
20260506
Application Date
20241104

Claims (15)

  1. A method (20) of operating a wind turbine (1) under potential icing conditions to reduce vibrations during idling or standstill operation, the method (20) comprising: determining a potential icing condition for one or more blades (2,3,4) of a wind rotor (9) of the wind turbine (1), establishing a danger zone (10), said danger zone (10) being an area where the falling of ice from the wind turbine (1) is to be avoided, identifying a risk of falling ice within the danger zone (10) based at least in part on the determined potential icing condition and the rotor's yaw orientation (W), wherein if a risk of falling ice in the danger zone (10) is identified, the method further comprises: a) setting a pitch angle (P) of a first rotor blade (2) close to 0°, in particular within -25° and 25°, and wherein a one or more further blades (3,4) comprise a pitch angle (P) differing by at least 30° from the first rotor blade (2), in particular by at least 40°, and/or wherein the further blades (3,4) comprise a pitch angle (P) equal to 90° or -90° or close to 90° or -90°, in particular within a range of 75° to 105° or -105° to -75°, and b) adjusting the rotor yaw orientation (W) away from the danger zone (10) or to a yaw orientation (W) that reduces the identified risk of falling ice onto the danger zone (10).
  2. The method (20) according to claim 1, wherein the sequence of executing steps a) and b) is interchangeable.
  3. - The method (20) according to claim 1 or 2, further comprising assessing whether a default idling operational mode is unsuitable due to the identified risk of falling ice in the danger zone (10), and if assessed as unsuitable, then executing steps a) and b) in either sequence.
  4. The method (20) of claim 3, wherein the default idling operational mode comprises adjusting the rotor yaw orientation (W) such that the wind rotor (9) is oriented substantially perpendicular to the wind flow, with all the blades (2,3,4) in a substantially feathered position with a pitch angle (P) equal to 90° or -90° or close to 90° or -90°, in particular within a range of 75° to 105° or -105° to -75°.
  5. The method (20) according to claim 1 or 4, wherein the potential icing condition is determined based at least in part on ambient temperature.
  6. The method (20) according to any one of claims 1 to 5, wherein the danger zone (10) is a fixed area established at least in part by the presence of permanent structures, in particular including but not limited to houses, buildings, or other infrastructure.
  7. The method (20) according to any one of claims 1 to 5, wherein the danger zone (10) is dynamically determined based at least in part on the presence of personnel or movable assets in the vicinity of the wind turbine (1).
  8. The method according to any one of claims 1 to 7, wherein the danger zone (10) is established based on a combination of fixed geographical features and real-time monitoring of human activity or equipment in the surroundings of the wind turbine (1) .
  9. The method (20) according to any one of claims 1 to 8, wherein adjusting the rotor (9) yaw orientation (W) away from the danger zone (10) comprises reorienting to a yaw orientation angle or to a range of angles associated with the safe zone (12), wherein the safe zone (12) is defined as an area where falling ice can safely occur.
  10. The method (20) according to claim 1 or 9, wherein the safe zone is defined as an area where ice falling from the rotor blades (2,3,4) does not pose a risk to personnel, equipment, and/or infrastructure.
  11. The method (20) according to any one of claims 1 to 10, further comprising maintaining the wind turbine (1) in a yaw orientation away from the danger zone (10) or in an orientation that reduces the identified risk of falling ice until the rotor blades (2,3,4) the identified risk is mitigated, in particular until when the rotor blades (2,3,4) are substantially deiced.
  12. The method (20) according to any one of claims 1 to 11, wherein the first rotor blade (2) is the rotor blade positioned at the highest point of the wind rotor (9) in its rotational plane, in particular such that in a wind rotor consisting of three blades (2,3,4), if two rotor blades (2,3,4) are positioned at approximately the same height, forming a 'Y' shape, the first rotor blade (2) refers to either of these two upper rotor blades.
  13. A control system for operating a wind turbine (1) under potential icing conditions for reducing vibrations during idling or standstill operation, wherein the control system is adapted to carry out the method according to any one of claims 1 to 12.
  14. A wind turbine (1), comprising: at least two rotor blades (2,3,4), said blades (2,3,4) attached to a hub (5), a wind rotor (9) mounted to a nacelle (6) which is in turn mounted on a tower (7), wherein the wind turbine (1) further comprises an electrical generator operationally connected to the wind rotor (9) for converting wind energy into electrical energy, a pitch-position adjustment unit for adjusting the blade (2,3,4) pitch angle (P), and a yawing mechanism for rotating the wind rotor (9) through a yaw axis, wherein the wind turbine (1) is characterized in that it comprises the control system of claim 13.
  15. Method for upgrading an existing wind turbine (1), the wind turbine (1) comprising at least two rotor blades (2,3,4), said blades (2,3,4) attached to a hub (5), a wind rotor (9) mounted to a nacelle (6) which is in turn mounted on a tower (7), further comprising an electrical generator operationally connected to the wind rotor (9) for converting wind energy into electrical energy, the wind turbine (1) comprising a pitch-position adjustment unit for adjusting the blade (2,3,4) pitch angle (P), and a yawing mechanism for rotating the rotor through a yaw axis, the method comprising providing and implementing a control system according to claim 13.

