Monitoring system and method for monitoring a time period of a locked state of a rotor of a wind turbine and wind turbine

Abstract

The present invention relates to a monitoring system (50) for monitoring the locked state of a rotor (60) of a wind turbine (1) for a period of time, wherein the monitoring system (50) includes at least one motion sensor (51) and at least one computing unit (52), wherein the computing unit (52) is configured to receive at least one motion measurement from the at least one motion sensor (51) and wherein the computing unit (52) is configured to determine whether the rotor (60) can remain in the locked state or whether the rotor (60) should be unlocked based on the at least one motion measurement. The invention also relates to a wind turbine (1) having a monitoring system (50) and a method (100) for monitoring the locked state of the rotor (60) of the wind turbine (1) for a period of time.

Description

[0001] The present invention relates to a monitoring system for monitoring the locked state of a wind turbine rotor for a period of time, a wind turbine including the monitoring system, and a method for monitoring the locked state of the wind turbine rotor for a period of time.

[0002] Components of the wind turbine's drive train, such as bearings and gears, must be exercised—that is, rotated—to prevent standstill marks from appearing on them. Such standstill marks can eventually lead to the failure of these components.

[0003] However, during certain maintenance tasks on wind turbines, particularly the drivetrain, the drivetrain must be locked to prevent rotation and protect technicians performing maintenance tasks from potential hazards caused by component rotation.

[0004] Therefore, during maintenance tasks, the drivetrain is locked, and there is a risk of developing traces of stagnation. This risk increases significantly with the duration of rotor locking. To avoid traces of stagnation, it is known to impose time limits on the period during which the rotor of the locked drivetrain is held, or in other words, on the locked state of the rotor. Such time limits may range from several hours.

[0005] However, if the maintenance task takes longer than the time limit, the maintenance task needs to be paused and the rotor rotated before it can continue due to the increased risk of downtime. However, pausing the maintenance task and rotating the rotor are cumbersome.

[0006] Other methods for reducing loads in wind turbines are known. US 2012 / 146333 A1 discloses a system for reducing the dynamic load on a wind power unit under parked or idle conditions. The system is configured to generate a braking signal in response to a dynamic load signal indicated by parameters sensed by sensors. The braking system, in response to the braking signal, executes a reduced torque braking mode to reduce the dynamic load on the wind power unit by allowing intermittent slippage of the braking system. Further prior art is referenced to US 2020 / 232446 A1, US 2008 / 181761 A1, EP 3 073 109 A1, and US2010 / 194114 A1.

[0007] Furthermore, even with the aforementioned preventative measures, the risk of damage to the transmission system due to rotor locking can only be reduced, not eliminated.

[0008] Therefore, the object of the present invention is to enable maintenance tasks that require locking the rotor of the wind turbine's drivetrain with a lower risk of damage due to stalling traces, while still performing the maintenance tasks with the least possible interruption for the long duration of the maintenance tasks.

[0009] This objective is achieved through the subject matter of the claims. In particular, this objective is achieved through a monitoring system according to the invention for monitoring the time period of lock-up of a wind turbine rotor, a wind turbine according to the invention, and a method according to the invention for monitoring the time period of lock-up of a wind turbine rotor. Further details of the invention are derived from the other claims, as well as the description and drawings. Therefore, the features and details described in conjunction with the wind turbine and method of the invention are intended to be mutually referenced.

[0010] According to a first aspect of the invention, this objective is achieved by a monitoring system for monitoring the locked state of a wind turbine rotor over a period of time, wherein the monitoring system includes at least one motion sensor and at least one computing unit, wherein the computing unit is configured to receive at least one motion measurement from the at least one motion sensor, and wherein the computing unit is configured to determine whether the rotor can remain locked or the rotor should be unlocked based on the at least one motion measurement.

[0011] Therefore, the present invention provides a monitoring system capable of detecting the motion of a wind turbine. Motion can, in particular, take the form of vibration and / or oscillation. Thus, the motion sensor configured to detect the motion of the wind turbine can be a vibration sensor and / or an oscillation sensor, and the motion measurement can be a vibration measurement and / or an oscillation measurement.

