Safety chain and method for operating a wind turbine

Abstract

A blade adjusting device for a wind turbine is connected to a plant safety chain and can open and close the plant safety chain by activating a switch. If a fault is detected in one of the blade adjusting devices, the respective control unit can open the plant safety chain. By opening the safety chain, a signal is sent to the blade adjusting devices, and so all the blade adjusting devices initiate a synchronous safety operation of at least two rotor blades when the signal is received.

Claims

1. A blade adjusting device for a rotor blade of a rotor of a wind turbine, Wherein the rotor comprises a hub, at least one rotor blade rotatably mounted on the hub for rotation about a longitudinal axis of the rotor blade, and wherein the rotor is rotatably mounted on a nacelle of the wind turbine, The rotor blade is rotatable by way of the blade adjusting device and arrestable at various pitch positions, The wind turbine comprises a central turbine controller for monitoring and controlling components in the wind turbine, among others the blade adjusting device, And wherein the blade adjusting device comprises an adjusting motor for driving and/or arresting the rotor blade, a converter for driving the adjusting motor, a control unit for controlling the converter and a battery for supplying emergency power to the blade adjusting device, The blade adjusting device comprises a plant safety chain and an internal safety chain integrated in the control unit of the adjusting device, wherein the converter comprises a power supply for generating an internal control voltage (U.sub.int) from the mains voltage (U.sub.N), wherein the power supply is arranged in a DC intermediate circuit of the converter.

2. The blade adjusting device according to claim 1, wherein the plant safety chain comprises at least one switch, the switch is connected to signal outputs of the control unit of the blade adjusting device and of the turbine controller, and the internal safety chain of the control unit and/or of the turbine controller is configured to generate signals for opening and/or closing of the plant safety chain and supply the signals to the switch.

3. The blade adjusting device according to claim 1, wherein the plant safety chain supplies a signal dependent on the state of the plant safety chain to a signal input of the control unit of the blade adjusting device and/or of the turbine controller.

4. The blade adjusting device according to claim 3, wherein the signal can have two different states, wherein the signal has a high voltage value when the plant safety chain is closed and a low voltage value when the plant safety chain is open.

5. The blade adjusting device according to claim 1, wherein the control unit of the converter of the blade adjusting device can be connected to a general external control power supply (U.sub.ext) and to the internal control voltage supply (U.sub.int).

6. The blade adjusting device according to claim 5, wherein the control unit of the converter of the blade adjusting device is supplied from the general external control voltage (U.sub.ext) during startup.

7. The blade adjusting device according to claim 5, wherein the control unit of the converter of the blade adjusting device is supplied from the internal control voltage (U.sub.int) when the internal safety chain is closed.

8. A wind turbine comprising a nacelle rotatably mounted on a tower and a rotor connected via a drive shaft to a generator mounted in the nacelle, wherein the rotor has a hub and at least one rotor blade, the rotor blade is rotatably connected to the hub by a bearing for rotation about its blade axis extending in the axial direction, and the rotor blade can be driven by a blade adjusting device and arrested at different pitch positions, wherein the blade adjusting device is constructed according to claim 1.

9. A method of starting up a wind turbine, wherein the wind turbine comprises a blade adjusting device according to claim 1, the rotor blades are in the starting position in the vane position, and the method comprises the following steps: Supplying the control unit of the converter of the blade adjusting device via a general external control voltage supply U.sub.ext, Starting the converter Checking the functionality of the converter and/or of the other components of the blade adjusting device with the control unit the blade adjusting device, Connecting the battery and the mains power (U.sub.N), Performing a functional test of the battery and of the mains power (U.sub.N) with the control unit of the adjusting device, When no faults are present, generating an internal control voltage (U.sub.int) by using the power supply arranged in the DC intermediate circuit of the converter, Performing a functional test of the internal control voltage supply U.sub.int with control unit of the blade adjusting device, When the internal control voltage supply U.sub.int is in order, switching over from the general external control voltage supply (U.sub.ext) to the internal control voltage (U.sub.int) and closing the internal safety chain, When the internal safety chains of the blade adjusting devices are closed and the turbine controller system also reports operational readiness, closing the plant safety chain, Setting the signal in the plant safety chain to high for unblocking departure from the vane position.

