Wind power generation plant evaluation system, wind power generation system and wind power generation plant evaluation method

Abstract

To evaluate damage to a floating wind power generation plant to which loads due to natural phenomena such as wind, waves, and ocean currents are applied.SOLUTION: A wind power generation plant evaluation system comprises: an acceleration measuring instrument that is installed at a measurement point of a wind power generation plant and measures an acceleration at the measurement point when a wave load is applied to the wind power generation plant; a displacement acquisition unit that acquires a displacement at the measurement point; a response quantity wave load estimation unit that estimates a response quantity at a representative point of the wind power generation plant, and a wave load applied to the wind power generation plant, based on the acceleration measured by the acceleration measuring instrument and the displacement acquired by the displacement acquisition unit; and a damage evaluation unit that evaluates damage to the wind power generation plant based on stress or strain generated in the wind power generation plant calculated from the estimation result of the response quantity wave load estimation unit.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] An embodiment of the present invention relates to a wind power plant evaluation system, a wind power generation system, and a wind power plant evaluation method. [Background technology]

[0002] Floating wind power plants located on the ocean are known. Such wind power plants may be subjected to loads (wave loads) caused by natural phenomena such as wind, waves, and ocean currents that exceed expectations. For this reason, in order to ensure stable operation of the plant, it is necessary to understand the degree of damage caused by fatigue, etc. of the plant structures and to plan and implement appropriate maintenance and repairs. A commonly known method for assessing damage to wind power plants is to evaluate damage to blades, towers, etc. caused by wind by capturing signals from strain gauges. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-31610 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the above-mentioned method requires the installation of a large number of strain gauges, for example, on a floating structure in a floating wind power plant that is subject to wave loads caused by waves, ocean currents, etc. Therefore, it is considered that a large amount of money will be incurred for the installation of strain gauges and their maintenance, particularly in a large-scale wind power plant.

[0005] In consideration of the above, an object of the present invention is to provide a wind power plant evaluation system, a wind power generation system, and a wind power plant evaluation method that are capable of evaluating damage to a floating wind power plant that is subjected to loads from natural phenomena such as wind, waves, and ocean currents. [Means for solving the problem]

[0006] A wind power plant evaluation system according to an embodiment evaluates damage to a floating wind power plant located on the ocean and subjected to wave loads. The wind power plant evaluation system includes an acceleration measuring device installed at a measurement point of the wind power plant and measuring acceleration at the measurement point when wave loads act on the wind power plant, and a displacement acquisition unit acquiring displacement at the measurement point. The wind power plant evaluation system also includes a response amount wave load estimating unit estimating a response amount at a representative point of the wind power plant and a wave load acting on the wind power plant based on the acceleration measured by the acceleration measuring device and the displacement acquired by the displacement acquisition unit. The wind power plant evaluation system also includes a damage evaluation unit evaluating damage to the wind power plant based on stress or strain occurring in the wind power plant calculated from an estimation result by the response amount wave load estimating unit.

[0007] Moreover, a wind power generation system according to the embodiment includes a wind power generation plant and the above-described wind power generation plant evaluation system.

[0008] A wind power plant evaluation method according to an embodiment is a method for evaluating damage to a floating wind power plant located on the ocean and subjected to wave loads. The wind power plant evaluation method includes an acceleration measurement step of measuring acceleration at a measurement point of the wind power plant when a wave load acts on the wind power plant, and a displacement acquisition step of acquiring a displacement at the measurement point. The wind power plant evaluation method also includes a response amount wave load estimation step of estimating a response amount at a representative point of the wind power plant and a wave load acting on the wind power plant based on the acceleration measured in the acceleration measurement step and the displacement acquired in the displacement acquisition step. The wind power plant evaluation method also includes a damage evaluation step of evaluating damage to the wind power plant based on a stress or strain generated in the wind power plant calculated from an estimation result in the response amount wave load estimation step. Effect of the Invention

[0009] According to the present invention, it is possible to evaluate damage to a floating wind power plant that is subjected to loads due to natural phenomena such as wind, waves, and ocean currents. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic diagram showing a wind power generation system according to a first embodiment. [Diagram 2] FIG. 1 is a diagram for explaining wave loads acting on a wind power plant. [Diagram 3] FIG. 13 is a diagram showing an example of a wave load estimation result using a nonlinear Kalman filter. [Figure 4] FIG. 13 is a diagram showing an example of a waveform estimation result using an ARMA model. [Diagram 5] FIG. 2 is a flowchart of a plant evaluation method according to the first embodiment. [Figure 6] FIG. 11 is a schematic diagram showing a wind power generation system according to a second embodiment. [Figure 7] FIG. 11 is a flowchart of a plant evaluation method according to a second embodiment. [Figure 8] FIG. 11 is a schematic diagram showing a wind power generation system according to a fourth embodiment. [Figure 9] FIG. 13 is a flowchart of a plant evaluation method according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A wind power plant evaluation system, a wind power generation system, and a wind power plant evaluation method according to embodiments of the present invention will be described below with reference to the drawings.

[0012] (First embodiment) A wind power plant evaluation system, a wind power plant, and a wind power plant evaluation method according to a first embodiment will be described with reference to Figs. 1 to 5.

[0013] First, a wind power plant evaluation system and a wind power generation system according to the present embodiment will be described with reference to FIG.

[0014] As shown in FIG. 1, a wind power generation system 1 according to this embodiment includes a wind power generation plant 10 and a plant evaluation system 30 (wind power generation plant evaluation system).

