Pitch Lock Detection Method and Device for Wind Turbine

Abstract

The present invention provides a pitch locking detection method and device for a wind turbine. The pitch locking detection method includes: during the pitch change of the wind turbine, monitoring the rotational speed of the impeller of the wind turbine; and detecting whether a blade in the impeller of the wind turbine has a pitch locking based on the change in the rotational speed. The pitch locking detection device includes: a rotational speed monitoring unit that monitors the rotational speed of the impeller of the wind turbine during the pitch change of the wind turbine; and a pitch locking detection unit that detects whether a blade in the impeller of the wind turbine has a pitch locking based on the change in the rotational speed. Using the pitch locking detection method and device of the present invention not only simplifies the pitch locking detection model for the wind turbine, but also makes the pitch locking detection model for the wind turbine more accurate, and effectively eliminates the interference to the pitch locking detection result caused by reasons such as torque mutation and data jump in the rotational speed sensor acquisition.

Description

Technical Field

[0001] The present application relates to the technical field of wind power generation, and in particular, to a method and device for detecting blade jamming of a wind turbine. Background Art

[0002] The loads borne by a wind turbine are usually related to the blade jamming conditions of the blades in the impeller of the wind turbine. This is because inconsistent or unbalanced pitch angles of the three blades of the wind turbine will cause vibrations in the wind turbine. The greater the vibration, the greater the loads borne by the wind turbine will be. Excessive loads borne by the wind turbine will cause the wind turbine to operate in a fatigued state for a long time, reducing the service life of the wind turbine and even endangering the safety of the wind power generating set. Therefore, the accuracy of blade jamming condition detection becomes increasingly important. However, in the prior art, it is not possible to directly determine the blade jamming condition of the wind turbine based on the pitch angles of the blades. The reasons are as follows:

[0003] (1) The pitch angles of the blades are collected by a pitch control system and transmitted to the main control system (PLC) through DP communication. Therefore, the determination of the pitch angles of the blades will be affected by DP communication. For example, if the DP communication is interrupted, the value of the pitch angle of the blade received by the main control system will be 0, and thus the actual pitch angles of the three blades cannot be obtained;

[0004] (2) The pitch angles of the blades are the values of the rotary encoders collected by the pitch control system. Therefore, in the case where the rotary encoder is subject to electromagnetic interference, line breakage, or rotary encoder failure, the collected values of the pitch angles may be abnormal;

[0005] (3) Although a drive failure or a failure of the electromagnetic brake relay controlling the brake valve can be judged by a drive fault word, the fault word is also transmitted through communication. Therefore, when the communication is abnormal, the collected fault word may be 0 (0 indicates no fault), and even in the case where the blade is jammed, the drive fault word may also be 0 because the trigger condition for the drive fault alarm is not reached, and thus the actual pitch angles of the three blades cannot be obtained.

[0006] Therefore, there is an urgent need for a method and device for detecting blade jamming that can solve the above problems. Summary of the Invention

[0007] The object of the present invention is to provide a method and device for detecting blade jamming of a wind turbine.

[0008] According to one aspect of the present invention, there is provided a pitch locking detection method for a wind turbine, the pitch locking detection method including: during pitch variation of the wind turbine, monitoring the rotational speed of the impeller of the wind turbine; and detecting whether a blade in the impeller of the wind turbine has pitch locked based on a change in the rotational speed.

[0009] Preferably, the step of detecting whether a blade in the impeller of the wind turbine has pitch locked based on a change in the rotational speed may include: acquiring the rotational speeds of the impeller of the wind turbine at multiple consecutive moments; calculating the rotational speed difference between any two adjacent moments of the impeller of the wind turbine; and determining that a blade in the impeller of the wind turbine has pitch locked when the rotational speed difference presents a predetermined abnormal condition.

[0010] Preferably, the predetermined abnormal condition may include at least one of the following conditions: the rotational speed difference is greater than a predetermined threshold; and the number of times that the rotational speed difference is greater than the predetermined threshold occurs within a predetermined continuous time period reaches a predetermined number of times.

