Condition monitoring system for wind turbine, wind turbine and method for monitoring operation of wind turbine

Abstract

A condition monitoring system for a wind turbine wherein the wind turbine comprises a tower, a nacelle, a hub and wind turbine blades attached to the hub wherein each blade comprises an electrical conductor system, in particular a lightning protection system, and wherein the tower, the nacelle and the hub comprise a fixed electrical conductor system, in particular a lightning protection system. The present invention relates to a condition monitoring system, in particular a stationary electrical conductor system, comprising an electrical grounding system of a wind turbine, the condition monitoring system comprising: a controller configured to provide an input probe signal for injection into the electrical conductor system of the blades when the respective blades are aligned with the tower; and at least one measuring device configured to detect a response signal, the response signal being a system response after injection of the detection signal, where the system response is generated by an electrical conductor system of the blade and a stationary electrical conductor system coupled to the electrical conductor system via a capacitive coupling between the blade and the tower, and where the stationary electrical conductor system is coupled to the electrical conductor system via a capacitive coupling between the blade and the tower. The fixed electrical conductor system is coupled to the electrical conductor system via a capacitive coupling between the blade and the tower, in particular when the blade is aligned with the tower; the condition monitoring system is configured to provide input probe signals for injection into the electrical conductor system of the blade at predetermined intervals or on demand whenever the blade is aligned with the tower or when the blade is aligned with the tower.

Description

Technical Field

[0001] The invention relates to a condition monitoring system for a wind turbine according to claim 1 , a condition monitoring system according to claim 3 , a wind turbine according to claim 19 and a method for operational monitoring of a wind turbine according to claim 20 . Background Art

[0002] The lightning protection system of a wind turbine blade is usually a physical electrical conductor embedded in the structure of the blade. These conductors are usually arranged inside the blade and / or integrated into the shell of the blade.

[0003] The integrity of a wind turbine's lightning protection system is typically verified by measuring DC continuity between the blade's external receptor and the blade root. These measurements are typically performed after manufacture, after installation, and are typically repeated every two to four years during the turbine's operation.

[0004] However, DC continuity measurements can be misleading, as the path of least resistance primarily determines the result of such measurements. If the lightning protection system features several conducting elements in parallel (as is often the case, for example, in carbon fiber reinforced polymer blades, or for blades with additional conducting parts at the same potential as the down conductor), there is a high probability that the fault will not be detected and the blade will be severely damaged by the next lightning strike.

[0005] Furthermore, DC continuity measurement is labor-intensive, subject to HSE (Health, Safety, and / or Environment) concerns, and relatively slow because it requires rope access from the outside of the wind turbine blade. Personnel must lower the blade using a rope and connect the DC measurement equipment to the outside of the receiver at the blade's tip to verify electrical continuity at the root end of the LPS.

[0006] As a result, these measurements are considered to be quite time-consuming and complex, inflexible and expensive. In addition, these measurements may only be taken at discrete single intervals, so that damage that occurs shortly after the last measurement may remain unnoticed for a longer period of time.

[0007] A condition monitoring device is described in European application no. 21216911.4 filed on December 22, 2021. The content of this application is incorporated herein by reference. Summary of the Invention

[0008] In view of the above, an object of the present invention is to provide a condition monitoring device / system which overcomes the above disadvantages and allows direct, reliable and operator-friendly condition monitoring of the interfaces of wind turbine blade LPS and other conducting components.

[0009] The objects of the invention are solved by a condition monitoring device comprising the features of claim 1 ; a condition monitoring system comprising the features of claim 3 ; and a method for operational monitoring of a wind turbine comprising the features of claim 20 .

[0010] Preferred embodiments of the invention are described in the dependent claims, the description and the drawings.