[0015] A wind power plant 10 according to this embodiment is a floating wind power plant located on the ocean. The wind power plant 10 is a power generation facility that generates power using wind power on the ocean. As shown in FIG. 1, the wind power plant 10 includes a wind turbine 11 and a floating body 20.

[0016] The wind turbine 11 is a device that generates electricity using wind power. As shown in Fig. 1, the wind turbine 11 has a tower 12, a nacelle 13, a rotor 14, and a generator (not shown). The nacelle 13 and the rotor 14 are collectively referred to as an RNA 15 (rotor nacelle assembly).

[0017] The tower 12 supports the nacelle 13 from below. The tower 12 is formed in a slender columnar shape extending in the vertical direction. The nacelle 13 functions as a housing. The nacelle 13 houses a rotating shaft of the rotor 14, a speed change mechanism, and a generator (none of which are shown). The nacelle 13 is configured to be rotatable in the yaw direction relative to the tower 12. The nacelle 13 also rotatably supports the rotor 14. The rotor 14 includes a plurality of blades 14a, a hub 14b, and a rotating shaft (not shown). The plurality of blades 14a and the hub 14b are located in front of the nacelle 13. The hub 14b supports the plurality of blades 14a. The plurality of blades 14a are arranged radially around the hub 14b. One end of the rotating shaft is connected to the hub 14b, and the other end is connected to the speed change mechanism. The rotating shaft is connected to the generator via the speed change mechanism.

[0018] The blades 14a rotate by wind power to generate rotational energy. More specifically, the blades 14a rotate integrally with the hub 14b and the rotating shaft, and convert fluid energy obtained from the wind power into rotational energy. The rotating shaft transmits the rotational energy generated by the blades 14a to the generator. More specifically, the rotational energy is transmitted by the rotating shaft to the generator via a speed change mechanism. The speed change mechanism increases the rotation speed and transmits the rotation to the generator. Note that the rotation may be transmitted directly to the generator without the speed change mechanism, as in a direct drive system. The generator generates power using the transmitted rotational energy. In this way, the wind turbine 11 generates power by wind power.

[0019] The floating body 20 is a structure that supports the wind turbine 11 on the ocean by buoyancy. As shown in FIG.

[0020] The column 21 is formed in a slender column shape extending in the vertical direction. The column 21 has a cavity inside. At least a part of the column 21 is located in the sea, and the cavity generates buoyancy. The connecting portion 22 connects the multiple columns 21 to each other. The tower 12 is connected to one of the multiple columns 21. As a result, the multiple columns 21 generate buoyancy to support the wind turbine 11 on the sea. Note that the connecting portion 22 may also have a cavity inside, and generate buoyancy by this cavity. A footing 23 may be provided at the bottom of the column 21. In addition, a mooring rope 24 may be connected to the footing 23. The float 20 is moored to the seabed via the mooring rope 24. As a result, the wind power plant 10 remains in a predetermined sea area.

[0021] 2, loads (wave loads) due to natural phenomena such as wind 2, waves 3, and ocean currents 4 act on the wind power plant 10. For this reason, the wind power plant 10 may be damaged by fatigue or the like caused by the wave loads. The plant evaluation system 30 according to this embodiment evaluates such damage to the wind power plant 10.

[0022] As shown in FIG. 1, the plant evaluation system 30 includes an acceleration measuring device 31, a signal receiving unit 32, a displacement calculation unit 33, a response wave load estimation unit 34, a waveform estimation unit 35, a response calculation unit 36, a damage evaluation unit 37, a database 38, and a display unit 39.

[0023] The acceleration measuring device 31 is installed at a measurement point of the wind power plant 10. The acceleration measuring device 31 is configured to be able to measure the acceleration a. The acceleration measuring device 31 is, for example, an acceleration sensor. The acceleration measuring device 31 measures the acceleration at the measurement point when a wave load acts on the wind power plant 10. The acceleration measuring device 31 is installed at each of the measurement points of the wind turbine 11 and the measurement point of the floating body 20. The acceleration measuring device 31 is installed at a plurality of measurement points such as the tower 12 and nacelle 13 of the wind turbine 11 and the column 21 of the floating body 20 so as to measure each of the surge, sway, heave, roll, pitch, and yaw motions caused by the oscillation of the wind power plant 10. The acceleration measuring device 31 measures the vibration when the wave load acts on the wind power plant 10 as time-series data of the acceleration a. The acceleration measuring device 31 may be a three-dimensional acceleration sensor that measures acceleration in a total of three directions, two horizontal directions and one vertical direction. In this case, the acceleration a due to each of the roll, pitch, and yaw movements is calculated from the measurement data of a plurality of acceleration measuring devices 31.

[0024] The signal receiving unit 32 receives acceleration a (time series data) from the acceleration measuring device 31 installed at each measurement point via the communication network 5. The signal receiving unit 32 transmits this acceleration a together with the identification information of the acceleration measuring device 31, including the position information of the acceleration measuring device 31, to the displacement calculation unit 33, the response amount wave load estimation unit 34, and the database 38.

[0025] The displacement calculation unit 33 is an example of a displacement acquisition unit. That is, the displacement acquisition unit includes the displacement calculation unit 33. The displacement calculation unit 33 acquires a displacement x at a measurement point. More specifically, the displacement calculation unit 33 calculates the displacement x at the measurement point based on the acceleration a measured by the acceleration measuring device 31. For example, the displacement calculation unit 33 calculates the displacement x at the measurement point by numerically integrating using a central difference method as shown in the following (Equation 1).

