Activating and deactivating a safety operating mode of a wind turbine

Abstract

A method of activating and / or deactivating a safety operation mode of a wind turbine (100) is described, the method comprising: receiving at least one measurement signal (112) related to a weather condition; filtering the measurement signal related quantity to obtain a filtered signal (624, 615a,..., 615d), wherein the filtered signal depends on the measurement signal related quantity and / or whether the filtered signal is increasing or decreasing over time; activating and / or deactivating the safety operation mode based on the filtered signal.

Description

Technical Field

[0001] This invention relates to a method and corresponding apparatus for activating and / or deactivating a safe operating mode of a wind turbine. Furthermore, this invention relates to a wind turbine including the apparatus. Background Technology

[0002] For example, wind turbines included in a wind farm may be subjected to various environmental conditions, including normal environmental conditions, where normal operation and power generation are possible. However, wind turbines may also be subjected to abnormal environmental conditions, including high wind speeds. Wind turbines need to be configured to respond to such abnormal environmental conditions. Therefore, wind turbines can be designed with safe operating modes, which increase the likelihood of avoiding damage during severe weather events. Such severe weather events may be storms or tropical cyclones, which are described as rotating storms with a low-pressure center and a closed, low-level atmospheric circulation with strong winds.

[0003] Operating modes designed to avoid damage from severe weather events may involve operating the wind turbine in a manner deviating from standard operating procedures. This could include shutting down the wind turbine or orienting components of the wind turbine in a way that reduces the likelihood of damage.

[0004] Conventional methods may have already monitored wind speed and may have activated or deactivated the safe operating mode based on whether the measured wind speed is below or above a wind speed threshold.

[0005] Conventional methods may deactivate the safe operating mode before the severe weather event ends. Typically, a threshold margin may be used such that the threshold for deactivating the safe operating mode is on the safe side of the threshold for activating it. However, when a threshold margin is used so that deactivation of the safe operating mode only occurs at relatively low wind speeds, activation of the safe operating mode may already be performed if the wind speed is relatively low. This may reduce production. Conventionally, a fixed-length delay may also be used for deactivation, ensuring that deactivation does not occur before a predetermined duration has elapsed, during which the deactivation criteria are met. However, this may also reduce production. Conventional methods may use, for example, a time-averaged wind speed as the measured environmental condition. When the measurement result or average signal is above a predetermined threshold, the conventional method may have already activated the safe operating mode. When the measurement result or average signal is below the predetermined threshold, deactivation is conventionally performed. However, the aforementioned problems may occur in conventional methods.

[0006] However, it has been observed that the conventional method of activating or deactivating safe operating modes does not ensure reliable or safe operation of wind turbines in all situations.

[0007] Therefore, a method and corresponding apparatus may be needed to activate and / or deactivate a safe operating mode for a wind turbine, wherein the wind turbine can operate safely and respond appropriately to changing weather conditions. Summary of the Invention

[0008] This need can be met by the subject matter of the independent claims. Advantageous embodiments of the invention are described in the dependent claims.

[0009] According to an embodiment of the present invention, a method for activating and / or deactivating a safe operating mode of a wind turbine is provided, the method comprising: receiving at least one measurement signal related to weather conditions; filtering a correlation quantity of the measurement signal to obtain a filtered signal, wherein the filtered signal and / or the filtered signal depends on whether the correlation quantity of the measurement signal and / or the filtered signal is increasing or decreasing over time; and activating and / or deactivating the safe operating mode based on the filtered signal.

[0010] This method can be implemented in software and / or hardware. It can be performed, for example, by a module of a wind turbine controller. Safe operating modes may include setting the wind turbine to an operating mode that reduces or even prevents damage to components of the wind turbine that could occur due to severe weather events such as excessive wind speeds and / or wind turbulence.

[0011] Activating a safe operating mode can include, for example, altering the wind turbine's operating state by changing the orientation or settings of one or more components (such as yaw angle, blade pitch angle, converter reference signal, or combinations thereof). Activating a safe operating mode can disable power generation and prevent the supply of power to the utility grid. Activating a safe operating mode may also involve disconnecting the wind turbine from the utility grid.

[0012] For example, to activate a safe operating mode, it might be beneficial to stop operating a horizontal-axis wind turbine facing upwind and orient it so that the rotor is downwind. In a downwind orientation, it is easier to ensure optimal orientation relative to the wind direction. However, in this orientation, the wind turbine may not be able to generate energy for the grid. Therefore, it is undesirable to orient a normally upwind wind turbine in this position unless necessary. Orienting the turbine to this downwind position and then back again also consumes power, which could cause problems if the wind turbine is operating off-grid under battery or diesel power.

[0013] Another example of a safe operating mode is a downwind-facing horizontal axis wind turbine with a set of cantilevered rotor blades that can fold inward or collapse in adverse weather conditions to reduce the cross-sectional surface area exposed to the wind. Another example is a upwind-facing horizontal axis wind turbine with a cantilevered tail rudder blade assembly.

[0014] Deactivating the safe operating mode may involve restoring the wind turbine to normal operation, in which the wind turbine generates electrical energy and supplies it to the public power grid.

[0015] Weather-related measurement signals may include information about wind speed, wind turbulence, atmospheric pressure, atmospheric pressure and / or pressure changes at a specific distance, solar irradiance, rainfall, etc. Weather-related measurement signals may specifically indicate wind speed and / or wind turbulence and / or atmospheric pressure or pressure changes. Measurement signals may include electrical / optical signals and / or wireless signals.

