System including a wind turbine and method for operating the system

Abstract

A wind turbine system and a method for operating the system are disclosed. The system further includes a detection device configured to detect body waves generated by an earthquake. In one aspect, the present disclosure is directed to a system that includes: a wind turbine, particularly an onshore wind turbine; a wind turbine controller for controlling the wind turbine; and at least one detection device connected to the wind turbine controller for transmitting signals. The wind turbine includes at least: a rotor having at least one rotor blade, wherein the rotor is rotatably mounted to a rotational support device of the wind turbine; and a tower having a support end and a top end for supporting the rotational support device. The detection device is configured to detect and measure the primary wave (P-wave) generated by an earthquake. The detection device may include at least one sensor or a plurality of sensors, wherein the sensor is configured to detect and / or measure the P-wave generated by an earthquake. Such a sensor may be further configured to detect the acceleration caused by an earthquake using a built-in accelerometer, and then calculate and output a synthetic acceleration, and provide an estimated Japan Meteorological Agency seismic intensity level (shindo level) value.

Description

Technical Field

[0001] The present subject matter generally relates to a system including a wind turbine and a method for operating the system. In particular, the system further includes a detection device configured to detect body waves generated by an earthquake. Background Art

[0002] Wind power is considered to be one of the cleanest and most environmentally friendly energy sources currently available, and in this regard, wind turbines have received increasing attention. Modern wind turbines typically include a tower, a generator, a gearbox, a nacelle, and one or more rotor blades. The rotor blades use the known airfoil principle to capture kinetic energy from the wind and transfer the kinetic energy by rotational energy to rotate a shaft that couples the rotor blades to the gearbox or directly to the generator in the case where a gearbox is not used. The generator then converts the mechanical energy into electrical energy that can be deployed to the public power grid.

[0003] Generally, onshore wind turbines are mounted on ground support means, where the torques and forces caused by the mass and load of the wind turbine are directed into the surrounding ground of the wind turbine.

[0004] More specifically, the forces acting on the wind turbine from the ground are also transmitted via the ground support means. For example, seismic-induced movement of the surrounding ground of the wind turbine related to the mass and load of the wind turbine causes displacement of the structure of the wind turbine relative to the ground and thus causes additional forces and accelerations that need to be considered when designing the components of the wind turbine. Summary of the Invention

[0005] Aspects and advantages of the present invention will be set forth in part in the following description, or may be obvious from the description, or may be learned by practice of the present invention.

[0006] In one aspect, the present disclosure is directed to a system that includes: a wind turbine, particularly an onshore wind turbine; a wind turbine controller for controlling the wind turbine; and at least one detection device connected to the wind turbine controller for transmitting signals. The wind turbine at least includes: a rotor having at least one rotor blade, wherein the rotor is rotatably mounted to a rotational support means of the wind turbine; and a tower having a support end and a top end for supporting the rotational support means. The detection device is configured to detect and measure primary waves (P-waves) generated by an earthquake, particularly to measure motion and / or vibration having a frequency of 0.00118 Hz to 500 Hz.

[0007] The detection device may include at least one sensor or a plurality of sensors, wherein the sensor is configured to detect and / or measure the P-waves generated by an earthquake. Such a sensor may be further configured to detect the acceleration caused by the earthquake using a built-in accelerometer, and then calculate and output the combined acceleration, and provide an estimated Japan Meteorological Agency seismic intensity level (shindo level) value.

[0008] When an earthquake occurs, seismic waves are generated in the form of body waves and surface waves. Body waves may consist of primary waves (so-called P-waves) and secondary waves (S-waves). P-waves are compression waves and / or longitudinal waves, which cause the ground to vibrate in their propagation direction, and their speed is greater than that of all other waves, i.e., 4 to 8 km / s. In contrast, S-waves are shear waves that cause the ground to vibrate perpendicular to the propagation direction and have a slower speed than P-waves.

[0009] According to an embodiment, the wind turbine may be a horizontal-axis wind turbine or a vertical-axis wind turbine. The horizontal-axis wind turbine includes a nacelle rotatably mounted around a vertical axis to the top of a tower. In this case, the rotary support device is implemented as a substantially horizontal bearing arrangement for supporting the rotor, in particular the main shaft of the rotor, on the main frame of the nacelle. In the case of an embodiment as a vertical-axis wind turbine, the rotary support device is implemented as a vertical bearing arrangement for allowing the rotor to rotate around a substantially vertical axis of rotation.

[0010] According to an embodiment, the system includes a ground support device, which is located on the ground of the wind turbine and is configured to support the support end, thereby carrying the weight and load of the entire wind turbine.

[0011] The term "ground of the wind turbine" describes the area of the lithosphere that supports the wind turbine, wherein the area covers a circle around the wind turbine, and the circle has a radius of no more than 10 km, particularly no more than 5 km, specifically no more than 1 km, preferably no more than 500 m, and most preferably no more than 100 m. In addition, the ground includes the volume formed by the foregoing and a depth of no more than 100 m, particularly no more than 50 m, and preferably no more than 20 m.

[0012] According to a specific embodiment, the detection device is arranged on and / or in the ground of the wind turbine, for example, in the surrounding environment of the wind turbine, in and / or on the ground support device, and / or mounted to the support end of the tower. Thereby, data related to the earthquake is provided to the wind turbine controller, and the wind turbine controller is enabled by this measure to operate the wind turbine so that unacceptable loads can be prevented.

[0013] According to a specific embodiment, the support end is mounted to the ground support device by a fixing device, which particularly includes at least one screw and at least one nut. In addition, the detection device is directly mounted to the fixing device, particularly to the screw or the nut. This results in a very precise measurement, which is also highly correlated with the physical events occurring at the specific connection area between the ground support device and the support end.

[0014] According to a further embodiment, the detection device is configured to determine the impact time of the S-wave generated by the same earthquake that causes the measured P-wave. Particularly, in the case where multiple P-waves are detected, the detection device is configured to distinguish whether multiple earthquakes have occurred, and thus is configured to detect multiple impact times of the inferred corresponding S-waves.

