Method and system for monitoring the condition of blades and towers of wind turbines

Abstract

The invention relates to a method for monitoring the condition of the blades and the tower of a wind turbine (1), particularly a wind turbine with a vertical or horizontal axis of rotation, and the method involves continuously measuring the distance of at least one point on each of the rotating blades (5) of the wind turbine (1) from at least one device (10) measuring distance and / or velocity, which is mounted at least at one point on the circumference of the tower (2) and at least at one height of the tower (2), for each blade rotation in front of the tower, and / or the velocity of at least one point of each of the rotating blades (5) of the wind turbine (1) for each blade rotation in front of the tower (2) in directions perpendicular and / or oblique to the vertical y axis of the tower (2), as well as the acceleration of at least one point of the tower (2) in at least one direction and the rotational velocity of the wind turbine (1) Subsequently, the amplitudes of displacements and / or velocities of each rotating blade of the wind turbine are determined, along with the vibration frequencies of each rotating blade (5) of the wind turbine (1) for each blade rotation in front of the tower, or the amplitudes of accelerations and the vibration frequencies of at least one point of the tower (2) are determined by transforming the measured distances, velocities, and accelerations from the time domain to the amplitude-frequency domain. Then, the determined acceleration amplitudes of at least one point of the tower (2) are converted into displacement amplitudes of at least one point of the tower (2) and / or velocity amplitudes of at least one point of the tower (2), alternatively, the determined displacement amplitudes of at least one point on each rotating blade (5) of the wind turbine (1) are converted into acceleration amplitudes of at least one point on each rotating blade (5) and / or velocity amplitudes of at least one point on each rotating blade (5), alternatively, the determined velocity amplitudes of at least one point on each rotating blade (5) of the wind turbine (1) are converted into acceleration amplitudes of at least one point on each rotating blade (5) and / or displacement amplitudes of at least one point on each rotating blade (5). Next, the actual displacement amplitudes of points and the actual vibration frequencies of the rotating blades (5) of the wind turbine (1) by filtering out the displacement amplitudes and vibration frequencies of the tower (2) from the displacement amplitudes and vibration frequencies of the rotating blades (5) of the wind turbine (1), or the actual acceleration amplitudes of the points and the actual vibration frequencies of the rotating blades (5) of the wind turbine (1) by filtering out the acceleration amplitude and vibration frequencies of the tower (2) points from the acceleration amplitudes and vibration frequencies of the rotating blades (5) of the wind turbine, or the actual velocity amplitudes of the points and the actual vibration frequencies of the rotating blades (5) of the wind turbine (1) by filtering out the velocity amplitude and vibration frequencies of the tower (2) points from the velocity amplitudes and vibration frequencies of the rotating blades (5) of the wind turbine. As a result, the service life condition of the blades and the tower of the wind turbine is assessed by comparing the actual vibration frequencies of the blades (5), the actual displacement amplitudes of the rotating blades (5), the actual vibration frequencies of the tower (2), the actual displacement amplitudes of the tower (2), the actual acceleration amplitudes of the rotating blades (5), the actual acceleration amplitudes of the tower (2), the actual velocity amplitudes of the rotating blades (5), and / or the actual velocity amplitudes of the tower (2) with their reference values for specified turbine rotational velocities, determined in an analytical model, a numerical model, or a nominal state without damage to the wind turbine (1). The invention also relates to a system for monitoring the condition of the blades and towers of wind turbines, particularly wind turbines with a vertical or horizontal axis of rotation, which comprises at least one accelerometer (7), an inertial sensor, a gyroscope, and / or an tilt sensor (8) for measuring the accelerations of points of the tower of the wind turbine (1), at least one device (10) for measuring the distance and / or velocity of the rotating blades (5) of the wind turbine (1) from the device (10) measuring distance and / or velocity of the rotating blades (5) of the wind turbine (1) in directions perpendicular and / or oblique to the vertical y axis of the tower (2), in the form of a non-contact sensor or a camera, at least one rotational velocity meter for the turbine (1) and a unit for recording and analysing measurement data.

Description

[0001] Method and System for Monitoring the Condition of Blades and Towers of Wind Turbines

[0002] Technical filed

[0003] The object of the invention is a method and system for monitoring the condition of the blades and towers of wind turbines, enabling the determination of the current condition of the structure and the remaining useful life of the blades and tower of the wind turbine. The method and system according to the invention are applicable, in particular, to all types of wind turbines with a horizontal axis of rotation (HAWT, Horizontal Axis Wind Turbine) as well as those with a vertical axis of rotation (VAWT, Vertical Axis Wind Turbine), both those already existing and those yet to be constructed.

[0004] State of the art

[0005] The individual components of a wind turbine, in particular the tower, nacelle, and rotor blades, are constantly exposed to external factors and the associated wear and damage. Constantly changing loads on the individual structural components of the turbine, caused by wind and / or marine or ocean waves, may contribute to or cause damage, thereby shortening the remaining useful life (RUL) of the turbine before repair or replacement is required. Additionally, changing environmental conditions, such as temperature fluctuations, humidity changes, or other factors, can affect its remaining useful life.

[0006] Therefore, it is necessary to monitor the condition of the blades and towers of wind turbines to determine their remaining useful life and appropriately plan maintenance actions.

[0007] In documents EP1359321A1 and US8454311B2, systems for monitoring the condition of wind turbine blades and towers are presented, which require the installation of measuring devices inside the blade, making the measurement technique expensive in practical application, and these methods are limited to individual test measurements rather than monitoring all turbines and their blades, for example, within a single wind farm. Meanwhile, international application PCT / US2014 / 062329 discloses the use of wireless acoustic sensors mounted inside the blade. The patent US8039981B2 is based on an accelerometer measuring the vibrations of the hub, which is attached to the rotating hub of the wind turbine. Vibration signals from each blade are separated from all the measurements as well as from the measurement of the sensor measuring the azimuth angle. This method is insufficient to identify damage to the rotating blades in their initial stages and is not accurate enough in the case of higher vibration modes of the blade.

[0008] The European patent application EP4077930A1 relates to a method for determining the clearance between the tip of the blade and the wind turbine tower, wherein the wind turbine consists of a wind turbine tower, where a distance sensor assembly is placed on at least one blade of the wind turbine and consists of at least one transmitter and receiver, wherein the method comprises the following steps: transmitting a signal from the distance sensor assembly towards the wind turbine tower, measuring the signal reflected from the wind turbine tower, determining the distance between the wind turbine tower and at least one blade of the wind turbine based on the transmitted and reflected signals, wherein the method further comprises the step of correcting the measured distance based on at least one of the actual tilt angles and yaw angles of at least one blade of the wind turbine at the location of the distance sensor assembly.

[0009] The European application EP2527651A3 discloses a wind turbine containing multiple blades, a plurality of micro-inertial measurement units (MIMUs) mounted on each blade, detecting blade parameter signals, and a parameter processing unit receiving the detected parameter signals and determining blade parameters based on the detected parameter signals. This document also discloses a method for determining wind turbine parameters, comprising receiving signals from micro-inertial measurement units (MIMUs) mounted on each blade of the wind turbine and determining parameters based on signals from the MIMUs. Preferably, receiving the detected signals comprises receiving detected signals from two MIMUs mounted respectively at the root and tip of the corresponding blade. And determining parameters based on signals from the MIMUs comprises determining at least one of the following parameters: blade tilt, blade rotational velocity, structural vibrations, blade bending moment, blade torsional moment, tip displacement, and three-dimensional motion trajectory.