10. The method according to claim 9, wherein the method in normal operation of the wind turbine comprises the following steps: Monitoring critical functions of the converter and/or of the components of the blade adjusting device with the control unit of the blade adjusting device, Transmitting the state of the blade adjusting device to the turbine controller, upon detection of a fault condition: The blade adjusting devices are controlled by the turbine controller to initiate a slow synchronous movement toward the vane position, The blade adjusting devices remain connected to the internal power supply (U.sub.int) during the safety operation and in the vane position, Checking the function of the converter and/or of the components of the blade adjusting device and, when everything is in order, attempting another startup.

11. The method according to claim 9, wherein in event of failure of the mains voltage the method includes the following steps: Battery for supplying emergency power to the blade adjusting device is connected, Safety operation of the blade adjusting devices is controlled by the turbine controller When reaching the vane position, the battery is disconnected after a predetermined time, and the external common power supply (U.sub.ext) is switched on, For critical faults, switching to the external general power supply (U.sub.ext) before the predetermined time has elapsed and opening the plant safety chain, Checking the function of the converter and/or of the other components of the blade adjusting device and, if everything is in order, repeat the startup.

12. The method according to claim 9, wherein for critical faults, such as failure of the turbine controller, or a critical fault in the blade adjusting device, the method comprises the following steps: Detecting a fault condition with the control unit of the adjusting device, Opening the internal safety chain in the control unit and thus opening the plant safety chain, The signal is set to low by opening the plant safety chain, When receiving the low signal, simultaneous safety operation of the blade adjusting devices.

Description

(1) In the drawings:

(2) FIG. 1 shows a wind turbine,

(3) FIG. 2 shows an adjusting device of the wind turbine,

(4) FIG. 3 shows the functionality of the internal safety chain in the controller of the blade adjusting device, and

(5) FIG. 4 shows a plant safety chain of the wind turbine.

(6) FIG. 1 shows a wind turbine 2 with a tower 3, a nacelle 4 rotatably mounted on the tower 3 and a rotor 5 connected via a rotor shaft with a generator disposed in the nacelle 4. The rotor 5 includes a hub 8, three rotor blades 6, each of which being mounted for rotation about a blade axis 7, and a bearing mounted between the hub 8 and the rotor blade 6. Each rotor blade 6 includes a blade adjusting device P1, P2, P3 (FIG. 4) for adjusting the pitch position of the rotor blade 6, and a brake for holding the rotor blade in a desired pitch position. The blade adjusting device P1, P2, P3 includes an adjusting motor 9, a drive pinion 11 disposed on an output shaft 10 of the adjusting motor 9, a sprocket wheel in engagement with the drive pinion 11, a converter 12 for supplying a current and/or a voltage to the adjusting motor 9, and a control unit 13 for controlling and/or regulating the converter 12.

(7) FIG. 2 shows the blade adjusting device P1, P2, P3 of the wind turbine 2. The rotor blade 6 is adjusted via the adjusting motor 9 connected to the hub 8, wherein the adjusting motor 9 moves the rotor blade 6 that is rotatably supported on the hub 8 via a drive pinion 11 that can be mounted on a drive shaft 10 of the adjusting motors 9. A converter 12 supplies an operating voltage to each of the blade adjusting devices P1, P2, P3. Each of the blade adjusting devices P1, P2, P3 also includes a control unit 13 for controlling or regulating the operating voltage supplied to the adjusting motor 9 by the converter 12 and for monitoring the status and functions of the components in the blade adjusting device P1, P2, P3. In this exemplary embodiment, the control unit 13 is integrated in the converter 12.

