Method, system and device for measuring fatigue load spectrum of wind turbine generator and tower drum of wind turbine generator

Abstract

The invention discloses a wind turbine generator and a tower fatigue load spectrum measurement method, system and device thereof, and the method comprises the steps: setting a first section in the length direction of a tower, and obtaining the actual measurement strain data of the first section; calculating a bending moment load of each first section according to the obtained actually measured strain data; calculating a first stress value corresponding to the first section according to the actually measured strain data; second sections are arranged from the first sections to the tower top or the tower bottom or among the multiple first sections, and bending moment loads of the second sections are calculated; calculating a second stress value corresponding to the second section according to the second bending moment load; according to the first stress value and the second stress value obtained through calculation, a rain flow counting method is adopted for analysis, and the fatigue load spectrum of each point of the tower drum is obtained. The system comprises modules corresponding to the method, the device comprises a strain detection device, a first control device, a second control device, a server and a fatigue load spectrum analysis module, and loads and load spectrums of multiple sectors of different sections can be obtained through the method.

Description

Technical Field

[0001] The present invention relates to the technical field of wind turbine generator sets, and in particular to a method, system and device for measuring fatigue load spectrum of a wind turbine generator set and a tower thereof. Background Art

[0002] At present, the fatigue design of tower is mainly based on the fatigue load spectrum obtained by load calculation according to IEC 61400-1, and the fatigue life of welds with different sections is calculated. This method does not consider the influence of wind direction change and unit yaw on the fatigue load of tower, which makes the fatigue design of tower have a large margin; or according to the micro-site selection results of the machine position, the fatigue load of different sectors is calculated separately. This method does not fully consider the design risks caused by the difference with the actual wind resource data.

[0003] In addition, tower load measurement is mainly carried out using traditional strain sensors, which have problems such as susceptibility to electromagnetic interference and poor stability in long-term measurements. Summary of the invention

[0004] In order to solve some or all of the technical problems existing in the above-mentioned prior art, the present invention provides a method, system and device for measuring the fatigue load spectrum of a wind turbine and its tower, which has the characteristics of being not affected by electromagnetic interference and having stable and reliable long-term test data. The loads and load spectra of multiple sectors of different cross-sections can be obtained, and the tower load can be monitored and compared with the design load spectrum. The tower can be finely designed and fatigue life predicted, and can also be used for life extension evaluation of wind turbine towers.

[0005] The technical solution of the present invention is as follows:

[0006] In a first aspect, the present invention provides a method for measuring a fatigue load spectrum of a wind turbine tower, comprising:

[0007] A first section is set in the length direction of the tower, and measured strain data of the first section is obtained;

[0008] Calculating the bending moment load of each first section according to the acquired measured strain data;

[0009] Calculate a first stress value corresponding to the first cross section according to the measured strain data;

[0010] A second section is set from the first section to the tower top or the tower bottom, or between multiple first sections, and the bending moment load of the second section is calculated;

[0011] Calculate a second stress value corresponding to the second cross section according to the second bending moment load;

[0012] According to the calculated first stress value and second stress value, the fatigue load spectrum of each point of the tower is obtained by using the rain flow counting method.

[0013] Furthermore, in the above-mentioned method for measuring fatigue load spectrum of a wind turbine tower, a first section is set in the length direction of the tower, and obtaining measured strain data of the first section includes:

[0014] A plurality of sections are set at any position of the tower, and a plurality of strain detection devices of the same number are arranged on each section, and the arranged strain detection devices are set to measure the strain data along the length direction of the tower with the main wind direction as the starting point;

[0015] Wherein, the strain detection device includes an optical fiber strain sensor or a strain gauge, the number of the strain detection devices includes an even number, and the even number of strain detection devices are evenly arranged on the cross section of the wind turbine tower.