[0026]

number

[0027] Here, Δt represents the sampling period of the acceleration waveform, and i (=1, 2, . . .) represents the time step. Since the displacement x calculated by the above (Equation 1) has drift due to noise and numerical integration errors, a low-pass filter or high-pass filter may be applied to the displacement x to remove these.

[0028] The response amount wave load estimation unit 34 estimates the response amount at a representative point of the wind power plant 10 and the wave load E acting on the wind power plant 10 based on the acceleration a measured by the acceleration measuring instrument 31 and the displacement x acquired by the displacement acquisition unit (displacement calculation unit 33).

[0029] TIFF2025086101000003.tif52164

[0030]

number

[0031]

number

[0032] Here, x(t) represents a state variable such as displacement, velocity, acceleration, load, etc., f and h represent nonlinear functions of x(t), u(t) represents system noise, and w(t) represents observation noise.

[0033] Furthermore, the state equation is formulated using the equation of motion of a mass-spring system that is a simplified model of the wind power plant 10 shown in the following (Equation 4).

[0034]

number

[0035] TIFF2025086101000007.tif17164

[0036]

number

[0037] TIFF2025086101000009.tif47170

[0038] FIG. 3 is a diagram showing an example of the estimation result of the wave load E by the nonlinear Kalman filter. This wave load E is a wave load in the heave direction acting on the floating body 20. In FIG. 3, the horizontal axis indicates time t [sec], and the vertical axis indicates the wave load E [N]. Here, the heave acceleration obtained by a numerical simulation of a virtual wind power plant oscillating under the wave load is regarded as a measurement value by the acceleration measuring device 31, and the wave load E is estimated by the above-mentioned method. In FIG. 3, the graph of "True" shows the wave load E obtained by the numerical simulation, and the graph of "Estimation" shows the wave load E obtained by the above-mentioned nonlinear Kalman filter. As shown in FIG. 3, the method using the nonlinear Kalman filter allows the wave load E to be calculated with high accuracy.

[0039] In this case, a one-mass, one-degree-of-freedom equation of motion for the heave oscillation of the wind power plant 10 is used as the equation of motion of the above (Equation 4), and the state equation shown in the above (Equation 2) and the equation of motion shown in the above (Equation 3) are respectively set to the following (Equation 6) and (Equation 7).

[0040]

number

[0041]

number

[0042] TIFF2025086101000012.tif34170

[0043] TIFF2025086101000013.tif30170

[0044] The above equations of motion, state equations, and observation equations can be easily extended to a mass-spring model that represents the motion of the wind power plant 10 in each of the surge, sway, heave, roll, pitch, and yaw directions.

[0045] The waveform estimation unit 35 estimates the waveform ζ of the waves incident on the float 20 based on the wave load E estimated by the response quantity wave load estimation unit 34. For example, the waveform estimation unit 35 estimates the waveform ζ from the wave load E using a transfer function H that takes the wave load E acting on the float 20 as an input and takes the waveform ζ of the waves incident on the float 20 as an output. More specifically, the waveform estimation unit 35 calculates the waveform ζ by multiplying the wave load E acting on the float 20 by the transfer function H, as shown in the following (Equation 8).

[0046]

number

[0047] In this embodiment, the transfer function H is obtained by identifying parameters of an auto-regressive moving average model (ARMA) by a recursive least squares estimation method using time series data of a waveform obtained in advance and time series data of a wave load calculated from the time series data of the waveform by a numerical simulation or a water tank experiment.

[0048] FIG. 4 is a diagram showing an example of the estimation result of the waveform ζ by the ARMA model. In FIG. 4, the horizontal axis indicates time t [sec], and the vertical axis indicates the waveform ζ [m]. Here, the parameters of the ARMA model are calculated from the relationship between the time series data of the waveform and the time series data of the wave load calculated by a numerical simulation from the time series data of the waveform. In FIG. 4, the graph of "True" shows the waveform ζ obtained by the numerical simulation, and the graph of "Estimation" shows the waveform ζ obtained by the above-mentioned ARMA model. Note that in FIG. 4, the waveform ζ is estimated from a wave load E different from the wave load used to identify the parameters of the ARMA model. As shown in FIG. 4, the method using the ARMA model allows the waveform ζ to be calculated with high accuracy.

[0049] TIFF2025086101000015.tif35163

[0050] The damage assessment unit 37 assesses the damage of the wind power plant 10 based on the stress or strain generated in the wind power plant 10 calculated from the estimation result of the response wave load estimation unit 34. More specifically, the damage assessment unit 37 calculates the stress or strain generated in the tower 12 based on the response estimated by the response wave load estimation unit 34, and assesses the damage of the tower 12 based on the stress or strain. For example, the damage assessment unit 37 calculates the stress or strain generated in the tower 12 using the relative displacement between the nacelle 13 and the floating body 20 estimated by the response wave load estimation unit 34. The damage assessment unit 37 uses the stress or strain generated in the tower 12 to calculate a cumulative fatigue damage coefficient from a fatigue diagram stored in advance in the database 38. Then, the damage assessment unit 37 evaluates the damage of the tower 12 by comparing the cumulative fatigue damage coefficient with a tolerance stored in advance in the database 38. The damage assessment unit 37 transmits the assessment results to a database 38 and a display unit 39 .