[0012] Based on the detected motion, the computing unit determines, specifically through calculation, the risk of the rotor remaining in a locked state, i.e., the risk of a stoppage while locked. As long as the measured motion is small, the risk of a stoppage is low, and the computing unit can determine that the rotor can remain in a locked state. The rotor's locked state can be a safety measure to allow maintenance tasks to be performed at the wind turbine. Maintenance tasks performed by technicians may therefore continue while it is determined that the rotor is likely to remain locked.

[0013] However, if the measured motion is high, the risk of creating a stalling effect is also high, and the calculation unit can determine whether the rotor should be unlocked based on at least one motion measurement. Therefore, when the rotor is unlocked, it can be rotated to continue the maintenance task, or if the motion is very high, the maintenance task may need to be paused or postponed. The calculation unit can be configured to distinguish between such determinations that require rotating the rotor to continue the maintenance task or that require pausing or postponing the maintenance task. Thus, when it is determined that the rotor should be unlocked, these determinations can be sub-determinations.

[0014] Therefore, this invention considers the movement of the wind turbine as a risk factor that goes further than previously considered in the prior art. As a result, it is possible to significantly reduce the risk of damage to the transmission system due to stalling, because this risk is more relevant to the movement of the wind turbine, particularly the transmission system, due to environmental conditions surrounding the turbine than to time. Therefore, maintenance tasks can be performed completely uninterrupted and for very long durations when environmental conditions are favorable and the correspondingly measured movement is low.

[0015] Clearly, the monitoring system can be configured to continuously monitor the rotor's locked state by continuously measuring the motion of the wind turbine, particularly the motion of at least one or more components of the drivetrain. The computing unit then continuously receives motion measurements from at least one motion sensor and can continuously determine, based on environmental conditions, whether the rotor can remain locked or should be unlocked. Therefore, changes in environmental conditions leading to significant motion can be quickly noticed. Consequently, the computing unit can quickly determine whether the rotor should be unlocked to prevent any damage to the wind turbine's drivetrain.

[0016] This determination can be based on a comparison of at least one motion measurement and a predetermined threshold. The threshold can be predetermined such that if it is exceeded—that is, when at least one motion measurement exceeds it—the rotor should be unlocked, taking into account the increased risk of stalling traces on the transmission components. Alternatively, the rotor can be kept locked as long as at least one motion measurement value is below the predetermined threshold.

[0017] The predetermined threshold can be based on a study of a damaged drivetrain of a wind turbine and at least one measurement from at least one motion sensor during the time period leading to the drivetrain failure. Therefore, the predetermined threshold is based on prior experience and can thus be determined very accurately in advance. The actual predetermined threshold can be equipped with a safety buffer compared to the empirical motion at the time of drivetrain failure studied. Alternatively or additionally, the predetermined threshold can be based on computer simulations of the wind turbine's drivetrain.

[0018] Furthermore, if there are more than one motion sensor, each motion measurement from each of the motion sensors can be compared to a predetermined threshold or a different predetermined threshold for each of the motion sensors. Alternatively, the predetermined threshold could be a value representing all motion measurements from the multiple motion sensors, such as the average of the measured motions.

[0019] Furthermore, the predetermined threshold can be based on at least one motion measurement and a specified time period. Therefore, the determination can be based on both the motion of the wind turbine caused by environmental conditions and the duration of maintenance work. Thus, the calculation unit's determination regarding whether the rotor can remain locked or should be unlocked can be based not only on at least one motion measurement but also on a specified time period of the locked state. This can further reduce the risk of downtime traces. For example, the predetermined threshold can be in the format of a motion threshold and a time threshold. When either of these is reached or exceeded, the calculation unit can determine accordingly that the rotor should be unlocked. Alternatively, the predetermined threshold can include a motion threshold and a time threshold that consider both motion and time.