[0016] Furthermore, in the above-mentioned method for measuring fatigue load spectrum of a wind turbine tower, calculating the first stress value corresponding to the first section according to the measured strain data includes:

[0017] Assuming that three sections are set at the top, middle and bottom of the wind turbine tower, and 8 strain detection devices are set on each section to obtain the measured strain data of sections at different positions along the length direction of the tower, we have:

[0018]

[0019] Among them, M A 、M B and M C Respectively represent the bending moment loads of the upper, middle and lower sections of the wind turbine tower, W A , W B , W C They represent the bending modulus of the upper, middle and lower sections of the wind turbine tower, E represents the elastic modulus of the wind turbine tower material, ε A0° , ε A45 , ε A90° , ε A135° , ε A180° , ε A225° , ε A270° and ε A315° They represent the strain values ​​measured at each measuring point of the strain detection equipment installed on the lower section of the wind turbine tower, ε B0° , ε B45 , ε B90° , ε B135° , ε B180° , ε B225° , ε B270° and ε B315° They represent the strain values ​​measured at each measuring point of the strain detection equipment in the middle section of the wind turbine tower, ε C0° , ε C45, ε C90° , ε C135° , ε C180° , ε C225° , ε C270° and ε C315° They respectively represent the strain values ​​measured at each measuring point of the strain detection equipment installed on the upper section of the wind turbine tower.

[0020] Furthermore, in the above-mentioned method for measuring fatigue load spectrum of a wind turbine tower, a second section is set from the first section to the tower top or the tower bottom, or between multiple first sections, and calculating the bending moment load of the second section includes:

[0021] If the second section is located between the two first sections in the middle and lower parts of the wind turbine tower, the bending moment load on the second section is:

[0022] M X =M A -(M A -M B )L X / L AB ;

[0023] Among them, M X The second section is located between the two first sections in the middle and lower parts of the wind turbine tower. L X Indicates the distance between the second section and the lower part of the wind turbine tower, L AB Indicates the distance between the first two sections in the middle and lower parts of the wind turbine tower;

[0024] If the second section is located between the two first sections in the middle and upper parts of the wind turbine tower, the bending moment load on the second section is:

[0025] M Y =M B -(M B -M C )L Y / L BC ;

[0026] Among them, M Y The second section is located between the two first sections in the middle and upper parts of the wind turbine tower, L Y Indicates the distance between the second section and the middle of the wind turbine tower, L AB It indicates the distance between the first two sections in the middle and upper parts of the wind turbine tower.

[0027] Furthermore, in the above-mentioned method for measuring fatigue load spectrum of a wind turbine tower, calculating the first stress value corresponding to the first section according to the measured strain data includes:

[0028] The first stress value is obtained by multiplying the strain value of the obtained measured strain data by the elastic modulus of the wind turbine tower material.

[0029] Furthermore, in the above-mentioned method for measuring fatigue load spectrum of a wind turbine tower, calculating the second stress value corresponding to the second cross section according to the second bending moment load includes:

[0030] The second bending moment value of the second section is divided by the bending modulus of the corresponding section to obtain a second stress value.

[0031] Furthermore, in the above-mentioned method for measuring fatigue load spectrum of a wind turbine tower, it also includes testing the acquired measured strain data, and the testing method includes:

[0032] In a breeze, the eccentric bending moment generated by the nacelle-wind rotor assembly relative to the tower axis is used as an external load. The nacelle is rotated at a constant speed for one circle to obtain a strain curve similar to a sine signal at each measuring point on the first section. The average value of the difference between the maximum and minimum values ​​of each measuring point on the same section is taken as the judgment index. If the measured value of any measuring point on the same section is greater than the preset value, the measured strain data obtained is unqualified.

[0033] The measured value of any measuring point is calculated by the following formula:

[0034] Ci=Δε i / ε a ;

[0035] Where Ci represents any measuring point on the same section, Δε i It represents the difference between the maximum and minimum values ​​of each measuring point on the same section of the tower, ε a It represents the average value of the difference between the maximum and minimum values ​​of each measuring point on the same section of the tower.