[0051] Furthermore, the damage assessment unit 37 assesses the damage to the float 20 based on the stress or strain generated in the float 20 calculated by the response calculation unit 36. For example, the damage assessment unit 37 uses the stress or strain generated in the float 20 to calculate a cumulative fatigue damage coefficient from a fatigue diagram previously stored in the database 38. The damage assessment unit 37 then assesses the damage to the float 20 by comparing the cumulative fatigue damage coefficient with an allowable value previously stored in the database 38. The damage assessment unit 37 transmits the assessment result to the database 38 and the display unit 39.

[0052] The database 38 stores various data. For example, the database 38 stores parameters of the equation of motion used in the response quantity wave load estimation unit 34, a transfer function used in the waveform estimation unit 35, and an FEM model used in the response calculation unit 36. The database 38 also stores fatigue diagrams and allowable values ​​used in the damage assessment unit 37. The database 38 also stores the results of assessment by the damage assessment unit 37.

[0053] The display unit 39 displays the evaluation results obtained by the damage evaluation unit 37. For example, the display unit 39 displays, in the form of a list, the areas of the wind power plant 10 being evaluated that are damaged in order of severity.

[0054] Next, the plant evaluation method (wind power plant evaluation method) according to this embodiment will be described with reference to FIG.

[0055] The plant evaluation method according to the present embodiment is a method for evaluating damage to a floating wind power plant 10 located on the ocean and subjected to wave loads. In the plant evaluation method according to the present embodiment, damage to the wind power plant 10 is evaluated using the above-mentioned plant evaluation system 30.

[0056] Fig. 5 is a diagram showing a flowchart of a plant evaluation method according to this embodiment. As shown in Fig. 5, the plant evaluation method according to this embodiment includes an acceleration measurement step (step S1 in Fig. 5), a displacement acquisition step (step S2 in Fig. 5), a response wave load estimation step (step S3 in Fig. 5), a waveform estimation step (step S4 in Fig. 5), a response calculation step (step S5 in Fig. 5), and a damage evaluation step (steps S6 and S7 in Fig. 5). The plant evaluation method according to this embodiment will be described below with reference to the flowchart in Fig. 5.

[0057] First, in step S1, acceleration a is measured at a measurement point of the wind power plant 10. More specifically, acceleration measuring device 31 measures acceleration a at a measurement point of the wind turbine 11 and at a measurement point of the floating body 20. The measured acceleration a is transmitted to signal receiving unit 32 via communication network 5, and signal receiving unit 32 receives the measured acceleration a. The acceleration a received by signal receiving unit 32 is transmitted to displacement calculation unit 33, response amount wave load estimation unit 34, and database 38.

[0058] Next, in step S2, the displacements at the measurement points are acquired. In this embodiment, the displacement acquisition step includes a displacement calculation step. That is, the displacement x at the measurement points is calculated based on the measured acceleration a. For example, as described above, the displacement calculation unit 33 calculates the displacement x at each measurement point by numerically integrating it using the central difference method.

[0059] TIFF2025086101000016.tif46170

[0060] Next, in step S4, the waveform ζ of the waves incident on the float 20 is estimated based on the wave load E estimated in the response quantity wave load estimation step. For example, as described above, the waveform estimation unit 35 estimates the waveform ζ from the wave load E using a transfer function H that inputs the wave load E acting on the float 20 and outputs the waveform ζ of the waves incident on the float 20.

[0061] TIFF2025086101000017.tif40170

[0062] Thereafter, in step S6, damage to the wind power plant 10 is evaluated based on the stress or strain occurring in the wind power plant 10 calculated from the estimation result in the response wave load estimation step. More specifically, as described above, the damage assessment unit 37 evaluates damage to the float 20 based on the stress or strain calculated in the response calculation step. For example, as described above, the damage assessment unit 37 calculates a cumulative fatigue damage coefficient from a fatigue diagram stored in advance in the database 38 using the stress or strain occurring in the float 20. Then, as described above, the damage assessment unit 37 compares this cumulative fatigue damage coefficient with a tolerance stored in advance in the database 38 to evaluate damage to the float 20.

[0063] In step S7, damage to the wind power plant 10 is evaluated based on the stress or strain generated in the wind power plant 10 calculated from the estimation result in the response wave load estimation process. More specifically, as described above, the damage evaluation unit 37 calculates the stress or strain generated in the tower 12 based on the response estimated in the response wave load estimation process, and evaluates the damage to the tower 12 based on the stress or strain. For example, as described above, the damage evaluation unit 37 calculates the stress or strain generated in the tower 12 using the relative displacement between the nacelle 13 and the floating body 20 estimated in the response wave load estimation process. The damage evaluation unit 37 calculates a cumulative fatigue damage coefficient from a fatigue diagram stored in advance in the database 38 using the stress or strain generated in the tower 12. Then, the damage evaluation unit 37 compares the cumulative fatigue damage coefficient with a tolerance stored in advance in the database 38 to evaluate the damage to the tower 12.

[0064] The results of the assessment by the damage assessment unit 37 are displayed on the display unit 39. For example, as described above, the display unit 39 displays a list of the areas of the wind power plant 10 being assessed in descending order of severity of damage. By looking at the assessment results displayed on the display unit 39, an operator can grasp the degree of damage to the wind power plant 10 and can plan and implement appropriate maintenance and repair of the wind power plant 10.