[0010] Meanwhile, the patent CN107829885 discloses a method for monitoring the vibrations of wind turbine blades using dual-axis acceleration sensors installed at various points of the blades and hub, in which recorded blade and hub vibration data are analysed, the natural vibration frequency of the blade is extracted, and the natural vibration frequency introduced by the tower and hub is removed.

[0011] Meanwhile, the patent application US20150159632A1 concerns a method for measuring rotor blade vibrations in a wind turbine comprising a wind turbine tower and at least one rotating blade, wherein this method comprises providing at least one Doppler radar unit operatively configured to emit and receive radar signals, mounted on the wind turbine tower at a position above the lowest position of at least one blade, wherein the radar unit is positioned in such a way as to measure reflections of the emitted radar signal from the blade of the turbine; emitting a radar signal and receiving its reflections from the blade; analysing the Doppler shift of the received radar signals relative to the transmitted signals to determine the velocity of the blade movement towards or away from the turbine tower.

[0012] The document EP3232051A1 discloses a method and device for measuring the load on a wind turbine blade. The wind turbine blade contains at least one acceleration sensor. The blade has also an integrated measurement device that measures the distance between the sensor and the tower. Acceleration sensors measure accelerations that are directly dependent on the load. Due to the nature of double integration of acceleration to determine displacement, and measurement errors from the sensors, an absolute blade position gradually result in increasingly inaccurate. To update the correct position, a measurement device is used, which measures the distance between this section of the blade and the tower. The measurement result is used to update the correct position. The current blade tilt angle signal is received, as well as the current blade rotation angle signal, indicating the rotational position of individual blades. All these signals are then processed in a central control unit, which calculates deflection and load at each accelerator sensor location.

[0013] The object of the invention is to develop a method and system for the simple and economical monitoring of the condition of blades and towers of wind turbines, enabling the detection of structural damage to turbine components and the estimation of the remaining useful life of the turbine.

[0014] Essence of the invention

[0015] The first aspect of the invention is a method for monitoring the condition of the blades and towers of a wind turbine, comprising the following: a) continuous measurements over time of:

[0016] - the distance of each rotating blade of the wind turbine from at least one device for measuring distance and / or velocity, mounted at least one point on the circumference of the tower and at least one height of the tower, during each rotation of the blade in front of the tower, and / or the velocity of at least one point of each rotating blade of the wind turbine during each rotation of the blade in front of the tower, in a direction perpendicular and / or oblique relative to the vertical axis y of the tower, and

[0017] - the acceleration of at least one point of the tower in at least one direction,

[0018] - the rotational velocity of the turbine. b) determining:

[0019] - the displacement amplitudes and / or velocity amplitudes of each rotating blade of the wind turbine and the vibration frequencies of each rotating blade of the wind turbine during each rotation in front of the tower, along with phase shifts, and the amplitudes of accelerations, amplitudes of velocities, and vibration frequencies of at least one point of the tower, by transforming the measured distances, velocities, and accelerations in the time domain into the amplitude-frequency domain. c) transforming the determined acceleration amplitudes of at least one point of the tower into displacement amplitudes of at least one point of the tower and / or velocity amplitudes of at least one point of the tower, alternatively, transforming the determined displacement amplitudes of at least one point of each rotating blade of the wind turbine into acceleration amplitudes of at least one point of each rotating blade of the wind turbine and / or velocity amplitudes of at least one point of each rotating blade of the wind turbine, alternatively transforming the determined velocity amplitudes of at least one point of each rotating blade of the wind turbine into acceleration amplitudes of at least one point of each rotating blade of the wind turbine and / or displacement amplitudes of at least one point of each rotating blade of the wind turbine, d) determining, along with phase shifts:

[0020] - the actual displacement amplitudes of points and the vibration frequencies of the rotating blades of the wind turbine by filtering out the displacement amplitudes and vibration frequencies of the tower from the displacement amplitudes and vibration frequencies of the rotating blades of the wind turbine, or

[0021] - the actual acceleration amplitudes of the points and the vibration frequencies of the rotating blades of the wind turbine by filtering out the acceleration amplitude and vibration frequencies of the tower points from the acceleration amplitudes and vibration frequencies of the rotating blades of the wind turbine, or

[0022] - the actual velocity amplitudes of the points and the vibration frequencies of the rotating blades of the wind turbine by filtering out the velocity amplitude and vibration frequencies of the tower points from the velocity amplitudes and vibration frequencies of the rotating blades of the wind turbine e) assessing the service life condition of the blades and tower of the wind turbine by comparing the actual vibration frequencies of the blades, actual displacement amplitudes of the rotating blades, actual vibration frequencies of the tower, actual displacement amplitudes of the tower, actual acceleration amplitudes of the rotating blades, actual acceleration amplitudes of the tower, actual velocity amplitudes of the rotating blades, and / or actual velocity amplitudes of the tower against their reference values, determined for specified turbine rotational velocities, are derived from an analytical model, a numerical model, or a nominal, undamaged state of the wind turbine, wherein detection of deviations from the reference values indicates damage to at least one blade and / or tower of the wind turbine.

[0023] The method according to the invention is based on changes in frequencies and amplitudes of vibrations of the tower and rotating blades of wind turbines caused by structural and material damage, such as delamination, cracking, material bulging, buckling, and instability, as well as damage resulting from impacts of foreign objects, lightning strikes, icing, or degradation of connections between components, such as the blade root and hub. Changes in vibration frequencies and amplitudes of the blades and towers are used to determine the current condition of the blades and tower of the wind turbine and to estimate their remaining useful life by employing a material load-cycle accumulation process.

[0024] Preferably, an increase in deviations of actual displacement amplitudes of the rotating blades and / or displacement amplitudes of the tower relative to recorded reference values indicates the progression of damage.

[0025] Preferably, the time domain measured distances and / or accelerations are transformed into the amplitude-frequency domain using Fourier analysis, wavelet analysis, artificial intelligence, or another time signal decomposition method.

[0026] Preferably, the distance and / or velocity measuring device is a non-contact distance sensor that receives a signal reflected from the surface of the rotating blades or a camera.

[0027] Preferably, the non-contact sensor receives optical, microwave, radar, laser, LIDAR, acoustic, or ultrasonic signals reflected from the surface of the rotating blade to measure the distance and / or velocity of each blade relative to the tower continuously over time.

[0028] Distance and / or velocity measurement devices based on eddy currents phenomena, or the Hall effect may also be used, provided there are metallic elements inside or on the surface of the rotating wind turbine blades.

[0029] Preferably, the measurement of acceleration of at least one point of the tower in at least one direction is carried out using at least one accelerometer, inertial sensor, gyroscope, and / or tilt sensor. One of the simultaneously carried out acceleration measurements may be used as a backup in the event of a measurement device failure and may also confirm the results of the primary measurements.

[0030] It is recommended to measure wind velocity, temperature, pressure, and / or humidity continuously over time. This increases the precision of estimating deviations from reference values under varying environmental conditions. Preferably, the measurement of tower acceleration in at least one direction is carried out using at least one accelerometer and at least one tilt sensor.

[0031] If the device for measuring distance and / or velocity is configured to measure the velocity of at least one point of each rotating blade of the wind turbine, the distance of at least one point on each rotating blade of the wind turbine to at least one device for measuring distance and / or velocity is preferably determined by integration of the velocity waveform in the time domain.

