METHOD FOR OPERATING A WINDMILL, WINDMILL AND COMPUTER PROGRAM PRODUCT

Abstract

The invention relates to a method for operating a wind turbine (1), a wind turbine (1) designed to carry out the method, and a computer program product. The method according to the invention for operating a wind turbine (1), in which at least one measured value is observed over a predefined monitoring time period for the system start of the wind turbine (1) on request and the system start occurs only if the at least one measured value in the monitoring time period corresponds to defined specifications, is characterized by the fact that the at least one measured value is continuously stored in a data memory, wherein the storage time period in the data memory corresponds at least to the specified monitoring time period; and in the event of a request for a system start it is checked by means of the data memory whether the at least one measured value corresponds to the defined specifications (16) in the time before the request corresponding to the monitoring time period. The wind turbine (1) according to the invention and the computer program product according to the invention are designed to carry out this method.

Description

Method for operating a wind turbine, wind turbine and computer program product. The invention relates to a method for operating a wind turbine, a wind turbine designed to carry out the method and a computer program product. Wind turbines are known from the prior art. They generally comprise a rotor that is rotatably mounted on a nacelle, which in turn is rotatably mounted on a tower. The rotor may drive a generator via a rotor shaft and a gearbox. Wind-induced rotation of the rotor can thus be converted into electrical energy, which can then be transmitted via inverters and / or Transformers – depending on the generator design, sometimes even partially directly – allow the power to be fed into an electrical grid. If a wind turbine stops generating or feeding power into the grid, for example due to a fault in the grid or the wind turbine itself, or because the grid operator requests it, the wind turbine is put into idle or spin-down mode. If the wind turbine is to be restarted after the fault has been rectified or at the request of the grid operator, the state of the art routinely monitors the wind conditions at the turbine for a certain period after the fault has been resolved or after the request has been received. Such a check over a period of, for example, two minutes is necessary to rule out the possibility that a sufficient wind speed for starting the turbine is assumed solely based on a gust of wind. The latter could occur, for example, if only the currently measured wind speed were checked at startup.Since each start-up of a wind turbine can place a considerable strain on individual components, monitoring wind conditions over a certain period before the rotor actually starts ensures that the turbine is not unsuccessfully attempted to start due to a gust of wind. A disadvantage of this technology is that after a fault in the wind turbine or the grid has been resolved, or after a request from the grid operator, a certain period of time, e.g., two minutes or more, elapses before the wind turbine actually starts up to feed electrical energy into the grid. The invention is based on the objective of creating a method for operating a wind turbine, a wind turbine and a computer program product in which the disadvantages of the prior art no longer occur or only occur to a reduced extent. This problem is solved by a method for operating a wind energy plant according to the main claim, a wind energy plant according to claim 10, and a computer program product according to claim 12. Advantageous further developments are the subject of the dependent claims.Accordingly, the invention relates to a method for operating a wind turbine, wherein, for the start-up of the wind turbine on request, at least one measured value is observed over a predetermined monitoring period, and the turbine start only occurs if the at least one measured value in the monitoring period corresponds to defined specifications, wherein the at least one measured value is continuously stored in a data storage device, the storage period in the data storage device corresponding at least to the predetermined monitoring period; and, upon a request for a turbine start, it is checked using the data storage device whether the at least one measured value in the period corresponding to the monitoring period before the request corresponds to the defined specifications. The invention further relates to a wind turbine comprising a rotor with several rotor blades, which is rotatably arranged on a nacelle rotatably mounted on a tower and connected to a generator arranged in the nacelle for converting wind energy acting on the rotor into electrical energy, and a control device for controlling the wind turbine and its components, wherein the wind turbine further comprises at least one sensor for detecting at least one measured value, a data storage device for continuously storing the at least one detected measured value for a storage period, and a verification module for checking, upon a request for a turbine start, whether the at least one measured value corresponds to defined specifications within the period prior to the request, corresponding to a predetermined monitoring period.where the storage period corresponds at least to the specified monitoring period, and the control device is designed such that the wind turbine is only started if the result of the check by the verification module is positive. The invention further relates to a computer program product comprising program parts which, when loaded into a computer, are designed to carry out the method according to the invention. First, some terms used in connection with the invention will be explained. "Plant start-up" refers to the transfer of a wind turbine into a production operation, during which kinetic energy is generated. Wind energy is converted into electrical energy, which is fed into the grid. A wind turbine does not feed any electrical power generated from the