[0015] In another aspect, the present disclosure is directed to a method for operating a system according to any of the foregoing embodiments, wherein the method includes the following steps:

[0016] Measuring and / or detecting the P-wave generated by an earthquake; using suitable methods and devices to measure and detect the P-wave;

[0017] Comparing the measured value of the detected P-wave with a first threshold; for example, during the design of a wind turbine and / or during the process of determining the load envelope of the wind turbine design of the wind turbine, the threshold can be pre-determined; in the case where the measured value exceeds the first threshold, the operating state of the wind turbine is changed to a safe mode or a shutdown mode. Particularly, the safe mode includes operating the wind turbine with a reduced power output or idling (operating without any output while remaining connected to the grid). For example, the safe mode may include a first safe mode, in which a maximum of 70% of the rated power is generated and fed into the grid, or may include a second safe mode, in which a maximum of 50% of the rated power is generated and fed into the grid, or may include a third safe mode, in which no power is generated (0% of the rated power), however, the rotor remains rotating (idling) and the generator remains connected to the grid. Particularly, the first safe mode may include a maximum power output of 60%, preferably 50%, more preferably 40% and / or greater than 55%, preferably greater than 45%, more preferably greater than 35% of the rated power. Optionally, the second safe mode may include a maximum power output of 40%, preferably 30%, more preferably 20% and / or greater than 35%, preferably greater than 25%, more preferably greater than 15% of the rated power.

[0018] By providing embodiments of the proposed system and related methods, for the first time, it is achieved to reduce the loads and forces caused by the operation of a wind turbine before the wind turbine is impacted by the S-wave of an earthquake. This results in the benefit of designing a wind turbine with an optimized safety margin, especially because it can prevent: the negative effects of the S-wave from affecting the structure of the wind turbine, while the loads and forces of the wind turbine increase due to the elevated operating state. Therefore, when considering the maximum loads and / or forces that the wind turbine needs to withstand, it is not necessary to add the loads and / or forces caused by the S-wave to the operating loads and / or forces. In particular, the system and method provide an opportunity for the loads caused by the S-wave and the high or maximum operating loads not to affect the wind turbine simultaneously, specifically because the operating loads will be reduced before the S-wave hits the wind turbine.

[0019] According to a further embodiment, the first reduced power output of the first safety mode depends on the magnitude of the measured value of the P-wave. For example, the reduction of the power output increases with the increase of the measured value of the P-wave (the overall power output decreases), preferably, where the first reduced power output is determined by a function of the measured value. In particular, the details of the measured value of the P-wave can indicate the intensity, amplitude, direction, and / or frequency of the subsequent S-wave. Therefore, in order to keep the loads and / or forces affecting the wind turbine at a tolerable level, if the measured P-wave indicates high loads and forces caused by the subsequent S-wave, the operating costs, wear, loads, and forces can be reduced by activating the (first) safety mode.

[0020] According to an embodiment, it is disclosed that the method may include the following additional steps:

[0021] Determine the propagation direction of the detected P-wave; for example, the detection device is configured to measure the P-wave at at least two, preferably three positions at the ground, on / inside the ground support device, and / or at the support end. The difference in the measured values can be used to determine the propagation direction, for example, by analyzing the path difference of the measured values;

[0022] Determine the sensitive direction range of the wind turbine; in particular, the term "sensitive direction range" reflects a range of directions, for example, where the range reflects the change in the azimuth position of the nacelle and / or the wind direction within a predetermined time period; surprisingly, it has been found that the loads and / or forces applied to the structure of the wind turbine in the first direction can be more critical than the loads and forces applied to the wind turbine in another direction. Therefore, the first direction is determined as the sensitive direction. As a result, when it is determined by analyzing the P-wave that the S-wave will hit the wind turbine from / according to the predetermined sensitive direction and / or structurally related to the predetermined sensitive direction, the power reduction amount of the safety mode, especially the first safety mode, is adjusted so as to keep the overall loads and forces applied to the wind turbine within an acceptable limit.

[0023] For example, the reduction in power output according to the second safety mode may be higher than the reduction in power output according to the first safety mode, where the first safety mode is activated if the measured value of the P wave is higher than a first threshold, but the propagation direction of the P wave is not correlated with the sensitive direction, and where the second safety mode is activated if the determined propagation direction is also correlated with the sensitive direction.

[0024] The details as described can be at least partially summarized by the step of comparing the propagation direction with the sensitive direction range, and if the propagation direction lies within and / or is correlated with the sensitive direction range, and if the measured value exceeds the first threshold, this changes the operating state of the wind turbine to a second safety mode with a second reduced power output or to a shutdown mode, where the second reduced power output is less than the first reduced power output.

[0025] According to an additional or alternative embodiment, the step of performing a load assessment of the loads applied to the structure of the wind turbine is carried out, the loads including the measured value of the detected P wave and the current and / or estimated operating loads of the wind turbine. Furthermore, if the load assessment results in the definition of a critical load situation, the operating state of the wind turbine is changed to a safety mode with a reduced power output or no power output or to a shutdown mode.

[0026] According to a further embodiment, the method includes the step of determining a determined load value of a component of the wind turbine. For example, the determined load value can be determined by performing a load assessment, a load estimation, in particular a load simulation, of the loads and / or forces acting on the structure of the wind turbine, at least based on the current and / or estimated operating values of the wind turbine, in particular firstly based on the power output, the measured and / or estimated wind speed and / or wind direction, the pitch angle of the pitch system of the wind turbine and / or the rotational speed of the rotor and / or power generator of the wind turbine, and secondly based on the measured value of the detected P wave. The determined load value represents the combined load of the load caused by the S wave and the operating load when the S wave hits the wind turbine.

[0027] According to a specific embodiment, the method includes the steps of comparing the determined load value with a load threshold; and if the determined load value exceeds the load threshold, changing the operating state of the wind turbine to a safety mode with a reduced power output or to a shutdown mode.

[0028] According to a more specific embodiment, the method includes the step of determining a reduced power output by estimating, in particular simulating, at least based on the measured value of the detected P wave and the expected maximum load to be applied to the structure of the wind turbine, the determined reduced power output, and the current and / or estimated operating values of the wind turbine.

