Automatic monitoring of fluid-filled damper of wind turbine

Abstract

A method for monitoring a fluid-filled damper (1) of a wind turbine (10) is described. A method for monitoring a fluid-filled damper (1) of a wind turbine (10) comprises the steps of measuring a pressure value (PV) within the fluid-filled damper (1) of the wind turbine (10), comparing the pressure value (PV) with a predetermined threshold (TH), and initiating an idle state of a rotor (5) of the wind turbine (10) if it is detected that the threshold (TH) has been exceeded. Furthermore, a leakage monitoring device (6) is described. In addition, a wind turbine (10) is described.

Description

Technical Field

[0001] The invention relates to a method for monitoring a fluid-filled damper of a wind turbine. The invention also relates to a leakage monitoring device. Furthermore, the invention also relates to a wind turbine. Background Art

[0002] A wind turbine comprises a fluid filled container which is installed in the tower of the wind turbine and is used as a damper for changing the dynamics of the tower of the wind turbine. The dynamics obtained are crucial to keep the turbine within safe operating limits. The dynamics depend on the fluid type, weight etc. Therefore, it is crucial that the fluid does not leak, resulting in a change in the damper dynamics.

[0003] To maintain the dampers, during annual maintenance, technicians visually inspect the fluid containers for leaks. However, regular maintenance by technicians is expensive and carries the risk of running the turbine with a faulty fluid container between inspections.

[0004] In EP 3 757 309 A1, a damper for buffering vibrations of a wind turbine is described, wherein the damper comprises a gas pressure regulating unit for adjusting the damping coefficient of the damper by changing the pressure of the gas filled in the upper space of the mass body according to wind speed, tower vibration acceleration and amplitude parameters of tower sway.

[0005] In CN 203 716 322U a damper for damping vibrations of a wind turbine is described, the damper comprising a horizontal section of a U-shaped tube with a damping valve capable of adjusting the damping force, wherein the frequency of the damper is varied by adjusting the gas pressure.

[0006] In EP 1 811 171 A2 a system and method for damping oscillations of a wind turbine tower is described which comprises a shock absorber comprising a water tank.

[0007] There therefore exists the problem of more reliable monitoring and operation of a wind turbine comprising a damper comprising a fluid-filled container. Summary of the invention

[0008] This problem is solved by a method for monitoring a fluid-filled damper of a wind turbine according to claim 1 , a leakage monitoring device according to claim 11 and a wind turbine according to claim 13 .

[0009] According to the method for monitoring a fluid-filled damper of a wind turbine, a pressure value within the fluid-filled damper of the wind turbine is measured. Since the fluid-filled damper contains a vacuum when it is operating correctly, an increase in pressure in the fluid-filled damper indicates that the damper contains a leak, which may degrade the damping performance of the damper.

[0010] Furthermore, the pressure value is compared with a predetermined threshold value and, if it is detected that the threshold value has been exceeded, an idle state of the rotor of the wind turbine is initiated. The threshold value is selected such that safe operation is ensured if the threshold value is not exceeded. Activating the idle state of the rotor means that the rotor blades are fully turned into the feathered position, i.e. they are turned "out of the wind", so that lift is lost and the rotor stops.

[0011] Advantageously, the fluid filled damper is automatically monitored and if a leak is detected the wind turbine is automatically stopped. Advantageously, any damage or increased wear of the wind turbine is avoided. Furthermore, periodic manual inspections of the fluid damper can be omitted and operation of the wind turbine with a faulty fluid filled damper between inspections is avoided.

[0012] The leakage monitoring device according to the invention comprises a pressure measuring sensor for measuring a pressure value within a fluid-filled damper of a wind turbine, wherein a pressure increase in the fluid-filled damper indicates that the damper comprises a leak. For measuring the pressure value within the fluid-filled damper, the pressure measuring sensor is preferably arranged in a container comprised by the fluid-filled damper. Furthermore, the leakage monitoring device comprises a control unit for comparing the measured pressure value with a predetermined threshold value and for initiating an idle state of the rotor of the wind turbine if it is detected that the threshold value has been exceeded and a leak has been detected. The leakage monitoring device shares the advantages of the described method for monitoring a fluid-filled damper of a wind turbine.

[0013] The wind turbine according to the invention comprises a wind turbine nacelle and a tower on which the wind turbine nacelle is arranged. Furthermore, the wind turbine according to the invention comprises a rotor rotatably mounted on the wind turbine nacelle. Furthermore, the wind turbine comprises a fluid-filled damper installed in the tower of the wind turbine and a leakage monitoring device according to the invention. Furthermore, the wind turbine according to the invention comprises a safety pitch system, which is activated by the leakage monitoring device based on a measured pressure value in the fluid-filled damper. The wind turbine according to the invention shares the advantages of the leakage monitoring device.

[0014] Particularly advantageous embodiments and features of the invention are given by the dependent claims, as revealed in the following description. Features of different claim categories can be combined as appropriate to give further embodiments not described herein.