[0011] Preferably, the predetermined threshold may be 0.1 revolutions per minute.

[0012] Preferably, the pitch locking detection method may further include: calculating the ratio of the squares of the rotational speeds of the impeller of the wind turbine at any two adjacent moments; and estimating the maximum angular difference between the pitch angles of the blades in the impeller according to the ratio of the squares of the rotational speeds to determine the imbalance degree between the blades in the impeller.

[0013] According to another aspect of the present invention, there is provided a pitch locking detection device for a wind turbine, the pitch locking detection device including: a rotational speed monitoring unit configured to monitor the rotational speed of the impeller of the wind turbine during pitch variation of the wind turbine; and a pitch locking detection unit configured to detect whether a blade in the impeller of the wind turbine has pitch locked based on a change in the rotational speed.

[0014] Preferably, the pitch locking detection unit may include: a rotational speed acquisition unit configured to acquire the rotational speeds of the impeller of the wind turbine at multiple consecutive moments; a rotational speed difference calculation unit configured to calculate the rotational speed difference between any two adjacent moments of the impeller of the wind turbine; and a pitch locking determination unit configured to determine that a blade in the impeller of the wind turbine has pitch locked when the rotational speed difference presents a predetermined abnormal condition.

[0015] Preferably, the predetermined abnormal condition may include at least one of the following conditions: the rotational speed difference is greater than a predetermined threshold; and the number of times that the rotational speed difference is greater than the predetermined threshold occurs within a predetermined continuous time period reaches a predetermined number of times.

[0016] Preferably, the predetermined threshold may be 0.1 revolutions per minute.

[0017] Preferably, the blade jamming detection device may further include: a speed ratio calculation unit configured to calculate the square ratio of the rotational speeds of the impeller of the wind turbine at any two adjacent moments; an imbalance determination unit configured to estimate the maximum angular difference between the pitch angles of the blades in the impeller according to the square ratio of the rotational speeds to determine the imbalance between the blades in the impeller.

[0018] According to another aspect of the present invention, there is provided a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the blade jamming detection method for a wind turbine as described above.

[0019] According to another aspect of the present invention, there is provided a computer device including: a processor; a memory storing a computer program, which, when executed by the processor, implements the blade jamming detection method for a wind turbine as described above.

[0020] The method and device for blade jamming detection for a wind turbine according to an exemplary embodiment of the present invention not only simplify the blade jamming detection model for a wind turbine, but also make the blade jamming detection model for a wind turbine more accurate, and can accurately identify whether the wind turbine is jammed even when the DP communication between the main control system and the pitch control system is interrupted or the rotary encoder in the pitch control system malfunctions. In addition, it effectively eliminates the interference to the blade jamming detection result caused by reasons such as torque mutation and data jump of the rotational speed sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Through the following description with reference to the drawings, the above objects and features of the present invention will become clearer, where:

[0022] Figure 1 shows a curve graph of the change in the rotational speed difference of the impeller of a wind turbine when no blade jamming occurs according to an exemplary embodiment of the present invention;

[0023] Figure 2 shows a curve graph of the change in the rotational speed difference of the impeller of a wind turbine when blade jamming occurs according to an exemplary embodiment of the present invention;

[0024] Figure 3 shows a flowchart of the blade jamming detection method for a wind turbine according to an exemplary embodiment of the present invention;

[0025] Figure 4 shows a schematic process of the blade jamming detection for a wind turbine according to an exemplary embodiment of the present invention;

[0026] Figure 5Shows a schematic process for frequency detection in pitch detection of a wind turbine according to an exemplary embodiment of the present invention;

[0027] Figure 6 Shows a curve graph of the change in the ratio of the square of the rotational speed of the impeller of a wind turbine when pitch locking occurs according to an exemplary embodiment of the present invention;

[0028] Figure 7 Shows a curve graph of the case where the pitch reduction speed is slow according to an exemplary embodiment of the present invention;

[0029] Figure 8 Shows a curve graph of the case of complete pitch locking according to an exemplary embodiment of the present invention;

[0030] Figure 9 Is a structural block diagram showing a pitch detection device for a wind turbine according to an exemplary embodiment of the present invention. Detailed implementation manners

[0031] When the pitch angles of the three blades of the impeller of a wind turbine are inconsistent or unbalanced, the magnitudes of the wind forces received by the three blades are also different, which will cause a rotational excitation force to be generated during the rotation of the impeller of the wind turbine, and the excitation force acting on the tower base will cause the wind turbine to vibrate.