[0029] For example, the current and / or estimated operating values may be measured and / or estimated wind speed and / or wind direction, the current or desired pitch angle of a pitch system of a wind turbine, and / or the current or desired rotational speed of a rotor and / or a power generator of a wind turbine.

[0030] Furthermore, the magnitude of the reduced power output depends on the magnitude of the determined load value, in particular, wherein the reduced power output decreases as the determined load value increases, preferably, wherein the magnitude is a function of the estimated or determined load value of the load.

[0031] By performing at least one of the steps described above, the safety mode for operating the wind turbine with a reduced power output can be customized to the current situation according to the operating load of the wind turbine and the load caused by S-waves. This can result in an increased power output while ensuring an optimized operation of the load of the wind turbine.

[0032] Furthermore, independent of the specific embodiments as described, the effects of the present disclosure are increased by performing the following additional steps: determining the impact time of the S-waves generated by the same earthquake that caused the measured P-waves; and determining the change time required to change the operation of the wind turbine from the current operating state to the safety mode or the shutdown mode with and / or without performing active braking measures, and if the impact time is shorter than the change time, applying active braking measures to the rotor.

[0033] Specifically, the foregoing embodiments may include direct or indirect steps of implementing the braking measures to reduce the rotational speed and / or torque of the rotor. For example, engaging a friction brake in the drivetrain of the rotor of a wind turbine can be understood as a direct reduction step, wherein pitching the rotor blades towards a position that causes a reduction in the energy extracted from the wind hitting the rotor can be understood as an indirect braking measure.

[0034] These and other features, aspects, and advantages of the present invention will be further supported and described with reference to the following description and the appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0035] Even though specific embodiments have been described previously, combinations of parts of the embodiments are also disclosed, wherein, for example, when combined with the definition and consideration of the sensitive direction, the step of simulating the determined load value can also be used when operating the wind turbine according to multiple thresholds for the measured S-waves. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] A complete and enabling disclosure of the present invention (including its best mode) for a person of ordinary skill in the art is set forth in the specification with reference to the accompanying drawings, in which:

[0037] Figure 1 Perspective view of an embodiment of a system including a wind turbine and a detection device according to the present disclosure;

[0038] Figure 2 Simplified internal view of an embodiment of a nacelle of a wind turbine according to the present disclosure;

[0039] Figure 3 Schematic flowchart representing a method for operating a system according to a first embodiment; and

[0040] Figure 4 Schematic flowchart showing a method for operating a system according to a second embodiment.

[0041] Individual features depicted in the drawings are shown relative to one another and are not necessarily drawn to scale. Like or identical elements in the drawings are denoted by the same reference numerals even when shown in different embodiments. Detailed Description

[0042] Reference will now be made in detail to embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided by way of explanation of the invention and not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For example, features illustrated or described as part of one embodiment can be used with another embodiment to yield yet another additional embodiment. Accordingly, it is intended that the present invention cover such modifications and variations as come within the scope of the appended claims and their equivalents.

[0043] Figure 1 is a perspective view of an exemplary wind turbine 10. In an exemplary embodiment, the wind turbine 10 is a horizontal axis wind turbine. Alternatively, the wind turbine 10 can be a vertical axis wind turbine.

[0044] In an exemplary embodiment, the wind turbine 10 includes a tower 12 extending from a ground support device 14, a nacelle 16 mounted on the tower 12, and a rotor 18 coupled to the nacelle 16. The rotor 18 includes a rotatable hub 20 and at least one rotor blade 22, the rotor blade 22 being coupled to the hub 20 and extending outwardly from the hub 20. In an exemplary embodiment, the rotor 18 has three rotor blades 22. In alternative embodiments, the rotor 18 includes more or fewer than three rotor blades 22.

[0045] In an exemplary embodiment, the tower 12 includes a top end 11 and a support end 13, wherein the tower 12 is supported by the ground support device 14 via the support end 13, and wherein the tower 12 carries the nacelle 16 via the top end 11.

[0046] The tower 12 can be made of tubular steel to define a cavity between the ground support device 14 and the nacelle 16 ( Figure 1 not shown in ). In an alternative embodiment, the tower 12 is any suitable type of tower having any suitable height.

[0047] The ground support device 14 is arranged in the ground 15 surrounding the wind turbine 10, where the ground 15 can be considered as the area of the lithosphere that supports the wind turbine 10. According to a specific embodiment, the ground support device 14 is implemented as a foundation made of, for example, concrete and includes anchor screws.

[0048] The rotor blades 22 are spaced around the hub 20 to facilitate rotation of the rotor 18 so that kinetic energy can be converted from wind energy into useful mechanical energy and subsequently into electrical energy. The rotor blades 22 are fitted to the hub 20 by connecting the blade root portions 24 to the hub 20 at a plurality of load transfer regions 26. The load transfer regions 26 can have a hub load transfer region and a blade load transfer region ( Figure 1 both not shown in ). The loads induced to the rotor blades 22 are transferred to the hub 20 via the load transfer regions 26.

[0049] In one embodiment, the rotor blades 22 have a length ranging from about 15 meters (m) to about 100 m. Alternatively, the rotor blades 22 can have any suitable length such that the wind turbine 10 can operate as described herein. For example, other non-limiting examples of blade lengths include lengths of 20 m or less, 37 m, 48.7 m, 50.2 m, 52.2 m, or greater than 91 m. When the wind strikes the rotor blades 22 from the wind direction 28, the rotor 18 rotates about the rotational axis 30. When the rotor blades 22 rotate and are subject to centrifugal force, the rotor blades 22 are also subject to various forces and torques. Accordingly, the rotor blades 22 can deflect and / or rotate from a neutral or non-deflected position to a deflected position.