[0032] In turn, if the device for measuring distance and / or velocity is configured to measure the acceleration of at least one point of each rotating blade of the wind turbine, the distance of at least one point on each rotating blade of the wind turbine from at least one device for measuring distance and / or velocity is preferably determined by double integration of the acceleration waveform in the time domain. In the case of measuring distance in an oblique direction relative to the vertical axis y of the tower, the component perpendicular to the vertical axis y of the tower is determined using trigonometric functions, particularly the sine function of the angle of deviation of the sensor.

[0033] The use of sensors for measuring velocities and accelerations, along with indirect determination of displacements (here through integration or double integration) and the use of measurements in an oblique direction, allows these sensors to be housed together and mounted at a single point of the tower, enabling the measurement of displacements at multiple points of the blades.

[0034] Preferably, the velocities of at least two points on each rotating blade of the wind turbine is measured simultaneously, such that the velocity of one point of each blade is measured in a direction perpendicular to the vertical axis y of the tower, and the velocity of at least one other point of each blade is measured in an oblique direction relative to the vertical axis y of the tower. This allows for the reconstruction of deformations and vibrations of the blades at various heights of the blades. This also enables more accurate determination of the approximate location of damage.

[0035] The second aspect of the invention is a system for monitoring the condition of the blades and towers of wind turbines, designed to implement the method according to the first aspect of the invention. This system comprises at least one accelerometer, inertial sensor, gyroscope, and / or tilt sensor for measuring accelerations at points on the wind turbine tower; at least one device for measuring the velocity of rotating blade points in a direction perpendicular and / or oblique to the vertical axis y of the tower and / or the distance of the rotating wind turbine blades from the measurement device, in the form of at least one non-contact sensor or camera; at least one rotational velocity meter for the turbine; and a data recording and analysis unit configured to record measurement data gathered in step a) and to implement steps b)-e) as described in the first aspect of the invention. The system monitors the current service life condition of the structural health of the wind turbine. It enables the identification of initial damage in the material, such as material bulges, delaminations, cracks, buckling / loss of stability, damage caused by impacts from foreign objects and lightning, icing, or damage to mechanical joints, as well as their progression over time. This allows for the determination of the remaining useful life (RUL) of the turbine blades and tower.

[0036] The sensors described continuously transmit the measured data to the unit for recording and analysing measurement data, which uses this data to determine the remaining useful life of the blades and tower, as well as hazardous events caused by icing, lightning strikes, earthquakes, and other physical phenomena.

[0037] Preferably, the system comprises at least one temperature, pressure, humidity, and / or wind velocity sensor.

[0038] Measurements of temperature, humidity, wind velocity, and pressure taken by the system according to the invention allow for the determination of the remaining useful life of the blades and tower by due to the impact of atmospheric conditions and material property ageing, using a process of accumulation of load cycles of materials, following rain-flow-counting algorithm or other approaches, including the classical Palmgren-Miner rule.

[0039] For example, measurements of air humidity and temperature allow for a more accurate determination of air density, and consequently, wind pressure force, which in turn enables a more precise assessment of turbine degradation.

[0040] Accelerometers, tilt sensors, inertial sensors, gyroscopes, distance and / or velocity measurement devices, or temperature, pressure, humidity, and / or wind velocity sensors may be mounted directly on the tower.

[0041] However, preferably, accelerometers, tilt sensors, inertial sensors, gyroscopes, distance and / or velocity measurement devices, or temperature, pressure, humidity, and / or wind velocity sensors are mounted on at least one supporting structure designed for attachment to the wind turbine tower or suspension from the nacelle.

[0042] The supporting structure can be installed on existing wind turbines without the need for factory installation or disassembly of the wind turbine.

[0043] The supporting structure is secured at specific heights of the tower corresponding to measurement locations on the rotating blades. The supporting structure can be attached to the wind turbine tower or suspended from the nacelle either in a detachable manner (e.g., bolted connections) and / or in a non-detachable manner (e.g., welded or bonded connections).

[0044] The supporting structure suspended directly beneath the nacelle ensures optimal orientation of the sensors relative to the vibrating and rotating turbine blades, as the supporting structure rotates along with the nacelle and blades according to the current alignment of the wind turbine.

[0045] Preferably, the supporting structure is made of rods, beams, thin-walled elements, or other components made of steel, composites, or polymers.

[0046] Preferably, the supporting structure is adapted to rotate relative to the wind turbine tower. Installation of the supporting structure using standard bearings, magnetic bearings, or gear connections allows it to rotate relative to the turbine tower.

[0047] Preferably, the rotating supporting structure is equipped with a stabiliser acting as an aerodynamic tail to rotate the supporting structure into the wind. The stabiliser automatically rotates the structure with the measurement devices into the wind, aligning perpendicularly to the rotating wind turbine blades, thereby allowing optimal sensor orientation relative to the vibrating and rotating turbine blades. The stabiliser ensures that the conditions for measuring blade vibrations are independent of wind direction and velocity.

[0048] Preferably, accelerometers, tilt sensors, inertial sensors, gyroscopes, distance and / or velocity measurement devices, or temperature, pressure, humidity, and / or wind velocity sensors are mounted on a supporting structure in the form of a rod for attaching to the wind turbine nacelle.

[0049] Preferably, accelerometers, tilt sensors, inertial sensors, gyroscopes, distance and / or velocity measurement devices, or temperature, pressure, humidity, and / or wind velocity sensors are connected to the data recording and analysis unit either by wired or wireless means.

[0050] Preferably, the system comprises a plurality of accelerometers, tilt sensors, inertial sensors, gyroscopes, distance and / or velocity measurement devices, or temperature, pressure, humidity, and / or wind velocity sensors intended for direct installation around the circumference of the wind turbine tower, at the same or different heights.

[0051] Preferably, at least one distance and / or velocity measurement device is configured to simultaneously measure the velocity of at least two points on each rotating blade of the wind turbine, such that the velocity of one point of each blade is measured in a direction perpendicular to the vertical axis y of the tower, and the velocity of at least one other point of each blade is measured in an oblique direction relative to the vertical axis y of the tower. This allows for the reconstruction of deformations and vibrations of the blades at various heights of the blades. This also enables more accurate determination of the approximate location of damage.

[0052] Advantages of the invention

[0053] The solution according to the invention enables the monitoring of the frequencies and amplitudes of vibrations of both the tower and the rotating blades of onshore and offshore wind turbines.

[0054] The solution according to the invention allows for the monitoring of the turbine tower and its rotating blades under all environmental and weather conditions.

[0055] The system according to the invention is easy to transport and can be installed on already erected turbines. The system does not require special calibration. Due to its simplicity, any onshore or offshore wind turbine can be equipped with this monitoring system. Furthermore, the straightforward design ensures the durability of the system, making the system according to the invention suitable for longterm monitoring of the turbine tower and its rotating blades.

[0056] The proposed method and system are cost-effective and can be applied to all types of horizontal and vertical axis wind turbines, whether already operational or newly constructed. The monitoring system according to the invention can be attached to both solid towers and lattice towers. This system can also be installed on-site at existing wind farms.

[0057] It is possible to apply the system according to the invention to monitor offshore turbines on any type of fixed foundation, such as monopile, lattice, tripod, gravity-based, as well as floating foundations, including TLP (Tension Leg Platform) systems, floating jackets, semi-submersible systems, and floating spar foundations, etc.

[0058] The sensors and accelerometers used are not sensitive to dirt and can be employed under harsh environmental conditions. As a result, no additional cleaning system is required for proper operation.