[0036] In a second aspect, the present invention provides a wind turbine tower fatigue load spectrum measurement system, comprising:

[0037] A strain data acquisition module, wherein the strain data acquisition module is used to set a first section in the length direction of the tower and acquire measured strain data of the first section;

[0038] A first section bending moment load calculation module, the first section bending moment load calculation module is used to calculate the bending moment load of each first section according to the acquired measured strain data;

[0039] A first stress value calculation module, the first stress value calculation module is used to calculate a first stress value corresponding to the first cross section according to the measured strain data;

[0040] A second section bending moment load calculation module, wherein the second section bending moment load calculation module is used to set a second section from the first section to the tower top or the tower bottom, or between multiple first sections, and calculate the bending moment load of the second section;

[0041] A second stress value calculation module, the second stress value calculation module is used to calculate a second stress value corresponding to the second cross section according to the second bending moment load;

[0042] The fatigue load spectrum module is used to obtain the fatigue load spectrum of each point of the tower by analyzing the first stress value and the second stress value obtained by calculation using the rain flow counting method.

[0043] In a third aspect, the present invention provides a wind turbine tower fatigue load spectrum measuring device, comprising:

[0044] A strain detection device, wherein the number of the strain detection devices includes a plurality, and the plurality of strain detection devices are arranged on the tower of the wind turbine generator set, and the plurality of strain detection devices form a cross section on the tower of the wind turbine generator set that can divide the tower, and the strain detection devices on each cross section are evenly distributed, and are used to sense the tower strain through wavelength changes;

[0045] A first control device, the first control device is connected to a plurality of strain detection devices, and is used to collect strain data detected by the plurality of strain detection devices, and is used to aggregate signals of a plurality of sensors on the same cross section;

[0046] a second control device, the second control device being connected to the first control device and being used to store the strain data collected by the first control device;

[0047] a server, the server being connected to the first control device and the second control device respectively, the server demodulating and processing strain signals detected by a plurality of strain detection devices, and further being used to perform fatigue load spectrum analysis on corresponding fatigue load spectrum analysis modules;

[0048] A fatigue load spectrum analysis module is connected to the server and is used to perform fatigue load spectrum analysis according to the strain data stored in the second control device.

[0049] In a fourth aspect, the present invention provides a wind turbine generator set, on which the wind turbine generator set tower fatigue load spectrum measuring device described above is provided.

[0050] The main advantages of the technical solution of the present invention are as follows:

[0051] A method for measuring fatigue load spectrum of a wind turbine tower of the present invention obtains measured strain data of a first section and calculates corresponding bending moment load and stress value, sets a second section from the first section to the top or bottom of the tower, or between multiple first sections, calculates bending moment load of the second section, and calculates corresponding second stress value, and adopts rain flow counting method to analyze according to the calculated first stress value and second stress value, and obtains fatigue load spectrum of each point of the tower. The method has the characteristics of not being affected by electromagnetic interference and long-term test data being stable and reliable, and can obtain loads and load spectra of multiple sectors of different sections. At the same time, by monitoring the tower load corresponding to the obtained load spectrum and comparing it with the designed load spectrum, the tower is finely designed and fatigue life predicted, and it can also be used for life extension evaluation of wind turbine tower at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The drawings described herein are used to provide a further understanding of the embodiments of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0053] Figure 1 A schematic flow chart of a method for measuring fatigue load spectrum of a wind turbine tower according to an embodiment of the present invention;

[0054] Figure 2 A schematic structural diagram of a wind turbine tower fatigue load spectrum measurement system provided by an embodiment of the present invention;

[0055] Figure 3 A schematic structural diagram of a section arranged on a tower in a wind turbine tower fatigue load spectrum measuring device provided by an embodiment of the present invention;

[0056] Figure 4 for Figure 3 A schematic diagram of the cross-sectional structure in the middle A direction;

[0057] Figure 5 A schematic diagram of a wind turbine tower fatigue load spectrum measurement device provided by an embodiment of the present invention for realizing tower fatigue load spectrum measurement;

[0058] Description of reference numerals:

[0059] 10. Strain data acquisition module; 11. First section bending moment load calculation module; 12. First stress value calculation module; 13. Second section bending moment load calculation module; 14. Second stress value calculation module; 15. Fatigue load spectrum module;

[0060] 100, tower; 101, first section; 102, first control device; 103, strain detection device; DETAILED DESCRIPTION

[0061] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0062] The following is combined with Figure 1-5 , describes in detail the technical solution provided by the embodiments of the present invention.

