A method for monitoring the in situ state of an offshore engineering structure

Abstract

The present application relates to a kind of marine engineering structure in situ state monitoring method, comprising: (1) the sensor ring arrangement and signal decomposition reconstruction are carried out;(2) the space displacement at the flange position where each sensor is located is calculated by the Planiol signal decomposition reconstruction technique;(3) flange plate plane posture fitting and inclination early warning.The present application arranges multiple acceleration sensors in ring on the fan flange ring, based on the dynamic response signal of offshore wind turbine flange plate, the space displacement at the flange position where each sensor is located is calculated by the Planiol signal decomposition reconstruction technique, and the flange plate plane motion trajectory and inclination angle of coordinate fitting are used to judge the flange tightness, and then judge whether the in situ state of tower tube changes.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of online monitoring of offshore wind turbines, and particularly relates to a method for monitoring the in-situ state of a marine engineering structure. BACKGROUND

[0002] Among many renewable energy power generation technologies, wind power generation is attracting attention in terms of social, environmental and economic benefits. Since the new century, the state has continuously increased investment in offshore wind power and policy support, and the offshore wind power industry has developed rapidly. However, the environment of offshore wind turbines is relatively harsh, the wind direction and wave height change rapidly, and there are also extreme conditions such as typhoons and tsunamis. Compared with the construction of onshore wind farms, offshore wind turbines have greater safety and investment risks. At the same time, regular maintenance and repair make the operation and maintenance cost of offshore wind power high, and it is also easily affected by the weather at sea. Through online monitoring of offshore wind turbines, the in-situ state of offshore wind turbines can be monitored in real time, and signals collected by various instruments can be analyzed in real time. If a fault signal is found, the wind turbine control protection can be triggered, thereby avoiding the occurrence of wind turbine tower collapse accidents.

[0003] Due to the offshore environment of the wind turbine, the vibration displacement becomes difficult to measure. Currently, the industry usually uses an inclination measurement method, which arranges a certain number of inclination sensors at multiple elevations of the offshore wind turbine tower, and then obtains the displacement curve of the tower through a physical model. However, this device is inconvenient to install, and cannot measure the vibration displacement of the tower at a high frequency. In addition, the existing GPS monitoring technology has poor accuracy and high cost, and the lack of offshore base stations makes it impossible to dynamically track the in-situ state of the wind turbine. Furthermore, the existing video measurement technology mainly captures the identification points through a panoramic camera, and then obtains the vibration displacement of the offshore wind turbine through image recognition. However, compared with the inclination sensor, the measurement accuracy is poor and the monitoring cannot be performed at night. Therefore, it is necessary to find a more accurate and convenient method for monitoring the in-situ state of the offshore wind turbine tower. SUMMARY

[0004] The embodiments of the present application provide a method for monitoring the in-situ state of a marine engineering structure. To have a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This part is not a general review, nor is it intended to determine the key / important elements or delineate the protection scope of these embodiments. Its only purpose is to present some concepts in a simple form as a prelude to the detailed description that follows.

[0005] The embodiments of the present application provide a method for monitoring the in-situ state of a marine engineering structure, which is improved in that it comprises:

[0006] (1) performing sensor ring arrangement and signal decomposition and reconstruction;

[0007] (2) Calculate the spatial displacement of the flange where the sensor is located by the Planiaron signal decomposition reconstruction technology;

[0008] (3) Flange plane posture fitting and inclination warning.

[0009] Preferably, the step (1) comprises arranging sensors around the key nodes of the flange to ensure that the sensors effectively capture the vertical vibration signals of the flange.

[0010] Preferably, the step (2) comprises obtaining reconstructed acceleration signals by using the Planiaron signal decomposition reconstruction technology, and obtaining vibration displacement in three directions by integral transformation, manifesting the displacement signals in the spatial coordinate system, and obtaining the displacement trajectory and spatial plane of the flange measuring point.

[0011] Further, the step (2) comprises

[0012] 2-1 Real-time decomposition of acceleration signals by Planiaron signal decomposition reconstruction technology:

[0013]

[0014] Wherein, γ m is the corresponding residue, λ m is the extreme value, and ξ m is the damping coefficient.