[0050] In addition, the pitch angle of the rotor blades 22 (i.e., the angle that determines the viewing angle of the rotor blades 22 relative to the wind direction) can be changed by the pitch system 32 to control the loads and power generated by the wind turbine 10 by adjusting the angular position of at least one rotor blade 22 relative to the wind vector. The pitch axis 34 of the rotor blade 22 is shown. During operation of the wind turbine 10, the pitch system 32 can change the pitch angle of the rotor blades 22 such that the rotor blades 22 move to the feather position, so that the viewing angle of at least one rotor blade 22 relative to the wind vector provides the minimum surface area of the rotor blade 22 that will be oriented towards the wind vector, which facilitates reducing the rotational speed and / or facilitating the stall of the rotor 18.

[0051] In an exemplary embodiment, the blade pitch of each rotor blade 22 is controlled individually by the wind turbine controller 36 or by a pitch control system 80. Alternatively, the blade pitch for all rotor blades 22 can be controlled simultaneously by the control system.

[0052] In addition, in an exemplary embodiment, when the wind direction 28 changes, the yaw direction of the nacelle 16 can rotate about the yaw axis 38 to position the rotor blades 22 relative to the wind direction 28.

[0053] In an exemplary embodiment, the wind turbine controller 36 is shown as being centralized within the nacelle 16. However, the wind turbine controller 36 can be a distributed system spread throughout the wind turbine 10, on the ground support device 14, within a wind farm, and / or at a remote control center. The wind turbine controller 36 includes a processor 40 configured to execute the methods and / or steps described herein. Additionally, many of the other components described herein include a processor. As used herein, the term "processor" is not limited to an integrated circuit known as a computer in the art, but rather broadly refers to a controller, a microcontroller, a microcomputer, a programmable logic controller (PLC), an application specific integrated circuit, and other programmable circuits, and these terms may be used interchangeably herein. It should be understood that the processor and / or control system may also include a memory, an input channel, and / or an output channel.

[0054] Figure 2 is an enlarged cross-sectional view of a portion of the wind turbine 10. In an exemplary embodiment, the wind turbine 10 includes a nacelle 16 and a rotor 18 rotatably coupled to the nacelle 16. More specifically, the hub 20 of the rotor 18 is rotatably coupled to a generator 42 positioned within the nacelle 16 via a main shaft 44, a gearbox 46, a high-speed shaft 48, and a coupling 50. In an exemplary embodiment, the main shaft 44 is arranged to be at least partially coaxial with a longitudinal axis (not shown) of the nacelle 16. Rotation of the main shaft 44 drives the gearbox 46, which then drives the high-speed shaft 48 by converting the relatively slow rotational movement of the rotor 18 and the main shaft 44 into a relatively fast rotational movement of the high-speed shaft 48. The high-speed shaft 48 is connected to the generator 42 by means of a coupling 50 for generating electrical energy.

[0055] The gearbox 46 and the generator 42 can be supported by a main support structure frame of the nacelle 16, which is optionally implemented as a main frame 52. The gearbox 45 may include a gearbox housing 102 connected to the main frame 52 by one or more torque arms 47. In an exemplary embodiment, the nacelle 16 further includes a main front support bearing 60 and a main rear support bearing 62. Additionally, the generator 42 can be mounted to the main frame 52 by means of a decoupling support device 54, particularly to prevent vibrations of the generator 42 from being introduced into the main frame 52 and thus causing a noise emission source.

[0056] Preferably, the main frame 52 is configured to carry the weight of the components of the rotor 18 and the nacelle 16 as well as all the loads caused by the wind and the rotational load, and furthermore to introduce these loads into the tower 12 of the wind turbine 10. The rotor shaft 44, the generator 42, the gearbox 46, the high-speed shaft 48, the coupling 50 and any associated fastening, supporting and / or fixing devices (including but not limited to the support 52 and the front support bearing 60 and the rear support bearing 62) are sometimes referred to as the drivetrain 64.

[0057] However, the present disclosure is not limited to wind turbines including a gearbox, but also includes wind turbines without a gearbox, and thus may also relate to so-called direct drive.

[0058] The nacelle 16 may further include a yaw drive mechanism 56, which may be used to rotate the nacelle 16 about the yaw axis 38 and thus also rotate the rotor 18 about the yaw axis 38 to control the angle of view of the rotor blades 22 relative to the wind direction 28.

[0059] In order to properly position the nacelle relative to the wind direction 28, the nacelle 16 may further include at least one weather mast 58, which may include a wind vane and an anemometer (both not shown Figure 2 in the figure). The mast 58 provides information to the wind turbine controller 36, which information may include the wind direction and / or the wind speed.

[0060] In an exemplary embodiment, the pitch system 32 is at least partially arranged as a pitch assembly 66 in the hub 20. The pitch assembly 66 includes one or more pitch drive systems 68 and at least one sensor 70. Each pitch drive system 68 is coupled to a corresponding rotor blade 22 (shown Figure 1 in the figure) for modulating the pitch angle of the rotor blade 22 along the pitch axis 34. Figure 2 Only one of the three pitch drive systems 68 is shown in the figure.

[0061] In an exemplary embodiment, the pitch assembly 66 includes at least one pitch bearing 72, which is coupled to the hub 20 and a corresponding rotor blade 22 (shown Figure 1 in the figure) for rotating the corresponding rotor blade 22 about the pitch axis 34. The pitch drive system 68 includes a pitch drive motor 74, a pitch drive gearbox 76 and a pitch drive pinion 78. The pitch drive motor 74 is coupled to the pitch drive gearbox 76 such that the pitch drive motor 74 applies a mechanical force to the pitch drive gearbox 76. The pitch drive gearbox 76 is coupled to the pitch drive pinion 78 such that the pitch drive pinion 78 is rotated by the pitch drive gearbox 76. The pitch bearing 72 is coupled to the pitch drive pinion 78 such that the rotation of the pitch drive pinion 78 causes the rotation of the pitch bearing 72.

[0062] The pitch drive system 68 is coupled to the wind turbine controller 36 for adjusting the pitch angle of the rotor blades 22 upon receipt of one or more signals from the wind turbine controller 36. In an exemplary embodiment, the pitch drive motor 74 is any suitable motor driven by electrical power and / or a hydraulic system, which enables the pitch assembly 66 to function as described herein. Alternatively, the pitch assembly 66 may include any suitable structure, configuration, arrangement, and / or component, such as but not limited to hydraulic cylinders, springs, and / or servo mechanisms. In certain embodiments, the pitch drive motor 74 is driven by energy extracted from the rotational inertia of the hub 20 and / or a stored energy source (not shown) that supplies energy to components of the wind turbine 10.