(8) The blade adjusting device P1, P2, P3 is started up by supplying a general external control voltage U.sub.ext to the control unit 13 of the converter 12 of the blade adjusting device P1, P2, P3. After the control unit 13 has started the converter 12, the mains supply U.sub.N and the battery 21 is switched on to supply emergency power to the blade adjusting device P1, P2, P3. After the battery 21 and the power supply U.sub.N have been checked for faults and if there are no faults, the converter 12 of the blade adjusting device P1, P2, P3 generates from the mains voltage U.sub.N an internal control voltage U.sub.int with the power supply 25 arranged in the DC intermediate circuit 27. After checking the internal control voltage U.sub.int and if no faults are detected, a switch 26 is actuated to switch from the general external control voltage U.sub.ext to the internal control voltage, and the control unit 13 of the converter 12 is supplied with the internal control voltage U.sub.int. The switch 26 may hereby be connected to the control unit 13 and may be controlled by the control unit 13. To stop the blade adjusting process, the control unit 13 is connected to a several limit switches 14 which transmit a signal to the control unit 13 when a certain pitch position is reached. The functionality of the components of the blade adjusting device P1, P2, P3 is monitored by an internal safety chain 23 which is integrated in the control unit 13.

(9) FIG. 3 shows the functionality of the internal safety chain 23 that is integrated in the control unit 13 of the converter 12. To check the functionality and the status of the components of the blade adjusting device P1, P2, P3, the control unit 13 sends at step (1) a query to the respective components of the blade adjusting device P1, P2, P3. The components respond to this query with the respective operating parameters x.sub.1-n. At step (2), the operating parameters x.sub.1-n are compared with threshold values y.sub.11-1n and y.sub.2-2n stored in a memory module of the control unit 13. The operating parameters may include conditions such as temperature, position, voltage, vibrations and rotational speed and controls that the status lies in the permitted range defined by the threshold values y.sub.11-1n and y.sub.21-2n. When the monitored operating parameters are in order, a signal is sent to the switch 17 to close the plant safety chain 1; otherwise, a signal to open the plant safety chain is sent to the switch 17. The control unit 13 also indicates operational readiness to the turbine controller 15, i.e. absence of faults.

(10) FIG. 4 shows a plant safety chain 1 with the blade adjusting devices P1, P2, P3 of the three rotor blades 6, a turbine controller 15 and the communication paths of the components. The blade adjusting devices P1, P2, P3 are connected via their control units 13 to the turbine controller 15 via the communication path 24 and can both transmit data to the turbine controller 15, as well as receive data from the turbine controller 15. In normal operation of the wind turbine 2, the communication and the regulation of the blade adjusting devices P1, P2, P3 is routed via the communication path 24. In addition to the communication between the control unit 13 and the turbine controller 15, the internal safety chains 23 integrated in the control units 13 of the blade adjusting devices P1, P2, P3 and the turbine controller 15 are connected to the plant safety chain 1 via at least one switch 17, allowing them to open and/or close the plant safety chain 1. Additional systems may also be connected to the switch 17 for opening and/or closing the plant safety chain 1. These systems may include, for example, a chain 18 of emergency stop switches 19 for manually opening the plant safety chain 1 or a sensor 20 for monitoring operating parameters of the wind turbine 2, such as temperature, vibration and/or rotational speed. Advantageously, the systems for opening and/or closing the plant safety chain are each connected to the plant safety chain 1 via a dedicated switch 17. The plant safety chain 1 is connected to the signal inputs 16 of the blade adjusting devices P1, P2, P3 and of the turbine controller 15. When the plant safety chain is closed, a signal having a high voltage is sent from the plant safety chain 1 to the control unit 13 of the blade adjusting devices P1, P2, P3 to release a blade adjusting process. When the plant safety chain 1 is open, no current flows through the plant safety chain 1 and consequently no voltage is applied to the components connected to the plant safety chain 1. The voltage of the signal thus changes from a high to a low value when the plant safety chain 1 is opened. When the control units 13 of the blade adjusting devices P1, P2, P3 receive a low signal from the plant safety chain 1, the release of the blade adjustment is canceled and the blade adjusting device P1, P2, P3 remains in vane position or initiates a safety operation unless the rotor blades 6 are already in the vane position.

(11) When the wind turbine 2 is switched-off, the rotor blades 6 are in the vane position and both the internal safety chains of the blade adjusting devices P1, P2, P3 and the plant safety chain 1 are open. Because the converter 12 is unable to generate a control voltage from the mains voltage U.sub.N when starting from an off-state, the blade adjusting device P1, P2, P3 is powered for startup from a general external control voltage U.sub.ext. Before the rotor blades 6 are able to exit the vane position, the state of the converter 12 and of the other components of the blade adjusting devices P1, P2, P3 is checked. If no faults are present in the blade adjusting devices P1, P2, P3, the control unit 13 of the blade adjusting device P1, P2, P3 switches the supply voltage U.sub.N and the battery 21 on to supply emergency power to the blade adjusting device. Thereafter, the battery 21 and the connection to the power mains are checked by the control unit 13 for faults.