[0015] 2-2 Integrate the time term in the acceleration signal to obtain the velocity signal:

[0016]

[0017] 2-3 Integrate the time term in the discrete velocity signal to obtain the displacement signal:

[0018]

[0019] Further, according to the calculated displacement signal, the x, y, z displacement of the flange measuring point in three directions is input into the three-dimensional space coordinate to obtain the change of the flange measuring point relative to the initial state and the motion trajectory of the flange measuring point.

[0020] Preferably, the step (3) comprises fitting the measured spatial coordinates based on the measuring base point on the flange plane to obtain the real-time normal vector of the flange plane posture;

[0021] According to the median plane equation of the linearly independent space sphere, the least square solution of the center is obtained, and the real-time posture of the flange fitting plane is drawn in space;

[0022] According to the spatial normal vector of the flange plane, the flange inclination angle of the flange fitting plane in space is calculated.

[0023] Sensor displacement and flange tilt angle are used as tower monitoring indicators, and early warnings are issued in a timely manner for abnormal points that exceed the designed indicator warning thresholds.

[0024] Furthermore, including

[0025] 3-1 The flange measuring points are arranged circumferentially on the flange plane. Based on the flange measuring point coordinates obtained in step (1), the spatial plane attitude fitting of the flange measuring point coordinates is performed. The plane equation can be expressed as:

[0026] MA = L1#(4);

[0027] in, A = [a, b, c] T L1 = [1, 1, 1] T ;

[0028] 3-2 For solving the overdetermined equations, the normal vector A of the flange plane orientation can be obtained using the least squares method;

[0029] 3-3 For any two measuring points on the flange, their vectors This can be represented as (x2-x1, y2-y1, z2-z1), where N is the midpoint of the circle passing through the center N0(x0, y0, z0) and N1 and N2. 12 The vector can be represented as At this point, the two spatial vectors are perpendicular;

[0030] 3-4 Based on n effective measuring points on the flange, n-1 linearly independent expressions are obtained:

[0031] BC = L2#(5);

[0032] in

[0033] 3-5 The center of the flange lies in the plane constrained by (4), and this serves as a constraint condition, thus satisfying:

[0034] A T C = 1#(6);

[0035] 3-6 By constructing an optimization problem under the constraint of equation (6), the normal equation is derived, and the coordinates of the flange center under the least squares method are obtained;

[0036] The equation is:

[0037]

[0038] Where λ is the constrained Lagrange operator and K is the identity matrix;

[0039] The least squares solution is:

[0040]

[0041] 3-7 The center coordinates N0 can be solved according to equation (8). The flange radius is determined based on the average distance from the measuring point coordinates to the center of the circle.

[0042] 3-8 θ n The angle between the flange fitting plane and the flange face in its initial state is determined by the normal vectors of the two planes, and L is calculated. n This refers to the displacement of the accelerometer in spatial coordinates.

[0043] 3-9 Based on two monitoring indicators, flange tilt angle and displacement, an early warning threshold is set to monitor whether the in-situ status of the offshore wind turbine tower has changed;

[0044] Flange tilt angle: |θ n |<θ * ;

[0045] Flange displacement: |L n |<L *

[0046] Furthermore, if none of the above conditions are met, it is considered that the in-situ status of the offshore wind turbine tower has changed, and a warning should be issued in a timely manner, and the wind turbine should be shut down if necessary.

[0047] Furthermore, when one of the conditions is met, staff should be given a warning; when both conditions are met, the wind turbine's position remains unchanged and it can operate normally.

[0048] Preferably, the flange is monitored online for a long period of time to determine the in-situ status of the wind turbine tower.

[0049] The technical solutions provided by the embodiments of the present invention may include the following beneficial effects:

[0050] This invention arranges multiple acceleration sensors circumferentially on the wind turbine flange ring. Based on the response signal of the dynamic change of the offshore wind turbine flange, the spatial displacement at the flange position of each sensor is calculated by the Planni signal decomposition and reconstruction technology. The flange tightness is determined by the plane motion trajectory and tilt angle of the flange through coordinate fitting, and then it is determined whether the in-situ state of the tower has changed.