[0059] The system according to the invention is easy to maintain. In the event any of the sensors is damaged, its replacement is simple and can be performed directly on the turbine without the need for dismantling and transporting it to a service facility. In a system according to the invention equipped with a plurality of distance and / or velocity measuring devices, accelerometers, inertial sensors, gyroscopes, and / or tilt sensors, the failure of a single component does not disrupt the operation of the system. Using more distance and / or velocity measuring devices, accelerometers, inertial sensors, gyroscopes, and / or tilt sensors within the system allows for the measurement of higher vibration modes of the blades and tower based on the results of numerical simulations.

[0060] The measurement of temperature, humidity, wind velocity, and pressure performed by the system according to the invention enables the determination of the remaining useful life of the blades and the tower, taking into account the atmospheric conditions in which the turbine operates.

[0061] Monitoring the measured frequencies and amplitudes of vibrations allows for the detection of lightning strikes, the counting of their occurrences, the recognition of earthquakes or storms, and the assessment of wave impact forces through the interpretation of variations in measured parameters, and it also facilitates the estimation of the remaining useful life of the blades and the tower.

[0062] Comparison of the measurement data with the analytical model of the wind turbine enables real-time recognition of extraordinary events, which may indicate the need to shut down the turbine immediately to prevent the expansion of identified damage and / or to avoid total destruction of the blades and / or the tower.

[0063] The analysis of the measurement data and the analytical model of the turbine, for instance, using the Finite Element Method, also allows for the determination of the probable location of a failure (e.g., the location of a crack).

[0064] Monitoring the measured frequencies and amplitudes of vibrations facilitates the detection of blade icing or partial damage threatening the mechanical integrity of the blades, which could progress to the complete detachment of a blade from the rotor, which enables the issuance of an immediate stop signal to halt the turbine's operation to minimise damage.

[0065] The system according to the invention enables the optimisation of turbine performance to prevent damage caused by vibrations and to identify and track the progression of damage over time. This allows for planning the repair of a damaged blade without dismantling it from the wind turbine tower. Consequently, the application of the system according to the invention reduces the repair costs of wind turbines.

[0066] The system does not require a wired connection to an external power network, as its functionality is ensured even when powered by batteries or alternative power sources, such as self-sustained energy harvesting from photovoltaic cells, wireless or wired power supply from the energy generated by the wind turbine on which the system is mounted. The system according to the invention does not require the use of a telemetry system for wireless transmission of vibration measurement data of rotating blades to the unit for recording and analysing measurement data, as the sensors are mounted on non-rotating structural elements of the wind turbine.

[0067] Description of drawing figures

[0068] The subject of the invention is illustrated in embodiments presented in the drawings, wherein:

[0069] Fig. 1 shows a schematic representation of a system according to the invention mounted on a wind turbine according to the first, second, and third embodiments;

[0070] Fig. 2 shows a schematic representation of a system according to the invention mounted on a wind turbine according to the fourth embodiment;

[0071] Fig. 3 shows a schematic representation of a system according to the invention mounted on a wind turbine according to the fifth embodiment;

[0072] Fig. 4 shows a schematic representation of a system according to the invention mounted on a wind turbine according to the sixth embodiment;

[0073] Fig. 5 shows a schematic representation of a system according to the invention mounted on a wind turbine according to the seventh embodiment;

[0074] Detailed description of the invention

[0075] First embodiment

[0076] Fig. 1 illustrates a wind turbine 1 equipped with a system for monitoring the condition of the blades and tower of a wind turbine, according to the invention. The wind turbine 1 comprises a turbine tower 1, nacelle 3, hub 4, turbine blades 5, and a wind velocity and direction sensor 6.

[0077] The wind turbine 1 is equipped with a system for monitoring the condition of the blades and towers of wind turbines, which comprise an accelerometer 7 and a tilt sensor 8 used for measuring the accelerations of specific points of the tower of the wind turbine 1. It is also possible to use inertial sensors and gyroscopes for measuring the accelerations of points of the tower. The accelerometer 7 is mounted on a supporting structure 9 in the form of a rod attached to the nacelle 3 of the wind turbine 1, while the tilt sensor 8 is mounted on the tower 2. In other embodiments, the system may comprise more accelerometers 7 and / or tilt sensors 8, which can be installed on the supporting structure and / or structural elements of the turbine 1. The monitoring system comprises also a device 10 for measuring the distance between the rotating blades 5 of the wind turbine 1 and the device 10 for measuring distance in the form of a non-contact sensor that receives a signal reflected from the surface of the rotating blades 5 and returned to the sensor. This sensor may receive, for instance, optical, microwave, radar, laser, lidar, acoustic, or ultrasonic signals. Preferably, the signal transmitter is integrated within the non-contact sensor. In other embodiments, the device 10 for measuring distance may take the form of a camera. In yet other embodiments, where the monitoring system is intended to monitor rotating blades 5 that contain a metallic element mounted inside or on the surface of the rotating blades 5, the devices 10 for measuring distance may operate based on the phenomenon of eddy currents or the Hall effect.

[0078] The device 10 for measuring the distance of the rotating blades 5 of the wind turbine 1, like the accelerometer 7, is mounted on the supporting structure 9 in the form of a rod attached to the nacelle 3 of the wind turbine 1. In another embodiment, the accelerometer 7 and the device 10 for measuring distance may be mounted on the tower 2.

[0079] In other embodiments, the system may comprise more devices 10 for distance measurement, which can be mounted on the supporting structure and / or structural components of the turbine 1. Preferably, the devices 10 for measuring distance are mounted at least at two points around the circumference of the tower 2 and at least at two heights of the tower 2. This provides us with an additional measurement that confirms the first measurement and provides redundancy in case of a failure of the first sensor. Using more sensors increases the number of measurement points, allowing for the measurement of higher modes of blade vibrations.

[0080] The method of mounting the individual components of the system enables its use both in existing and new wind farms with a plurality of wind turbines.

[0081] The supporting structure 9 can also be made of beams, thin-walled elements, or other components constructed from steel, composites such as fibreglass or carbon fibre laminates, or polymers. The supporting structure 9 facilitates the mounting of accelerometers 7, tilt sensors 8, distance measurement devices 10 for rotating blades, and other sensors on existing towers, at a height of the tower 2 that corresponds to the measurement point for the rotating blade 5, defined as the radius from the axis of rotation of the rotating blade 5.

[0082] The monitoring system also comprises a rotational velocity meter for the turbine and a unit for recording and analysing measurement data (not shown in the figures), wherein the unit for recording and analysing measurement data is configured to record measurement data and process it to detect damage to at least one blade and / or tower of the wind turbine. In other embodiments, the system may also comprise temperature, pressure, and humidity sensors, allowing for increased precision in estimating deviations from reference values under different environmental conditions.

[0083] The accelerometer 7, tilt sensor 8, measuring device 10, and other sensors are connected to the unit for recording and analysing measurement data by wired connections. However, it is also possible to connect these components by wireless connections.

[0084] The monitoring system for the condition of blades and towers of wind turbines according to the invention operates by continuously performing measurements over time of: the distance of at least one point on each of the rotating blades 5 of the wind turbine 1 from the device 10 for measuring distance, using the device 10 configured for measuring distance, the acceleration of at least one point of the tower 2 in at least one direction, using the accelerometer 7 and tilt sensor 8, the rotational velocity of the wind turbine 1, using the turbine rotational velocity meter.

[0085] In the case of more measurement devices (accelerometers 7, tilt sensors 8, and devices 10 for measuring distance), measurements are taken for each of them. These measurements are recorded by the unit for recording and analysing measurement data.