[0011] The present invention relates, at least in some aspects, to a condition monitoring system for a wind turbine, comprising a tower, a nacelle, a hub, and wind turbine blades attached to the hub, wherein each blade includes an electrical conductor system, particularly a lightning protection system. The tower, nacelle, and hub include a fixed electrical conductor system, particularly the fixed electrical conductor system comprising the wind turbine's electrical grounding system. The condition monitoring system includes a controller and at least one measuring device. The controller is configured to provide an input probe signal for injection into the blade's electrical conductor system when the corresponding blade is aligned with the tower, and the at least one measuring device is configured to detect a response signal, the response signal being a system response after the injection of the probe signal. The system response is generated by the blade's electrical conductor system and the fixed electrical conductor system, which is coupled to the electrical conductor system via a capacitive coupling between the blade and the tower, particularly when the blade is aligned with the tower. The condition monitoring system is configured to provide the input probe signal for injection into the blade's electrical conductor system whenever the blade is aligned with the tower, at predetermined intervals, or on demand.

[0012] A condition monitoring system can be used to monitor the condition of an electrical conductor system, such as a lightning protection system, of a wind turbine blade by injecting pulses and / or repetitive signals with a specific rise time and within a specific frequency range into the blade's electrical conductor system, for example, into a blade's down conductor. Signal processing of the detected response signal can then be performed (in the system and / or in a remote computing system), thereby determining the condition of the electrical conductor system.

[0013] Since the condition monitoring system is configured to provide an input detection signal for injection into the electrical conductor system of the blade whenever the blade is aligned with the tower, at predetermined intervals, or on demand when the blade is aligned with the tower, continuous and automatic monitoring of the blades of the wind turbine can be achieved. This can help to enhance the operational safety of the wind turbine.

[0014] During the feasibility study, it was shown that a return path for the response signal can be important for ensuring consistent results. Therefore, measurements were performed while the blade was aligned with the tower, providing a capacitive connection between the blade's electrical conductor system, particularly the lightning protection system, and a fixed electrical conductor system, such as the grounding system, extending through the tower, thereby enabling a return path for the response signal. This concept allows the condition of the blade's electrical conductor system to be continuously verified during turbine operation. This makes it possible to verify the condition of the wind turbine without requiring the physical presence of a technician, thus avoiding potentially dangerous rope access operations.

[0015] Additionally, damage that develops over time can be identified early on, allowing repairs to begin at the appropriate time. Repairing a wind turbine (its blades or lightning protection system) before damage worsens will save repair costs and reduce wind turbine downtime.

[0016] The system response can be considered in particular to be due to impedance or reflection (of the signal) in a path or system comprising the blade and / or its electrical conductor system, such as a lightning protection system, the tower conducting unit, and a wireless (in particular capacitive) connection between these components. Optionally, the tower conducting unit is electrically connected to the wind turbine, in particular serving as a conductor for returning the signal to the condition monitoring device.

[0017] The tower conducting unit may be part of a fixed electrical conductor system.In some embodiments, the tower conducting unit is at least partially formed by an exterior of a tower of the wind turbine.

[0018] By using the tower of the wind turbine, a reproducible (return) path for the signal can be directly achieved. In particular, using the exterior of the tower can be cost-effective, as the exterior of the tower is typically made of metal (preferably steel) and / or reinforced concrete and therefore inherently provides conductors, eliminating the need to install separate or additional conductors. Furthermore, if the coupling electrode used is an electrical conductive system of the tower conductive element and the blade, the measurement can be independent of measurements from the ground terminal. Alternatively or additionally, the tower conductive element can include a conductor such as a straight conductive element or a coaxial cable that can be arranged on the exterior or interior of the tower.

[0019] In some embodiments, the condition monitoring system can be configured to inject a response signal into each blade and detect the response signal for each blade. This allows for determination of condition monitoring for each blade. Furthermore, the system, and in particular the controller, can be configured to compare the measurements from all blades. Since blades are always evenly loaded during operation, a deviation in the measurement from one blade relative to the measurements from the remaining blades can indicate a fault in the blade. Furthermore, by utilizing this comparison, the blade causing the fault can be identified. This comparison can be performed by the controller or by an external unit.

[0020] In some embodiments, the at least one measuring device is configured to provide the detected response signal to a controller for further processing. Alternatively, the at least one measuring device can be configured to provide the detected response signal to an external system, such as a cloud computing system or a server system or an external computer.

[0021] At least in some embodiments also claimed in the independent claims, the condition monitoring system can be configured to provide the input detection signal when the wind turbine is operating under predetermined operating conditions, such as under predetermined loads on the blades, or in a predetermined operating mode, such as an idle mode, or at a predetermined generator output level.