[0020] According to the invention, the monitoring system also includes one or more signals configured to be output based on a determination by the computing unit. These signals can be configured for use by a technician performing a maintenance task. Thus, the technician can readily receive feedback regarding the computing unit's determination that the risk of a stall has increased and suggests unlocking the rotor, or receive feedback based on a determination by the computing unit that the rotor can remain locked. Therefore, for safety reasons, the technician can still decide for themselves whether the rotor remains locked or unlocked. The technician can operate a locking control unit to lock the rotor based on the determination. However, alternatively, or in cases of increased risk, it is also anticipated that the monitoring system or computing unit may be operatively connected to the locking control unit. In this case, the monitoring system can operate the locking control unit, for example, to unlock the rotor after a predetermined time following the output of one or more signals to the technician, said one or more signals possibly containing a warning that the rotor will be unlocked.

[0021] Furthermore, the signaling system can be configured to output one of three different signals based on a determination by the computing unit. One signal can be a green signal or an "ok" signal. This signal can be issued when it is determined that the rotor can remain locked. Another signal can be a red signal or a warning signal. This signal can be issued when it is determined that the rotor should be unlocked. The third signal can be a yellow signal or a "caution" signal. This signal can be issued between another determination by the computing unit that the rotor can remain locked or that the rotor should be unlocked. For example, when continuous motion measurements have not exceeded a predetermined threshold but the measured motion becomes large, a yellow signal or a caution signal can be issued to notify technicians that the rotor may soon need to be unlocked and maintenance work may need to be interrupted.

[0022] The signaling system can be configured such that the signal is visual and / or audible. Therefore, the signaling system may include alarms, screens, and / or lights as signal output units to output signals. Preferably, the signal is emitted on multiple of the aforementioned signal output units, making it more noticeable to a technician. One or more signals may be emitted at predetermined time intervals, such as those ranging from 5 to 15 minutes.

[0023] At least one motion sensor can be an accelerometer. The accelerometer measures the acceleration of a wind turbine, that is, its structure, and more specifically, one or more components of the wind turbine. The accelerometer may be, for example, a MEMS accelerometer. MEMS accelerometers feature low noise, high resistance to repeated high shocks, and high insensitivity to temperature differences.

[0024] According to a second aspect of the invention, this objective is achieved by a wind turbine that includes a monitoring system according to a first aspect of the invention.

[0025] At least one motion sensor can be provided at a component of the wind turbine's drivetrain. Therefore, motion, i.e., vibration and / or oscillation, can be measured directly at the component of the drivetrain experiencing motion, making it possible to infer the risk of the development of stall traces at the component from measurements performed directly at the component itself. In particular, at least one motion sensor can be provided at, especially, a component attached to the mechanical drivetrain, such as a bearing or gearbox. These components of the drivetrain have been found to be most susceptible to stall traces.

[0026] At least one motion sensor may be attached to a component of the transmission system. Specifically, at least one motion sensor may be embedded in the container and fixed to a component of the transmission system to measure its motion, i.e., oscillation and / or vibration, for example. The container may be a biaxial or triaxial container. Vibration measurement can be achieved by detecting frequency differences.

[0027] Furthermore, the monitoring system may include multiple motion sensors provided at different components of the wind turbine's drivetrain. Specifically, motion sensors may be provided at each or at least one bearing in the drive shaft and gearbox. Measurement of motion at different components of the drivetrain enables local determination of the risk of stalling traces at the respective components. This increases the likelihood of identifying a high risk of stalling traces before their development. In this respect, each component or motion sensor may have its own predetermined threshold.

[0028] At least one motion sensor can be derived from the wind turbine control system. The wind turbine control system is configured to control the operation of the wind turbine and therefore has motion determined by motion sensors, particularly accelerometers attached to components of the drivetrain. Thus, at least one motion sensor for the monitoring system is already included in the wind turbine, saving the cost of implementing monitoring systems in both existing and new wind turbines.

[0029] The locking of the wind turbine rotor, i.e., the locked state, can be achieved by at least one locking unit of the wind turbine locking system. The at least one locking unit can be in the form of a brake or at least one locking pin and a corresponding pin insertion hole in the transmission system, for example, in a gearbox, such as when using a gear topology of the transmission system. A locking control unit of the locking system can be provided for controlling one or more locking units of the wind turbine rotor, i.e., for locking and unlocking the rotor. In the locked state, the rotor cannot rotate. In the unlocked state, the rotor can rotate freely.