[0051] The application verifies that the signal decomposition and reconstruction method is effective and accurate by capturing the acceleration signals of four key nodes at the flange and reconstructing the acceleration signals by the Plannar signal decomposition, which fits well with the original signals. In terms of the flange plane posture fitting, the data points are located on the flange fitting plane, and the flange fitting planes in different time periods intuitively reflect the inclination angle changes of the flange relative to the initial state, and then determine whether the in-situ state of the tower drum changes.

[0052] The application proposes a new acceleration measuring point arrangement mode, which can intuitively reflect the dynamic response characteristics of the flange compared with the traditional tower drum distributed measuring points. Meanwhile, the Plannar signal decomposition and reconstruction technology can obtain the displacement of each measuring point position, and then convert the coordinates of the flange measuring points in the three-dimensional coordinate system to obtain the real-time motion trajectory of the offshore wind turbine flange.

[0053] According to the Plannar signal decomposition and reconstruction of the flange measuring point coordinates, the spatial circle fitting method is used to fit the in-situ plane of the flange measuring point coordinates, the inclination angle dynamic change reflecting the relative initial position of the flange plane is measured, and the in-situ state of the offshore wind turbine tower drum is captured in real time. Meanwhile, the in-situ state monitoring of the wind turbine sets up two monitoring indexes of flange inclination angle and flange displacement, and realizes the real-time monitoring of the in-situ state of the offshore wind turbine tower drum.

[0054] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the application. BRIEF DESCRIPTION OF DRAWINGS

[0055] The drawings incorporated into the specification and forming a part thereof, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the application.

[0056] Figure 1 Fig. 1 is a flow diagram of a method for monitoring the in-situ state of an offshore engineering structure according to an exemplary embodiment.

[0057] Figure 2 Fig. 2 is a diagram of the reconstructed results of the vertical direction acceleration signal of the No. 1 sensor according to embodiment 2.

[0058] Figure 3 Fig. 3 is a diagram of the displacement signal of the No. 1 sensor after integral transformation according to embodiment 2.

[0059] Figure 4 Fig. 4 is a diagram of the coordinates of the flange measuring points in different time periods according to embodiment 2.

[0060] Figure 5is a schematic diagram of the flange plane attitude fitting at different time periods according to the flange measurement point shown in embodiment 2.

[0061] Figure 6 is a schematic diagram of the flange inclination angle fitting at different time periods according to the flange plane attitude fitting shown in embodiment 2. DETAILED DESCRIPTION

[0062] The following description and drawings are illustrative of specific embodiments of the application and are not intended to be limiting thereof. The embodiments are presented solely for the purpose of enabling one of ordinary skill in the art to practice the application. Separate components and functions are optional, and the order of operations can vary. Parts and features of some embodiments can be included or substituted in other embodiments. The scope of embodiments of the application encompasses the entire scope of the claims, and all available equivalents of the claims. In this document, the terms "cha racterized by," "determined by," "defined by," "comprised of," and the like are intended to encompass the corresponding open-ended terms "comprising," "comprised of," "com prising," "comprised," "comprise," "com prising," "include," "including," and the like; the terms "consisting of," "consist of," "consisting," "consist," and the like are intended to mean the inclusion of the recited items that are optional, and the exclusion of items that are not recited; and the term "consisting essentially of" and the like are intended to mean the inclusion of the recited items that are optional, and the exclusion of items that are not recited, except for those that do not materially affect the basic and novel characteristic(s) of the claimed application. In this document, relational terms such as first and second, and the like can be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual relationship or order between such entities or actions. In this document, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or." That is, unless specified otherwise, or clear from context, "X employs A or B" is intended to mean any of the natural inclusive permutations. That is, if X employs A; or if X employs B; or if X employs both A and B, then "X employs A or B" is satisfied. In addition, the articles "a" and "an" as used in this document are intended to mean "one or more" or at least "one" unless specified otherwise or clear from context. To the extent that the term "includes" is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to "comprising" as comparable terms are interpreted when employed as

[0063] The application is further described below in conjunction with the accompanying drawings and embodiments:

[0064] The application provides a method for monitoring the in-situ state of an offshore wind turbine tower, to monitor complex signals generated by the offshore wind turbine tower in real time and convert them into images that are easy to identify. For the first time, multiple acceleration sensors are arranged circumferentially on the flange ring of the wind turbine, and based on the dynamic response signals of the offshore wind turbine flange, the spatial displacement at the flange position of each sensor is calculated by the Planiol signal decomposition and reconstruction technology, and the flange plate plane motion trajectory and inclination angle are fitted by coordinates to judge the flange tightness, and then judge whether the in-situ state of the tower has changed, and set up a warning threshold to avoid the occurrence of wind turbine collapse accidents.