[0016] The quantity related to the measurement signal can be a quantity that depends on the measurement signal. In one embodiment, this quantity can be equal to the measurement signal, but in other embodiments, the quantity related to the measurement signal can be derived from the measurement signal through processing and can be different from the measurement signal itself. The quantity related to the measurement signal can, for example, correspond to the average value of the measurement signal over a specific time, as explained in more detail below.

[0017] The measured signal correlation quantity is then filtered (e.g., using a (low-pass) filter with an adjustable or settable time constant or other filter parameters) to obtain a filtered signal. If the measured signal correlation quantity and / or the filtered signal are increasing, the filtered signal may differ from the filtered signal when the measured signal correlation quantity and / or the filtered signal are decreasing over time. This allows for addressing different desired activation and deactivation requirements of safe operating modes. In particular, rapid activation of safe operating modes can be achieved to reduce damage to wind turbine components. Furthermore, wind turbine deactivation can be performed faster than conventionally, while protecting wind turbine components from damage by preventing premature deactivation of the safe mode. Filtering may include processing by a processor, for example, using appropriate software.

[0018] The embodiments of the present invention can achieve the following beneficial effects, for example:

[0019] 1. Ensure rapid activation at the onset of severe weather events.

[0020] 2. Avoid activating the system too early, before the severe weather event has ended.

[0021] 3. Avoid prolonged delays (and consequent production losses) after severe weather events have ended.

[0022] According to an embodiment of the present invention, the method further includes: activating a safe operation mode if the filtered signal is higher or lower than an activation threshold; and / or deactivating the safe operation mode if the filtered signal is lower or higher than a deactivation threshold different from the activation threshold.

[0023] When activating and / or deactivating the safety operating mode based on a filtered signal, the criteria used to activate or deactivate the safety operating mode can be set to address, in a more effective way, factors such as increasing or decreasing wind speed over time. This protects wind turbine components from damage and also improves production efficiency.

[0024] If the filtered signal exceeds the activation threshold, further operation under normal production conditions could potentially damage components of the wind turbine. Therefore, activating the safe operating mode protects the wind turbine components from damage. When the safe operating mode is deactivated (and normal operating mode, which involves generating electricity, may be entered), if the filtered signal is below the deactivation threshold, it is anticipated that major weather conditions (especially wind speed) will not damage the wind turbine components. Therefore, normal operation can be resumed to continue generating electricity and supplying it to the utility grid.

[0025] The flexibility of the method is increased when the deactivation threshold differs from the activation threshold, allowing adaptation to expected environmental characteristics and the features of the wind turbine. For example, the activation threshold can be set higher than the deactivation threshold. Therefore, reliable operation of the wind turbine can be achieved while ensuring increased energy production.

[0026] According to an embodiment of the present invention, filtering includes: employing filter parameters, particularly low-pass filtering, wherein the filter parameters include a filter time constant, the filter time constant being different for the increasing or decreasing correlation quantity of the measurement signal and / or the filtered signal.

[0027] Low-pass filtering can be implemented in many different ways. The filters used can include multi-rate filters to which low-pass filtering can be applied.

[0028] Therefore, this method may involve predetermined activation and deactivation thresholds based on one or more signals associated with environmental conditions (e.g., wind speed, atmospheric pressure, etc.). The measured environmental conditions(s) can be converted into filtered signals using a multi-rate filter. The multi-rate filter can determine its output using different filter parameters depending on whether the input measurement result and / or the filtered signal is increasing or decreasing. A safe operating mode can be activated when the filtered signal exceeds the predetermined activation threshold, and deactivated when the filtered signal exceeds the predetermined deactivation threshold in the opposite direction.

[0029] For cases where the activation threshold is exceeded, the multi-rate filter can apply only a light low-pass filter to the increasing input and / or filtered signal of the measured condition. Light filtering can mean that the filter has a small time constant τ when filtering the input signal. The filter can be such that there is no filtering of the increasing input signal and / or the filtered signal, i.e., τ = 0. This can be called an envelope filter. This ensures that when the measured condition exceeds the threshold used for activation, the safe operating mode is activated quickly with little or no delay.

[0030] Multi-rate filters can have a large amount of low-pass filtering for the decreasing input and / or the filtered signal. The time constant here can be approximately τ = 1 to 4 hours. This ensures that a rapid decrease in the measured condition does not lead to a corresponding rapid decrease in the filtered signal used in the evaluation of the deactivation threshold. For a gradual decrease in the measured input to the filter, the filtered output may only deviate slightly.

[0031] When the activation of the safe operating mode requires the signal to drop below the activation threshold, the filtering of the increasing and decreasing signals and / or the filtered signals, as described in the previous two paragraphs, is reversed.

[0032] The benefit of this approach may be that severe weather events typically end with a gradual change in measured environmental conditions, such as wind speed.

[0033] Low-pass filtering of the measured signal, when it changes direction in the deactivation threshold, ensures virtually no delay from the end of the weather event to the return of operation. This is because a fixed time delay, large threshold margin, and / or long-duration averaging may not be necessary to avoid deactivation due to the short-duration behavior of the measured signal.