[0030] According to a third aspect of the invention, this objective is achieved by a method for monitoring a time period of the locked state of a wind turbine rotor, wherein the method comprises the following steps:

[0031] Measure at least one motion of the wind turbine and determine, based on the at least one measured motion, whether the rotor can remain locked or should be unlocked.

[0032] This method can be specifically configured to be performed using a monitoring system according to the first aspect of the invention. Thus, at least one motion of the wind turbine, specifically vibration and / or oscillation, can be measured by means of at least one motion sensor of the monitoring system. Furthermore, a determination can be made, based on at least one measured motion, whether the rotor can remain locked or should be unlocked.

[0033] According to the present invention, the method includes the additional step of outputting one or more signals based on the determination. For this purpose, a signaling system previously described with respect to a monitoring system can be used.

[0034] Finally, the method may include the additional step of unlocking the locked rotor within a monitored time period when it is determined, based on at least one measured motion, that the rotor should be unlocked. As previously mentioned, this step may be performed by a technician upon receiving one or more signals, or automatically by a monitoring system or computing unit controlling the locking control unit.

[0035] Further advantages, features, and details of the present invention are set forth in the following description, with reference to the accompanying drawings. Figures 1 to 4 Embodiments of the invention have been described in detail. Therefore, the features from the claims and the features mentioned in the specification, individually or in any combination, are essential to the invention. In the accompanying drawings, the following are schematically shown:

[0036] Figure 1 It is a side view of a wind turbine.

[0037] Figure 2 It is through the nacelle and about Figure 1 A cross-sectional view of the drivetrain inside the nacelle of a wind turbine.

[0038] Figure 3 yes Figure 1 and 2 An illustration of a monitoring system for a wind turbine, and

[0039] Figure 4 It is used for monitoring Figure 1 and 2 A diagram illustrating the method for locking the rotor of a wind turbine over a specific time period.

[0040] Figures 1 to 4 Identical objects in a diagram are named with the same reference number. If there is more than one scorpion of the same type in a diagram, the ascending numbers of the objects are separated from their reference numbers by dots to number objects of the same type in ascending order.

[0041] Figure 1 A side view of a wind turbine 1 is shown. The wind turbine 1 includes a support tower 20 and a nacelle 30 mounted on the support tower 20. The nacelle 30 contains the drivetrain 10 of the wind turbine 1, such as... Figure 2 The cross-sectional view of the nacelle 30 is shown. The rotor 60 of the transmission system 10 is provided outside the nacelle 30. The rotor 60 consists of a hub 11 having two rotor blades 40.1 and 40.2 attached thereto. However, the number of rotor blades 40 may alternatively be more than two, such as, for example, three.

[0042] Figure 2 It shows crossing Figure 1A cross-sectional view of the nacelle 30 of the wind turbine 1 and the drivetrain 10 within the nacelle 30. The nacelle 30 includes a main frame 31. The drivetrain 10 is supported on the main frame 31 of the nacelle. The topology of the drivetrain 10 is shown in... Figure 2 The type is gear-driven, but it can also be a direct drive type.

[0043] The mechanical transmission system 10 includes several components 11, 12, 13.1, 13.2, 14, 15, 16, and 17. These are a hub 11, a drive shaft 12 with its main bearings 13.1 and 13.2, a gearbox 14, and a generator 16. The generator 16 is connected to the gearbox 14 via a generator shaft 15 equipped with a brake 17. The brake 17 is a locking unit of a locking system having a locking control unit (not shown) for locking the generator shaft 15 in place and thereby locking the drive shaft 12 and the rotor 60. When the rotor 60 is locked, i.e., in the locked state, the rotor 60 cannot rotate.

[0044] The rotor 60 may alternatively or additionally be locked by a locking unit consisting of one or more locking pins (not shown). This is achieved by inserting one or more locking pins on either side of the gearbox 14. This may be preferred over brake 17, as friction-based brake 17 should only be trusted to a limited extent. The locking unit may be located on either the high-speed or low-speed portion of the transmission 10.