kinetic energy of the wind into the grid before it starts up. The wind turbine may be disconnected from the grid at this time. However, it is not impossible for a wind turbine to be connected to the grid before it starts up and, for example, be used to regulate reactive power in the grid. Typical reasons why a wind turbine does not feed in electrical power generated from the kinetic energy of the wind include, for example, excessively high or low wind speeds, malfunctions and technical defects of the wind turbine, grid faults, and maintenance and repair work on the turbine. The cause could be a wind turbine or a component in the distribution network, shadow flicker, or icing. In such cases, the rotor blades are typically tilted into a feathered position, so that the rotor no longer rotates or only rotates at a very low speed (idle speed). It is also possible that the rotor is locked in place by a brake. In the context of the invention, “continuous storage” means that the measured values ​​to be stored are stored continuously and independently of the operating state of the wind turbine, i.e. both during the feeding of electrical power into the grid by the wind turbine and during the times in which the wind turbine does not feed any electrical power generated from the kinetic energy of the wind into the grid. A "request to start up a wind turbine" can be a request submitted by the operator of the wind turbine, the operator of the grid into which the wind turbine feeds the electricity it generates, or by an electricity broker in the case of direct marketing of the energy. However, it can also be an automatically generated request, triggered, for example, after a fault in the wind turbine or the grid has been rectified, after successful completion of maintenance and repair work, or due to suitable wind conditions.The invention offers the advantage that, when a wind turbine start-up request is received, the measured values ​​required for starting the turbine are retrospectively available over a certain monitoring period. This allows the system to verify, immediately after the start-up request, that the basic prerequisites defined by the specifications are met, based on the previously stored measured values. Therefore, it is possible to check immediately upon receiving the start-up request whether the requested start-up can be carried out. The waiting time of, for example, two minutes, which is regularly required in the prior art, can be eliminated. In principle, it is possible to implement the data storage as a mass storage device. However, it is preferable for the data storage to be a ring buffer. A ring buffer continuously stores data over a certain period and overwrites it after a predetermined storage period has elapsed. This allows the storage space occupied by data older than the predetermined storage period to be used for newer, more current data. The ring buffer can be implemented as a ring buffer. By using a ring buffer, complex storage logic or large mass storage devices that record historical data over long periods can be avoided. The defined parameters that must be met by at least one measured value during the monitoring period can be, for example, absolute or relative minimum and / or maximum values. It is also possible that parameters exist regarding the maximum permissible change of the at least one measured value over the monitoring period. Such parameters can be defined by a maximum permissible spread of the measured values, a maximum permissible gradient, and / or a maximum permissible standard deviation. It is preferred that at least two measured values ​​are continuously stored in the data memory and checked when a system start-up is requested. The monitoring period and / or the storage period for the at least two measured values ​​can be the same. However, it is also possible that the monitoring period and / or the storage period are individually defined for each measured value.If two or more measured values ​​are checked for a system start-up, the specifications for these values ​​can also be combined. For example, the specifications for one measured value can depend on another, with this dependency being defined beforehand. More complex dependencies for specifications and / or measured values ​​are also possible, which can be expressed, for example, as an (in)equation with a number of variables corresponding to the number of measured values, or as characteristic curves. At least one measurement can reflect information about the environment of the wind turbine, e.g., the wind conditions, or the condition of the wind turbine itself. In particular, at least one measurement can reflect at least one The measured value comprises a group of parameters including wind direction, wind speed, nacelle azimuth position, tower head acceleration, tower vibration signals, grid parameters (in particular voltage and frequency), and / or ambient temperature or temperature of individual components of the wind turbine. The measured value can be obtained directly from data of a sensor capable of acquiring the information in question. A possible conversion of the sensor data into measured values ​​is not excluded. It is also possible that the measured value provided according to the invention is a hybrid measured value in which various pieces of information, such as data from several sensors, are bundled and / or combined. The monitoring period for at least one measurement can be at least approximately 60 seconds, preferably at least approximately 120 seconds. A corresponding monitoring period can be useful, for example, for measuring wind direction and / or wind speed. For other measurements, e.g., the Tower head acceleration and / or tower vibration signals can be used, but monitoring periods of approximately 10 seconds or preferably approximately 20 seconds may also be sufficient. It is preferred if reference data is continuously stored in the data storage over a storage period, wherein the reference data is suitable for verifying the plausibility of the at least one measured value and the storage period of the reference data corresponds at least to the monitoring period of the at least