[0065] A plurality of acceleration sensors are arranged in the circumferential direction at key measuring points of the fan flange, and based on the measured acceleration signals, the reconstructed acceleration signals are obtained by using the Plancher signal decomposition reconstruction technology, and the vibration displacement in three directions is obtained by integral transformation, the displacement signal is manifested in the spatial coordinate system, and the displacement motion trajectory and the spatial plane of the flange measuring point are obtained.

[0066] Based on the measuring base point on the flange plane, the spatial coordinates obtained by measurement are fitted in the plane to obtain the real-time normal vector of the flange plane posture. According to the median plane equation of the linearly independent space sphere, the least square solution of the center is obtained, and the real-time posture of the flange fitting plane is drawn in the space. According to the spatial normal vector of the flange plane, the flange inclination angle of the flange fitting plane in space is calculated. The "sensor displacement" and "flange inclination angle" are taken as the tower monitoring indicators, and according to the designed index warning threshold, the abnormal points exceeding the threshold are timely warned.

[0067] Embodiment 1:

[0068] The application provides a kind of offshore wind turbine tower in situ state monitoring method, to monitor the complex signal generated by offshore wind turbine tower in real time, and convert into image convenient to identify.As shown in Figure 1 Specific method as follows:

[0069] 1, sensor circumferential arrangement and signal decomposition reconstruction are carried out;

[0070] According to the vibration characteristics of the flange, sensors are arranged in the circumferential direction at the key nodes of the flange to ensure that the sensors can effectively capture the vertical vibration signals of the flange.

[0071] 2, the spatial displacement at the flange position of each sensor is calculated by using the Plancher signal decomposition reconstruction technology.

[0072] The reconstructed acceleration signals are obtained by using the Plancher signal decomposition reconstruction technology, and the vibration displacement in three directions is obtained by integral transformation, the displacement signal is manifested in the spatial coordinate system, and the displacement motion trajectory and the spatial plane of the flange measuring point are obtained.

[0073] 2-1) apply Plancher signal decomposition reconstruction technology to real-time decomposition of acceleration signals:

[0074]

[0075] wherein γ m is the corresponding residue, λ m is the extreme value, and ξ m is the damping coefficient.

[0076] 2-2) integrate the time term in the acceleration signal to obtain the velocity signal:

[0077]

[0078] 2-3) Integrate the time term in the discrete velocity signal to obtain the displacement signal:

[0079]

[0080] 2-4) According to the calculated displacement signal, the x, y, z direction displacement of the flange measurement point is input into the three-dimensional space coordinates, and the change of the flange measurement point relative to the initial state and the motion trajectory of the flange measurement point can be obtained. When the flange state changes, the acceleration sensor will also move, so the attitude change of the acceleration sensor can also reflect the in-place state of the flange.

[0081] 3, the flange plane attitude fitting and inclination early warning;

[0082] Based on the measurement base point on the flange plane, the space coordinates obtained by measurement are fitted in the plane to obtain the real-time normal vector of the flange plane attitude; According to the median plane equation of the linearly independent space sphere, the least square solution of the center of the circle is obtained, and the real-time attitude of the flange fitting plane is drawn in the space; According to the space normal vector of the flange plane, the flange inclination angle of the flange fitting plane in space is calculated; The sensor displacement and the flange inclination angle are taken as the tower drum monitoring index, and according to the designed index warning threshold, the abnormal points exceeding the threshold are warned in time.