[0045] If possible Figure 2 Furthermore, it was found that the oscillations of the nacelle 30 were measured by multiple motion sensors 51.1, 51.2, 51.3, and 51.4. These motion sensors 51.1, 51.2, 51.3, and 51.4 are configured as accelerometers and are part of the wind turbine control system (not shown). The wind turbine control system is configured to indirectly monitor the conditions of the rotor 60. The measurements used for this purpose are the transverse and axial nacelle oscillations associated with the drive shaft 12. Figure 2 An exemplary configuration of motion sensors 51.1, 51.2, 51.3, and 51.4 is shown in this regard for measuring nacelle oscillations of a horizontal axis wind turbine 1.

[0046] Because the nacelle oscillation frequency caused by the rotor is quite low (typically from 0.1 Hz to 10 Hz), motion sensors 51.1, 51.2, 51.3, and 51.4 are configured to perform measurements within a bandwidth of 0 Hz (DC) to a maximum of approximately 20 Hz.

[0047] The nacelle can exhibit three oscillation modes relevant to rotor condition monitoring and fault prediction: transverse to the rotor axis, in line with the rotor axis, and torsion about the vertical tower axis. To monitor these oscillations, three motion sensors 51 are required. Motion sensor 51.3 is sensitive in the axial direction (corresponding to the rotor axis). Motion sensors 51.2 and 51.4 are sensitive in the transverse direction of the rotor axis. Motion sensor 51.1 is an inductive distance sensor. When one of the rotor blades 40 is in a vertical position, this sensor provides a reference signal for the absolute position of the rotor 60. The position information of the rotor 60 is needed to calculate phase information, which helps in detecting fault mass imbalances and aerodynamic asymmetries in the rotor 60.

[0048] Figure 3 Now it is shown that will be Figure 1 and 2 A schematic representation of a monitoring system 50 used in a wind turbine. The monitoring system 50 can be provided at the wind turbine 1 or at any desired location outside the wind turbine 1. However, for applications such as... Figure 2 The motion sensors 51.1, 51.2, 51.3, and 51.4 of the monitoring system 50 shown must obviously be located in the drivetrain 10 and, in this case, are already present in the wind turbine 1 for the wind turbine control system. Furthermore, the signaling system 53 and its signaling units 54.1, 54.2, and 54.3 should also be present in the wind turbine 1 itself, for example, inside the nacelle 30.

[0049] The computing unit 52 of the monitoring system 50 is wirelessly or via cable connected to motion sensors 51.1, 51.2, 51.3, 51.4 and to signaling system 53.

[0050] Figure 4 It shows the method for passing through Figure 3 A schematic representation of a method 100 for monitoring the locked state of the rotor 60 of a wind turbine 1 for a period of time using a monitoring system 50.

[0051] According to method 100, the first method step 101 is that motion sensors 51.1, 51.2, 51.3, and 51.4 continuously measure the oscillations of the rotor 60 at different positions in the transmission system 10 and transmit them to the computing unit 52.

[0052] The calculation unit 52 contains in a storage unit (not shown) one or more predetermined thresholds for the measured oscillations of each of the motion sensors 51.1, 51.2, 51.3, and 51.4. In the second method step 102, the calculation unit 52 compares the one or more predetermined thresholds with the measured values ​​received from the motion sensors 51.1, 51.2, 51.3, and 51.4. This determines whether the rotor 60 can remain in a locked state or should be unlocked. Because the measured oscillations depend on the environmental conditions around the wind turbine 1, the measured oscillations are associated with the risk of stalling traces at the drivetrain 10, a risk that must be avoided to reduce the risk of failure of one of the components 11, 12, 13.1, 13.2, 14, 15, 16, and 17 of the drivetrain 10 of the wind turbine 1.

[0053] In the third method step 103, the signaling system 53 is controlled by the computing unit 52 based on the determination that the rotor 60 can remain in the locked state. Signaling unit 54.1 is an alarm, signaling unit 54.2 is a screen, and signaling unit 54.3 is an indicator light. Therefore, when it is determined that the rotor 60 should be unlocked, the alarm can be activated, the screen can display a notification that the rotor 60 should be unlocked and rotated, and the indicator light can turn red, for example. Otherwise, when it is determined that the rotor 60 can remain locked, the alarm can be deactivated, the screen can display a notification that it is safe to perform maintenance work, and the indicator light can turn green under the control of the computing unit 52.