one measured value to be verified. The reference data can be measured values ​​from the wind turbine or information acquired via sensors, which, while not themselves requiring verification against defined specifications when a turbine start-up is requested, are suitable for verifying the plausibility of the measured values ​​that must be verified accordingly. The reference data can also be externally supplied data, e.g., from...This involves a weather station separately installed from the wind turbine. The reference data can be used to verify the plausibility of the continuously recorded measurements. It is also possible to use the reference data and / or the measurements themselves to check each other's plausibility. Furthermore, the measurements can be directly validated using maximum or minimum values, maximum permissible gradients, maximum permissible standard deviations, or similar parameters, potentially even without reference to the data. The plausibility check of the measured values ​​and / or reference data to be stored or already stored in the data storage can be performed either during continuous storage or when checking at least one measured value upon request for a system start. By checking the plausibility of the measured values ​​and / or reference data during storage, a potentially time-consuming plausibility check is no longer necessary when a system start is requested, thus enabling a faster system start. If a plausibility check is only performed upon request for a system start, simple patterns in the measured values ​​and / or reference data, such as oscillations, may be detected that could prevent a system start. If a plausibility issue is detected, it is preferable to clear the data memory. Simultaneously, if possible, the sensors for those measured values ​​and / or reference data for which a plausibility issue was detected can be re-initialized. By clearing the data memory, the verification that at least one measured value meets the defined specifications cannot usually be successfully completed until the monitoring space for that at least one measured value in the data memory is completely filled with measured values. Particularly after a re-initialization of the affected sensors, this effectively prevents a system start-up based on faulty measured values ​​and / or reference data. The plausibility of measured values ​​and / or reference data can be verified by checking maximum and / or minimum values, and / or gradients, mean values, and / or standard deviations, whereby corresponding target values ​​may be defined depending on other measured values ​​and / or reference data. The corresponding target values ​​are predefined. The reference data can include, for example, the angle of attack of the rotor blades and / or the rotor speed. The wind turbine according to the invention is designed to carry out the method according to the invention. For an explanation of the wind turbine and advantageous further developments of the wind turbine, reference is made to the preceding explanations. Reference is also made to the preceding explanations for an explanation of the computer program product according to the invention. The invention will now be described by way of example with reference to the accompanying drawings, using a preferred embodiment as an example. The drawings show: Figure 1: a first embodiment of a wind turbine according to the invention; and Figure 2: a schematic representation of the monitoring module and the data storage of the wind turbine from Figure 1. Figure 1 schematically shows a wind turbine 1 according to the invention. The wind turbine 1 comprises a rotor 2 with several rotor blades 3, the angle of attack of which can be adjusted, and which is rotatably mounted on a nacelle 4. The nacelle 4 is in turn rotatably mounted on a tower 5. The rotor 2 drives a gearbox 6 via the rotor shaft, which is connected to a generator 7 on its output side. A wind-induced rotational movement of the rotor 2 can thus be converted into electrical energy, which can then be fed into an electrical grid 9 via inverters (not shown) and / or transformers 8. The wind turbine 1 also includes a control unit 10, which is connected to the various components of the wind turbine 1 via control lines (not shown) in order to control them. Among other things, the control unit 10 is designed to align the rotor 2 with the wind by rotating the nacelle 4 relative to the tower 5. The control unit 10 also regulates the pitch angle of the rotor blades 3 and the electrical power fed into the grid 9. By changing the pitch angle of the rotor blades 3 and the electrical power fed into the grid 9, the control unit 10 can influence the rotor torque and the generator torque, respectively. The control unit 10 is connected to various sensors 11 to perform the desired control tasks. One of these sensors 11 is the wind sensor 11, which determines the wind direction and wind speed. Furthermore, an acceleration sensor 11λλ is connected to the control unit, which detects the tower head acceleration. An additional acceleration sensor 11λλλ is also provided at approximately half the height of the tower 5, which can detect vibration modes of the tower 5 that cannot be detected by the acceleration sensor 11λλ alone. Information about the state of the electrical network 9 can be acquired via the voltage sensor 11IV. The sensor 11v detects the rotational speed of the rotor 2. In addition, further (not shown) sensors 11 can be provided for the nacelle azimuth position – i.e., the angular position of the nacelle 4 relative to the tower 5 – or the pitch angle of the rotor blades 3. The sensors 11 are regularly already provided for the general control of the wind turbine 1 by the control unit 10. According to the invention, a monitoring module 12 is provided as part of the control device 10, which is connected to a data storage device 13. The control device 10 or the monitoring module 12 is designed such that data acquired by at least one of the sensors 11 are continuously stored in the data storage device 13, which is designed as a ring buffer 13λ, for a storage period. If, for example, the wind turbine 