[0034] The filtered signal at discrete time step i (e.g., y) i(e.g., output by a filter module) can depend on the quantity of the measured signal correlation at that time step (e.g., u). i ) and / or the measurement signal correlation quantity at the previous time step (e.g., u) i-1 ), and / or may depend on the filtered signal (e.g., y) at the previous time step (especially in a linear manner). i-1 The filter coefficients (e.g., B0 and B1) can be defined by a time constant (e.g., τ) and the duration (time step) Δt between samples. The time constant can depend on the output y. i Is it greater than or less than the previous output sample y? i-1 .

[0035] When the filtered time constant is set differently for the correlated quantities of increasing or decreasing measurement signals and / or the filtered signals, activation of the safe operating mode can be performed with minimal delay after weather conditions change to potentially damaging conditions. Therefore, rapid activation at the onset of severe weather events can be ensured.

[0036] Furthermore, by setting the filter time constant for the decreasing correlation quantity of the measurement signal and / or the filtered signal to a larger value than that for the increasing correlation quantity of the measurement signal and / or the filtered signal, premature activation of the safe operating mode before the severe weather event ends can be avoided. However, by appropriately setting the filter time constant for the decreasing correlation quantity of the measurement signal and / or the filtered signal, a long delay after the severe weather event ends can also be avoided.

[0037] According to an embodiment of the present invention, when the safe operation mode is activated, if the filtered signal is higher than the activation threshold and the safe operation mode is deactivated, and if the filtered signal is lower than the deactivation threshold, the following applies: when the measured signal correlation quantity and / or the filtered signal is increasing, the time constant is set to a low time constant; and when the measured signal correlation quantity and / or the filtered signal is decreasing, the time constant is set to a high time constant, wherein the high time constant is greater than the low time constant.

[0038] A low time constant for the filter, set when the correlated quantity of the measured signal and / or the filtered signal is increasing, ensures that the deactivation or activation of the safe operating mode is performed with minimal or no delay, such as a small delay after the measured signal indicates potentially damaging weather conditions (e.g., excessively high wind speeds). Conversely, setting a high time constant when the correlated quantity of the measured signal and / or the filtered signal is decreasing prevents premature deactivation of the safe operating mode.

[0039] A low-pass filter can have the effect of gradually adjusting the output signal when there are rapid changes in the input signal. Rapid changes in the time domain require high-frequency components in the frequency domain. Therefore, if the high-frequency components of the input signal are filtered out, rapid changes in the output are prevented.

[0040] For example, a high time constant can be selected based on the specific application. The same applies to a low time constant.

[0041] The predetermined thresholds used for activation and deactivation can have different values, allowing for a margin between activation and deactivation in the safe operating mode. Once the filtered signal exceeds the activation threshold, the mode remains active until the filtered signal returns to the deactivation threshold. The margin does not need to be large, and for the example of wind speed measurement, it can be only 5-10 m / s between the two thresholds.

[0042] According to an embodiment of the invention, the activation threshold is greater than the deactivation threshold, wherein the activation threshold is particularly between 1.2 times and 2.0 times the deactivation threshold.

[0043] When the activation threshold is greater than the deactivation threshold, the system may not prematurely enter the safe operation mode, nor may it prematurely enter the deactivation safe operation mode, i.e., when the severe weather event may not have ended.

[0044] According to an embodiment of the present invention, when the safe operation mode is activated, if the filtered signal is below the activation threshold and the safe operation mode is deactivated, and if the filtered signal is above the deactivation threshold, the following applies: when the measured signal correlation quantity and / or the filtered signal is increasing, the time constant is set to a high time constant; and when the measured signal correlation quantity and / or the filtered signal is decreasing, the time constant is set to a low time constant, wherein the high time constant is greater than the low time constant.

[0045] Compared to the previously described embodiments, this embodiment can be considered a reversed setup, wherein activation is performed for filtered signals below an activation threshold, and deactivation is performed for filtered signals above a deactivation threshold. Furthermore, the effects of the described embodiment can be similar to those described with respect to the previously described embodiments.

[0046] According to embodiments of the invention, the low time constant is between 0 and 60 minutes, particularly between 0 and 10 minutes, and / or wherein the high time constant is between 30 minutes and 300 minutes, particularly between 60 minutes and 180 minutes.

[0047] This provides typical time values ​​that have been found suitable for the safe control of wind turbines through simulation and application to historical wind data. Other time values ​​are also possible.

[0048] According to an embodiment of the present invention, filtering the correlation quantity of the measurement signal includes: averaging the measurement signal over a predetermined averaging time to obtain an average signal; and filtering the average signal to obtain the filtered signal.

[0049] Therefore, the average signal can also have fewer high-frequency components than the measurement signal itself. This allows for the application of smoothing. Consequently, the reliability of the method can be improved. The averaging can also include, for example, a weighted average, where the weights of past values ​​of the measurement signal are considered or are deemed to have less intensity than the values ​​of the measurement signal closer to the current time point. In other embodiments, a simple averaging can be performed without waiting.

[0050] The measured signals(s) can be pre-filtered using, for example, an averaging window. However, the averaging time does not have to be on the order of hours and can be as short as 5 to 10 minutes. This is especially important in the case of wind speed measurements, as it ensures that fluctuations (e.g., due to turbulence) do not lead to unintentional activation and / or deactivation. A 10-minute averaging of the input signal may also have no significant impact on operational delays at the end of a severe weather event.