[0063] The pitch assembly 66 also includes one or more pitch control systems 80 for controlling the pitch drive system 68 in specific priority situations and / or during rotor 18 overspeed in accordance with control signals from the wind turbine controller 36. In an exemplary embodiment, the pitch assembly 66 includes at least one pitch control system 80 that is communicatively coupled to a corresponding pitch drive system 68 for controlling the pitch drive system 68 independently of the wind turbine controller 36. In an exemplary embodiment, the pitch control system 80 is coupled to the pitch drive system 68 and the sensors 70. During normal operation of the wind turbine 10, the wind turbine controller 36 controls the pitch drive system 68 to adjust the pitch angle of the rotor blades 22.

[0064] In one embodiment, particularly when the rotor 18 is operating at rotor overspeed, the pitch control system 80 overrides the wind turbine controller 36 such that the wind turbine controller 36 no longer controls the pitch control system 80 and the pitch drive system 68. Accordingly, the pitch control system 80 is capable of causing the pitch drive system 68 to move the rotor blades 22 to the feather position for reducing the rotational speed of the rotor 18.

[0065] According to an embodiment, a power generator 84, such as including a battery and / or a capacitor, is disposed at or within the hub 20 and coupled to the sensors 70, the pitch control system 80, and the pitch drive system 68 to provide a power source to these components. In an exemplary embodiment, the power generator 84 provides a continuous power source to the pitch assembly 66 during operation of the wind turbine 10. In an alternative embodiment, the power generator 84 provides power to the pitch assembly 66 only during an electrical power loss event of the wind turbine 10. The electrical power loss event may include a power grid loss or voltage dip, a fault in the electrical system of the wind turbine 10, and / or a failure of the wind turbine controller 36. During the electrical power loss event, the power generator 84 operates to provide electrical power to the pitch assembly 66 such that the pitch assembly 66 can operate during the electrical power loss event.

[0066] In an exemplary embodiment, the pitch drive system 68, the sensor 70, the pitch control system 80, the cable, and the power generator 84 are each positioned within a cavity 86 defined by the inner surface 88 of the hub 20. In an alternative embodiment, the components are positioned relative to the outer surface 90 of the hub 20 and are directly or indirectly coupled to the outer surface 90.

[0067] According to the embodiment shown in Figure 1 System 1 includes a wind turbine 10, a detection device 100 configured to detect and measure the primary wave (P-wave) generated by an earthquake, and a turbine controller. The turbine controller can be the same device as the wind turbine controller 36 or can be incorporated into the wind turbine controller 36. The turbine controller of system 1 can also be located at a position different from the wind turbine 10 and the wind turbine controller 36, where the controller will be connected for communication of signals and control instructions.

[0068] Specifically, but not limited thereto, the detection device 100 is arranged in the transition region between the ground support device 14 and the support end 13. In particular, the detection device 100 can be mounted to a connecting device configured to attach the support end 13 to the ground support device 14. For example, the connecting device can be implemented as a screw anchored within the ground support device 14, where the support end 13 is configured to receive a portion of the anchored screw such that the support end 13 can be attached to the ground support device 14 in a pre-tensioned manner.

[0069] According to an additional or alternative embodiment, the detection device 100 can be fixed to the ground 15 while establishing a distance to the tower 12.

[0070] Furthermore, according to an additional or alternative embodiment, the detection device 100 can include a plurality of sensors configured to detect and / or measure the P-waves generated by an earthquake, particularly to measure motions and / or having frequencies ranging from 500 Hz to 0.00118 Hz. In particular, at least one sensor (preferably at least two sensors) is attached to the ground support device 14 and / or at least one sensor is attached to the support end 13.

[0071] Optionally, at least one additional sensor configured to detect and / or measure the P-waves generated by an earthquake is arranged on the ground 15 and thus has a certain distance to the ground support device 14. Such a distance is greater than 10 m, preferably greater than 100 m, particularly greater than 1000 m, and / or where such a distance does not exceed 2000 m, preferably 200 m, particularly does not exceed 20.

[0072] Figure 3 and Figure 4Embodiments of the present disclosure are schematically disclosed, in particular embodiments of corresponding methods 200, 300 for operating system 1 and / or wind turbine 10. However, the present disclosure is not limited to certain specific embodiments, and in particular, each of the embodiments may also include steps of corresponding other embodiments. For example, Figure 4 method 300 may further include, according to Figure 3 method 200, a step 210 of defining a sensitive direction range.

[0073] Method 200 ( Figure 3 ) and 300 ( Figure 4 ) both include an initial step of detecting a so-called primary wave (P-wave) generated by an earthquake and transmitted via the ground from the earthquake epicenter to the location of the detection device 100 and / or the location of the wind turbine 10. Therefore, the detection device 100 or one or more sensors of the detection device 100 measure 202 at least the magnitude or magnitude and direction of the P-wave.

[0074] Optionally included is the interpretation of the measurement signal (e.g., specifying the magnitude and / or direction of the P-wave), which is either performed by the detection device 100 itself, for example by including a detection controller configured to detail the measurement data into the detection device 100, or by the turbine controller (specifically by the wind turbine controller 36).

[0075] Another step includes determining 208 the impact time of the S-wave associated with the P-wave detected at the wind turbine 10 and / or at the ground support device 14. This determination 208 may include analyzing at least one of the following: the frequency, wavelength, propagation speed of the P-wave, the soil properties of the ground 15 or the ground between the epicenter and the ground support device 14, external data sources, such as earthquake alert data from a dedicated data provider, and / or data obtained from tests and general experience. Specifically, data describing the relationship between the propagation speed of the P-wave and the S-wave in a specific geographical area may be considered in order to determine 208 the impact time of the S-wave of the relevant earthquake. Alternatively or additionally, determining 208 the impact time may include steps of simulating the earthquake and / or the relevant propagation of the S-wave and P-wave.