1 does not feed any electrical power generated from the kinetic energy of the wind into the grid due to a fault in the grid 9 or in the wind turbine 1 itself, the control unit 10 receives a request to restart after the fault has been rectified. In this case, the monitoring module 12 is designed to check, based on the data stored in the ring buffer 13λ, whether a turbine start is possible. The operation of the monitoring module 12 and the ring buffer 13λ is now explained in more detail with reference to Figure 2. The ring storage 13 λ is constructed in the form of several ring buffers and is supplied, for example, via the control device 10 or via the verification module 12 with the data from the sensors 11 for wind speed (sensor 11 λ), rotor speed (sensor llv), tower head acceleration (sensor 11 λ λ), acceleration at half height of the tower 5 (sensor 11λ λ λ) and rotor speed (sensor llv). These sensor data are continuously stored in separate ring buffers 14 within the ring storage 13λ – regardless of whether the wind turbine is feeding electrical power generated from the kinetic energy of the wind into the grid or not. The data concerning wind speed and rotor speed are stored in ring buffers 14λ and 14v, each with a storage period of 120 seconds; the tower acceleration data from sensors 11λλ and 11λλλ are stored in ring buffers 14λλλ and 14λλλλ with a storage period of 20 seconds. The sectors of the ring buffers 14 shown in Figure 2 only illustrate the length of the storage period of the individual ring buffers 14 in seconds, but not the temporal resolution in which the data of the sensors 11 are available. In particular, the data from sensors 11λλ and 11λλλ concerning the tower acceleration data are available at a high resolution of several measurements per second. It is also possible that the high-resolution tower acceleration data are in a (Not shown) sensor data processing is preprocessed, and only status signals for the tower acceleration are stored in the ring buffer 13 λ at a lower resolution than the high-resolution tower acceleration data. Received data is written to the position of the pointers 15, 15 λ circulating in the 90° direction, so that after a complete revolution of a pointer 15, 15 λ, the data at a The stored data will be overwritten by new data. The rotational speeds of pointers 15 and 15λ are different. Pointer 15 takes 120 seconds for one rotation, while pointer 15λ takes only 20 seconds. The data on wind speed and tower accelerations stored in the ring buffers 14 14 λ λ and 14 λ λ λ are measured values ​​within the meaning of the present invention, while the data stored in the ring buffer 14v are reference data which - as explained below - are used only for plausibility checks of the other data, but not for direct verification of whether a system start-up is permitted. If the control unit 10 of the wind turbine 1, which is not feeding any electrical power generated from the kinetic energy of the wind into the grid, receives a request to restart, the monitoring unit first checks the plausibility of the data currently stored in the ring buffers 14λ and 14v. To do this, it checks whether the wind speeds (ring buffer 14λ) correlate temporally with the rotor speed (ring buffer 14v) – which, in the case of a wind turbine not feeding any electrical power generated from the kinetic energy of the wind into the grid, is the spin-up speed – over the entire storage period. If this is not the case, it may indicate that at least one of the sensors 11λ or 11v is defective. In this case, the monitoring module 12 prevents a turbine start and a warning – e.g.,output via a SCADA system (Supervisory Control and Data Acquisition System) that is not shown. If the plausibility check is successfully completed, the verification module 12 then checks whether the measured values ​​stored in the ring buffers 14 14 λ λ and 14 λ λ λ in the verification module 12 meet the specifications 16 . Additionally or alternatively, plausibility checks can also be performed continuously, i.e., during data storage. Faulty sensors 11 can thus be detected more quickly. Only the case of a corrupt data storage device 13 is then only detectable when the data is read out. For the ring buffer 14 λ, it is checked whether the stored measured values ​​remain within a range defined by a minimum and a maximum value over the entire storage period. By checking the measured values ​​over the entire storage period, the monitoring period for wind speed corresponds to the storage period, i.e., 120 seconds in the illustrated embodiment. The measured values ​​stored in the ring buffers 14 λ λ and 14 λ λ λ relating to the tower accelerations are fed to an analysis module 17 in the verification module 12 over the entire storage period, which thus corresponds to the monitoring period for the tower accelerations, where the energy in the individual mode shapes of the tower 5 is determined from the measured values. For each mode shape, a specification 16 for the maximum vibration energy is available. If all measured values ​​in the ring buffers 14 14 λ λ and 14 λ λ λ correspond to the defined specifications 16 over the respective monitoring period, the test performed by the verification module 12 yields a positive result, whereupon the control unit 10 starts up the wind turbine 1 according to a predefined process. If the test is negative, the wind turbine 1 is not started up initially, and the aforementioned verification of the measured values ​​is carried out until the test is successfully completed. In the event of a negative test result, a corresponding message can also be issued – e.g., via a SCADA system not shown. If the plausibility check described above is not completed successfully, all data in the ring buffers 14 λ and 14v are deleted or set to zero by the verification module, and simultaneously the sensors 11 λ and llv are re-initialized. Consequently, the previously described verification of the measured values ​​from ring buffer 14 λ will remain unsuccessful at least until at least the ring buffer 14 λ is completely filled again with measured values ​​obtained after the re-initialization of sensors 11 and llv.