[0015] According to a variant of the method of the invention for monitoring a fluid-filled damper of a wind turbine, the fluid-filled damper comprises a fluid container comprising a damper fluid and a vacuum. If a leak occurs, the pressure in the container increases. In order to detect such a leak immediately, preferably, a pressure measuring sensor is arranged in the container of the fluid-filled damper so that the pressure increase in the container acts directly on the pressure measuring sensor. It has to be mentioned that a wind turbine usually comprises more than one single fluid-filled damper for reducing the movement of the tower of the wind turbine. Therefore, preferably, each of these fluid-filled dampers comprises a fluid container containing a damper fluid and a vacuum.

[0016] Preferably, the pressure measurement sensor comprises a pressure transducer. The pressure transducer measures a pressure value and generates a signal representing the measured pressure value.

[0017] If the wind turbine comprises more than one fluid filled damper, it is preferred that more than one, preferably each fluid damper is monitored by a pressure measuring sensor, wherein a pressure measuring sensor is arranged in or on each of these fluid filled dampers.

[0018] Preferably, in the method for monitoring a fluid-filled damper of a wind turbine, the comparison between the measured pressure value and the threshold value is performed by a control unit. The control unit may be implemented as a central control unit for a plurality of pressure measuring sensors. Alternatively, if a plurality of pressure measuring sensors are used to monitor a plurality of fluid-filled dampers, the control unit may be implemented as a plurality of control units, wherein each single one of these control units is assigned to a different pressure measuring sensor. Using a single central control unit has the advantage that the number of control units for monitoring the fluid-filled dampers and for initiating a reaction to a possible detected leak in one of these fluid-filled dampers is reduced. Using a plurality of control units in parallel has the advantage that in the event of a failure of only one control unit or a subset of these control units, the other correctly functioning control units may further continue to monitor the fluid-filled dampers assigned to the correctly functioning control unit.

[0019] In another variant of the method according to the invention, the control unit comprises a programmable control unit. Advantageously, the control unit can be adapted to different application scenarios by programming the control unit individually.

[0020] Preferably, the programmable control unit comprises a turbine safety PLC (PLC=Programmable Logic Controller). Advantageously, this turbine safety PLC is basically technically arranged to control the pitch of the rotor and to initiate an idle state of the rotor of the wind turbine for safety reasons, and enables such an analysis of the pressure values ​​and possible safety reactions to be controlled by the same technical unit. Due to said dual functionality of the control unit, the number of electronic computing devices is minimized.

[0021] Preferably, the control unit is used for starting the idle state of the rotor of the wind turbine. As mentioned above, in this variant, the control unit is used for the analysis of the pressure values ​​and enables possible safety reactions to be controlled by the same technical unit. Thus, the number of electronic computing devices is minimized.

[0022] Preferably, the wind turbine comprises a tower and the fluid filled damper is installed in the tower of the wind turbine. Advantageously, the damper has the function of reducing tower vibrations caused by the movement of the rotor and the nacelle, so that the possibility of damage and high wear of the tower structure is reduced.

[0023] In one variant of the method for monitoring a fluid-filled damper of a wind turbine according to the invention, an idle state of the rotor of the wind turbine is initiated by controlling a safety pitch system installed on the rotor of the wind turbine. Such a safety pitch system enables the rotor blades of the wind turbine to be turned "out of the wind", so that the rotor blades are stationary and movements and vibrations of the tower caused by the movement of the rotor blades are avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. However, it is to be understood that the drawings are designed for illustrative purposes only and are not intended to be limiting of the present invention. They are not necessarily drawn to scale.

[0025] Figure 1 shows a schematic cross-sectional view of a wind turbine according to an embodiment of the present invention,

[0026] Figure 2 A flow chart illustrating a method according to the present invention for monitoring a fluid-filled damper of a tower of a wind turbine is shown,

[0027] Figure 3 A block diagram illustrating a leakage monitoring device according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0028] exist Figure 1In FIG. 1 , a schematic cross-sectional view of a wind turbine 10 according to an embodiment of the invention is shown. The wind turbine 10 comprises a tower 8 on which a nacelle 7 is mounted, the nacelle 7 carrying a wind propeller, i.e. a rotor 5. The upper part of the tower 8 comprises a plurality of fluid-filled dampers 1, in particular fluid-filled damper containers, which contain a fluid and are evacuated. Also, in each of these fluid damper containers, a pressure measuring sensor 2 is mounted, which is arranged to measure a pressure value PV in the assigned fluid damper container. Each of these pressure measuring sensors 2 is electrically connected to a control unit 3, in particular a turbine safety PLC. The control unit 3 determines whether the measured pressure value PV exceeds a predetermined pressure difference threshold TH, and if this threshold TH is exceeded, the control unit 3 controls a dedicated safety pitch system 4, so that the wind turbine 10 enters an idle safety state. The signal for initiating the idle safety state is transmitted via a contactor 3a between the nacelle 7 and the rotor 5.