[0076] Referring to method 200, the measured value of the detected P-wave is compared 204 with a first threshold. For example, the magnitude of the P-wave is analyzed and compared 204 with a threshold for the magnitude of the P-wave, where the magnitude of the P-wave is related to the magnitude of the subsequent S-wave expected to hit the wind turbine 10.

[0077] Thus, according to an embodiment, the detection device 100, the turbine controller, or the wind turbine controller 36 may include threshold data representing a critical magnitude of the P-wave. A first threshold may be determined such that when the relationship of the magnitude of the S-wave relative to the magnitude of the previous P-wave is known, the first threshold for the P-wave represents a certain quantity and / or quality of the associated S-wave, which will create a critical load situation for the wind turbine. The critical load situation may be a situation where the load exceeds (and also temporarily exceeds) an acceptable level.

[0078] According to an embodiment, the step 204 of comparing the measured value with the first threshold may include further analyzing the measured value of step 202 and comparing the analysis result with the first threshold. For example, the measured value of the P-wave may be interpreted and converted into an additional load value, where the load value will represent the load situation of the component of the wind turbine expected to be hit by the S-wave. The load value is compared with the first threshold, where the first threshold is a first load threshold. This specific embodiment of step 204 may be similar to two steps 306 and subsequent comparison of method 300 ( Figure 4 ).

[0079] Generally speaking, the comparison step 204 may also be understood as a step of determining the magnitude, frequency, and / or load-related result of the S-wave after the detected P-wave with respect to the structure of the wind turbine. Therefore, the first threshold may be determined accordingly. In fact, the first threshold may be the magnitude / frequency of the measured P-wave, and / or the assumed magnitude / frequency of the associated S-wave, and / or the specific maximum load generated by the associated S-wave.

[0080] If the result of comparing the measured, inferred, and / or assumed data with the first threshold 204 results in a negative decision, the operation of the wind turbine 10 continues 228 without changing the operating state in response to the detected P-wave.

[0081] If the comparison 204 results in the aforementioned data exceeding the first threshold, the result of the sensitivity direction analysis / definition 210 may be considered. The direction analysis may include defining 210 the range of sensitive directions of the wind turbine 10. The range of sensitive directions may include one direction or a range of directions, thus including an angular region. When the wind turbine 10 is hit by an S-wave propagating from a direction within the range of sensitive directions, the impact on any structure of the wind turbine 10 related to the earthquake-generated load is more critical than when the wind turbine 10 is hit by the same S-wave from a direction outside the range of sensitive directions.

[0082] Therefore, according to the direction evaluation and comparison step 206, the propagation direction of the P-wave and / or the expected S-wave is determined, including, for example, determining whether the determined propagation direction is within the range of sensitive directions by comparison 206.

[0083] If the evaluation and comparison step 206 results in a negative evaluation (and thus the determined propagation direction is not within the sensitive direction range), the operation of the wind turbine 10 is changed to a first safety mode 220.

[0084] For example, the first safety mode 220 may include operating the wind turbine 10 with a reduced power output of a first amount, in particular, the maximum power output of the wind turbine 10 is limited to 70% of the rated power.

[0085] However, in the case where the direction evaluation and comparison 206 results in a positive outcome (the determined propagation direction is within the sensitive direction range), a second safety mode 222 of the wind turbine 10 is activated. For example, the second safety mode 222 may include operating the wind turbine 10 with a reduced power of a second amount, in particular, the maximum power output of the wind turbine 10 is limited to 50% of the rated power. This reflects the fact that S-waves impinging on the wind turbine 10 from directions within the sensitive direction range have an increased critical load-related impact on the wind turbine 10. Therefore, by reducing the maximum power output of the wind turbine 10, the operating load is further reduced.

[0086] When returning to step 204 of comparing the result of the measurement 202 with a threshold, according to an embodiment, a second threshold is determined and used for the comparison 204. The second threshold for the comparison step 204 is higher than the first threshold.

[0087] If the second threshold is exceeded, the result of the evaluation and comparison 206 of the propagation direction within the sensitive direction range can be considered similar to that described previously.

[0088] In fact, according to an embodiment, the step of understanding and comparing the direction 206 can also occur during the measurement 202 of the P-wave or during another suitable activity.

[0089] If the comparison step 206 of the direction results in a negative outcome, the wind turbine 10 can operate in an additional safety mode and / or in the second safety mode 222. In the latter case, when the second threshold is exceeded but the direction is not critical, the cumulative load situation of the wind turbine 10 is comparable to the situation described above, where only the first threshold is exceeded but the step 206 of the direction results in a positive outcome.

[0090] Additionally, if in comparison step 204 the second threshold is exceeded and the direction comparison 206 has a positive result, then the third safety mode 224 can be activated. In particular, the third safety mode 224 can have a further reduced power output. For example, the maximum power output is limited to 30% of the rated power, preferably 20%, and in particular 10%, more specifically 0%. If the power output is reduced to 0%, the generator 46 of the wind turbine 10 can still be connected to the grid and / or the rotor 18 of the wind turbine 10 can rotate idly (rotate without extracting excess energy from the wind, but in order to maintain rotation). The benefit of reducing to 0% and remaining connected to the grid is the ability to immediately resume energy generation and supply to the grid.

[0091] According to an embodiment, the comparison step 204 can include a third threshold, where exceeding such a threshold causes a shutdown mode 226 of the wind turbine 10. This means that, based on the analysis 202 of the P-wave, the expected S-wave will have such a critical impact on the load of the wind turbine 10 that when the expected S-wave will hit the wind turbine 10, any load associated with power generation will be reduced or minimized in order to have an increased safety margin.

[0092] In summary, according to the method 200 as depicted in Figure 3 the measured value and / or analysis 202 of the detected P-wave can be compared with a first threshold, a second threshold, and / or a third threshold, which will cause a change in the operation of the wind turbine 10 to the first safety mode 220, the second safety mode 222, or the shutdown mode 226.