Claims

Claims Method for operating a wind turbine (1) wherein, for the start-up of the wind turbine (1) on request, at least one measured value is observed over a predetermined monitoring period and the start-up only takes place if the at least one measured value in the monitoring period corresponds to defined specifications, characterized in that at least one measured value is continuously stored in a data storage device (13), wherein the storage period in the data storage device (13) corresponds at least to the specified monitoring period; and when a request is made for a plant start, it is checked using the data storage device (13) whether at least one measured value in the period corresponding to the monitoring period before the request corresponds to the defined specifications (16). Method according to claim 1, characterized by the fact that the data storage (13) is a ring storage (13 λ). Method according to claim 1 or 2, characterized by the fact that at least two measured values ​​are continuously stored in the data storage (13) and checked when a plant start is requested, preferably with different monitoring periods and / or storage periods specified for the at least two measured values. Method according to any of the preceding claims, characterized in that reference data are continuously stored in the data storage (13) over a storage period, wherein the reference data are suitable for plausibility checks of the at least one measured value and the storage period of the reference data corresponds at least to the monitoring period of the at least one measured value to be plausible. Method according to any of the preceding claims, characterized by the fact that During continuous storage or when checking the at least one measured value upon request for a system start, the at least one measured value and / or reference data to be stored or saved in the data storage (13) are checked for plausibility. Method according to claim 4, characterized by the fact that If a plausibility deficiency is detected, the data storage (13) is emptied. Method according to any one of claims 3 to 5, characterized by the fact that Plausibility is checked by verifying maximum and / or minimum values, and / or gradients, means and / or standard deviations. Method according to any one of claims 3 to 6, characterized by the fact that The reference data include the pitch angle of the rotor blades (3) and / or the rotor speed. A method according to any one of the preceding claims, characterized by the fact that which may include at least one measurement from the group consisting of wind direction, wind speed, nacelle zimuth position, tower head acceleration, tower vibration signals and / or ambient temperature or temperature of individual components of the wind turbine (1). Method according to any of the preceding claims, characterized by the fact that The monitoring period is at least 60 seconds, preferably at least 120 seconds. Wind turbine (1) comprising a rotor (2) with several rotor blades (3) rotatably arranged on a nacelle (4) rotatably mounted on a tower (5) and connected to a generator (7) arranged in the nacelle (4) for converting wind energy acting on the rotor (3) into electrical energy, and a control device (10) for controlling the wind turbine (1) and its components, wherein the wind turbine (1) further comprises at least one sensor (11) for recording at least one measured value, a data storage device for the continuous storage of at least one recorded measurement value for a storage period, and a verification module (12) for checking, on the basis of a request for a plant start, whether at least one measured value in the period corresponding to a specified monitoring period before the request corresponds to the defined specifications (16), wherein the storage period corresponds at least to the specified monitoring period, and the control device (10) is designed such that the wind turbine (1) is only started if the result of the check by the verification module (12) is positive.

2. Wind turbine according to claim 11, characterized by the fact that the data storage (13) is a ring storage (13 λ).

3. Wind turbine according to claim 12 or 12, characterized by the fact that the wind turbine is designed to carry out the method according to one of claims 1 to 10.

4. Computer program product comprising program parts which, when loaded into a computer, are designed to carry out a method according to any one of claims 1 to 10.