[0063] As attached Figure 1 As shown, an embodiment of the present invention provides a method for measuring fatigue load spectrum of a wind turbine tower, the method comprising the following steps S1 to S6:

[0064] Step S1: setting a first section in the length direction of the tower and obtaining measured strain data of the first section;

[0065] Specifically, a first section is set in the length direction of the tower, and obtaining measured strain data of the first section includes:

[0066] A plurality of sections are set at any position of the tower, and a plurality of strain detection devices of the same number are arranged on each section, and the arranged strain detection devices are set to measure the strain data along the length direction of the tower with the main wind direction as the starting point;

[0067] In some optional implementations of this embodiment, the strain detection device includes an optical fiber strain sensor or a strain gauge, and the number of the strain detection devices includes an even number, such as any number of 6, 8, 10, 12, 14 and 16, and the even number of strain detection devices is evenly arranged on the cross-section of the wind turbine tower.

[0068] It should be noted that the number of the above-mentioned strain detection devices is not limited to an even number. Of course, according to actual application conditions and needs, an odd number can be set, for example, any number among 5, 7, 9, 11, 13 and 15.

[0069] In addition, it can be imagined that the greater the number of the above-mentioned strain detection devices, the more strain detection data of the cross section, and the more accurate the corresponding detection results. However, the values ​​listed above are only exemplary descriptions, and strain detection devices within the listed numerical ranges are preferred. Of course, any number of strain detection devices, such as 1-20, 1-50 or 1-100, can also be selected to obtain actual measured strain data.

[0070] As an example, the same number of optical fiber strain sensors are arranged at the upper, middle and lower sections of the tower to measure the strain signal along the length of the tower. The arrangement takes the main wind direction as the starting point and the eight optical fiber strain sensors are evenly arranged along the circumference of the section to ensure that the optical fiber strain sensors in different sections have the same orientation.

[0071] Specifically, in a method for measuring fatigue load spectrum of a wind turbine tower of the present invention, in order to make the tower load spectrum finally measured more accurate, the calculation process of measuring the tower load spectrum is more accurate, and the obtained measured strain data is also tested. The testing method includes:

[0072] In the breeze state, the eccentric bending moment generated by the nacelle-wind rotor assembly relative to the tower axis is used as the external load. The nacelle is rotated at a constant speed for one circle to obtain the strain curve of each measuring point of the first section similar to the sine signal. The average value of the difference between the maximum and minimum values ​​of each measuring point on the same section is taken as the judgment index. If the measured value of any measuring point on the same section is greater than the preset value, the measured strain data obtained is unqualified; the optical fiber strain sensor of the measuring point needs to be replaced and reinstalled. After installation, recheck according to the above process. Make the measurement results of each measuring point meet the judgment index to ensure the accuracy of the measurement data.

[0073] The measured value of any measuring point is calculated by the following formula:

[0074] Ci=Δε i / ε a ;

[0075] Where Ci represents any measuring point on the same section, Δε i It represents the difference between the maximum and minimum values ​​of each measuring point on the same section of the tower, ε a It represents the average value of the difference between the maximum and minimum values ​​of each measuring point on the same section of the tower.

[0076] Among them, the difference between the maximum and minimum values ​​of each measuring point on the same section of the tower is Δε i Calculated using the following formula:

[0077] Δε i =ε imax -ε imin ;

[0078] Among them, ε imax Indicates the maximum value of each measuring point on the same section of the tower, ε imin Indicates the minimum value of each measuring point on the same section of the tower;

[0079] Among them, the average value of the difference between the maximum and minimum values ​​of each measuring point on the same section of the tower is ε a Calculated by the following formula:

[0080]

[0081] Where n represents the number of optical fiber sensors in a certain section of the tower.

[0082] It should be noted that the above-mentioned breeze state includes a state where the instantaneous wind speed is less than 3m / s.