[0022] The distance between the blades and the tower can change depending on the load on the blades. Thus, the capacitive coupling between the blades and the tower can change depending on the load on the blades. Therefore, detecting the response signal when the wind turbine is operating under predetermined operating conditions can be advantageous because the response signal can be compared with a predetermined fingerprint signal to identify faults in the electrical conductor system of the blades. When assuming that the blades are free of defects and when the wind turbine is operating under predetermined operating conditions, a fingerprint signal can already be obtained for each blade in response to the injection of the input probe signal.

[0023] In some embodiments, the controller is configured to determine an operating condition of the wind turbine. This may be accomplished using at least one sensor and / or using an output level generated by the wind turbine.

[0024] In some embodiments, the controller, eg a measurement unit of the controller, may be configured to process the response signals from all blades.The response signals may be stored by the controller and / or further analyzed by the controller.

[0025] In some embodiments, the controller is configured to analyze or compare response signals from all blades, wherein, optionally, the controller is configured to analyze or compare only response signals obtained during at least approximately the same operating conditions of the wind turbine.

[0026] In some embodiments, the controller is configured to compare at least the response signal obtained from the blade with a predetermined fingerprint signal for the blade. The controller may identify a fault in the blade based on the comparison of the response signal and the fingerprint signal. For example, a fault may be identified if the response signal does not correspond to the fingerprint signal.

[0027] In some embodiments, the controller may be configured to determine a fault in the blade based on the detected response signal of the blade and in particular based on the detection of a change in a signal pattern in the response signal of the blade over time. To detect changes in the signal pattern over time, historical signals may be stored so that they are available for comparison.

[0028] In some embodiments, the controller is configured to determine at least one of the following based on the detected response signal, and in particular based on detecting changes in signal patterns in the response signal over time: at least an approximate location of the fault, a time when the fault occurred, and a type of fault. The fault type can be detected when the response signal is correlated with a schematic diagram of the blade design and / or when an expected response signal indicative of the fault type has been previously determined and provided to the controller. The controller can then identify the type of fault by comparing the measured response signal with a stored expected response signal.

[0029] In some embodiments, the controller comprises a signal generating unit which generates the probe pulse and provides the probe pulse for injection into the electrical conductor system of the blade when the blade is aligned with the tower.

[0030] In some embodiments, the condition monitoring system comprises, for each blade, a measuring device dedicated to the respective blade, wherein the measuring device is optionally located at the root of the blade, at the junction between the hub and the blade, or in the hub, the nacelle or the tower.

[0031] In some embodiments, the condition monitoring system includes a signal generating unit for each blade, specifically for that blade. Optionally, the signal generating unit is located at the root of the blade, at the junction between the hub and the blade, or in the hub, nacelle, or tower. Alternatively, a single signal generating unit may be used for all blades. The single signal generating unit may be included in the controller or in a separate housing.

[0032] In some embodiments, the condition monitoring system comprises one measuring device for all blades, wherein, optionally, the measuring device is located at the junction between the hub and the blades, or in the hub, the nacelle or the tower.

[0033] In some embodiments, at least one measuring device is configured to record / store the detected response signal.

[0034] In some embodiments, the controller is located in a hub, in particular in a cabinet.

[0035] In some embodiments, the controller, in particular the signal generating unit, is configured to trigger the injection of a detection signal into the electrical conductor system of the blade when the respective blade is aligned with the tower.

[0036] In some embodiments, the controller is configured to compare the detected response signal with a predetermined fingerprint signal and set an alarm if the response signal deviates from the fingerprint signal. This can also be done externally.

[0037] In some embodiments, the controller is configured to determine a time delay between injection of the detection signal and detection of the corresponding response signal, wherein, optionally, an alarm is set if the time delay exceeds a threshold. The alarm can be set in various forms, such as an optical or acoustic alarm or by sending an alarm to an operator, such as by means of email, SMS, etc.