[0054] Locking method 200 operates in parallel with method 100, which monitors the locking status of rotor 60 over a period of time. In the first locking method step 201, rotor 60 is locked by locking unit 17. This step can benefit from method 100 because calculation unit 52 can determine whether locking rotor 60 is safe.

[0055] After rotor 60 is locked, in the second locking method step 202, a technician performs maintenance work on wind turbine 1. However, when the third method step 103 determines that rotor 60 should be unlocked, according to arrow 300, which refers to signaling from signaling system 52, rotor 60 is unlocked and rotated in the third locking method step 203. Alternatively, arrow 300 may refer to the control of the locking control unit of the monitoring system 50 that automatically unlocks rotor 60, rotates it, and relocks rotor 60. However, such optional control and operation can be signaled to the technician via signaling system 53 before being performed, thereby ensuring the safety of the technician.

Claims

1. A monitoring system (50) for monitoring the locked state of a rotor (60) of a wind turbine (1) for a period of time, wherein the monitoring system (50) comprises at least one motion sensor (51) and at least one computing unit (52), wherein the computing unit (52) is configured to receive at least one motion measurement from the at least one motion sensor (51) and wherein the computing unit (52) is configured to determine, based on the at least one motion measurement, whether the rotor (60) can remain in a locked state or the rotor (60) should be unlocked, characterized in that, The monitoring system (50) further includes a signaling system (53) configured to output a signal for a technician performing a maintenance task based on a determination by the computing unit (52), wherein the signaling system (53) is configured such that the signal is visual and / or audible, and wherein the signaling system (53) is configured to output a signal while the rotor (60) is held in a locked state.

2. The monitoring system (50) according to claim 1, characterized in that The determination is based on a comparison of the at least one motion measurement with a predetermined threshold.

3. The monitoring system (50) according to claim 2, characterized in that The predetermined threshold is based on a study of at least one measurement by at least one motion sensor during the period of damage to the transmission system (10) of the wind turbine (1) and the time period during which the failure of the transmission system (10) occurred.

4. The monitoring system (50) according to claim 2 or 3, characterized in that The predetermined threshold is based on the at least one motion measurement and a specified time period.

5. The monitoring system (50) according to any one of claims 1-3, characterized in that, The signaling system (53) is configured to output one of three different signals based on the determination of the computing unit (52).

6. The monitoring system (50) according to any one of claims 1-3, characterized in that, The at least one motion sensor (51) is an accelerometer.

7. A wind turbine (1), comprising a monitoring system (50) according to any one of the preceding claims.

8. Wind turbine (1) according to claim 7, characterized in that The at least one motion sensor (51) is configured to be provided at a component (11, 12, 13, 14, 15, 16, 17) of the drivetrain (10) of the wind turbine (1).

9. Wind turbine (1) according to claim 7 or 8, characterized in that The monitoring system (50) includes multiple motion sensors (51) provided at different parts (11, 12, 13, 14, 15, 16, 17) of the drive system (10) of the monitoring system (50).

10. The wind turbine (1) according to claim 7 or 8, characterized in that, The at least one motion sensor (51) is from the wind turbine control system of the wind turbine.

11. A method (100) for monitoring a time period of the locked state of the rotor (60) of a wind turbine (1), wherein the method (100) comprises the following steps: Measure at least one motion of the wind turbine (1), and Based on at least one measured motion, it is determined whether the rotor (60) can remain in the locked state or the rotor (60) should be unlocked. The method (100) is characterized by comprising determining a signal for a technician to perform a maintenance task based on output, wherein the signal is visual and / or auditory, and wherein the output signal is maintained in a locked state with the rotor (60).

12. The method (100) according to claim 11, characterized in that, The method (100) includes an additional step of unlocking the locked rotor (60) during a monitored time period when it is determined, based on at least one measured motion, that the rotor (60) should be unlocked.

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