[0032] The excitation force formula based on eccentric vibration is:

[0033] F = meω 2 (1)

[0034] In Equation (1), F is the excitation force generated by the eccentric block; m is the mass of the eccentric block; e is the eccentricity of the eccentric block; ω is the rotational angular velocity of the eccentric block. For a wind turbine, F can be equivalently regarded as the vibration force generated on the wind turbine; m can be equivalently regarded as the equivalent mass of the rotation of the impeller of the wind turbine (which is related to the density distribution of the rotating body); e can be equivalently regarded as a function of the blade length of the wind turbine; ω can be equivalently regarded as the rotational angular velocity of the impeller of the wind turbine. Since the rotational force received by the wind turbine mainly comes from the magnitude of the wind force received by the blades of the wind turbine and the longer the blade, the larger the windward area (and the greater the resulting deviation), so e can characterize the imbalance of the three blades of the wind turbine.

[0035] Based on Equation (1), it can also be known that the magnitude of the vibration value of the wind turbine (i.e., the exciting force) caused by the imbalance of the pitch angles of the three blades of the wind turbine is not only proportional to the difference between the pitch angles of the three blades of the wind turbine (i.e., the difference between the maximum pitch angle and the minimum pitch angle among the three blades), but also proportional to the square of the angular velocity of the rotation of the impeller of the wind turbine. This unbalanced force will cause the rotational speed of the blades of the wind turbine to change suddenly during rotation. In addition, due to the inconsistency of the pitch angles of the three blades of the wind turbine, the wind forces acting on the wind turbine are also inconsistent and constantly changing. Therefore, the angular velocity ω or the rotational speed of the impeller of the wind turbine will also be erratic.

[0036] Figure 1 Figure 100 showing the variation of the rotational speed difference of the impeller of the wind turbine when no blade jamming occurs according to an exemplary embodiment of the present invention is presented.

[0037] Referring to Figure 1 , Figure 1 the abscissa in Figure 1 can indicate each moment during the pitch change of the wind turbine, and Figure 1 the ordinate in

[0038] can indicate the rotational speed difference of the impeller of the wind turbine at each moment (i.e., the difference between the rotational speed at the current moment and the rotational speed at the adjacent previous moment). It can be seen from Figure 2 that during the pitch change of the wind turbine, the maximum value of the change in the rotational speed of the impeller of the wind turbine is approximately 0.032 revolutions per minute (rpm).

[0039] As a comparison, Figure 2 , Figure 2 Figure 200 showing the variation of the rotational speed difference of the impeller of the wind turbine when blade jamming occurs according to an exemplary embodiment of the present invention is presented. Figure 2 Figure 2 Referring to

[0040] the abscissa in

[0041] can indicate each moment during the pitch change of the wind turbine, and the ordinate inFigure 3 Describe in detail the identification of the above-mentioned pitch failure.

[0042] Figure 3 The flowchart of a pitch detection method 300 for a wind turbine according to an exemplary embodiment of the present invention is shown. The method 300 can be executed by any terminal processing device including a processor (such as, but not limited to, the main control system of the wind turbine or the controller of its pitch system, etc.).

[0043] Refer to Figure 3 , the method 300 may include the following steps:

[0044] In step 310, the rotational speed of the impeller of the wind turbine can be monitored during the pitch of the wind turbine. The rotational speed of the impeller of the wind turbine can be obtained by a wind speed sensor installed on the wind turbine.