[0038] In some embodiments, the electrical conductor system of the blade includes at least one electrical conductor, in particular a down conductor, located in the blade, the electrical conductor providing an injection site for injecting an input detection signal. The injection site may include a portion of the electrical conductor and at least one ferrite core arranged around the portion of the electrical conductor. The input detection signal may be injected into the electrical conductor system via a first electrical injection line and a second electrical injection line. The first electrical injection line may be connected to the portion of the electrical conductor at a first connection point, and the second electrical injection line may be connected to the portion of the electrical conductor at a second connection point. The at least one ferrite core is located between the first connection point and the second connection point.

[0039] The ferrite core can affect the impedance of the closed conductor.The ferrite core provides low impedance in the frequency band of lightning current (below 1 MHz) and high impedance at typical signal processing frequencies, for example above 30 MHz.

[0040] In some embodiments, the first electrical injection line and the second electrical injection line are further used to detect the response signal.

[0041] In some aspects, the present invention also relates to a wind turbine comprising at least one condition monitoring system according to embodiments of the present invention.

[0042] In some aspects, the present invention also relates to a method for operational monitoring of a wind turbine, preferably a method for operational monitoring of a wind turbine by a condition monitoring system according to the present invention. The method comprises the following steps:

[0043] injecting at least one detection signal into an electrical conductor system of a blade of the wind turbine when the respective blade is aligned with a tower of the wind turbine,

[0044] detecting at least one response signal, the response signal being a system response after the injection of the probing signal, wherein the system response is obtained from an electrical conductor system of the blade and a fixed electrical conductor system of a tower, a nacelle and a hub of the wind turbine, wherein the fixed conductor system is coupled to the electrical conductor system via a capacitive coupling between the blade and the tower, in particular when the blade is aligned with the tower,

[0045] wherein injecting at least one probe signal comprises providing an input probe signal for injection into the electrical conductor system of the blade whenever the blade is aligned with the tower or at predetermined intervals or on demand when the blade is aligned with the tower, and / or

[0046] Therein, the at least one input detection signal is injected only when the wind turbine is operating under predetermined operating conditions, eg under predetermined loads on the blades or in a predetermined operating mode, like idle mode or at a predetermined generator output level.

[0047] In some embodiments, one or more predetermined fingerprint signals are obtained at different loads on the blade, and the response signal of the ongoing detection is compared with at least one fingerprint signal captured at the current load. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The invention is described below with respect to further details, features and advantages, which are explained in more detail with reference to the accompanying drawings. As shown in the drawings and described below with reference to the drawings, the described features and combinations of features can be used not only in the respective combinations indicated, but also in other combinations or independently without thereby departing from the scope of the invention.

[0049] Figure 1a A first example of an embodiment of a condition monitoring device with hardwired connections and corresponding protection devices is shown;

[0050] Figure 1b A second example of embodiment of a condition monitoring device comprising an inductive measuring device is shown;

[0051] Figure 1c A third example of an embodiment of a condition monitoring device including a signal sensing device is shown;

[0052] Figure 1d A fourth example of embodiment of a condition monitoring device comprising a signal sensing device and an inductive measuring device is shown;

[0053] Figure 1eA fifth example of embodiment of a condition monitoring device comprising a waveguide coupler is shown;

[0054] Figure 2 Shown Figure 1e Examples of implementations of waveguide couplers;

[0055] Figure 3 An example of a wind turbine blade including an example of a lightning protection system and an embodiment of a condition monitoring device is shown;

[0056] Figure 4a A first example of a method for operational monitoring of a wind turbine blade using a condition monitoring device is shown, wherein a detection signal is injected into a lightning protection system of the blade;

[0057] Figure 4b A second example of a method for operational monitoring of a wind turbine blade using a condition monitoring device is shown, wherein a detection signal is injected into a tower conduction unit;

[0058] Figure 5 An example of an implementation of a condition monitoring system for operational monitoring of a wind turbine is shown;

[0059] Figure 6 Schematically shows a partial view of a wind turbine having three rotor blades and having a condition monitoring device in the hub and a sensor node with a ferrite core in the blade root;

[0060] Figure 7 A in FIG schematically shows Figure 6 A side view of a wind turbine wherein a potential fault is detected in a blade;

[0061] Figure 7 B in FIG schematically shows an embodiment of a condition monitoring system located in the hub and connected to a ferrite core in the blade root via a coaxial cable; and

[0062] Figure 8 Schematically shows Figure 6 View of the area between the hub and blades of a wind turbine.