[0086] Subsequently, the displacement amplitudes and vibration frequencies of each of the rotating blades 5 of the wind turbine 1, as well as the amplitudes of accelerations and vibration frequencies of the points of the tower 2, are determined by transforming the measured distances and accelerations from the time domain to the amplitude-frequency domain, along with phase shifts. This transformation may be performed, for example, using Fourier analysis, wavelet analysis, artificial intelligence, or other signal decomposition methods.

[0087] Next, the determined acceleration amplitudes of the points of the tower 2 are converted into displacement amplitudes of the points of the tower 2. Alternatively, the determined displacement amplitudes of the points on each of the rotating blades 5 of the wind turbine 1 are converted into acceleration amplitudes of the points on each of the rotating blades 5 of the wind turbine 1.

[0088] Furthermore, the actual displacement amplitudes and the actual vibration frequencies of the points on the rotating blades 5 of the wind turbine 1 are determined, along with phase shifts, by filtering out the displacement amplitudes and vibration frequencies of the tower 2 from the displacement amplitudes and vibration frequencies of the rotating blades 5 of the wind turbine 1. Alternatively, the actual acceleration amplitudes of the points and the actual vibration frequencies of the rotating blades 5 of the wind turbine 1 are determined by filtering out the acceleration amplitude and vibration frequencies of the tower 2 points from the acceleration amplitudes and vibration frequencies of the rotating blades 5 of the wind turbine.

[0089] As a result, the service life condition of the wind turbine blades and tower is assessed by comparing the actual vibration frequencies of the blades, the actual displacement amplitudes of the rotating blades, the actual vibration frequencies of the tower, the actual displacement amplitudes of the tower, the actual acceleration amplitudes of the rotating blades, and / or the actual acceleration amplitudes of the tower with their reference values for specific rotational velocities of the wind turbine, which are specified in an analytical or numerical model or the nominal (undamaged) state of the wind turbine 1, stored in the unit for recording and analysing measurement data. Any detected deviation from the reference values indicate damage to at least one blade 5 and / or the tower 2 of the wind turbine 1.

[0090] Alternatively, the service life condition of the wind turbine blades and tower is assessed by comparing the actual acceleration amplitudes of the rotating blades 5 and the acceleration amplitudes of the points of the tower 2 and / or vibration frequencies with their reference values for specific rotational velocities of the wind turbine, which are indicated in an analytical or numerical model or the nominal (undamaged) state of the wind turbine 1, stored in the unit for recording and analysing measurement data. Any detected deviation from the reference values indicates damage to at least one blade 5 and / or the tower 2 of the wind turbine 1.

[0091] If the system is equipped with temperature, pressure, humidity, and / or wind velocity sensors, these values are also continuously measured.

[0092] If the blades 5 of the wind turbine 1 were made from an ideally rigid material, they would not vibrate, and each rotating blade 5 would pass in front of the tower 2 of the wind turbine 1 at the same time intervals corresponding to the current rotational velocity of the turbine 1 and at the same distance from the tower. For actual materials and forces acting on the turbine 1 and blades 5, there are slight differences in time intervals and distances between the blades and the tower during each rotation. These time differences also depend on the dimensional tolerances of the blades 5 and their assembly tolerances. Such differences may be included in the analytical and / or numerical model or recognised and recorded by the data recording and analysis unit during the initial commissioning, determining the nominal condition (undamaged turbine, whether new or refurbished unit) for a given rotational velocity of the turbine.

[0093] During the monitoring of the wind turbine 1, any additional measured differences in the time intervals and the measured amplitudes of vibrations and / or displacements correspond to damage in one or more rotating blades 5. The system monitors the progression of changes, with increasing amplitudes of actual displacements of the rotating blades 5 and / or the displacement amplitudes of the tower 1, compared to the reference vibration and / or acceleration amplitudes recorded in the unit for recording and analysing measurement data, defined in the analytical or numerical model or nominal state, are interpreted as the progression of damage. Thus, the system monitors the progression of deterioration. The unit for recording and analysing measurement data also assesses the condition and estimates the remaining service life of the blades 5 and the tower 2.

[0094] Typically, emerging and progressing damage is associated with crack propagation or advancing delamination of the material in the blade structure, enabling the system to automatically detect and monitor damage and its progression in the inspected blade. In addition, changes in the measured deflections of the blade indicate a loss of structural stiffness due to crack propagation or material delamination.

[0095] The unit for recording and analysing measurement data can also identify crack formation using fracture mechanics and fatigue cycle counting methods, fatigue strength determination theories, or by modelling the wind turbine using the Finite Element Method or the Boundary Element Method.

[0096] Second embodiment

[0097] The system, as described in the first embodiment, with the difference that continuous measurements over time are carried out as follows: the velocity of a point on each of the rotating blades 5 of the wind turbine 1 in a direction perpendicular to the tower 2, measured using a device 10 configured for measuring velocity, the acceleration of at least one point of the tower 2 in at least one direction perpendicular to the vertical axis y, measured using an accelerometer 7 and a tilt sensor 8, and the rotational velocity of the wind turbine 1, using the turbine rotational velocity meter.

[0098] In the case of more measurement devices (accelerometers 7, tilt sensors 8, and devices 10 for measuring distance and / or velocity), measurements are taken for each of them.

[0099] The measured data is recorded by the unit for recording and analysing measurement data.

[0100] Next, the velocity amplitudes of points on each of the rotating blades 5 of the wind turbine 1, as well as the amplitudes of accelerations and vibration frequencies of the points of the tower 2, are determined by transforming the measured velocity and accelerations from the time domain to the amplitude-frequency domain, along with phase shifts. This transformation may be performed, for example, using Fourier analysis, wavelet analysis, artificial intelligence, or other signal decomposition methods. Subsequently, the determined acceleration amplitudes of the points of the tower 2 are converted into velocity amplitudes of the points of the tower 2. Alternatively, the determined velocity amplitudes of the points on each of the rotating blades 5 of the wind turbine 1 are converted into acceleration and / or displacement amplitudes of the points on each of the rotating blades 5 of the wind turbine 1.

[0101] Next, the actual velocity amplitudes and the vibration frequencies of the points on the rotating blades 5 of the wind turbine 1 are determined, along with phase shifts, by filtering out the velocity amplitudes and vibration frequencies of the tower 2 from the velocity amplitudes and vibration frequencies of the rotating blades 5 of the wind turbine 1.

[0102] As a result, the service life condition of the wind turbine blades and tower is assessed based on the actual vibration frequencies of the blades, the actual displacement amplitudes of the rotating blades, the actual vibration frequencies of the tower, the actual displacement amplitudes of the tower, the actual acceleration amplitudes of the rotating blades, the actual acceleration amplitudes of the tower, the actual velocity amplitudes of the rotating blades, and / or the actual velocity amplitudes of the tower with their reference values for specific rotational velocities of the wind turbine, which are specified in an analytical or numerical model or the nominal (undamaged) state of the wind turbine 1, stored in the unit for recording and analysing measurement data.

[0103] A detected deviation from reference values indicates damage to at least one blade 5 and / or the tower 2 of the wind turbine 1, wherein increasing deviations in the actual displacement amplitudes of the rotating blades 5 and / or the displacement amplitudes of the tower 2 relative to the recorded reference values are interpreted as the progression of damage.

[0104] Third embodiment

[0105] The system, as described in the first or second embodiment, differs in that the device 10 for measuring the distance and / or velocity of the rotating blades 5 of the wind turbine 1 is adapted to measure the velocity and / or acceleration of at least one point on each of the rotating blades 5 of the wind turbine 1.

