MONITORING SYSTEM AND METHOD FOR MONITORING A TIME PERIOD OF A LOCKING STATE OF A ROTOR OF A WIND TURBINE AND WIND TURBINE

Abstract

A monitoring system for monitoring a time period of a locking state of a rotor of a wind turbine includes at least one motion sensor and at least one computing unit, wherein the computing unit is confiugered 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 may remain in the locking state or the rotor should be unlocked based on the at least one motion measurement. A wind turbine having the monitoring system and a method for monitoring a time period of locking state of a rotor of a wind turbine is also provided.

Claims

1-13. (canceled)

14. A monitoring system for monitoring a time period of a locking state of a rotor of a wind turbine, comprising: at least one motion sensor; at least one computing unit, wherein the at least one computing unit is configured to receive at least one motion measurement from the at least one motion sensor and wherein the at least onecomputing unit is configured to determine whether the rotor may remain in the locking state or the rotor should be unlocked based on the at least one motion measurement; a signaling system configured for outputting a signal based on the determination of the at least one computing unit, wherein the signaling system is configured such that the signal is visual and/or acoustical, and wherein the signaling system is configured for outputting the signal with the rotor remaining in the locking state.

15. The monitoring system according to claim 14, wherein the determination is based on a comparison of the at least one motion measurement and a predetermined threshold.

16. The monitoring system according to claim 15, wherein the predetermined threshold is based on a study of damaged drive trains of wind turbines and at least one measurement of at least one motion sensor in the time period leading up to a failure of the drive trains.

17. The monitoring system according to claim 15, wherein the predetermined threshold is based on the at least one motion measurement and a specified time period.

18. The monitoring system according to claim 14, wherein the signaling system is configured for outputting one of three different signals based on the determination of the at least one computing unit.

19. The monitoring system according to claim 14, wherein the at least one motion sensor is an accelerometer.

20. A wind turbine comprising the monitoring system according to claim 14.

21. The wind turbine according to claim 20, wherein the at least one motion sensor is configured provided at a component of a drive train of the wind turbine.

22. The wind turbine according to claim 20, wherein the monitoring system comprises multiple motion sensors provided at different components of the drive train of the monitoring system.

23. The wind turbine according to claim 20, wherein the at least one motion sensor is from a wind turbine control system of the wind turbine.

24. A method for monitoring a time period of a locking state of a rotor of a wind turbine, of the method comprising: measuring at least one motion of the wind turbine; determining whether the rotor may remain in the locking state or the rotor or should be unlocked based on the at least one measured motion; and outputting a signal based on the determination, wherein the signal is visual and/or acoustical, and wherein the signal is outputted with the rotor remaining in the locking state.

25. The method according to claim 24, further comprising: unlocking the locked rotor in the monitored time period upon determining that the rotor should be unlocked based on the at least one measured motion.

Description

BRIEF DESCRIPTION

[0036] Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

[0037] FIG. 1 shows a side view on a wind turbine;

[0038] FIG. 2 shows a cross-sectional view through the nacelle and on the drive train inside the nacelle of the wind turbine of FIG. 1;

[0039] FIG. 3 shows an illustration of a monitoring system for the wind turbine of FIGS. 1 and 2; and

[0040] FIG. 4 shows an illustration of a method for monitoring a time period of a locking state of a rotor of the wind turbine of FIGS. 1 and 2.

DETAILED DESCRIPTION

[0041] FIG. 1 shows a side view on a wind turbine 1. The wind turbine 1 comprises a supporting tower 20 and a nacelle 30, which is mounted on the supporting tower 20. The nacelle 30 contains a drive train 10 of the wind turbine 1 as shown in the cross-sectional view of the nacelle 30 in FIG. 2. The rotor 60 of the drive train 10 is provided outside of the nacelle 30. The rotor 60 consists of the hub 11 with two rotor blades 40.1, 40.2 attached thereto. However, the number of rotor blades 40 may alternatively be more than two, such as three, for example.

[0042] FIG. 2 shows a cross-sectional view through the nacelle 30 and on the drive train 10 inside the nacelle 30 of the wind turbine 1 of FIG. 1. The nacelle 30 comprises a main frame 31. The drive train 10 is supported on the main frame 31 of the nacelle. The topology of the drive train 10 is geared in FIG. 2, but may alternatively also be of a direct drive type.

[0043] The mechanical drive train 10 comprises multiple components 11, 12, 13.1, 13.2, 14, 15, 16, 17. These are the hub 11, the drive shaft 12 with its main bearings 13.1, 13.2, the gearbox 14 and the generator 16. The generator 16 is connected to the gearbox 14 via a generator shaft 15 which is provided 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 a locking state, the rotor 60 cannot rotate.