[0083] Step S2: Calculating the bending moment load of each first section according to the acquired measured strain data;

[0084] Specifically, calculating the first stress value corresponding to the first cross section according to the measured strain data includes:

[0085] As an example, it is assumed that three sections are set at the upper part, middle part and lower part of the wind turbine tower. For the convenience of description, the upper part, middle part and lower part of the wind turbine tower in this embodiment are represented by capital letters A, B and C respectively. Eight strain detection devices are set on each section to obtain the measured strain data of the sections at different positions in the length direction of the tower, then:

[0086]

[0087] Among them, M A 、M B and M C Respectively represent the bending moment loads of the upper, middle and lower sections of the wind turbine tower, W A , W B , W C They represent the bending modulus of the upper, middle and lower sections of the wind turbine tower, E represents the elastic modulus of the wind turbine tower material, δ A0° , ε A45 , δ A90° , ε A135° , ε A180° , ε A225° , ε A270° and ε A315° They represent the strain values ​​measured at each measuring point of the strain detection equipment installed on the lower section of the wind turbine tower, ε B0° , ε B45 , ε B90° , ε B135° , ε B180° , ε B225° , ε B270° and ε B315° They represent the strain values ​​measured at each measuring point of the strain detection equipment in the middle section of the wind turbine tower, ε C0° , ε C45 , ε C90° , ε C135° , εC180° , ε C225° , ε C270° and ε C315° They respectively represent the strain values ​​measured at each measuring point of the strain detection equipment installed on the upper section of the wind turbine tower.

[0088] It can be understood that when there are multiple sections, the calculation method of the bending moment load of the multiple sections is consistent with the calculation method of the above-mentioned sections.

[0089] Step S3: calculating a first stress value corresponding to the first cross section according to the measured strain data;

[0090] Specifically, calculating the first stress value corresponding to the first cross section according to the measured strain data includes:

[0091] The first stress value is obtained by multiplying the strain value of the obtained measured strain data by the elastic modulus of the wind turbine tower material.

[0092] Step S4: setting a second section from the first section to the tower top or the tower bottom, or between multiple first sections, and calculating the bending moment load of the second section;

[0093] According to the tower bending moment load, which increases linearly from the tower top to the tower bottom, the bending moment load of different sections is obtained by linear interpolation according to the following formula:

[0094] Specifically, a second section is set from the first section to the tower top or the tower bottom, or between multiple first sections, and calculating the bending moment load of the second section includes:

[0095] If the second section is located between the two first sections in the middle and lower parts of the wind turbine tower, the bending moment load on the second section is:

[0096] M X =M A -(M A -M B )L X / L AB ;

[0097] Among them, M X The second section is located between the two first sections in the middle and lower parts of the wind turbine tower. L X Indicates the distance between the second section and the lower part of the wind turbine tower, L AB Indicates the distance between the first two sections in the middle and lower parts of the wind turbine tower;

[0098] If the second section is located between the two first sections in the middle and upper parts of the wind turbine tower, the bending moment load on the second section is:

[0099] M Y =MB -(M B -M C )L Y / L BC ;

[0100] Among them, M Y The second section is located between the two first sections in the middle and upper parts of the wind turbine tower, L Y Indicates the distance between the second section and the middle of the wind turbine tower, L AB It indicates the distance between the first two sections in the middle and upper parts of the wind turbine tower.

[0101] As an optional implementation method, by comparing the obtained bending moment load value of each section of the tower with the design limit load threshold, real-time monitoring and early warning of the tower load can also be achieved.

[0102] Step S5: calculating a second stress value corresponding to the second cross section according to the second bending moment load;

[0103] Specifically, calculating the second stress value corresponding to the second cross section according to the second bending moment load includes:

[0104] The second bending moment value of the second section is divided by the bending modulus of the corresponding section to obtain a second stress value.

[0105] Specifically, the above bending modulus is calculated by the following formula:

[0106]

[0107] Wherein, W represents the bending modulus, π represents the pi, D represents the outer diameter of the calculated or tested corresponding section of the tower, and d represents the inner diameter corresponding to the outer diameter of the calculated or tested corresponding section of the tower.