[0051] According to an embodiment of the invention, the predetermined average time is between 120 seconds and 700 seconds, particularly between 550 seconds and 650 seconds.

[0052] According to embodiments of the present invention, simulations have shown that these values ​​are appropriate.

[0053] According to an embodiment of the present invention, filtering a measurement signal correlation quantity includes: limiting the measurement signal correlation quantity to be equal to or greater than a lower limit value (e.g., V0), the lower limit value not greater than the activation threshold; or limiting the measurement signal correlation quantity to be equal to or lower than an upper limit value (V0), the upper limit value not lower than a deactivation threshold; the method further includes: filtering the limited measurement signal correlation quantity.

[0054] Limiting the measured values ​​to a lower limit can further improve the method, and in particular improve reliability, security, and / or robustness. An upper limit can be applied if activation occurs below an activation threshold and deactivation occurs above a deactivation threshold. Furthermore, by using this implementation or embodiment, the filtering results can be more restricted and predictable.

[0055] According to embodiments of the present invention, the weather-related measurement signals include at least one of the following: wind speed; atmospheric pressure; load on rotor blades and / or tower; thrust on turbine rotor.

[0056] Weather conditions can be measured by one or more measuring sensors installed on components of the wind turbine or, for example, on a weather mast. Therefore, conventionally, in embodiments of the invention, available measurement signals can be utilized, thereby simplifying the method.

[0057] According to embodiments of the present invention, the method is applied to multiple types of measurement signals, each type of measurement signal being associated with corresponding filter parameters and activation and deactivation thresholds. This improves the method in terms of reliability and adaptability to specific applications.

[0058] According to an embodiment of the present invention, activating and / or deactivating a safe operating mode includes supplying a control signal to at least one actuator to establish a safe operating mode, wherein the safe operating mode includes at least one of the following: shutting down the wind turbine; folding at least one rotor blade in the downwind direction; adjusting the blade pitch angle of at least one rotor blade to a feathered position; adjusting or allowing adjustment of yaw to a downwind position; idling in the yaw-downwind position; disconnecting the wind turbine from the power grid; fixing and / or braking the rotor.

[0059] The actuator can be configured, for example, to adjust the yaw angle, which defines the azimuth angle of the nacelle relative to the wind turbine tower. In other embodiments, the actuator may include an actuator for readjusting the blade pitch angle. The actuator may additionally or alternatively also actuate one or more circuit breakers, for example, for disconnecting or connecting the wind turbine to the public power grid. Idling in the yaw-downwind position may involve stopping power generation. The wind turbine rotor will then no longer face the wind as it does during normal operation, but will instead be oriented in the opposite direction. In particular, the hub can be oriented downwind (tailwind) in safe operating mode, where the rotor blades are attached.

[0060] It should be understood that features of methods for activating and / or deactivating safe operating modes of wind turbines, disclosed, explained, described, or provided individually or in any combination, are also individually or in any combination applicable to means for activating and / or deactivating safe operating modes of wind turbines according to embodiments of the present invention, and vice versa.

[0061] According to an embodiment of the present invention, an apparatus for activating and / or deactivating a safe operating mode of a wind turbine is provided. The apparatus includes: an input module configured to receive at least one measurement signal related to weather conditions; a processor configured to: filter a correlation quantity of the measurement signal to obtain a filtered signal, wherein the filtered signal depends on the correlation quantity of the measurement signal and / or whether the filtered signal is increasing or decreasing over time; and derive at least one control signal for activating and / or deactivating the safe operating mode based on the filtered signal.

[0062] The device can be, for example, part of a wind turbine controller.

[0063] According to an embodiment of the present invention, a wind turbine is provided, comprising: a tower; a nacelle mounted on top of the tower; a rotor housed in the nacelle; a plurality of rotor blades mounted on the rotor; a device according to the foregoing embodiment; a measuring sensor configured to generate a measuring signal based on weather conditions; and an actuator for receiving a control signal.

[0064] The above and other aspects of the invention will be apparent from the examples of the embodiments described below, and will be explained with reference to these examples. The invention will now be described in more detail with reference to examples of embodiments, but the invention is not limited to these embodiments. Attached Figure Description

[0065] Embodiments of the present invention will now be described with reference to the accompanying drawings. The present invention is not limited to the embodiments described or illustrated.

[0066] Figure 1 and Figure 2 The illustration schematically shows a wind turbine in two different operating modes according to an embodiment of the present invention;

[0067] Figure 3 , Figure 4 , Figure 5 The illustration schematically depicts wind turbines in different operational transition states according to embodiments of the present invention;

[0068] Figure 6 , Figure 7 , Figure 8 and Figure 9 The simulation illustrates the activation and deactivation of the safe operating modes of a wind turbine according to an embodiment of the present invention in response to different past weather events.

[0069] Figure 10 and Figure 11 The activation and deactivation of the secure operating modes according to the prior art and embodiments of the present invention are shown respectively; and

[0070] Figure 12 The implementation of the filter used in the embodiments of the present invention is illustrated schematically. Detailed Implementation

[0071] The illustrations in the accompanying drawings are schematic. Note that in different drawings, elements with similar or identical structures and / or functions have the same reference numerals or reference numerals that differ only in the first digit. Description of an element not described in one embodiment may be obtained from the description of that element in another embodiment.