[0083] 3-1) The flange measurement point is arranged circumferentially on the flange plane, and the flange measurement point coordinates obtained in step (1) are used to fit the space plane attitude of the flange measurement point coordinates, and the plane equation can be expressed as:

[0084] MA=L1#(4);

[0085] Wherein, A=[a, b, c] T , L1=[1, 1, 1] T

[0086] 3-2) For the solution of overdetermined equation, according to the least square method, the normal vector A of the flange plane attitude can be solved.

[0087] 3-3) For any two measurement points on the flange, the vector can be expressed as (x2-x1, y2-y1, z2-z1), and the vector of the midpoint N 12 of N1 and N2 passing through the center of the circle N0(x0, y0, z0) can be expressed as At this time, the two space vectors are perpendicular.

[0088] 3-4) Based on n effective measuring points on the flange plate, n-1 linearly independent expressions are obtained:

[0089] BC = L2#(5);

[0090] wherein

[0091] 3-5) The center of the flange plate is in the plane constrained by (4), and is taken as a constraint condition, i.e. satisfying:

[0092] A T C = 1#(6)

[0093] 3-6) The flange equation is derived by constructing an optimization problem under the constraint condition of (6), and the coordinates of the center of the flange plate under the least square method are obtained.

[0094] The flange equation is:

[0095]

[0096] wherein λ is the Lagrange operator of the constraint condition, and K is a unit matrix.

[0097] The least square solution is:

[0098]

[0099] 3-7) The coordinates of the center of the circle N0 can be solved according to formula (8), and the radius of the flange plate is determined according to the average value of the distance from the measuring point coordinates to the center of the circle.

[0100] 3-8) Let θ n be the angle between the fitting plane of the flange plate and the flange plate in the initial state, which is called the “flange inclination angle”, which can be determined by the normal vectors of the two planes. Let L n be the displacement of the acceleration sensor in the spatial coordinates.

[0101] 3-9) According to the two monitoring indexes of the flange inclination angle and the displacement, the in-situ state of the offshore wind turbine tower is monitored by setting a warning threshold to determine whether the in-situ state of the offshore wind turbine tower has changed.

[0102] Flange inclination angle: |θ n | < θ * (for example, θ * = 3°).

[0103] Flange displacement: |L n | < L, (for example, L * = 5 mm).

[0104] When none of the above conditions are met, it is considered that the in-situ state of the offshore wind turbine tower has changed, and timely warning should be given, and the wind turbine should be stopped if necessary. When one of the conditions is met, the workers should be warned, and when two conditions are met at the same time, the in-situ state of the wind turbine has not changed, and the wind turbine can work normally. The method can monitor the flange plate for a long time online, so that the in-situ state of the wind turbine tower can be judged in real time.

[0105] Example 2:

[0106] A wind turbine structure model is used, the acceleration sensor is arranged in the flange plate in a ring shape, the sampling frequency is 200 Hz, six bolts near the No. 1 sensor at the flange plate are removed to simulate structural damage, dynamic load is applied to the top of the model, and the dynamic response signals of each measuring point at the flange plate are obtained. According to the Plannar signal decomposition and reconstruction in step (1), the original signal is processed, and it can be seen that the original signal and the reconstructed signal are well fitted, as shown in Figure 2 , which illustrates the correctness of the Plannar decomposition and reconstruction technology in processing signals. The acceleration signal is integrated twice to obtain the reconstructed displacement signal, as shown in Figure 3 . Figure 4 The spatial coordinate state of the sensor measuring point at different time periods (initial state, t=0.11s, t=0.19s) is given. According to the method described in step (2), the plane attitude fitting of the measuring point is carried out, and the fitting result is as shown in Figure 5 , the flange fitting plane has produced an angle relative to the initial plane, as shown in Figure 6 , according to the flange inclination monitoring index, it can be judged whether the in-situ state of the tower of the wind turbine model has changed.