[0108] Step S6: According to the calculated first stress value and second stress value, a rain flow counting method is used to analyze and obtain a fatigue load spectrum of each point of the tower.

[0109] Specifically, for the first stress value, the rain flow counting method is used for the measured stress load history to obtain the fatigue load spectrum of each measuring point. For the second stress value, the rain flow counting method is used for its stress load history to obtain the fatigue load spectrum of each point.

[0110] As an optional implementation method, by comparing the fatigue load spectrum obtained above with the design load spectrum, it is also possible to achieve refined design and fatigue life prediction of the tower.

[0111] In summary, the method of the present invention is not subject to electromagnetic interference, and the long-term test data is stable and reliable. The load and load spectrum of multiple sectors with different cross sections can be obtained. In addition, the tower load can be monitored and compared with the design load spectrum, and the tower can be finely designed and fatigue life predicted. At the same time, the method of the present invention can also be used for the life extension evaluation of wind turbine towers.

[0112] Second, as Figure 2 As shown, the present invention provides a wind turbine tower fatigue load spectrum measurement system, including: a strain data acquisition module 10, a first section bending moment load calculation module 11, a first stress value calculation module 12, a second section bending moment load calculation module 13, a second stress value calculation module 14 and a fatigue load spectrum module 15, wherein:

[0113] The strain data acquisition module 10 is used to set a first section in the length direction of the tower and obtain the measured strain data of the first section; the first section bending moment load calculation module 11 is used to calculate the bending moment load of each first section according to the obtained measured strain data; the first stress value calculation module 12 is used to calculate the first stress value corresponding to the first section according to the measured strain data; the second section bending moment load calculation module 13 is used to set a second section from the first section to the top or bottom of the tower, or between multiple first sections, and calculate the bending moment load of the second section; the second stress value calculation module 14 is used to calculate the second stress value corresponding to the second section according to the second bending moment load; the fatigue load spectrum module 15 is used to analyze the calculated first stress value and second stress value using the rain flow counting method to obtain the fatigue load spectrum of each point of the tower.

[0114] Thirdly, Figure 3-5 As shown, the present invention provides a wind turbine tower 100 fatigue load spectrum measurement device, including: a strain detection device 103, a first control device 102, a second control device, a server and a fatigue load spectrum analysis module, wherein:

[0115] The number of strain detection devices 103 includes multiple strain detection devices 103, multiple strain detection devices 103 are arranged on the tower 100 of the wind turbine generator set, and multiple strain detection devices 103 form a cross section on the tower 100 of the wind turbine generator set that can divide the tower 100, for example Figure 3The three first sections 101 are shown, and the strain detection devices 103 on each section are evenly distributed, which are used to sense the tower strain through wavelength changes; the first control device 102 is connected to multiple strain detection devices 103, and is used to collect strain data detected by multiple strain detection devices 103 or to aggregate signals of multiple sensors on the same section; the second control device is connected to the first control device 102, and is used to store the strain data collected by the first control device 102; the server is connected to the first control device 102 and the second control device respectively, and the server is used to demodulate and process the strain signals detected by the multiple strain detection devices, and is also used to perform fatigue load spectrum analysis on the corresponding fatigue load spectrum analysis module; the fatigue load spectrum analysis module is connected to the server, or the server is integrated with the fatigue load spectrum analysis module to perform fatigue load spectrum analysis according to the strain data stored in the second control device.

[0116] In some optional implementations of this embodiment, the strain detection device 103 includes an optical fiber strain sensor, and the optical fiber strain sensor should be arranged inside the tower to sense the tower strain according to the wavelength change. The first control device 102 includes an optical fiber distribution box for collecting signals from multiple sensors of the same cross-section. The second control device includes an optical fiber demodulator, a server, and a fatigue load spectrum analysis module. The fatigue load spectrum analysis module includes load spectrum data analysis software or hardware and other equipment, or software for load spectrum data analysis is provided on hardware and other equipment, wherein the optical fiber demodulator is used for demodulation and processing of multiple optical fiber sensor signals; the server is used to control the entire system and store data and perform load spectrum analysis. The principles between the above-mentioned devices are as follows: Figure 5 As shown, through the device of the present invention, fatigue load spectra of multiple sections and multiple directions of the tower 100 can be obtained, and the obtained fatigue load spectrum can be compared with the design load spectrum to achieve refined design and fatigue life prediction of the tower 100.