[0072] According to embodiments of the present invention Figure 1 The wind turbine 100, schematically shown, includes a wind turbine tower 102, a nacelle 103 mounted on top of the tower 102, and a rotor 104 with a plurality of rotor blades 105 mounted on the rotor 104. The wind turbine 100 also includes a device 110 according to an embodiment of the invention for activating / deactivating a safe operating mode of the wind turbine 100. The device 110 may, for example, be installed within the nacelle 103.

[0073] The device 110 includes an input terminal 111 for receiving a measurement signal 112 related to weather conditions. The measurement signal 112 may be generated, for example, by a wind speed sensor 113 that may be mounted in the nacelle 103. The device 110 includes a processor (not shown) configured to filter the quantity related to the measurement signal (i.e., the quantity that depends on the measurement signal 112) to obtain a filtered signal.

[0074] For example, the filtered signal in Figure 6 , Figure 7 , Figure 8 , Figure 9 , Figure 11 As shown, and thus represented or labeled using reference numerals ending in 15 followed by letters. For example, such filtered signals in Figure 6 The diagram shows the components, and they are labeled with reference numerals 615a, ..., 615d. The device 110 is also configured to base on a filtered signal (e.g., ...). Figure 6 The signals 615a, ..., 615d shown derive at least one control signal 116 for activating and / or deactivating the safe operating mode. Control signal 116 may be provided to a yaw system (not shown in detail) that can be configured to change the yaw angle of the cabin, as indicated by arrow 117.

[0075] Therefore, in order to activate Figure 2 The safe operating mode shown indicates that control signal 116 can cause the yaw system to move the nacelle 103 around the vertical longitudinal axis of the wind turbine tower 102 from... Figure 1 The normal orientation shown is rotated to Figure 2 The indicated downwind position. For example, from... Figure 1 Understandably, wind 118 impacts rotor blades 105 for normal energy generation, while Figure 2 Wind 218 struck the wind turbine from behind because the wind turbine was yawed downwind. Figure 1 In the middle, the hub faces the wind at 118, while... Figure 2 In the middle, the hub is in the opposite direction, and the rotor blades 105 are mounted at the hub.

[0076] In addition to changing the yaw position of the nacelle to enter a safe operating mode, other actuations can be performed according to embodiments of the invention, such as adjusting the blade pitch angle.

[0077] Figure 3 , Figure 4 and Figure 5 Another embodiment of entering a safe operating mode is shown. In this embodiment, the wind turbine 300 includes rotor blades 305 that can fold inward or collapse during severe weather events to reduce the cross-sectional surface area exposed to wind. Thus, in Figure 3 In the middle, the wind turbine 300 has been adjusted to a yaw-downwind position. Figure 4 and Figure 5 The diagram illustrates further steps in the folding process of rotor blade 305. Figure 5 The process of entering safe operating mode has been completed. Furthermore, Figure 3 , Figure 4 and Figure 5 The wind turbine 300 shown includes a device 310 for activating and / or deactivating a safe operating mode, which can be used in conjunction with a reference... Figure 1 and Figure 2 The method described above is similar to the one described above and is configured and works in a similar manner.

[0078] Severe weather events can include, for example, tropical cyclones with an eye at their center. When a wind turbine is within the eye, it may experience relatively low wind speeds. In conventional methods, calm conditions within the eye may be mistakenly interpreted as evidence that the tropical cyclone has completely passed and ended. Consequently, wind turbines may conventionally experience potentially hazardous, time-consuming, and / or energy-consuming conditions. Within the eye, wind speeds can drop significantly from peak values ​​at the eyewall to the relatively calm conditions of the eye. Safe operating modes, conventionally applied and activated solely based on measured wind speeds, may be erroneously deactivated during these low-wind periods. Other severe weather conditions that can be addressed in embodiments of the invention may include multicellular thunderstorms, where relatively calm periods may occur within the severe weather system.

[0079] Figure 6 , Figure 7 , Figure 8 , Figure 9The graphs shown represent embodiments of a method for activating and / or deactivating a safe operating mode of a wind turbine according to an embodiment of the invention.

[0080] Where the horizontal axes 620, 720, 820, and 920 represent time, and the vertical axes 621, 721, 821, and 921 represent wind speed, for example, from Figure 1 The wind speed measured by the wind speed sensor 113 is shown. Figure 6 The activation threshold 622 and deactivation threshold 623 are shown to define these thresholds. Figure 7 , Figure 8 and Figure 9 The corresponding thresholds are also described, and their reference numerals differ only in the first position. These thresholds can be set differently or the same, and can be selected or set according to specific applications. These thresholds can be set, for example, based on geographical location, expected weather conditions, expected wind speed, etc.

[0081] Figure 6 , Figure 7 , Figure 8 , Figure 9 The thick curves 624, 724, 824, and 924 in the figure represent the average wind speed over an average duration of 600 seconds. According to an embodiment of the invention, this average wind speed can represent a quantity related to the measured signal.