[0045] In step 320, it can be detected whether a blade in the impeller of the wind turbine is jammed based on the change in the rotational speed of the impeller of the wind turbine.

[0046] As an example, the rotational speed of the impeller of the wind turbine at multiple consecutive moments can be obtained, the rotational speed difference between any two adjacent moments of the impeller of the wind turbine can be calculated, and in the case where the rotational speed difference shows a predetermined abnormal condition, it is determined that a blade in the impeller of the wind turbine is jammed.

[0047] In this example, this predetermined abnormal condition can be set as the rotational speed difference of the impeller of the wind turbine being greater than a predetermined threshold (such as Figure 2 shown as 0.1 rpm). Considering data jump interference caused by reasons such as torque mutation and data jump in the data collected by the rotational speed sensor, in this example, this predetermined abnormal condition can also be set as the number of times that the rotational speed difference of the impeller of the wind turbine is greater than the predetermined threshold within a predetermined continuous time period reaches a predetermined number of times (such as 50 times or 80 times).

[0048] It should be noted that although the above shows an example of identifying whether a blade in the impeller of a wind turbine has a pitch failure by detecting the rotational speed difference of the impeller, the present invention is not limited thereto.

[0049] In addition, although Figure 3 not shown, according to an exemplary embodiment of the present invention, when it is determined that a blade in the impeller of the wind turbine is jammed, an imbalance analysis can be further performed on the blade in the impeller of the wind turbine, thereby determining the load that the wind turbine can withstand.

[0050] As an example, the processor 300 can calculate the ratio of the squares of the rotational speeds of the impeller of the wind turbine at any two adjacent moments, and estimate the maximum angular difference between the pitch angles of the blades in the impeller according to the ratio of the squares of the rotational speeds, so as to determine the imbalance between the blades in the impeller.

[0051] Next, reference will be made to Figure 4 and Figure 5 to further describe in detail the above-mentioned process of identifying and handling the blade jamming fault.

[0052] Figure 4 FIG. shows a schematic process 400 for detecting blade jamming of a wind turbine according to an exemplary embodiment of the present invention.

[0053] Referring to Figure 4 , the process 400 can be started.

[0054] In step 401, the process 400 can read online the rotational speed value of the impeller of the wind turbine, or read the rotational speed value of the impeller of the wind turbine in the fault file.

[0055] In step 402, the process 400 can calculate the rotational speed difference of the impeller of the wind turbine at each moment.

[0056] In step 403, the process 400 can read the rotational speed difference of the impeller of the wind turbine at the current moment, and assign the rotational speed difference of the impeller of the wind turbine at the next moment to the rotational speed difference of the impeller of the wind turbine at the current moment.

[0057] In step 404, the process 400 can determine whether the read rotational speed difference is greater than a predetermined threshold of 0.1.

[0058] In step 405, if it is determined in step 404 that the read rotational speed difference is greater than the predetermined threshold of 0.1, the process 400 can increment the count value by 1; otherwise, return to step 403 to read the rotational speed difference of the impeller of the wind turbine at the current moment.

[0059] In step 406, the process 400 can determine whether the count value is greater than a predetermined number within a predetermined continuous time period (that is, determine whether the frequency value of the situation where the rotational speed difference is greater than the predetermined threshold of 0.1 is relatively high).

[0060] Considering that the change in the rotational speed of the impeller of a wind turbine is usually a single jump or several jumps with a low frequency, while the change in the rotational speed of the wind turbine (i.e., the rotational speed difference) caused by the inconsistency or imbalance of the pitch angles of the blades in the impeller of the wind turbine is a continuous and high-frequency change process. Therefore, step 406 can be used to detect the number or frequency of cases where the rotational speed difference is greater than 0.1, so as to eliminate the interference brought to the pitch jam detection result by reasons such as torque mutation and data jump in the rotational speed sensor acquisition, and thus improve the accuracy of pitch jam recognition and detection.