[0093] Optionally, the propagation direction of the P-wave (and thus also the S-wave) can be analyzed and / or compared 206 with respect to the determined sensitive direction range 210. If step 206 results in a positive outcome, the wind turbine 10 operates in the second mode 222 instead of the first mode 220, and in the third safety mode 224 instead of the second safety mode 222.

[0094] Alternatively or additionally, the impact time of the expected S-wave determined in step 208 can be used for the dynamic assessment step 212. This step 212 includes analyzing whether the change in the operating state from normal operation to the first safety mode 202, the second safety mode 222, the third safety mode 224, and / or to the shutdown mode 226 requires a period of time greater than the remaining time until the expected impact of the expected S-wave. If this assessment is positive, and thus the expected S-wave hits the wind turbine 10 before the safety mode can be established and have the effect of reducing the load, then additional braking measures are performed to reduce the torque and / or rotational speed of the rotor 18.

[0095] For example, if sufficient time remains before the impact, active braking 240 may not be performed, and thus, the mechanical and / or frictional losses of the drivetrain 64 and / or the rotor 18 are braking the rotor 18. If the time is critical, the wind turbine blade 22 may be pitched so as to achieve an aerodynamic braking effect, and / or a mechanical braking step 246 may be performed, for example by applying a friction brake of the drivetrain 64. By implementing one or more of the described braking measures, the transition time for changing the operating state of the wind turbine 10 can be shortened.

[0096] According to Figure 4 , method 300 includes a measurement / evaluation step 202 of the detected P-wave and / or a determination 208 of the impact time.

[0097] Subsequently, a step of performing a load assessment 304 of the current and upcoming load scenarios of the wind turbine 10 is carried out. For example, the load assessment 304 may include a step 306 of simulating the relevant load values of the components of the wind turbine 10. The step 304 of the load assessment may include the measured values of the measurement step 202 of the P-wave and at least the measurement and / or interpretation of at least one of the following data: the current and / or estimated power output 320, the current and / or estimated wind speed 222, the current and / or estimated wind direction 223, the current and / or estimated pitch angle of the rotor blade 22, the current and / or estimated rotational speed or torque of the rotor 18 or the generator 46.

[0098] If the load assessment results in a value not exceeding a pre-determined threshold value for the load value, the wind turbine 10 remains in continued operation 228. However, if a first load threshold is exceeded, the wind turbine is placed in a load safety mode 302 with a reduced power output.

[0099] In particular, the amount of power reduction is determined by an iterative adjustment step 330, in which a step 308 of simulating and / or estimating the simulated load values 310 of the components of the wind turbine 10 is performed. In the step 330, a first theoretical power reduction is assumed and used to estimate the simulated load value 310. If the value 310 exceeds the threshold, a new and thus further reduced theoretical power reduction is assumed, and another similar load value 310 is determined. This process is repeated until the threshold is no longer exceeded, and thus the amount of power reduction for the safety mode 302 is determined.

[0100] Step 310 includes the measured values of the measurement step 202 of the P-wave and at least the measurement and / or interpretation of at least one of the following data: the current and / or estimated power output 320, the current and / or estimated wind speed 222, the current and / or estimated wind direction 223, the current and / or estimated pitch angle of the rotor blade 22, the current and / or estimated rotational speed or torque of the rotor 18 or the generator 46.

[0101] Similar to method 200, particularly step 212, if the step 208 of determining the impact time results in a critical time situation, braking measures can be applied.

[0102] The present invention is not limited to the embodiments and modifications described above and can be implemented in various forms within its gist. For example, the technical features corresponding to the embodiments and modifications according to the aspects described in the Summary of the Invention section can be appropriately replaced or combined to solve some or all of the problems described above or to achieve some or all of the effects described above. For example, the step 310 of simulating the load value of method 300 and / or subsequent step 330 can also be applied to method 200, for example, to specify the amount of load reduction of the first safety mode 220, the second safety mode 222, and / or the third safety mode 224.