[0082] Figure 6 This represents measured and simulated values ​​from tropical cyclones. Figure 6 In the time interval 625 shown, the average wind speed 624 increases, while in the time interval 626, the average wind speed 624 decreases. According to an embodiment of the invention, different filters are applied in time interval 625 (when the average wind speed is increasing) and time interval 626 (when the average wind speed is decreasing). According to the depicted embodiment, in time window 625 and other time windows or time intervals 627 where the average wind speed is also increasing, the time constant τ of the filter is set to zero. Conversely, in time intervals 626 and 628 where the average wind speed 624 is decreasing, curves 615a, 615b, 615c, and 615d are represented, corresponding to filtering results with time constants τ = 1h, 2h, 3h, and 4h, respectively. The filtering with an increasing time constant in time intervals 626 and 628 results in the avoidance of premature deactivation of the safe operating mode. Deactivation of the safe operating mode occurs when a selected curve representing the filtered signal (curves 615a, ..., 615d) falls below the deactivation threshold 623. In the illustrated embodiment, deactivation may occur, for example, at time point 629 when curve 615a crosses the horizontal line representing the deactivation threshold 623. In other embodiments, another curve among 615a, ..., 615d may be selected as the filtered signal to be compared with the deactivation threshold 623.

[0083] When the average wind speed (corresponding to the filtered value obtained by filtering with a time constant of τ=0) crosses and exceeds the activation threshold 622, the safe operation mode is activated. The activation of the safe operation mode occurs when... Figure 6 At time point 630, the average wind speed of 624 crosses the horizontal line representing the activation threshold of 622.

[0084] exist Figure 6 In the process, the activation threshold 622 is set to a wind speed of 35 m / s, while the deactivation threshold 623 is set to a wind speed of 25 m / s.

[0085] Figure 7 This includes data from extratropical storms. Figure 7 In the process, the safe operating mode is activated at time point 730 and deactivated at time point 729.

[0086] Figure 8 and Figure 9 The embodiments shown also include defining and using a lower limit value V_0, which defines the minimum input value of the filter used to derive the filtered signal. Figure 8 and Figure 9 The lower limit value V_0 shown is set to 22 m / s, which is lower than the deactivation threshold 823 and also lower than the activation threshold 822. Figure 8 The system enters the safe operation mode at time 8:30 and deactivates at time 8:29.

[0087] As from Figure 8 and Figure 9 As can be understood, the filtered signals 815a, ..., 815d and 915a, ..., 915d derived in the embodiments of the present invention are different from those shown in the embodiments of the present invention. Figure 6 and Figure 7 The filtered signals 615a, ..., 615d, 715a, ..., 715d derived in the illustrated embodiment. Therefore, the method for activating / deactivating the safe operating mode can be further adapted to specific applications.

[0088] Figure 10 and Figure 11 The conventional method and the method according to embodiments of the present invention are illustrated comparatively for resolving the activation and / or deactivation of safe operating modes. Here, the horizontal axes 1020 and 1120 represent time, while the vertical axes 1021 and 1121 represent wind speed.

[0089] Figure 10Curve 1031 in the figure represents the average wind speed, and amount 1032 represents the speed threshold used in normal operation. Typically, activation occurs at time point 1033 when the wind speed 1031 crosses the threshold 1032. At time point 1034, the wind speed crosses the threshold 1032 for the second time. Typically, a waiting time interval or delay time Δt is performed before the safe operating mode is deactivated at time point 1035. Thus, a relatively large delay can lead to a significant reduction in energy output.

[0090] Curve 1115 represents the filtered signal, derived by filtering the average wind speed 1124 during the duration of the decrease in average wind speed 1124. According to an embodiment of the invention, the filtered signal 1115 derived from the average wind speed 1124 is considered for deactivation. Activation can occur at time point 1130, when the average wind speed 1124 crosses and exceeds the activation threshold 1122. Deactivation of the safe operating mode occurs at time point 1129, when the filtered signal 1115 crosses and lies below the activation threshold 1122, which in this embodiment is equal to the deactivation threshold 1123. Thus, as from... Figure 10 and Figure 11 It is understandable that the time point 1129 when normal operation can be restored is earlier than the time point 1035 when normal operation can be restored according to the conventional method by a duration Δt'.

[0091] Further details of specific embodiments of the invention, which are not limited thereto, are disclosed below:

[0092] For situations where activation of the safe operating mode is related to exceeding the activation threshold, a limit can be applied to the input of the multi-rate filter to ensure that the input value does not fall below a predetermined lower limit, which is not greater than the deactivation threshold. This lower limit can be used to ensure that the rate at which the filtered signal changes in response to a decrease in the input signal is not affected by a significant decrease in the signal. (An example of this lower limit is...) Figure 8 and Figure 9 (V0 is shown in the diagram). For cases where activation of a safe operating mode is related to a condition falling below the activation threshold, the lower limit will conversely act as the upper limit, which is not lower than the deactivation threshold. One or more signals can be used for both activation and deactivation of the safe operating mode.

[0093] Multiple measured conditions can be used in different ways. For example, wind speed, atmospheric pressure, load sensors on rotor blades or towers, or thrust measurements on turbine rotors can be used to activate and deactivate safe operating modes during tropical cyclones. One or more of these measured signals can be processed as described in this method and compared with unique activation and deactivation thresholds. Boolean logic can then be used to combine the activation and deactivation conditions such that activation occurs when the activation threshold for any signal is reached, and deactivation occurs only when the deactivation threshold for all signals is reached. Other Boolean combinations can be used where appropriate. Similarly, multiple measured signals can be used to improve the accuracy of a single signal processed by the method described herein. Again, in the example of a tropical cyclone, atmospheric pressure measurements and rotor blade load measurements can be used to improve the accuracy of the measured wind speed signal by using state estimates from measurements and mathematical models (e.g., observers and Kalman filters).