[0106] The monitoring system for the condition of blades and towers of wind turbines according to the invention, operates in the same manner as in embodiment 1 or 2, with the difference that continuous measurements are taken over time of: the distance of a point on each of the rotating blades 5 of the wind turbine 1 in a direction perpendicular to the tower 2, measured using a device 10 configured for measuring velocity and / or acceleration - the acceleration of at least one point of the tower 2 in at least one direction perpendicular to the vertical axis y, measured using an accelerometer 7 and a tilt sensor 8, and

[0107] - the rotational velocity of the wind turbine 1, using the turbine rotational velocity meter.

[0108] If the device 10 for measuring distance is configured to measure the velocity of at least one point of each rotating blade 5 of the wind turbine 1, the distance of at least one point on each rotating blade 5 of the wind turbine 1 from at least one device 10 for measuring distance is determined by integration of the velocity waveform in the time domain. Conversely, if the device 10 for measuring distance is configured to measure the acceleration of at least one point of each rotating blade 5 of the wind turbine 1, the distance of at least one point on each rotating blade 5 of the wind turbine 1 from at least one device 10 for measuring distance is determined by double integration of the acceleration waveform in the time domain.

[0109] Fourth embodiment

[0110] Fig. 2 shows the system described in embodiment 1, 2, or 3, with the difference that the accelerometer 7 , tilt sensor 8, and devices 10 for measuring the distance and / or velocity of the rotating blade 5 are mounted on the tower 2 of the wind turbine 1.

[0111] The monitoring system for the condition of blades and towers of wind turbines according to the invention operates in the same manner as described in embodiments 1, 2, or 3, respectively.

[0112] Fifth embodiment

[0113] Fig. 3 illustrates a wind turbine 1 equipped with a system for monitoring the condition of the blades and tower of a wind turbine, according to the invention. The wind turbine 1 comprises a turbine tower 2, nacelle 3, hub 4, turbine blades 5, and a wind velocity and direction sensor 6.

[0114] The wind turbine 1 is equipped with a system for monitoring the condition of the blades and towers of wind turbines, which comprises two accelerometers 7 and a tilt sensor 8 used for measuring the accelerations of specific points of the tower of the wind turbine 1. The accelerometers 7 are mounted on a supporting structure 9 in the form of a rod attached to the nacelle 3 of the wind turbine 1, while the tilt sensor 8 is mounted on the tower 2. In other embodiments, the system may comprise more accelerometers 7 and / or tilt sensors 8, which can be installed on the supporting structure and / or structural elements of the turbine 1.

[0115] The monitoring system comprises also two devices, mounted at least at two points on the circumference of the tower 2 and at least at two heights of the tower 2, for measuring the distance and / or velocity of the rotating blades 5 of the wind turbine 1 from the devices 10 in the form of noncontact sensors that receive the signal reflected from the surface of the rotating blades 5 and return to the sensor. This sensor may receive, for instance, optical, microwave, radar, laser, lidar, acoustic, or ultrasonic signals. Preferably, the signal transmitter is integrated within the non-contact sensor. In other embodiments, the device 10 for measuring the distance and / or velocity may take the form of a camera. In yet other embodiments, where the monitoring system is intended to monitor rotating blades 5 that contain a metallic element mounted inside or on the surface of the rotating blades 5, the devices 10 for measuring distance and / or velocity may operate based on the phenomenon of eddy currents or the Hall effect.

[0116] The devices 10 for measuring the distance and / or velocity of the rotating blades 5 of the wind turbine 1, like the accelerometers 7, are mounted on the circumference of the tower 2 on the supporting structure 9 in the form of a lattice frame suspended from the nacelle 3 of the wind turbine 1.

[0117] In other embodiments, the system may comprise more devices 10 for distance and / or velocity measurement, which can be mounted on the supporting structure and / or structural components of the turbine 1.

[0118] The method of mounting the individual components of the system enables its use both in existing and new wind farms with multiple wind turbines.

[0119] The supporting structure 9, in the form of a lattice frame, can be made of rods, beams, thin-walled components, or other components made from steel, composites such as glass or carbon fibre laminates, or polymers. The supporting structure 9 facilitates the mounting of accelerometers 7, tilt sensors 8, devices 10 for measuring distance and / or velocity for rotating blades, and other sensors on existing towers, at a height of the tower 2 that corresponds to the measurement point for the rotating blade 5, defined as the radius from the axis of rotation of the rotating blade 5.

[0120] The supporting structure 9, in the form of a lattice frame suspended from the nacelle 3, consists of at least two elements forming a single structure, which significantly facilitates its installation on already existing wind turbines. The individual parts of the supporting structure can be made as separable connections (e.g., bolted connections) and non-separable connections (e.g., welded connections), as well as combinations of separable and non-separable methods.

[0121] Depending on the shape of the tower 2, the supporting structure 9 may have a conical or cylindrical shape. In turn, the height at which the supporting structure 9 is mounted on the tower 2 depends on the length of the blades 5, the location of the deflection arrows, and the expected displacement amplitude values for selected vibration modes.

[0122] The nacelle of the wind turbine, with the rotating blades, changes its orientation in the plane due to changes in the wind direction to achieve maximum efficiency. If the supporting structure of the system with sensors is suspended directly beneath the nacelle, the sensor supporting structure remains optimally oriented with respect to the vibrating and rotating blades. Then, the supporting structure of the system rotates together with the nacelle and blades according to the current orientation of the wind turbine.

[0123] The monitoring system also comprises a rotational velocity meter for the turbine and a unit for recording and analysing measurement data (not shown in the figures), wherein the recording and analysis unit is configured to record measurement data and process it to detect damage to at least one blade and / or tower of the wind turbine.

[0124] In other embodiments, the system may also comprise temperature, pressure, humidity, and / or wind velocity sensors mounted on the structural elements of the wind turbine 1, which allows for increased precision in estimating deviations from reference values under different environmental conditions.

[0125] The accelerometers 7, tilt sensor 8, measuring device 10, and other sensors are connected to the unit for recording and analysing measurement data by wired connections. However, it is also possible to connect these components by wireless connections.

[0126] The monitoring system for the condition of blades and towers of wind turbines according to the invention operates in the same manner as described in embodiment 1 or 2.

[0127] Sixth embodiment

[0128] Fig. 4 illustrates a wind turbine 1 equipped with a system for monitoring the condition of the blades and tower of a wind turbine, according to the invention. The wind turbine 1 comprises a turbine tower 2, nacelle 3, hub 4, turbine blades 5, and a wind velocity and direction sensor 6.

[0129] The wind turbine 1 is equipped with a system for monitoring the condition of the blades and towers of wind turbines, which comprises an accelerometer 7 and a tilt sensor 8 used for measuring the accelerations of specific points of the tower of the wind turbine 1. The accelerometer 7 is mounted on a supporting structure 9 in the form of a ring or another solid-wall shell installed on the tower 2 of the wind turbine 1. The tilt sensor 8, in turn, is mounted directly on the tower 2. In other embodiments, the system may comprise more accelerometers 7 and / or tilt sensors 8, which may be mounted on at least one supporting structure installed at different heights of the tower and / or structural elements of the turbine 1.

[0130] The monitoring system also comprises a device 10 for measuring the distance between the rotating blades 5 of the wind turbine 1 and the device 10 for measuring distance in the form of a non-contact sensor that receives a signal reflected from the surface of the rotating blades 5 and returned to the sensor. This sensor may receive, for instance, optical, microwave, radar, laser, lidar, acoustic, or ultrasonic signals. Preferably, the signal transmitter is integrated within the non-contact sensor. In other embodiments, the device 10 for measuring the distance and / or velocity may take the form of a camera. In yet other embodiments, where the monitoring system is intended to monitor rotating blades 5 that contain a metallic element mounted inside or on the surface of the rotating blades 5, the device 10 for measuring distance and / or velocity may operate based on the phenomenon of eddy currents or the Hall effect.