[0029] exist Figure 2 In FIG. 2 , a flow chart 200 is shown, which depicts a method for monitoring a fluid-filled damper 1 of a wind turbine 10 according to an embodiment of the present invention. In step 2.I, the fluid-filled damper 1 is monitored using a pressure measuring sensor 2. In step 2.II, the measured pressure value PV is transmitted from the pressure measuring sensor 2 to a control unit 3, in particular a turbine safety PLC. In step 2.III, the control unit 3 compares the received pressure value PV with a predetermined threshold value TH. If the pressure value PV exceeds the threshold value TH, this is Figure 2 In step 2.IV, the wind turbine 10 is brought into the idle safety state IS by sending a control signal from the control unit 3 to the safe pitch system 4 of the wind turbine. If the pressure value PV does not exceed the threshold value TH, this Figure 2 denoted by “y” in the figure, the monitoring of the fluid-filled damper 1 continues with step 2.I.

[0030] exist Figure 3 In FIG. 1 , a block diagram illustrating a leakage monitoring device 6 according to an embodiment of the present invention is shown. The leakage monitoring device 6 comprises a plurality of pressure measuring sensors 2, wherein each of these pressure measuring sensors 2 is installed in a fluid-filled damper 1 ( Figure 1 The pressure measuring sensor 2 is electrically connected to a control unit 3, in particular a turbine safety PLC, which compares the measured value (i.e., the pressure value PV) with a threshold value TH. Furthermore, the leakage monitoring device 6 also comprises two contactors 3a, which are contactors ( Figure 1). These contactors 3a are redundant for increasing the robustness of the safety pitch system in the event of a failure of one of the contactors 3a. For this reason, two contactors 3a are installed. In addition, on the rotor 5 of the wind turbine 10, a safety pitch system 4 is arranged for changing the state of the rotor 5 of the wind turbine 10 to the idle state in the event of a leakage detected by the control unit 3.

[0031] Although the present invention has been disclosed in the form of preferred embodiments and variations thereon, it will be appreciated that many additional modifications and variations can be made thereto without departing from the scope of the present invention. For the sake of clarity, it is to be understood that the use of "a", "an" or "an" throughout this application does not exclude a plurality, and "comprising" does not exclude other steps or elements.

Claims

1. A method for monitoring a fluid-filled damper (1) of a wind turbine (10), comprising the following steps: - measuring a pressure value (PV) within the fluid-filled damper (1) of the wind turbine (10) using a pressure measurement sensor (2), wherein an increase in pressure in the fluid-filled damper indicates that the damper comprises a leak, - comparing said pressure value (PV) with a predetermined threshold value (TH), - if it is detected that the threshold value (TH) has been exceeded and a leakage is detected, an idle state of the rotor (5) of the wind turbine (10) is initiated.

2. The method according to claim 1, wherein: The fluid-filled damper (1) comprises a fluid container comprising a damper fluid and a vacuum.

3. The method according to claim 1 or 2, wherein: The pressure measuring sensor (2) is installed in the fluid-filled damper (1).

4. A method according to any one of the preceding claims, wherein: The pressure measuring sensor (2) comprises a pressure transmitter.

5. A method according to any one of the preceding claims, wherein: The comparison between the measured pressure value (PV) and the threshold value (TH) is performed by a control unit (3).

6. The method according to claim 5, wherein: The control unit (3) comprises a programmable control unit.

7. The method according to claim 6, wherein: The programmable control unit (3) comprises a turbine safety programmable logic controller.

8. The method according to any one of claims 5 to 7, wherein: The control unit (3) is used to activate an idle state of a rotor (5) of the wind turbine (10).

9. A method according to any one of the preceding claims, wherein: The wind turbine (10) comprises a tower (8), and the fluid-filled damper (1) is installed in the tower (8) of the wind turbine (10).

10. A method according to any one of the preceding claims, wherein: The idle state of the rotor (5) of the wind turbine (10) is initiated by controlling a safety pitch system (4) installed on the rotor (5) of the wind turbine (10).

11. A leakage monitoring device (6), comprising: a pressure measuring sensor (2) for measuring a pressure value (PV) inside a fluid-filled damper (1) of a wind turbine (10), wherein an increase in pressure in the fluid-filled damper indicates that the damper comprises a leak, - a control unit (3) for comparing the pressure value (PV) with a predetermined threshold value (TH) and for initiating an idle state of the rotor (5) of the wind turbine (10) if it is detected that the threshold value (TH) has been exceeded and a leak has been detected.

12. The leakage monitoring device (6) according to claim 11, wherein: The control unit (3) comprises a turbine safety programmable logic controller.

13. A wind turbine (10) comprising: - a wind turbine nacelle (7), - a tower (8) on which the wind turbine nacelle (7) is arranged, - a rotor (5) rotatably mounted on the wind turbine nacelle (7), - a fluid-filled damper (1) installed in said tower (8), - a leakage monitoring device (6) according to claim 11 or 12, - a safety pitch system (4) arranged to be activated by the leakage monitoring device (6) based on a measured pressure value (PV) in the fluid-filled damper (1).

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