[0094] exist Figures 6 to 9 In the illustrated embodiment, a 10-minute average of the wind speed is used as the input to the multi-rate filter. For increasing wind speeds, the filter has a time constant τ = 0, and for decreasing wind speeds, results with different time constants are shown: τ = 1, 2, 3, and 4 hours. The activation threshold is set to 35 m / s, and the deactivation threshold is set to 25 m / s. Figure 6 , Figure 7 In the multi-rate filter, the lower limit V0 of the input signal is set to 0 m / s (i.e., there is no lower limit), and... Figure 8 , Figure 9 In this context, the lower limit is V0 = 22 m / s.

[0095] The effect of this method is clearly visible in the following figures. Figure 6 In this case, by setting a time constant of only 1 hour, the safe operating mode will not be deactivated due to the decrease in wind speed during the eye of the tropical cyclone. When the tropical cyclone finally ends, the wind speed decreases at a slower rate, and for all cases except the 4-hour time constant case, there is no additional delay due to filtering. The same applies to extratropical storms. Figure 7 When the wind speed decreases below a certain level, there is almost no delay or even no delay at all.

[0096] Included Figure 8 , Figure 9 This is only to demonstrate the effect of changing the lower limit V0.

[0097] Using conventional solutions to avoid deactivation of safe operating modes due to the eye of a tropical cyclone can lead to significant delays in returning to operations after the cyclone has passed. The eye of a tropical cyclone is typically 30-65 km in diameter, but can range from just a few kilometers to very large diameters, such as Typhoon Carmen (1960) at 370 km. The eye typically travels at speeds of approximately 25 to 30 km / h, meaning that the relatively calm periods experienced by the wind turbines can last from one to several hours. This necessitates very large mean windows or fixed delays to avoid deactivation. Wind speeds within the eye can be very low, meaning that a very large margin will be required to avoid deactivation. These deactivation conditions can lead to significant delays in returning to operations after the severe weather event ends. Therefore, the solution described has been developed.

[0098] Figure 12 The filter 1250 used in embodiments of the invention is illustrated schematically (e.g., executed by a processor and included, for example, in...). Figure 1 The implementation in the device 110 shown is used to derive the filtered signal (e.g., y) at a discrete time step i. i (For example, output by filter module 1250).

[0099] At input module 1251, the measurement signal correlation quantity u at time step i is received. i The delay module 1252 generates a correlation quantity u from the measurement signal at the previous time step i-1. i-1 .

[0100] The correlation quantity u of the measurement signal at time step i i The correlation quantity u with the measurement signal at the previous time step i-1 Gain modules 1253 and 1254 with the same gain coefficients B1 and B1 are provided.

[0101] At adder 1255, the outputs of modules 1253 and 1254 are added to the output of gain module 1256, which has a gain coefficient B0 different from the gain coefficient B1. Gain module 1256 receives the filtered signal t at time step i-1 from delay element 1260. i-1 The delay element 1260 then receives the filtered signal y at time step i from block 1261. i .

[0102] The output of adder 1255 (provided to box 1261) is the filtered signal y at discrete time step i. i .

[0103] The output (i.e., the filtered signal y) iThe signal y is provided to the gain changing module 1257, which adjusts the signal based on the filtered signal y at step size i. i Is it greater than or less than the filtered signal t at step size i-1? i-1 To change the gain coefficient, see boxes 1258 and 1259.

[0104] Filter coefficients (e.g., B0 and B1) can be defined by a time constant (e.g., τ) and the duration (time step) Δt between samples. The time constant can depend on the output y. i Is it greater than or less than the previous output sample t? i-1 .

[0105] The following expression determines the output, that is, for the filtered signal y at time step i. i :

[0106] y i =B1u i +B1u i-1 +B o y i-1

[0107] The filter coefficients B0 and B1 are defined by the time constant τ and the duration (time step) Δt between samples.

[0108] B0=(2.0τ-Δt) / (2.0τ+Δt)

[0109] B1=Δt / (2.0τ+Δt)

[0110] The time constant depends on the output y i Is it greater than or less than the previous output sample t? i-1 :

[0111] If t i-1 >t i Then τ = τ 增大

[0112] If t i-1 ≤t i Then τ = τ 减小

[0113] Other equations may also derive the filtered signal.

[0114] It should be noted that the term "comprising" does not exclude other elements or steps, and "a" or "an" does not exclude multiple. Furthermore, elements described in association with different embodiments may be combined. It should also be noted that reference numerals in the claims should not be construed as limiting the scope of the claims.

Claims

1. A method for activating and / or deactivating a safe operating mode of a wind turbine (100), the method comprising: Receive at least one measurement signal (112) related to weather conditions; The correlation quantity of the measurement signal is filtered to obtain a filtered signal, wherein the filtered signal depends on the correlation quantity of the measurement signal and / or whether the filtered signal is increasing or decreasing over time; The safe operating mode is activated and / or deactivated based on the filtered signal. Activating and / or deactivating the safe operating mode includes supplying a control signal (116) to at least one actuator to establish the safe operating mode, wherein the safe operating mode includes shutting down the wind turbine. The filtering process includes filtering using filter parameters (τ), wherein the filter parameters include a filter time constant, which is different for the increasing or decreasing correlation quantity of the measurement signal and / or the filtered signal.