[0117] In a fourth aspect, the present invention further provides a wind turbine generator set, on which the wind turbine generator set tower fatigue load spectrum measuring device is provided.

[0118] Through this wind turbine, fatigue load spectra of multiple sections and multiple directions of the tower can be obtained. At the same time, the obtained fatigue load spectrum can be compared with the design load spectrum to achieve refined design and fatigue life prediction of the tower.

[0119] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In addition, "front", "back", "left", "right", "upper" and "lower" in this article are all referenced to the placement state shown in the accompanying drawings.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for measuring fatigue load spectrum of wind turbine tower, characterized in that: include: A first section is set in the length direction of the tower, and measured strain data of the first section is obtained; Calculating the bending moment load of each first section according to the acquired measured strain data; Calculate a first stress value corresponding to the first cross section according to the measured strain data; A second section is set from the first section to the tower top or the tower bottom, or between multiple first sections, and the bending moment load of the second section is calculated; Calculate a second stress value corresponding to the second cross section according to the second bending moment load; According to the calculated first stress value and second stress value, the fatigue load spectrum of each point of the tower is obtained by using the rain flow counting method.

2. A method for measuring fatigue load spectrum of wind turbine tower according to claim 1, characterized in that: The first section is set in the length direction of the tower, and the measured strain data of the first section is obtained including: A plurality of sections are set at any position of the tower, and a plurality of strain detection devices of the same number are arranged on each section, and the arranged strain detection devices are set to measure the strain data along the length direction of the tower with the main wind direction as the starting point; Wherein, the strain detection device includes an optical fiber strain sensor or a strain gauge, the number of the strain detection devices includes an even number, and the even number of strain detection devices are evenly arranged on the cross section of the wind turbine tower.

3. A method for measuring fatigue load spectrum of wind turbine tower according to claim 1, characterized in that: Calculating the first stress value corresponding to the first section according to the measured strain data includes: Assuming that three sections are set at the top, middle and bottom of the wind turbine tower, and 8 strain detection devices are set on each section to obtain the measured strain data of sections at different positions along the length direction of the tower, we have: Among them, M A 、M B and M C Respectively represent the bending moment loads of the upper, middle and lower sections of the wind turbine tower, W A , W B , W C They represent the bending modulus of the upper, middle and lower sections of the wind turbine tower, E represents the elastic modulus of the wind turbine tower material, ε A0° , ε A45 , ε A90° , ε A135° , ε A180° , ε A225° , ε A270° and ε A315° They represent the strain values ​​measured at each measuring point of the strain detection equipment installed on the lower section of the wind turbine tower, ε B0° , ε B45 , ε B90° , ε B135° , ε B180° , ε B225° , ε B270° and ε B315° They represent the strain values ​​measured at each measuring point of the strain detection equipment in the middle section of the wind turbine tower, ε C0° , ε C45 , ε C90° , ε C135° , ε C180° , ε C225° , ε C270° and ε C315° They respectively represent the strain values ​​measured at each measuring point of the strain detection equipment installed on the upper section of the wind turbine tower.

4. A method for measuring fatigue load spectrum of wind turbine tower according to claim 3, characterized in that: A second section is set from the first section to the top or bottom of the tower, or between multiple first sections. The calculation of the bending moment load of the second section includes: If the second section is located between the two first sections in the middle and lower parts of the wind turbine tower, the bending moment load on the second section is: M X =M A -(M A -M B )L X / L AB ; Among them, M X The second section is located between the two first sections in the middle and lower parts of the wind turbine tower. L X Indicates the distance between the second section and the lower part of the wind turbine tower, L AB Indicates the distance between the first two sections in the middle and lower parts of the wind turbine tower; If the second section is located between the two first sections in the middle and upper parts of the wind turbine tower, the bending moment load on the second section is: M Y =M B -(M B -M C )L Y / L BC ; Among them, M Y The second section is located between the two first sections in the middle and upper parts of the wind turbine tower. L Y Indicates the distance between the second section and the middle of the wind turbine tower, L AB It indicates the distance between the first two sections in the middle and upper parts of the wind turbine tower.