[0065] As described above, according to this embodiment, the plant evaluation system 30 includes a response wave load estimating unit 34 and a damage evaluating unit 37. The response wave load estimating unit 34 estimates a response at a representative point of the wind power plant 10 and a wave load E acting on the wind power plant 10 based on the acceleration a measured by the acceleration measuring device 31 and the displacement x acquired by the displacement acquiring unit. The damage evaluating unit 37 evaluates damage to the wind power plant 10 based on stress or strain occurring in the wind power plant 10 calculated from the estimation result of the response wave load estimating unit 34. As described above, according to this embodiment, it is possible to evaluate damage to the floating wind power plant 10 on which loads due to natural phenomena such as wind, waves, and ocean currents act. In addition, by performing a damage evaluation on the wind power plant 10, it is possible to estimate the lifespan and damage state of the wind power plant 10.

[0066] Furthermore, according to this embodiment, it is possible to eliminate the need to install strain gauges on the tower 12 or the floating body 20 of the wind power plant 10 in order to assess damage to the wind power plant 10. This makes it possible to reduce the costs of installing and maintaining the strain gauges in the plant evaluation system 30. As a result, the maintenance costs of the plant evaluation system 30 can be reduced.

[0067] Furthermore, according to this embodiment, the displacement calculation unit 33 calculates the displacement x at the measurement point based on the acceleration a measured by the acceleration measuring instrument 31. This makes it possible to reduce the costs of installing the displacement measuring instruments that measure displacement and maintaining them in the plant evaluation system 30. As a result, the maintenance costs of the plant evaluation system 30 can be further reduced.

[0068] Furthermore, according to this embodiment, the response quantity wave load estimator 34 estimates the response quantity and the wave load E using a nonlinear Kalman filter. This makes it possible to reduce measurement errors in the response quantity and to easily and accurately estimate the wave load E, which is difficult to measure directly. This makes it possible to appropriately evaluate damage to the wind power plant 10.

[0069] According to the present embodiment, the plant evaluation system 30 further includes a waveform estimation unit 35 and a response calculation unit 36. The waveform estimation unit 35 estimates the waveform ζ of the waves incident on the float 20 based on the wave load E estimated by the response wave load estimation unit 34. The response calculation unit 36 ​​calculates the stress or strain generated in the float 20 based on the response estimated by the response wave load estimation unit 34 and the waveform ζ estimated by the waveform estimation unit 35. Then, the damage evaluation unit 37 evaluates the damage of the float 20 based on the stress or strain calculated by the response calculation unit 36. In this way, the waveform ζ is estimated by the response wave load estimation unit 34 and the stress or strain generated in the float 20 is calculated by the response calculation unit 36, whereby the damage of the float 20 of the wind power plant 10 can be evaluated.

[0070] Furthermore, according to this embodiment, the waveform estimation unit 35 estimates the waveform ζ from the wave load E using a transfer function H that takes the wave load E acting on the float 20 as an input and the waveform ζ of the wave incident on the float 20 as an output. This makes it possible to easily and accurately estimate the waveform ζ from the wave load E. As a result, damage to the wind power plant 10 can be appropriately evaluated.

[0071] In the above embodiment, an example has been described in which the plant evaluation system 30 evaluates damage to the tower 12 and the floating body 20. However, this is not limited to the above, and for example, the plant evaluation system 30 may evaluate damage to other parts of the wind power plant 10, such as the nacelle 13 or the rotor 14. In addition, for example, the plant evaluation system 30 may evaluate only damage to the wind turbine 11 without evaluating damage to the floating body 20. In this case, the plant evaluation system 30 does not need to include the waveform estimation unit 35 and the response calculation unit 36. That is, it is sufficient that the plant evaluation system 30 includes at least the acceleration measuring device 31, the displacement acquisition unit, the response amount wave load estimation unit 34, and the damage evaluation unit 37.

[0072] (Second embodiment) Next, a wind power plant evaluation system, a wind power plant, and a wind power plant evaluation method according to a second embodiment will be described with reference to Figs.

[0073] The second embodiment shown in Figures 6 and 7 is different in that the displacement acquisition unit includes a displacement measuring device that measures the displacement at or near the measurement point. The other configurations are substantially the same as those of the first embodiment shown in Figures 1 to 5. In Figures 6 and 7, the same parts as those of the first embodiment shown in Figures 1 to 5 are given the same reference numerals and detailed description thereof will be omitted.

[0074] As shown in FIG. 6, the plant evaluation system 30 according to this embodiment includes a displacement measuring instrument 40 in addition to an acceleration measuring instrument 31. The displacement measuring instrument 40 is an example of a displacement acquisition unit. That is, in this embodiment, the displacement acquisition unit includes the displacement measuring instrument 40. The displacement measuring instrument 40 is configured to be able to measure displacement. The displacement measuring instrument 40 is, for example, a GPS (Global Positioning System) signal receiving device. The displacement measuring instrument 40 is installed at a measurement point where the acceleration measuring instrument 31 is installed or in the vicinity thereof. The displacement measuring instrument 40 measures the displacement at the measurement point or in the vicinity thereof.

[0075] 6, the plant evaluation system 30 according to this embodiment does not necessarily have to include the displacement calculation unit 33 (see FIG. 1) described in the above-mentioned first embodiment. That is, the plant evaluation system 30 according to this embodiment may include a displacement measuring instrument 40 instead of the displacement calculation unit 33.