2. The method according to claim 1, comprising: If the filtered signal is higher or lower than the activation threshold (622), the safe operation mode is activated; and / or If the filtered signal is lower than or higher than the deactivation threshold (623) which is the same as or different from the activation threshold (622), then the safe operation mode is deactivated.

3. The method according to claim 1 or 2, wherein, Filtering includes low-pass filtering using the filter parameters (τ).

4. The method according to claim 1 or 2, wherein, If the safe operation mode is activated, and the filtered signal is higher than the activation threshold (622) and the safe operation mode is deactivated, and if the filtered signal is lower than the deactivation threshold (623), then the following applies: When the correlation quantity of the measured signal and / or the filtered signal is increasing, the time constant (τ) is set to a low time constant; and When the correlation quantity of the measured signal and / or the filtered signal is decreasing, the time constant (τ) is set to a high time constant, wherein the high time constant is greater than the low time constant.

5. The method according to claim 4, wherein, The activation threshold (622) is greater than the deactivation threshold (623).

6. The method according to claim 5, wherein, The activation threshold is between 1.2 times and 2.0 times the deactivation threshold.

7. The method according to claim 1 or 2, wherein, If the safe operation mode is activated, and the filtered signal is below the activation threshold, the safe operation mode is deactivated; if the filtered signal is above the deactivation threshold, the following applies: When the correlation quantity of the measured signal and / or the filtered signal is increasing, the time constant is set to a high time constant; and When the correlation quantity of the measured signal and / or the filtered signal is decreasing, the time constant is set to a low time constant, wherein the high time constant is greater than the low time constant.

8. The method according to claim 4, in, The low time constant is between 0 minutes and 60 minutes, and / or The high time constant is between 30 minutes and 300 minutes.

9. The method according to claim 4, in, The low time constant is between 0 minutes and 10 minutes, and / or The high time constant is between 60 minutes and 180 minutes.

10. The method according to claim 7, in, The low time constant is between 0 minutes and 60 minutes, and / or The high time constant is between 30 minutes and 300 minutes.

11. The method according to claim 7, in, The low time constant is between 0 minutes and 10 minutes, and / or The high time constant is between 60 minutes and 180 minutes.

12. The method according to any one of claims 1-2, 5-6, and 8-11, wherein, Filtering the correlation quantities of the measured signal includes: The measured signal is averaged over a predetermined averaging time to obtain an average signal (624). The average signal (624) is filtered to obtain the filtered signal.

13. The method according to claim 12, wherein, The predetermined average time is between 120 seconds and 700 seconds.

14. The method according to claim 12, wherein, The predetermined average time is between 550 seconds and 650 seconds.

15. The method according to any one of claims 1-2, 5-6, 8-11, and 13-14, wherein, Filtering the correlation quantities of the measured signal includes: The correlation quantity of the measured signal is limited to be equal to or greater than a lower limit value (V_0), where the lower limit value (V_0) is not greater than the activation threshold; or The correlation quantity of the measured signal is limited to be equal to or lower than the upper limit value (V_0), and the upper limit value (V_0) is not lower than the deactivation threshold; The method further includes: Filter the correlation quantities of the restricted measurement signal.

16. The method according to any one of claims 1-2, 5-6, 8-11, and 13-14, wherein, The measurement signals related to the weather conditions include at least one of the following measurement signals (112): Wind speed; Atmospheric pressure; Loads on rotor blades and / or tower; The thrust on the turbine rotor.

17. The method according to claim 16, wherein, The method is applied to various types of measurement signals, each type of measurement signal being associated with corresponding filter parameters and activation and deactivation thresholds.

18. The method according to any one of claims 1-2, 5-6, 8-11, 13-14, and 17, wherein, Activating and / or deactivating the safe operating mode includes supplying a control signal (116) to at least one actuator to establish the safe operating mode, wherein the safe operating mode includes at least one of the following: Fold at least one rotor blade downwind; Adjust the blade pitch angle of at least one rotor blade to the feathering position; Adjust or allow adjustment of the yaw to a downwind position; Idling at a yaw with the wind at the yaw position; Disconnect the wind turbine from the power grid; Fix and / or brake the rotor.

19. A device (110) for activating and / or deactivating a safe operating mode of a wind turbine (100), said device comprising: An input module (111) is configured to receive at least one measurement signal (112) related to weather conditions. Processor, the processor being configured to: The correlation quantity of the measurement signal is filtered to obtain a filtered signal, wherein the filtered signal depends on the correlation quantity of the measurement signal and / or whether the filtered signal is increasing or decreasing over time; Based on the filtered signal, at least one control signal (116) is derived for activating and / or deactivating the safe operating mode. Specifically, for activating and / or deactivating the safe operating mode, the device is adapted to supply a control signal (116) to at least one actuator to establish the safe operating mode. The safe operating mode includes shutting down the wind turbine. The processor is adapted to filter the correlation quantity of the measurement signal using filter parameters (τ), wherein the filter parameters include a filter time constant, which is different for the increasing or decreasing correlation quantity of the measurement signal and / or the filtered signal.

20. A wind turbine (100), comprising: Tower (102); The nacelle (103) is mounted on top of the tower. Rotor (104) housed in the nacelle; Multiple rotor blades (105) are mounted on the rotor. The apparatus (110) according to claim 19; A measurement sensor (113) is configured to generate the measurement signal according to weather conditions; An actuator (117) is used to receive the control signal (116).

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