[0061] Step 407, if it is determined in step 406 that the count value is greater than the predetermined number within a predetermined continuous time period, then process 400 can output the pitch jam information of the unit (such as, but not limited to, outputting a flag bit regarding a pitch jam warning), and analyze the pitch jam reason according to the remaining variables and data; otherwise, end process 400.

[0062] After step 407, process 400 ends.

[0063] In addition, considering that the maximum sampling frequency of the main control system is relatively low and does not support advanced algorithms such as fast Fourier transform (FFT), that is, it is relatively difficult for the main control system to detect the frequency of the time domain to frequency domain conversion. Here, the following frequency detection method can be used.

[0064] Figure 5 Fig. shows a schematic process 500 for frequency detection in pitch jam detection of a wind turbine according to an exemplary embodiment of the present invention.

[0065] Referring to Figure 5 , process 500 can be started.

[0066] In step 501, process 500 can set a timer of 100 ms, and perform count detection using the on-off of this timer.

[0067] In step 502, process 500 can read the rotational speed difference of the impeller of the wind turbine at the current moment, and assign the rotational speed difference of the impeller of the wind turbine at the next moment to the rotational speed difference of the impeller of the wind turbine at the current moment.

[0068] In step 503, process 500 can determine whether the timer is turned off within 100 ms.

[0069] In step 504, if it is determined in step 503 that the timer is turned off within 100 ms (i.e., a rotational speed difference greater than 0.1 is read), then increment the count value of the timer by 1; otherwise, reset the timer and return to step 502 to read the rotational speed difference of the impeller of the wind turbine at the current moment.

[0070] In step 505, process 500 can determine whether the count value is greater than a threshold within 2 seconds (the threshold can usually be set to 50 times or 80 times), which is mainly used to detect whether there are sudden large and small changes in the rotational speed difference of the impeller of the wind turbine.

[0071] In step 506, if it is determined in step 505 that the count value is greater than the threshold within 2 seconds, process 500 can output the information of the unit's blade jamming and analyze the reason for the blade jamming according to the remaining variables and data; otherwise, process 500 ends.

[0072] After step 506, process 500 ends.

[0073] Compared with the threshold detection method without setting a time window, the Figure 5 shown frequency detection method can not only detect the frequency level of the change in rotational speed, but also does not require a large amount of CPU resources.

[0074] Next, the determination and analysis of the imbalance of the blade will be described in detail with reference to Figure 6 .

[0075] Figure 6 Fig. 600 shows a curve of the change in the ratio of the squares of the rotational speeds of the impeller of the wind turbine when blade jamming occurs according to an exemplary embodiment of the present invention.

[0076] Referring to Figure 6 , Figure 6 the abscissa in Figure 6 can indicate each moment during the pitch change of the wind turbine, and the ordinate in Figure 6 can indicate the ratio of the squares of the rotational speeds of the impeller of the wind turbine at each moment (i.e., Figure 6 ). It can be seen from Figure 6 that this ratio increases more and more with the extension of the pitch closing time, and the reason is that the angle difference between the pitch angles of the three blades of the wind turbine with blade jamming becomes larger and larger.

[0077] In addition, according to Figure 6 the black curve fitted in Figure 6 the imbalance between the three blades in the impeller of the wind turbine can also be obtained. As an example, starting from the moment when blade jamming is detected (which corresponds to Figure 6As shown by the circles in [Figure], since the angular difference e0 between the pitch angles of the three blades in the impeller of the wind turbine under normal operating conditions is approximately 0.5 degrees, the angular difference between the pitch angles of the three blades in the impeller of the wind turbine in the nth cycle can be obtained by the following formula:

[0078] e n = e0 * 1.008 n (2)

[0079] In formula (2), e n can indicate the angular difference between the pitch angles of the three blades of the impeller of the wind turbine in the nth cycle starting from the moment when blade jamming is detected; e0 can indicate the angular difference between the pitch angles of the three blades of the impeller of the wind turbine under normal operating conditions (0.5 degrees as mentioned above); n is the number of cycles. That is, by multiplying e0 by 1.008 for each cycle, the angular difference between the pitch angles of the three blades of the impeller of the wind turbine in the 500th cycle is approximately 26 degrees (here each cycle is approximately 20 ms, and 500 cycles are approximately 10 seconds), and thus the imbalance of the three blades in the impeller of the wind turbine can be determined.