Description

OBJECT OF THE INVENTION The present invention relates to methods of operating a wind turbine under potential icing conditions, particularly for preventing or reducing vibrations in wind turbines, during such icing conditions. The object of the present invention addresses the operational challenges associated with ice accumulation on rotor blades during idling or standstill operation and the mitigation of risks associated with falling ice, and the enhancement of damping properties to prevent aeroelastic instabilities during said icing conditions. BACKGROUND OF THE INVENTION In the field of wind turbine operation under icing conditions, there are known methods for detecting potential ice formation on turbine blades and implementing corrective actions to mitigate associated risks. Existing solutions often involve monitoring ambient temperature and other environmental factors to predict icing conditions. Some methods adjust the pitch of the blades to reduce aerodynamic loads and prevent ice accumulation or readapt the pitch angle to adapt the operation to the aerodynamic profile changed by the ice accretion. However, these known methods do not specifically address the dual challenges of enhancing aeroelastic stability during icing conditions in standstill or idling operation, and simultaneously allowing the wind rotor blades to deice while avoiding danger zones where falling ice poses a significant risk. Additionally, the presence of low ambient temperature, among other effects, may increase the power injected by the wind due to higher air density, and reduce structure capacity to dissipate injected power, specifically in blades due to composites structures tendency to reduce structural damping with lower temperature, further increasing the risk of different types of stand still turbine aeroelastic instabilities. Thus, there is an urgent need for a solution that efficiently attenuates and mitigates oscillations due to aeroelastic instabilities by increasing damping under icing conditions, while also allowing the rotor blades to safely deice and generally falling of ice without posing risks to surrounding areas. DESCRIPTION OF THE INVENTION The present invention pertains to a method for preventing, reducing or avoiding vibrations in a wind turbine under potential icing conditions. This method is particularly effective during idling or standstill operation, where the risk of ice accretion on the rotor blades is high, leading to operational challenges such as increased vibrations due to decreased damping during icing and low ambient temperature conditions, and the potential danger of falling ice. In one embodiment, the method involves determining the potential for ice formation on one or more blades of the rotor. This determination may be based on monitoring ambient temperature or other relevant environmental conditions, such as humidity and wind speed, which could indicate the likelihood of ice accumulation. Sensors on the blades may be utilized to detect the presence of ice directly or to monitor conditions conducive to icing, thereby allowing for an early and accurate identification of potential risks. Once a potential icing condition is identified, the method may further involve establishing a danger zone. The danger zone is defined as an area surrounding the wind turbine where falling ice is to be avoided, particularly where it may pose a risk to personnel, equipment, or infrastructure. In some embodiments, the danger zone may be determined based on the presence of fixed structures such as buildings or other permanent infrastructure. Alternatively, the danger zone could be dynamically determined based on real-time factors such as the presence of personnel or movable assets near the wind turbine. This dynamic determination allows the method to adapt to changing conditions, ensuring that the defined danger zone is always relevant to the current operational context. The method may also include identifying a risk of falling ice within the established danger zone. This assessment may be based on the identified potential icing condition in combination with the rotor's yaw orientation relative to the danger zone. If it is determined that the default standstill or idling operational mode is unsuitable due to the risk of falling ice in the danger zone, the method may involve adjusting the rotor configuration to reduce or eliminate this risk. In some embodiments, the rotor configuration is altered by setting the pitch angle of a first rotor blade close to 0°, typically within a range of -25° to 25°. One or more of the remaining blades may be adjusted to have a pitch angle that differs by at least 30° from the first blade, with a preferred difference of at least 40°. Optionally, these further blades may have a pitch angle close to 90° or -90°, within a range of 75° to 105° or -105° to -75°. This specific rotor configuration (or range of possible rotor configurations) has been unexpectedly identified as providing enhance