[0076] In this embodiment, the signal receiving unit 32 receives the displacement x from the displacement measuring instrument 40 via the communication network 5. The signal receiving unit 32 transmits this displacement x to the response quantity wave load estimating unit 34 and the database 38. In addition, the response quantity wave load estimating unit 34 estimates the response quantity at the representative point of the wind power plant 10 and the wave load E acting on the wind power plant 10, based on the acceleration a measured by the acceleration measuring instrument 31 and the displacement x measured by the displacement measuring instrument 40.

[0077] Fig. 7 is a diagram showing a flowchart of the plant evaluation method according to this embodiment. As shown in Fig. 7, the plant evaluation method according to this embodiment does not include the displacement calculation step (step S2 in Fig. 5) described in the above-mentioned first embodiment, but instead includes a displacement measurement step (step S11 in Fig. 7). That is, in this embodiment, the displacement acquisition step includes a displacement measurement step. The displacement measurement step is performed before the response amount wave load estimation step.

[0078] 7, in this embodiment, in step S11, a displacement x at or near a measurement point is measured by the displacement measuring device 40. Then, in step S3, the response amount at the representative point of the wind power plant 10 and the wave load E acting on the wind power plant 10 are estimated based on the acceleration a measured in the acceleration measuring step and the displacement x measured in the displacement measuring step.

[0079] According to this embodiment, the estimation accuracy of the wave load E can be improved by measuring the displacement x with the displacement measuring instrument 40. That is, in the floating wind power plant 10, the natural period of each motion is long, and it is considered that steady displacement occurs due to waves and wind. Therefore, by using the displacement x measured by the displacement measuring instrument 40, the low-frequency component of the displacement x can be estimated with high accuracy, and the estimation accuracy of the wave load E can be improved.

[0080] (Third embodiment) Next, a wind power plant evaluation system, a wind power generation system, and a wind power plant evaluation method according to a third embodiment will be described.

[0081] The third embodiment is different from the first embodiment in that the transfer function is obtained by identifying the parameters of a neural network model. The other configurations are substantially the same as those of the second embodiment shown in Figures 6 and 7. In the present embodiment, detailed descriptions of the same parts as those of the second embodiment are omitted.

[0082] As described above, the waveform estimation unit 35 estimates the waveform ζ from the wave load E using a transfer function H that takes as input the wave load E acting on the float 20 and outputs the waveform ζ of the wave incident on the float 20. More specifically, the waveform estimation unit 35 calculates the waveform ζ by multiplying the wave load E acting on the float 20 by the transfer function H, as shown in the above (Equation 8).

[0083] Here, in the above-described embodiment, the transfer function H is obtained by identifying the parameters of the ARMA model using time series data of the waveform and time series data of the wave load calculated from the time series data of the waveform by numerical simulation or water tank experiments.

[0084] In this embodiment, the transfer function H is obtained by identifying parameters of a neural network model using time series data of the waveform and time series data of the wave load calculated from the time series data of the waveform by numerical simulation or a water tank experiment. That is, in this embodiment, the waveform estimation unit 35 calculates the waveform ζ using a neural network that has previously been machine-learned to learn the relationship between the magnitude and direction of the wave load acting on the float 20 and the height and direction of the waves incident on the float 20.

[0085] According to this embodiment, the estimation accuracy of the waveform ζ can be improved by obtaining the transfer function H by identifying the parameters of the neural network model. In other words, it is considered that the frequency characteristics of the wave load E acting on the floating body 20 depend on the height and direction of the waves incident on the floating body 20. For this reason, by using a neural network model in which these relationships have been machine-learned in advance based on a numerical simulation or the like, the estimation accuracy of the waveform ζ can be improved.

[0086] (Fourth embodiment) Next, a wind power plant evaluation system, a wind power plant, and a wind power plant evaluation method according to a fourth embodiment will be described with reference to Figs.

[0087] The fourth embodiment shown in Figures 8 and 9 is different in that a response amount wave load estimating unit estimates a response amount and a wave load based on a wind speed acquired by a wind speed acquiring unit. The other configurations are substantially the same as those of the second embodiment shown in Figures 6 and 7. In Figures 8 and 9, the same parts as those of the second embodiment shown in Figures 6 and 7 are denoted by the same reference numerals and detailed description thereof will be omitted.

[0088] As shown in Fig. 8, the plant evaluation system 30 according to this embodiment includes an anemometer 50 in addition to the acceleration measuring instrument 31 and the displacement measuring instrument 40. The anemometer 50 is an example of a wind speed acquisition unit. That is, the wind speed acquisition unit includes the anemometer 50. The anemometer 50 is configured to be able to measure wind speed. The anemometer 50 is, for example, a wind vane and anemometer. The anemometer 50 measures the wind speed v at the rotor 14 of the wind turbine 11. The anemometer 50 is installed in the nacelle 13 of the wind turbine 11, for example.

[0089] Alternatively, as shown in Fig. 8, the plant evaluation system 30 according to this embodiment may include a wind speed estimation unit 51 instead of the wind speed measurement device 50. The wind speed estimation unit 51 is an example of a wind speed acquisition unit. In other words, the wind speed acquisition unit includes the wind speed estimation unit 51. The wind speed estimation unit 51 estimates the wind speed v at the rotor 14 of the wind turbine 11. For example, the wind speed estimation unit 51 estimates the wind speed v by an extended Kalman filter as described in the following reference document, using the balance between the rotor torque and the generator torque of the wind turbine 11 and a fluctuating wind speed model.