[0080] In addition, according to the embodiments of the present disclosure, blade jamming can include two situations: "complete blade jamming" and "slow blade retraction speed".

[0081] Figure 7 Figure 700 shows a curve diagram of the situation of slow blade retraction speed according to an exemplary embodiment of the present invention.

[0082] Referring to Figure 7 , Figure 7 the abscissa in [Figure] can indicate each moment during the pitch change of the wind turbine, Figure 7 and the ordinate in [Figure] can indicate the pitch angle of each blade in the impeller of the wind turbine at each moment. As can be seen from Figure 7 [Figure], curves 702 and 703 are the changes in the pitch angles of the blades during normal blade retraction, while curve 701 is the change in the pitch angle of the blade where blade jamming occurs. In this example, since the blade corresponding to curve 701 experiences blade jamming and has a slow blade retraction speed, the angular difference between the pitch angles of the three blades becomes larger and larger. This blade jamming may be caused by reasons such as abnormal speed analog output module, abnormal incremental signal of the rotary encoder, abnormal brake relay, abnormal opening of the brake solenoid valve, or mechanical jamming in the transmission mechanism of this blade.

[0083] Figure 6 and Figure 7 are curves drawn based on the same data file, and Figure 7 the moment with an abscissa of 5 in [Figure] corresponds to the moment with an abscissa of 1937 in Figure 6 [Figure]. As can be seen from Figure 7As can be seen, the angular difference between the pitch angles of the three blades of the wind turbine is about 25 degrees at the moment when the abscissa in Figure 7 is 15, which is close to the 26 degrees calculated above. And the ratio of the square of the rotational speed of the wind turbine at the moment when the abscissa in Figure 7 is 5 to the angular difference between the pitch angles of the three blades of the wind turbine is close to 1.008.

[0084] For comparison, Figure 8 FIG. 800 shows a graph of the situation of full pitch locking according to an exemplary embodiment of the present invention.

[0085] Referring to Figure 8 , Figure 8 the abscissa in Figure 8 can indicate each moment during the pitch change of the wind turbine, and the ordinate in Figure 8 can indicate the pitch angle of each blade in the impeller of the wind turbine at each moment. As can be seen from Figure 8 , curves 802 and 803 are the changes in the pitch angles of the normally feathering blades, while curve 801 is the change in the pitch angle of the blade that experiences pitch locking. In this example, since the blade corresponding to curve 801 experiences full pitch locking, the curve 801 shown in Figure 7 does not change with time as slowly as the curve 701 shown in

[0086] Figure 9 FIG. 900 is a structural block diagram of a pitch locking detection device for a wind turbine according to an exemplary embodiment of the present invention.

[0087] Referring to Figure 9 , Figure 9 the pitch locking detection device 900 shown may include a rotational speed monitoring unit 910 and a pitch locking detection unit 920. Among them, the rotational speed monitoring unit 910 can monitor the rotational speed of the impeller of the wind turbine during the pitch change of the wind turbine; the pitch locking detection unit 920 can detect whether the blades in the impeller of the wind turbine experience pitch locking based on the change in the rotational speed of the impeller of the wind turbine.

[0088] As an example, the blade jamming detection unit 920 may further include a rotational speed acquisition unit, a rotational speed difference calculation unit, and a blade jamming determination unit (all not shown). Among them, the rotational speed acquisition unit can acquire the rotational speeds of the impeller of the wind turbine at multiple consecutive moments; the rotational speed difference calculation unit can calculate the rotational speed difference of the impeller of the wind turbine at any two adjacent moments; the blade jamming determination unit can determine that a blade in the impeller of the wind turbine is jammed when the rotational speed difference presents a predetermined abnormal condition. In this example, this predetermined abnormal condition can be set as the rotational speed difference of the impeller of the wind turbine being greater than a predetermined threshold, or can also be set as the number of times that the rotational speed difference of the impeller of the wind turbine is greater than the predetermined threshold within a predetermined continuous time period reaches a predetermined number of times.