[0103] Reference numerals

[0104] 1 System

[0105] 10 Wind Turbine

[0106] 11 Tip

[0107] 12 Tower

[0108] 13 Support End

[0109] 14 Ground Support Device

[0110] 15 Ground

[0111] 16 Nacelle

[0112] 18 Rotor

[0113] 20 Rotatable Hub

[0114] 22 Rotor Blade

[0115] 24 Blade Root Portion

[0116] 26 Load Transfer Region

[0117] 28 Wind Direction

[0118] 30 Axis of Rotation

[0119] 32 Pitch System

[0120] 34 Pitch Axis

[0121] 36 Wind Turbine Controller

[0122] 38 Yaw Axis

[0123] 40 Processor

[0124] 42 Generator

[0125] 44 Main Shaft

[0126] 46 Gearbox

[0127] 47 Torque Arm

[0128] 48 High-Speed Shaft

[0129] 50 Coupler

[0130] 52 Main Frame

[0131] 54 Disengaging Support Device

[0132] 56 Yaw Drive Mechanism

[0133] 58 Meteorological Mast

[0134] 60 Front Support Bearing

[0135] 62 Rear Support Bearing

[0136] 64 Drivetrain

[0137] 66 Pitch Assembly

[0138] 68 Pitch Drive System

[0139] 70 Sensor

[0140] 72 Pitch Bearing

[0141] 74 Pitch Drive Motor

[0142] 76 Pitch Drive Gearbox

[0143] 78 Pitch Drive Pinion

[0144] 80 Pitch Control System

[0145] 84 Power Generator

[0146] 86 Cavity

[0147] 88 Inner Surface

[0148] 90 Outer Surface

[0149] 100 Detection Equipment

[0150] 200 Method

[0151] 202 Measurement

[0152] 204 Determine Propagation Direction

[0153] 206 Comparison

[0154] 208 Determine the impact time

[0155] 210 Determine the sensitive direction range

[0156] 212 Dynamic evaluation step

[0157] 220 First safety mode

[0158] 222 Second safety mode

[0159] 224 Third safety mode

[0160] 226 Shutdown mode

[0161] 228 Continue operation

[0162] 240 No active braking

[0163] 242 Active aerodynamic braking

[0164] 244 Mechanical braking

[0165] 300 Method

[0166] 302 Safety mode

[0167] 304 Conduct a load assessment

[0168] 306 Determine the load value

[0169] 308 Determine the reduced power output

[0170] 320 Current power output

[0171] 322 Wind speed

[0172] 324 Wind direction

[0173] 326 Blade pitch angle

[0174] 328 Rotation speed

[0175] 330 Iterative adjustment step

Claims

1. A method (200; 300) for operating a system (1) comprising a wind turbine (10), the method comprising the steps of: - Measuring (202) P-waves generated by an earthquake; - Comparing (204) the measured value of the detected P-waves with a first threshold; - If the measured value exceeds the first threshold, changing the operating state of the wind turbine (10) to a first safety mode (220) with a first reduced power output or to a shutdown mode (226); - Determining (208) the impact time of S-waves generated by the same earthquake that caused the measured P-waves; - Determining the change time required to change the operation of the wind turbine (10) from the current operating state to the first safety mode (220) or the shutdown mode (226) without performing active braking measures (242, 244); And - If the impact time is shorter than the change time, applying active braking measures (242, 244) to the rotor (18) of the wind turbine (10).

2. The method (200; 300) according to claim 1, wherein, The first reduced power output depends on the magnitude of the measured value.

3. The method (200; 300) according to claim 2, wherein, The first reduced power output decreases as the measured value increases.

4. The method (200; 300) according to claim 2, wherein, The first reduced power output is determined by a function of the measured value.

5. The method (200; 300) according to claim 1 or 2, comprising the steps of: - Determining (204) the propagation direction of the detected P-waves; - Determining (210) the sensitive direction range of the wind turbine; - Comparing (206) the propagation direction with the sensitive direction range; And If the propagation direction lies within the sensitive direction range, and If the measured value exceeds the first threshold, - Changing the operating state of the wind turbine to a second safety mode (222) with a second reduced power output or to a shutdown mode (226), wherein the second reduced power output is less than the first reduced power output.

6. The method (200; 300) according to any one of claims 1 to 4, comprising the steps of: - Performing a load assessment on the load applied to the structure of the wind turbine (10), the load including the measured value of the detected P-waves and the current and / or estimated operating loads of the wind turbine (10); and - If the load assessment results in the definition of a critical load situation, changing the operating state of the wind turbine to a load safety mode (302) with a reduced power output or to a shutdown mode (226).

7. The method (200; 300) according to claim 6, wherein, The load assessment is performed by using the wind turbine controller (36).

8. The method (300) according to any one of claims 1 to 4, comprising the steps of: - Determining an established load value of a component of the wind turbine (10) by estimating (306) the load applied to the structure of the wind turbine (10) at least based on the following during the performance of the load assessment: The current and / or estimated operating values of the wind turbine (10), which at least include: power output, measured and / or estimated wind speed (322) and / or wind direction (324), the pitch angle (326) of the pitch system (32) of the wind turbine (10), and / or the rotational speed of the rotor (18) and / or the power generator (84) of the wind turbine (10), and the measured value of the detected P-wave.

9. The method (300) according to claim 8, wherein, Performing an estimation of the loads applied to the structure of the wind turbine (10) includes simulating the loads applied to the structure of the wind turbine (10).

10. The method (300) according to claim 8, comprising the steps of: - Comparing the determined load value with a load threshold; and - If the determined load value exceeds the load threshold, changing the operating state of the wind turbine to a load safety mode (302) with a reduced power output or to a shutdown mode (226).

11. The method (300) according to claim 10, comprising the steps of: - Determining (308) the reduced power output by performing an estimation (310) based at least on: the desired maximum load applied to the structure of the wind turbine (10), the determined reduced power output, the current and / or estimated operating values of the wind turbine (10), which at least include: measured and / or estimated wind speed (322) and / or wind direction (324), the current or desired pitch angle (326) of the pitch system (32) of the wind turbine (10), and / or the current or desired rotational speed (328) of the rotor (18) and / or the power generator (84) of the wind turbine (10), and the measured value of the detected P-wave.

12. The method (300) according to claim 11, wherein, The estimation (310) includes simulation.

13. The method (200; 300) according to any one of claims 10 to 12, wherein, The magnitude of the reduced power output depends on the magnitude of the determined load value.

14. The method (200; 300) according to claim 13, wherein, The reduced power output decreases as the determined load value increases.

15. The method (200; 300) according to claim 13, wherein, The magnitude is a function of the estimated load or the determined load value.

16. A wind turbine system (1), comprising: - A wind turbine (10), which at least includes a rotor (18) having at least one rotor blade (22), a rotary support device for rotatably supporting the rotor (18), and a tower (12) having a support end (13) and a top end (11) for supporting the rotary support device, - A wind turbine controller (36) for controlling the wind turbine (10), and - At least one detection device (100) connected to the wind turbine controller (36) for signal transmission, wherein the wind turbine controller (36) and the detection device (100) are configured to perform the method according to any one of claims 1 to 15.

17. The system (1) according to claim 16, wherein, The detection device (100) is configured to measure motion and / or vibration having a frequency ranging from 500 Hz to 0.00118 Hz.

18. The system (1) according to claim 16, wherein, The detection device (100) is arranged on / in the ground (15) of the wind turbine (10), and / or is mounted to the support end (13), and / or wherein the system (1) further comprises a ground support device (14) located on / in the ground (15) for supporting the support end (13), and wherein the detection device (100) is arranged on / in the ground support device (14).

19. The system (1) according to claim 18, wherein, The support end (13) is mounted to the ground support device (14) by a fixing device, and wherein the detection device (100) is directly mounted to the fixing device.

20. The system (1) according to claim 19, wherein, The fixing device comprises at least one screw and at least one nut.

21. The system (1) according to any one of claims 16 to 20, wherein, The detection device (100) is configured to determine the propagation direction of the detected P-wave.

22. The system (1) according to any one of claims 16 to 20, wherein The rotary support device is embodied as a nacelle (16), the rotor (18) is rotatably supported by the nacelle (16) along a substantially horizontal rotation axis (30), and wherein the nacelle (16) is rotatably mounted on the top end (11) about the yaw axis (38) of the wind turbine (10).

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