[0090] Reference “NJAbbas, DSZalkind, L.Pao and A.Wright, A reference open-source controller for fixed and floating offshore wind turbines, Wind Energy. Sci., Vol.7, pp.53-73, 2022.”

[0091] As described above, in this embodiment, the wind speed v at the rotor 14 of the wind turbine 11 is obtained by the wind speed measuring device 50 or the wind speed estimating unit 51 .

[0092] 8, the plant evaluation system 30 according to the present embodiment includes a thrust force estimation unit 52. The thrust force estimation unit 52 estimates the thrust force T acting on the rotor 14 based on the wind speed v acquired by the wind speed acquisition unit. rThat is, the thrust force estimation unit 52 estimates the thrust force T acting on the rotor 14 based on the wind speed v measured by the anemometer 50 or the wind speed v estimated by the wind speed estimation unit 51. r For example, the thrust force estimation unit 52 estimates the thrust force T acting on the rotor 14 using the following (Equation 9): r Calculate.

[0093]

number

[0094] where ρ is the density of air, A r is the rotor area, C t is the rotor thrust coefficient, λ=ω r R / v is the tip speed ratio, ω r is the rotor rotational angular velocity, R is the rotor radius, and β is the blade pitch angle. r , R are recorded in advance in the database 38. t For the relation between the wind speed v and the blade pitch angle β, the relation between the wind speed v and the blade pitch angle β recorded in advance in the form of a table in the database 38 is used by interpolating v and β.

[0095] In the present embodiment, the response wave load estimation unit 34 calculates the response wave load based on the acceleration a measured by the acceleration measuring device 31, the displacement x acquired by the displacement acquisition unit, and the thrust force T estimated by the thrust force estimation unit 52. r For example, in the calculation of the response amount and wave load E by the response amount and wave load estimator 34, the equation of motion of the wind power plant 10 applied to the nonlinear Kalman filter is set to a three-degree-of-freedom equation of motion consisting of two mass points, the RNA 15 and the floating body 20, as shown in the following (Equation 10).

[0096]

number

[0097] where x r is the horizontal displacement of RNA15, x fis the surge displacement of the floating body 20, θ f represents the pitch rotation angle of the floating body 20. Also, m r is the mass of RNA15, m f is the mass of the floating body 20, I r is the moment of inertia of RNA15, I f represents the moment of inertia of the floating body 20. Also, C r is the damping coefficient of Tower 12, c f ,c θf is the damping coefficient of the floating body 20, k r is the stiffness of tower 12, k f represents the restoring force stiffness of the floating body 20, and h represents the height between the center of gravity of the RNA 15 and the floating body 20. Also, T r is the lotus thrust force, E x is the wave load in the surge direction, E θ represents the wave load moment in the pitch direction.

[0098] The above equation (10) is a simplified equation of motion, but it can be easily expanded to a two-mass, nine-degree-of-freedom model, with three degrees of freedom representing the horizontal and vertical motion of the RNA 15 and six degrees of freedom representing the surge, sway, heave, roll, pitch, and yaw motions of the floating body 20.

[0099] Fig. 9 is a diagram showing a flowchart of the plant evaluation method according to this embodiment. As shown in Fig. 9, the plant evaluation method according to this embodiment further includes a wind speed acquisition step (step S12 in Fig. 9) and a thrust force estimation step (step S13 in Fig. 9). The wind speed acquisition step and the thrust force estimation step are performed before the response quantity wave load estimation step.

[0100] As shown in Fig. 9, in this embodiment, in step S12, wind speed v at rotor 14 is acquired. The wind speed acquisition step includes a wind speed measurement step. That is, wind speed v at rotor 14 is measured by wind speed meter 50. Alternatively, the wind speed acquisition step includes a wind speed estimation step. That is, wind speed v at rotor 14 is estimated by wind speed estimator 51.

[0101] Then, in step S13, the thrust force T acting on the rotor 14 is calculated based on the wind speed v acquired in the wind speed acquisition process. r More specifically, as described above, the thrust force estimation unit 52 estimates the thrust force T acting on the rotor 14 based on the wind speed v measured in the wind speed measurement process or the wind speed v estimated in the wind speed estimation process. r Estimate.

[0102] Then, in step S3, the acceleration a measured in the acceleration measurement step, the displacement x acquired in the displacement acquisition step, and the thrust force T estimated in the thrust force estimation step are r More specifically, as described above, the response quantity and wave load estimating unit 34 calculates the response quantity and wave load by treating the equation of motion of the wind power plant 10 to be applied to the nonlinear Kalman filter as a three-degree-of-freedom equation of motion consisting of two mass points, the RNA 15 and the floating body 20.

[0103] According to this embodiment, the thrust force T acting on the rotor 14, which affects the motion of the floating body 20, r By taking the above into consideration, the estimation accuracy of the response amount and the wave load E can be improved. Therefore, the estimation accuracy of the waveform ζ can be improved.

[0104] The above-described embodiments may be combined as appropriate.

[0105] According to the embodiment described above, it is possible to evaluate damage to a floating wind power plant that is subjected to loads due to natural phenomena such as wind, waves, and ocean currents.