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

[0045] As can be further taken from FIG. 2, oscillations of the nacelle 30 are measured by multiple motion sensors 51.1, 51.2, 51.3, 51.4. These motion sensors 51.1, 51.2, 51.3, 51.4 are configured as accelerometers and are part of a wind turbine control system (not shown). The wind turbine control system is configured for indirect monitoring of the condition of the rotor 60. The measurements used for this are the transverse and axial nacelle oscillations related to the drive shaft 12. FIG. 2 in this respect shows an exemplar configuration of motion sensors 51.1, 51.2, 51.3, 51.4 for measuring the nacelle oscillation of the horizontal axis wind turbine 1.

[0046] Because rotor-induced nacelle oscillation frequencies are rather low (typically from 0.1 Hz to 10 Hz), the motion sensors 51.1, 51.2, 51.3, 51.4 are configured to be able to measure within a bandwidth of 0 Hz (DC) to a maximum of about 20 Hz.

[0047] The nacelle can perform three oscillation modes, which are relevant for the condition monitoring and fault prediction of the rotor: transverse to the rotor axis, in line with the rotor axis and as torsion around the vertical tower axis. To monitor these oscillations, three motion sensors 51 are required. The motion sensors 51.3 is sensitive in the axial direction (related to the rotor axis). The motion sensors 51.2, 51.4 are sensitive in the transverse direction to the rotor axis. The motion sensor 51.1 is an inductive distance sensor. This sensor gives a reference signal for the absolute position of the rotor 60, when one of the rotor blades 40 is in the vertical upright position. The position information of the rotor 60 is required to calculate the phase information, which helps to detect a faults mass imbalance and aerodynamic asymmetry of the rotor 60.

[0048] FIG. 3 now shows a schematic representation of a monitoring system 50 to be used in the wind turbine 1 of FIGS. 1 and 2. The monitoring system 50 may be provided at any desired location at the wind turbine 1 or outside of the wind turbine 1. However, the motion sensors 51.1, 51.2, 51.3, 51.4 used for the monitoring system 50 as shown in FIG. 2 obviously must be located at the drive train 10 and are in this case already present in the wind turbine 1 for the wind turbine control system. Further, the signaling system 53 with its signaling units 54.1, 54.2, 54.3 should as well be present in the wind turbine 1 itself, e.g. inside of the nacelle 30.

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

[0050] FIG. 4 shows a schematic representation of a method 100 for monitoring a time period of a locking state of the rotor 60 of the wind turbine 1 by means of the monitoring system 50 of FIG. 3.

[0051] According to the method 100, a first method step 101 is that the motion sensors 51.1, 51.2, 51.3, 51.4 constantly measure the oscillations of the rotor 60 at different locations at the drive train 10 and transmits them to the computing unit 52.

[0052] The computing unit 52 contains in a storage unit (not shown) one or more predetermined thresholds for the measured oscillations of each one of the motion sensors 51.1, 51.2, 51.3, 51.4. In a second method step 102, the computing unit 52 compares the predetermined threshold or thresholds to the measurements received from the motion sensors 51.1, 51.2, 51.3, 51.4. It thereby determines whether the rotor 60 may remain in the locking state or the rotor 60 should be unlocked. Because the measured oscillations depend on the environmental conditions around the wind turbine 1, the measured oscillations correlate to a risk of standstill marks at the drive train 10, which are to be avoided to reduce a risk of failure of one of the components 11, 12, 13.1, 13.2, 14, 15, 16, 17 of the drive train 10 of the wind turbine 1.

[0053] In a third method step 103, the signaling system 53 is controlled by the computing unit 52 based on the determination on whether or not the rotor 60 may remain in the locking state. The signaling unit 54.1 is a siren, the signal unit 54.2 is a screen and the signaling unit 54.3 is a lamp. Accordingly, when it is determined that the rotor 60 should be unlocked, the siren may be turned on, the screen may show a notice that the rotor 60 should be unlocked and turned and the lamp may turn red, for example. Otherwise, when it is determined that the rotor 60 may remain in the locking state, the siren may be turned off, the screen may show the notice that it is safe to perform maintenance work and the lamp may turn green according to the control of the computing unit 52.

[0054] The locking method 200 runs parallel to the method 100 of monitoring the time period of the locking state of the rotor 60. In the first locking method step 201, the rotor 60 is being locked by means of the locking unit 17. This step may benefit from the method 100 in that the computing unit 52 may determine whether it is safe or not to lock the rotor 60.

[0055] After locking of the rotor 60, in the second locking method step 202, the maintenance work on the wind turbine 1 is performed by technicians. However, when the third method step 103 determines that the rotor 60 should be unlocked, according to the arrow 300, which may refer to the signaling by means of the signaling system 52, the rotor 60 is unlocked und turned in the third locking method step 203. Alternatively, the arrow 300 may refer to a control of the monitoring system 50 of the locking control unit automatically unlocking the rotor 60, turning it and again locking the rotor 60. However, such optional control and operation may be signaled to the technicians via the signaling system 53 prior to being performed such that the safety of the technicians may be ensured.

[0056] Although the present invention has been disclosed in the form of embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention.

[0057] For the sake of clarity, it is to be understood that the use of “a” or “an” throughout this application does not exclude a plurality, and “comprising” does not exclude other steps or elements.