[0089] In addition, Figure 9 The shown blade jamming detection device 900 may further include a rotational speed ratio calculation unit and an imbalance analysis unit (both not shown). Among them, the rotational speed ratio calculation unit can calculate the ratio of the squares of the rotational speeds of the impeller of the wind turbine at any two adjacent moments; the imbalance degree determination unit can estimate the maximum angular difference between the pitch angles of the blades in the impeller according to the ratio of the squares of the rotational speeds to determine the imbalance degree between the blades in the impeller.

[0090] By adopting the above implementation process, the following technical effects can be achieved:

[0091] (1) Since the change in the rotational speed of the impeller of the wind turbine is directly analyzed instead of the vibration acceleration of the wind turbine, the method and device for blade jamming detection for a wind turbine according to the exemplary embodiments of the present invention do not need to consider the influences of various factors such as tower material, tower stiffness, tower height, nacelle mass, nacelle height, tower foundation stability, and balance degree, thus simplifying the blade jamming detection model for a wind turbine.

[0092] (2) The method and device for blade jamming detection for a wind turbine according to the exemplary embodiments of the present invention can make the blade jamming detection model for a wind turbine more accurate, thus further improving the recognition accuracy of blade jamming detection.

[0093] (3) Even when the DP communication between the main control system and the pitch control system is interrupted or the rotary encoder in the pitch control system malfunctions, the method and device for blade jamming detection for a wind turbine according to the exemplary embodiments of the present invention can accurately identify whether the wind turbine is jammed.

[0094] (4) Since there are few variables to be detected and the detected variables do not involve the data within the pitch system, the method and device for pitch locking detection for a wind turbine according to the exemplary embodiments of the present invention are not affected by the DP communication interruption between the main control system and the pitch system, and are even less likely to be interfered by abnormal signals (such as, rotary encoders, limit switches, motor operation data, fault words, status words);

[0095] (5) Since the vibration characteristics of the vibration values caused by different vibration reasons are the same (i.e., both are in the form of sinusoidal fluctuations), which makes the distinguishability of the judged frequency values (i.e., accurately distinguishing the vibration reasons) relatively low. Therefore, compared with the method of detecting the vibration amplitude and obtaining the vibration frequency, the method and device for pitch locking detection for a wind turbine according to the exemplary embodiments of the present invention are simpler to implement and have a higher distinguishability of the vibration reasons;

[0096] (6) Since the changes in the rotational speed values caused by torque mutations and abnormal rotational speed sensors are usually single jumps or several jumps with a relatively low frequency, while the excessive changes in the rotational speed caused by inconsistent or unbalanced blades in the impeller of a wind turbine are a continuous and high-frequency change process. Therefore, by detecting the number or frequency of cases where the rotational speed difference is greater than 0.1 rpm, the method and device for pitch locking detection for a wind turbine according to the exemplary embodiments of the present invention can effectively eliminate the interference to the pitch locking detection results caused by reasons such as torque mutations and data jumps in the rotational speed sensors collected, thereby further improving the accuracy of pitch locking detection;

[0097] (7) Compared with the detection method of simply counting by judging the threshold without setting a time window, the method and device for pitch locking detection for a wind turbine according to the exemplary embodiments of the present invention can accurately detect the speed of change of the rotational speed value.

[0098] According to the exemplary embodiments of the present invention, there is also provided a computer-readable storage medium storing a computer program. The computer-readable storage medium stores a computer program that, when executed by a processor, causes the processor to execute the method for pitch locking detection for a wind turbine according to the present invention. The computer-readable recording medium is any data storage device that can store data read by a computer system. Examples of the computer-readable recording medium include: read-only memory, random access memory, read-only optical discs, magnetic tapes, floppy disks, optical data storage devices, and carrier waves (such as data transmission via the Internet through wired or wireless transmission paths).