[0131] The device 10 for measuring the distance and / or velocity of the rotating blades 5 of the wind turbine 1, like the accelerometer 7, is mounted on the circumference of the tower 2 of the turbine on the supporting structure 9 in the form of a ring or another solid-wall shell installed on the tower 2 of the wind turbine 1.

[0132] In other embodiments, the system may comprise more devices 10 for measuring distance and / or velocity, which may be mounted on this or additional supporting structure and / or structural components of the turbine 1.

[0133] The method of mounting the individual components of the system enables its use both in existing and new wind farms with multiple wind turbines.

[0134] The supporting structure 9, in the form of a ring or another solid-wall shell, can be made of rods, beams, thin-walled components, or other components made from steel, composites such as glass or carbon fibre laminates, or polymers. The supporting structure 9 facilitates the mounting of accelerometers 7, tilt sensors 8, devices 10 for measuring distance and / or velocity for rotating blades, and other sensors on existing towers, at a height of the tower 2 that corresponds to the measurement point for the rotating blade 5, defined as the radius from the axis of rotation of the rotating blade 5.

[0135] The supporting structure 9, in the form of a ring or another solid-wall shell, consists of at least two parts connected around the circumference of the tower 2 to form a single structure, which significantly facilitates its installation on already existing wind turbines. The individual parts of the supporting structure can be made as separable connections (e.g., bolted connections) and non-separable connections (e.g., welded connections), as well as combinations of separable and non-separable methods.

[0136] The height at which the supporting structure 9 is mounted on the tower 2 depends on the length of the blades 5, the location of the deflection arrows, and the expected displacement amplitude values for selected vibration modes.

[0137] The nacelle of the wind turbine, with the rotating blades, changes its orientation in the plane due to changes in the wind direction to achieve maximum efficiency. The supporting structure 9 in this embodiment is equipped with a rotation system enabling the supporting structure to rotate around the tower 2 of the wind turbine 1.

[0138] The rotation system may be implemented, for example, through bearing arrangements, including magnetic bearings. The rotation system may also comprise rings mounted on the tower 2, along which rollers rotate, whose axes are attached to the supporting structure 9. Another possible implementation of the rotational connection involves using a geared connection. The internal gear is attached to the tower 2, while the external gear is attached to the internal part of the supporting structure 9. This arrangement of gears, consisting of at least two segments per gear, allows the supporting structure 9 to rotate around the tower 2, depending on the wind direction.

[0139] The supporting structure 9 in this embodiment is equipped with a stabiliser that automatically rotates the supporting structure in the direction of the wind. The stabiliser 11 causes the supporting structure with the mounted accelerometer and the device 10 for measuring the distance and / or velocity of the rotating blades to follow the wind direction, aligning itself perpendicularly to the rotating blades of the wind turbine. The stabiliser 11 ensures that the conditions for measuring blade vibrations are independent of wind direction and velocity.

[0140] The monitoring system also comprises a rotational velocity meter for the turbine and a unit for recording and analysing measurement data (not shown in the figures), wherein the recording and analysis unit is configured to record measurement data and process it to detect damage to at least one blade and / or tower of the wind turbine.

[0141] In other embodiments, the system may also comprise temperature, pressure, humidity, and / or wind velocity sensors mounted on the structural elements of the wind turbine 1, which allows for increased precision in estimating deviations from reference values under different environmental conditions.

[0142] The accelerometers 7, tilt sensor 8, measuring device 10, and other sensors are connected to the unit for recording and analysing measurement data by wired connections. However, it is also possible to connect these components by wireless connections.

[0143] The monitoring system for the condition of blades and towers of wind turbines according to the invention operates in the same manner as described in embodiment 1 or 2.

[0144] Seventh embodiment

[0145] Fig. 5 illustrates a wind turbine 1 equipped with a system for monitoring the condition of the blades and tower of the wind turbine as in embodiment 2, with the difference that the device 10 for measuring distance and / or velocity is adapted for simultaneous measurement of the velocity of at least two points of each of the rotating blades 5 of the wind turbine 1, in such a way that the velocity of one point of each of the blades 5 is measured in a direction perpendicular to the vertical axis y of the tower 1, and the velocity of at least one other point of each of the blades 5 is measured in a direction oblique to the vertical axis y of the tower 2. The system for monitoring the condition of the blades and tower of the wind turbine according to the invention operates in the same manner as in the other embodiments, with the difference that the velocity of at least two points of each of the rotating blades 5 of the wind turbine 1 is measured simultaneously. However, one measurement relates to the velocity of one point of each of the blades 5 in a direction perpendicular to the vertical axis y of the tower 2, while another measurement, of at least one point of each of the blades 5, relates to the velocity in a direction oblique to the vertical axis y of the tower 2. For measurements in a direction oblique to the vertical axis y of the tower 2, the perpendicular component with respect to the vertical axis y of the tower 2 (indicating the distance of the point from the tower) is determined using trigonometric functions.

[0146] This allows for the reconstruction of deformations and vibrations of the blades at various heights of the blades. This also enables the determination of the nature of deformations occurring in the region of a crack.

Claims

Claims1. A method for monitoring the condition of the blades and the tower of a wind turbine (1), in particular, a wind turbine with a vertical or horizontal axis of rotation, characterised in that: a) measurements are carried out continuously over time:- of the distance of at least one point on each of the rotating blades (5) of the wind turbine (1) from at least one device (10) for measuring distance and / or velocity mounted at least one point on the circumference of the tower (2) and at least at one height of the tower (2) during each rotation of the blades in front of the tower, and / or- of the velocity of at least one point on each of the rotating blades (5) of the wind turbine (1) for each rotation of the blades in front of the tower (2), in a direction perpendicular and / or oblique to the vertical axis y of the tower (2); and- of the acceleration of at least one point of the tower (2) in at least one direction, and- of the rotational velocity of the wind turbine (1). b) the following are determined:- the displacement amplitudes and / or velocity amplitudes of each rotating blade of the wind turbine and the vibration frequencies of each rotating blade (5) of the wind turbine (1) during each rotation in front of the tower,- the acceleration amplitudes and vibration frequencies of at least one point of the tower (2), by transforming the measured distances, velocities, and accelerations in the time domain into the amplitude-frequency domain with phase shifts, c) the determined acceleration amplitudes of at least one point of the tower (2) are transformed into displacement amplitudes of at least one point of the tower (2) and / or velocity amplitudes of at least one point of the tower (2), alternatively, the determined displacement amplitudes of at least one point of each rotating blade (5) of the wind turbine (1) are transformed into acceleration amplitudes of at least one point of each rotating blade (5) and / or velocity amplitudes of at least one point of each rotating blade (5), alternatively the determined velocity amplitudes of at least one point of each rotating blade (5) of the wind turbine (1) are transformed into acceleration amplitudes of at least one point of each rotating blade (5) and / or displacement amplitudes of at least one point of each rotating blade (5), d) the following are determined, together with phase shifts:- the actual displacement amplitudes of points and the actual vibration frequencies of the rotating blades (5) of the wind turbine (1) by filtering out the displacement amplitudes and vibration frequencies of the tower (2) from the displacement amplitudes and vibration frequencies of the rotating blades (5) of the wind turbine (1), or- the actual acceleration amplitudes of the points and the actual vibration frequencies of the rotating blades (5) of the wind turbine (1) by filtering out the acceleration amplitude and vibration frequencies of the tower (2) points from the acceleration amplitudes and vibration frequencies of the rotating blades (5) of the wind turbine, or- the actual velocity amplitudes of the points and the actual vibration frequencies of the rotating blades (5) of the wind turbine (1) by filtering out the velocity amplitude and vibration frequencies of the tower (2) points from the velocity amplitudes and vibration frequencies of the rotating blades (5) of the wind turbine, e) the service life condition of the blades and the tower of the wind turbine is assessed by comparing the actual vibration frequencies of the blades (5), the actual displacement amplitudes of the rotating blades (5), the actual vibration frequencies of the tower (2), the actual displacement amplitudes of the tower (2), the actual acceleration amplitudes of the rotating blades (5), the actual acceleration amplitudes of the tower (2), the actual velocity amplitudes of the rotating blades (5), and / or the actual velocity amplitudes of the tower (2) with their reference values for specified turbine rotational velocities, determined in an analytical model, a numerical model, or a nominal state without damage to the wind turbine (1), wherein deviations from the reference values indicate damage to at least one blade and / or the tower of the wind turbine (1).