[0107] It should be understood that the present application is not limited to the processes and structures described above and shown in the drawings, and various modifications and changes can be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A method of monitoring the in situ condition of an offshore engineering structure, characterised by, The method comprises the following steps: (1) arranging sensors in a ring shape and signal decomposition reconstruction; (2) calculating the spatial displacement at the flange position of each sensor by using the Planiaron signal decomposition reconstruction technology; (3) fitting the flange plane attitude and warning the inclination; The step (3) comprises fitting the spatial coordinates obtained by measurement in a plane to obtain a real-time normal vector of the flange plane attitude; According to the median plane equation of the linearly independent spatial sphere, the least square solution of the circle center is obtained, and the real-time attitude of the flange fitting plane is drawn in the space; According to the spatial normal vector of the flange plane, the flange inclination angle of the flange fitting plane in the space is calculated; The sensor displacement and the flange inclination angle are taken as the tower monitoring indexes, and the abnormal points exceeding the threshold are warned in time according to the designed index warning threshold. 3-1 The flange measurement points are arranged in a ring shape on the flange plane, and the flange measurement point coordinates obtained in the step (1) are fitted in a spatial plane attitude, and the plane equation is represented as: ； wherein , , ; 3-2 For the solution of the over-determined equations, according to the least square method, the normal vector of the plane attitude of the flange can be solved ; 3-3 The vector of any two measuring points on the flange plate is represented as , for the center of the circle and and the midpoint of is represented as , when the two spatial vectors are perpendicular; 3-4 Based on the n effective measurement points on the flange, n-1 linearly independent expressions are obtained: ； wherein , , ; 3-5 The flange center is in the plane constrained in (4), and is taken as a limiting condition, that is, the following condition is satisfied: ； 3-6 The flange equation is derived by constructing an optimization problem under the constraint condition of (6), and the flange center coordinates under the least square method are obtained; The equation is: ； wherein Lagrange operator for the constraints, I is the identity matrix; The least square solution is: ； 3-7The circle center coordinates can be solved according to formula (8) The flange radius is determined according to the average value of the distance from the measuring point coordinates to the circle center. 3-8 record The angle of the plane fitted for the flange plate relative to the flange face in the initial state is determined by the normal vectors of the two planes, and the angle is calculated as is the displacement of the acceleration sensor in the spatial coordinates; 3-9 According to the two monitoring indexes of the flange inclination angle and the displacement, the in-situ state of the offshore wind turbine tower is monitored by setting a warning threshold. Flange tilt angle: ; Flange displacement: .

2. A method of monitoring the in situ condition of an offshore structure according to claim 1, characterised in that, The step (1) comprises arranging sensors in a ring shape on the key nodes of the flange to ensure that the sensors can effectively capture the vertical vibration signals of the flange.

3. A method of monitoring the in situ condition of an offshore structure according to claim 1, characterised in that, The step (2) comprises obtaining the reconstructed acceleration signals by using the Planiaron signal decomposition reconstruction technology, and obtaining the vibration displacement in three directions by integral transformation, so that the displacement signals are realized in the spatial coordinate system, and the displacement motion track and the spatial plane of the flange measurement points are obtained.

4. A method of monitoring the in situ condition of a marine structure according to claim 1 or 3, characterised in that, The step (2) comprises 2-1 The Planiaron signal decomposition reconstruction technology is used to decompose the acceleration signals in real time: ； wherein is a corresponding residue, is an extreme value, is a damping coefficient; 2-2 The time term in the acceleration signal is integrated to obtain the velocity signal: ； 2-3 The time term in the discrete velocity signal is integrated to obtain the displacement signal: 。 5. A method of monitoring the in situ condition of an offshore structure according to claim 3, characterised in that, According to the calculated displacement signal, the x, y and z direction displacements of the flange measurement points are input into the three-dimensional space coordinates to obtain the change of the flange measurement points relative to the initial state and the motion track of the flange measurement points.

6. A method of monitoring the in situ condition of an offshore structure according to claim 1, characterised in that, When the above conditions are not met, it is considered that the in-situ state of the offshore wind turbine tower has changed, and warning should be given in time, and the wind turbine should be stopped if necessary.

7. A method of monitoring the in situ condition of an offshore structure according to claim 1, characterised in that, When one of the conditions is met, the workers should be warned, and when both conditions are met, the in-situ state of the wind turbine does not change, and the wind turbine can work normally.

8. A method of monitoring the in situ condition of an offshore structure according to claim 1, characterised in that, The flange is monitored on line for a long time, and the in-situ state of the wind turbine tower is judged in real time.

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