[0099] An exemplary embodiment according to the present invention further provides a computer device. The computer device includes a processor and a memory. The memory is used to store a computer program. The computer program is executed by the processor such that the processor executes the computer program for the pitch locking detection method for a wind turbine according to the present invention.

[0100] Although the present application has been shown and described with reference to the preferred embodiments, those skilled in the art should understand that various modifications and variations can be made to these embodiments without departing from the spirit and scope of the present application defined by the claims.

Claims

1. A pitch locking detection method for a wind turbine, characterized in that The blade jamming detection method includes: During the pitch change of the wind turbine, monitoring the rotational speed of the impeller of the wind turbine; Based on the change in the rotational speed, detecting whether a blade in the impeller of the wind turbine is jammed; Wherein, the step of detecting whether a blade in the impeller of the wind turbine is jammed based on the change in the rotational speed includes: Obtaining the rotational speeds of the impeller of the wind turbine at multiple consecutive moments; Calculating the rotational speed difference between any two adjacent moments of the impeller of the wind turbine; When the rotational speed difference presents a predetermined abnormal condition, determining that a blade in the impeller of the wind turbine is jammed.

2. The paddle detection method according to claim 1, wherein The predetermined abnormal condition includes at least one of the following conditions: The rotational speed difference is greater than a predetermined threshold; and The number of times that the rotational speed difference is greater than the predetermined threshold occurs within a predetermined continuous time period reaches a predetermined number of times.

3. The paddle detection method according to claim 2, wherein The predetermined threshold is 0.1 revolutions per minute.

4. The paddle detection method according to claim 1, characterized in that The blade jamming detection method further includes: Calculating the ratio of the squares of the rotational speeds of the impeller of the wind turbine at any two adjacent moments; Estimating the maximum angular difference between the pitch angles of the blades in the impeller according to the ratio of the squares of the rotational speeds to determine the imbalance between the blades in the impeller.

5. A pitch locking detection device for a wind turbine, characterized in that, The blade jamming detection device includes: A rotational speed monitoring unit configured to monitor the rotational speed of the impeller of the wind turbine during the pitch change of the wind turbine; A blade jamming detection unit configured to detect whether a blade in the impeller of the wind turbine is jammed based on the change in the rotational speed; Wherein, the blade jamming detection unit includes: A rotational speed obtaining unit configured to obtain the rotational speeds of the impeller of the wind turbine at multiple consecutive moments; A rotational speed difference calculating unit configured to calculate the rotational speed difference between any two adjacent moments of the impeller of the wind turbine; A blade jamming determination unit configured to determine that a blade in the impeller of the wind turbine is jammed when the rotational speed difference presents a predetermined abnormal condition.

6. The paddle card detection device according to claim 5, wherein The predetermined abnormal condition includes at least one of the following conditions: The rotational speed difference is greater than a predetermined threshold; and The number of times that the rotational speed difference is greater than the predetermined threshold occurs within a predetermined continuous time period reaches a predetermined number of times.

7. The paddle card detection device according to claim 6, characterized in that, The predetermined threshold is 0.1 revolutions per minute.

8. The paddle detection device according to claim 5, characterized in that, The blade jamming detection device further includes: A rotational speed ratio calculating unit configured to calculate the ratio of the squares of the rotational speeds of the impeller of the wind turbine at any two adjacent moments; An imbalance determination unit configured to estimate the maximum angular difference between the pitch angles of the blades in the impeller according to the ratio of the squares of the rotational speeds to determine the imbalance between the blades in the impeller.

9. A computer-readable storage medium storing a computer program, wherein, When the computer program is executed by a processor, the blade jamming detection method for a wind turbine according to any one of claims 1 to 4 is implemented.

10. A computing device, comprising: A processor; A memory storing a computer program, when the computer program is executed by the processor, implementing the blade jamming detection method for a wind turbine according to any one of claims 1 to 4.

Images