[0106] Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0107] 1: wind power generation system, 10: wind power generation plant, 11: wind turbine, 12: tower, 14: rotor, 14a: blade, 14b: hub, 20: floating body, 30: plant evaluation system, 31: acceleration measuring device, 33: displacement calculation unit, 34: response wave load estimation unit, 35: waveform estimation unit, 36: response calculation unit, 37: damage evaluation unit, 40: displacement measuring device, 50: wind speed measuring device, 51: wind speed estimation unit, 52: thrust force estimation unit

Claims

1. A wind power plant evaluation system for evaluating damage to a floating wind power plant located on the ocean and subjected to wave loads, comprising: an acceleration measuring device that is installed at a measurement point of the wind power plant and measures acceleration at the measurement point when the wave load acts on the wind power plant; a displacement acquisition unit that acquires a displacement at the measurement point; a response amount wave load estimating unit that estimates a response amount at a representative point of the wind power plant and the wave load acting on the wind power plant based on the acceleration measured by the acceleration measuring device and the displacement acquired by the displacement acquiring unit; and a damage assessment unit that assesses damage to the wind power plant based on a stress or strain generated in the wind power plant calculated from an estimation result of the response wave load estimation unit.

2. The wind power plant evaluation system according to claim 1 , wherein the displacement acquisition unit includes a displacement calculation unit that calculates the displacement at the measurement point based on the acceleration measured by the acceleration measuring device.

3. The wind power plant evaluation system according to claim 1 , wherein the displacement acquisition unit includes a displacement measuring device that measures a displacement at the measurement point or in a vicinity thereof.

4. The wind power plant evaluation system according to claim 1 , wherein the response quantity wave load estimating unit estimates the response quantity and the wave load by using a nonlinear Kalman filter.

5. 5. The wind power plant evaluation system according to claim 4, wherein in the nonlinear Kalman filter, state quantities to be estimated include parameters representing displacement, speed, acceleration, jerk, wave load, time derivative of wave load, and speed of motion at the representative point of the wind power plant, and observed quantities include displacement and acceleration at the representative point of the wind power plant.

6. The wind power plant includes a wind turbine having a tower and a floating body, the acceleration measuring device is installed at a measurement point of the wind turbine and a measurement point of the floating body, The wind power plant evaluation system includes: a waveform estimation unit that estimates a waveform of a wave incident on the floating body based on the wave load estimated by the response wave load estimation unit; and a response calculation unit that calculates a stress or strain generated in the floating body based on the response amount estimated by the response amount wave load estimation unit and the waveform estimated by the waveform estimation unit, 2. The wind power plant evaluation system according to claim 1, wherein the damage assessment unit calculates a stress or strain generated in the tower based on the response estimated by the response wave load estimation unit, evaluates damage to the tower based on the stress or strain, and evaluates damage to the floating body based on the stress or strain calculated by the response calculation unit.

7. 7. The wind power plant evaluation system according to claim 6, wherein the waveform estimation unit estimates the waveform from the wave load using a transfer function that has the wave load acting on the float as an input and the waveform of the wave incident on the float as an output.

8. 8. The wind power plant evaluation system according to claim 7, wherein the transfer function is obtained by identifying parameters of an autoregressive moving average model using time series data of the waveform and time series data of the wave load calculated from the time series data of the waveform by numerical simulation or a water tank experiment.

9. 8. The wind power plant evaluation system according to claim 7, wherein the transfer function is obtained by identifying parameters of a neural network model using time series data of the waveform and time series data of the wave load calculated from the time series data of the waveform by numerical simulation or a water tank experiment.

10. The wind power plant comprises a wind turbine having a rotor including blades and a hub; The wind power plant evaluation system includes: a wind speed acquisition unit that acquires a wind speed at the rotor; a thrust force estimating unit that estimates a thrust force acting on the rotor based on the wind speed acquired by the wind speed acquiring unit, 2. The wind power plant evaluation system according to claim 1, wherein the response amount wave load estimating unit estimates the response amount and the wave load based on the acceleration measured by the acceleration measuring device, the displacement acquired by the displacement acquiring unit, and the thrust force estimated by the thrust force estimating unit.

11. The wind power plant; A wind power generation system comprising: the wind power generation plant evaluation system according to any one of claims 1 to 10.

12. A method for evaluating damage to a floating wind power plant located on the ocean and subjected to wave loads, comprising the steps of: an acceleration measuring step of measuring an acceleration at a measurement point of the wind power plant when the wave load acts on the wind power plant; a displacement acquiring step of acquiring a displacement at the measurement point; a response amount wave load estimating step of estimating a response amount at a representative point of the wind power plant and the wave load acting on the wind power plant based on the acceleration measured in the acceleration measuring step and the displacement acquired in the displacement acquiring step; a damage assessment step of assessing damage to the wind power plant based on stress or strain generated in the wind power plant calculated from an estimation result in the response wave load estimation step.

13. The wind power plant includes a wind turbine having a tower and a floating body, In the acceleration measuring step, accelerations at a measurement point on the wind turbine and a measurement point on the floating body are measured, The wind power plant evaluation method includes: a waveform estimation step of estimating a waveform of a wave incident on the floating body based on the wave load estimated in the response wave load estimation step; A response calculation step of calculating a stress or strain generated in the floating body based on the response amount estimated in the response amount wave load estimation step and the waveform estimated in the waveform estimation step, 13. The wind power plant evaluation method according to claim 12, wherein, in the damage assessment step, a stress or strain generated in the tower is calculated based on the response amount estimated in the response amount wave load estimation step, and damage to the tower is evaluated based on the stress or strain, and damage to the floating body is evaluated based on the stress or strain calculated in the response calculation step.

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