5. A method for measuring fatigue load spectrum of wind turbine tower according to claim 1, characterized in that: Calculating the first stress value corresponding to the first section according to the measured strain data includes: The first stress value is obtained by multiplying the strain value of the obtained measured strain data by the elastic modulus of the wind turbine tower material.

6. A method for measuring fatigue load spectrum of a wind turbine tower according to claim 1, characterized in that: Calculating the second stress value corresponding to the second section according to the second bending moment load includes: The second bending moment value of the second section is divided by the bending modulus of the corresponding section to obtain a second stress value.

7. A method for measuring fatigue load spectrum of wind turbine tower according to claim 1, characterized in that: The method also includes testing the acquired measured strain data, wherein the testing method includes: In a breeze, the eccentric bending moment generated by the nacelle-wind rotor assembly relative to the tower axis is used as an external load. The nacelle is rotated at a constant speed for one circle to obtain a strain curve similar to a sine signal at each measuring point on the first section. The average value of the difference between the maximum and minimum values ​​of each measuring point on the same section is taken as the judgment index. If the measured value of any measuring point on the same section is greater than the preset value, the measured strain data obtained is unqualified. The measured value of any measuring point is calculated by the following formula: Ci=No i / e a ; Where Ci represents any measuring point on the same cross section, Δε i It represents the difference between the maximum and minimum values ​​of each measuring point on the same section of the tower, ε a It represents the average value of the difference between the maximum and minimum values ​​of each measuring point on the same section of the tower.

8. A wind turbine tower fatigue load spectrum measurement system, characterized in that: include: A strain data acquisition module, wherein the strain data acquisition module is used to set a first section in the length direction of the tower and acquire measured strain data of the first section; A first section bending moment load calculation module, the first section bending moment load calculation module is used to calculate the bending moment load of each first section according to the acquired measured strain data; A first stress value calculation module, the first stress value calculation module is used to calculate a first stress value corresponding to the first cross section according to the measured strain data; A second section bending moment load calculation module, wherein the second section bending moment load calculation module is used to set a second section from the first section to the tower top or the tower bottom, or between multiple first sections, and calculate the bending moment load of the second section; A second stress value calculation module, the second stress value calculation module is used to calculate a second stress value corresponding to the second cross section according to the second bending moment load; The fatigue load spectrum module is used to obtain the fatigue load spectrum of each point of the tower by analyzing the first stress value and the second stress value obtained by calculation using the rain flow counting method.

9. A wind turbine tower fatigue load spectrum measuring device, characterized in that: include: A strain detection device, wherein the number of the strain detection devices includes a plurality, and the plurality of strain detection devices are arranged on the tower of the wind turbine generator set, and the plurality of strain detection devices form a cross section on the tower of the wind turbine generator set that can divide the tower, and the strain detection devices on each cross section are evenly distributed, and are used to sense the tower strain through wavelength changes; A first control device, the first control device is connected to a plurality of strain detection devices, and is used to collect strain data detected by the plurality of strain detection devices or to aggregate signals of a plurality of sensors of the same cross section; a second control device, the second control device being connected to the first control device and being used to store the strain data collected by the first control device; a server, the server being connected to the first control device and the second control device respectively, the server being used to demodulate and process strain signals detected by a plurality of strain detection devices, and also being used to perform fatigue load spectrum analysis on corresponding fatigue load spectrum analysis modules; A fatigue load spectrum analysis module is connected to the server and is used to perform fatigue load spectrum analysis according to the strain data stored in the second control device.

10. A wind turbine generator set, characterized in that: The wind turbine generator set is provided with the wind turbine generator set tower fatigue load spectrum measuring device as described in claim 9 above.

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