(12) When there are no faults, the converter switches from the external power supply switches U.sub.ext to the internal control voltage U.sub.int generated by the power supply 25 disposed in the DC intermediate circuit 27. The internal control voltage supply U.sub.int is designed so that the control voltage supplies of the blade adjusting devices P1, P2, P3 are galvanically isolated from each other and a fault in one of the control voltage supplies can not affect the other control power supplies. The functions of the blade adjusting device P1, P2, P3 are checked once more and if everything is in order, the general external control supply voltage U.sub.ext is switched off and the internal control voltage supply U.sub.int is switched on. Thereafter, the internal safety chain in the blade adjusting device is closed. The control unit 13 then sends a signal to the switch 17 to close the plant safety chain 1 and a signal to notify the turbine controller 15 of the operational readiness.

(13) The plant safety chain 1 is closed when the turbine controller 15 and other components connected to the plant safety chain 1, such as for example at least one sensor 20 measuring the rotational speed and/or vibrations and the chain 18 of emergency stop switches 19, also report operational readiness. When the plant safety chain 1 is closed, a current can again flow through the plant safety chain and a signal having a high voltage is present at the signal inputs 16 of the control units 13 connected to the plant safety chain 1. When a high signal is present at the signal input 16 of the control unit 13 of the blade adjusting devices P1, P2, P3, the blade adjusting devices P1, P2, P3 have permission to move the rotor blade 6 out of the vane position, and the wind turbine 2 can be started.

(14) During the operation of the wind turbine 2, the status of blade adjusting devices P1, P2, P3 is normally transmitted continuously by the respective control units 13 to the turbine controller 15. If one of the blade adjusting devices P1, P2, P3 fails, then this event is communicated to the turbine controller 15. The turbine controller then commands either via the direct connection 24 or via the switch 17 a synchronous movement of the rotor blades 6 toward the vane position.

(15) When the power mains fail, the emergency supply of the blade adjusting device P1, P2, P3 is switched on by the battery 21. The battery is connected to the DC intermediate circuit of the converter 27 and is hence able to supply both an operating voltage to the adjusting motor 9 via the converter 12 as well as a control voltage to the control unit 13 via the power supply 25. The blade adjusting device P1, P2, P3 can then move the rotor blades 6 into the vane position despite a failure of the mains voltage.

(16) For critical faults, for example when the turbine controller 15 fails or when the communication between the turbine controller 15 and the control unit 13 of the blade adjusting device P1, P2, P3 is faulty or interrupted, the plant safety chain 1 can be opened by one of the controllers 13. When the plant safety chain is opened, the signal is set to low and the blade adjusting devices P1, P2, P3 synchronously initiate a safety operation upon receiving the low signal at the signal input 16 of the control unit 13. When all control units 16 of the blade adjusting devices P1, P2, P3 fail, the plant safety chain 1 can also be opened by the at least one sensor 20 or by the chain 18 of emergency stop switches 19.

(17) The combinations of features disclosed in the described exemplary embodiments are not intended to limit the scope of the invention; instead, the features of different embodiments can also be combined.

LIST OF REFERENCE SYMBOLS

(18) TABLE-US-00001 1 plant safety chain 2 Wind turbine 3 Tower 4 Nacelle 5 Rotor 6 Blade 7 Blade axis 8 Hub 9 Adjusting motor 10 Power 11 Drive pinion 12 Converter 13 Control unit 14 Limit switch 15 Turbine controller 16 Signal Input 17 Switch 18 Chain of emergency stop switches 19 Emergency stop switch 20 Sensor 21 Battery 22 Signal output 23 Internal safety chain 24 Communication path 25 Power supply 26 Switch 27 DC intermediate circuit P1 Blade adjusting device P2 Blade adjusting device P3 Blade adjusting device U.sub.N Mains voltage U.sub.ext External control voltage supply U.sub.int Internal control voltage supply