2. The method according to claim 1, characterised in that an increase in the deviations of the actual displacement amplitudes of the rotating blades (5) and / or the displacement amplitudes of the tower (2) relative to the recorded reference values is interpreted as the progression of damage.

3. The method according to claim 1 or 2, characterised in that the measured distances and / or accelerations and / or velocities in the time domain are transformed into the amplitude-frequency domain using Fourier analysis, wavelet analysis, artificial intelligence, or another time signal decomposition method.

4. The method according to claim 1, 2, or 3, characterised in that the device (10) for measuring distance and / or velocity is either a non-contact distance sensor that receives a signal reflected from the surface of the rotating blades or a camera.

5. The method according to any of the preceding claims, characterised in that the acceleration of at least one point of the tower (2) in at least one direction is measured using at least one accelerometer (7), inertial sensor, gyroscope, and / or tilt sensor (8).

6. The method according to any of claims 4 or 5, characterised in that the non-contact sensor receives an optical, microwave, radar, laser, LIDAR, acoustic, or ultrasonic signal reflected from the surface of the rotating blade to measure the distance of each blade from the tower continuously over time.

7. The method according to any of the preceding claims, characterised in that measurements of wind velocity, temperature, pressure, and / or humidity are carried out continuously over time.

8. The method according to any of the preceding claims, characterised in that the measurement of the acceleration of the tower (2) in at least one direction is carried out using at least one accelerometer (7) and at least one tilt sensor (8).

9. The method according to any of the preceding claims, characterised in that, where the device (10) for measuring distance and / or velocity is configured to measure the velocity of at least one point on each of the rotating blades (5) of the wind turbine (1), the distance of at least one point on each of the rotating blades (5) of the wind turbine (1) from at least one device (10) for measuring distance and / or velocity is determined by integration of the velocity waveform in the time domain.

10. The method according to any of the preceding claims from 1 to 8, characterised in that, where the device (10) for measuring distance and / or velocity is configured to measure the acceleration of at least one point on each of the rotating blades (5) of the wind turbine (1), the distance of at least one point on each of the rotating blades (5) of the wind turbine (1) from at least one device (10) for measuring distance and / or velocity is determined by double integration of the acceleration waveform in the time domain.

11. The method according to any of the preceding claims from 1 to 10, characterised in that, in the case of measurements in a direction oblique to the vertical axis y of the tower (2), the component perpendicular to the vertical axis y of the tower (2) is determined using trigonometric functions.

12. The method according to any of the preceding claims from 1 to 11, characterised in that the velocity of at least two points on each of the rotating blades (5) of the wind turbine (1) is measured simultaneously, such that the velocity of one point of each blade (5) is measured in a direction perpendicular to the vertical axis y of the tower (2), and the velocity of at least one other point of each blade (5) is measured in a direction oblique to the vertical axis y of the tower (2).

13. A system for monitoring the condition of the blades and towers of wind turbines for implementing the method according to claims 1 to 12, comprising:- at least one accelerometer (7), inertial sensor, gyroscope and / or tilt sensor (8) for measuring the acceleration of points of the wind turbine tower (1),- at least one device (10) for measuring the distance and / or velocity of the rotating blades (5) of the wind turbine (1) from the device (10) for measuring the distance and / or velocity of the rotating blades (5) of the wind turbine (1) in a direction perpendicular and / or oblique to the vertical axis y of the tower (2), in the form of at least one non-contact sensor or camera,- at least one measuring device of the rotational velocity of the turbine (1),- a unit for recording and analysing measurement data, configured to record the measurement data measured in step a) and to implement steps b) to e) according to any one of claims 1 to 11.

14. The system according to claim 13, characterised in that it comprises at least one temperature, pressure, humidity, and / or wind velocity sensor.

15. The system according to claim 13 or 14, characterised in that the devices (10) for measuring distance and / or velocity, accelerometers (7), inertial sensors, gyroscopes, temperature, pressure, humidity, and / or wind velocity sensors and / or cameras are mounted on at least one supporting structure (9) intended for mounting on the tower (2) of the wind turbine (1) or for suspension from the nacelle (3).

16. The system according to claim 15 characterised in that the supporting structure (9) is made of rods, beams, thin-walled elements or other components made of steel, composites, or polymers.

17. The system according to any one of claims 15 to 16, characterised in that the supporting structure (9) is configured to rotate relative to the tower (2) of the wind turbine (1).

18. The system according to any one of claims 15 to 17, characterised in that the supporting structure (9) is equipped with a stabiliser (11) serving as an aerodynamic tail to rotate the supporting structure in the direction of the wind.

19. The system according to claim 15, characterised in that the devices (10) for measuring distance and / or velocity, accelerometers (7), inertial sensors, gyroscopes, temperature, pressure, humidity, and / or wind velocity sensors are mounted on the supporting structure (9) in the form of a rod for attaching to the nacelle (3) of the wind turbine (1).

20. The system according to any one of claims 13 to 19, characterised in that the devices (10) for measuring distance and / or velocity, accelerometers (7), inertial sensors, gyroscopes, tilt sensors (8), temperature, pressure, humidity, wind velocity sensors, and / or cameras are connected to the unit for recording and analysing measurement data by wired or wireless means.

21. The system according to any one of claims 13 to 20, characterised in that it comprises a plurality of devices (10) for measuring distance and / or velocity, inertial sensors, gyroscopes, tilt sensors (8), cameras, and / or accelerometers (7) for direct mounting on the circumference of the tower (2) of the wind turbine (1) at the same or different heights of the tower (2).

22. The system according to any one of claims 13 to 22, characterised in that at least one device (10) for measuring the distance and / or velocity of the rotating blades (5) of the wind turbine (1) from the device (10) for measuring distance is configured to measure the velocity and / or acceleration of at least one point on each of the rotating blades (5) of the wind turbine (1).

23. The system according to any one of claims 13 to 23, characterised in that at least one device (10) for measuring distance and / or velocity is configured to simultaneously measure the velocity of at least two points on each of the rotating blades (5) of the wind turbine (1), such that the velocity of one point of each blade (5) is measured in a direction perpendicular to the vertical axis y of the tower (2), and the velocity of at least one other point of each blade (5) is measured in a direction oblique to the vertical axis y of the tower (2).

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