[0063] The accompanying drawings are of a schematic nature only and are intended only for the purpose of understanding the invention.In the description of the examples of embodiment, similar elements are provided with the same reference numerals. DETAILED DESCRIPTION

[0064] exist Figures 1a to 1e In FIG. 1 , an example of an embodiment of the condition monitoring device 10 is shown. Figures 1a to 1eThe condition monitoring device 10 includes a signal generating unit 11 , a measuring unit 12 and a control unit 13 .

[0065] Faults in the lightning protection system (LPS) detected by the condition monitoring device 10 include, but are not limited to, completely disconnected conductors, such as disconnected downconductors 23, disconnected lightning receptors 5, 6 or expanded metal foil, and changes in the internal impedance of the blade, such as changes in the impedance of specific conductors or equipotential bonding. An algorithm is designed to analyze the response signals S2, which provide information about the location and time of the fault.

[0066] Furthermore, the response signal S2 may identify or predict a potential failure of the lightning protection system LPS of the blade 20 in the future based on the slow changes in the impedance matrix of the lightning protection system LPS of the blade 20 , which will result in changes in the measured response (system response).

[0067] Various algorithms are used to detect faults in lightning protection systems (LPS) and to identify the location of potentially faulty or slowly degrading connections.

[0068] In addition, a fingerprint signal can be generated for a specific blade, and machine learning and artificial intelligence analysis methods can be applied to track significant changes in the response signal S2 and thereby map changes in the conductive system of the blade 20. The fingerprint signal can, for example, refer to an initial signal measured at initial installation. Significant changes in the original characteristics of the fingerprint signal (during short-term conditions or during long-term changes) can indicate different failure modes in the blade.

[0069] exist Figure 4b In FIG. 1 , an alternative embodiment of an arrangement of the condition monitoring device 10 is shown.

[0070] In such Figure 4b In the embodiment shown in FIG, one (single) condition monitoring device 10 is arranged inside a nacelle 32 of a wind turbine.

[0071] The detection signal S1 is generated by the signal generating unit 11 and injected into the tower conducting unit 30 .

[0072] Preferably, the tower conducting unit 30 is at least partially formed by the exterior of the wind turbine's tower 31. In a possible embodiment, the exterior of the tower 31 comprises metal (particularly steel) and / or reinforced concrete to enable conduction of high frequency signals.

[0073] Alternatively or additionally, the tower conducting unit 30 includes a conductor such as a straight conducting element or a coaxial cable arranged outside or inside the tower 31 .

[0074] This enables the combination with Figure 4aThe same features and characteristics are described above with respect to the condition monitoring of the lightning protection system LPS, except that the signal paths are directed in opposite directions. Figure 4a The description also applies to Figure 4b The advantage of this embodiment is that we can have only one measurement system that observes the three blades in sequence.

[0075] exist Figure 5 , a wind turbine comprising a condition monitoring system for operational monitoring is shown.

[0076] In this example, the condition monitoring system comprises three condition monitoring devices 10 , wherein each device 10 is arranged in a respective blade 20 of a wind turbine.

[0077] Each blade 20 comprises a lightning protection system LPS and Figure 3 The arrangement of the condition monitoring device 10 is the same as or similar to the condition monitoring device described.

[0078] Furthermore, the condition monitoring system includes a remote data storage and analysis device 50. The system is configured so that the corresponding control unit 13 of the condition monitoring device 10 can communicate (exchange data) with the remote data storage and analysis device 50.

[0079] Preferably, the communication with the remote data storage and analysis device 50 is wireless communication.

[0080] In a possible embodiment, the data storage and analysis device 50 is designed as a computer system or as part of a cloud computing system.

[0081] The data storage and analysis device 50 is configured to perform signal processing on the received response signal S2, such as combining Figure 4a described.

[0082] It is also possible that the data storage and analysis device 50 is connected to a plurality of wind turbines (or the corresponding condition monitoring devices 10 of said plurality of wind turbines). Thus, the quantitative assessment of the condition of a wind turbine using the corresponding condition monitoring devices can be compared across a group of similar wind turbines, for example, to allow the original equipment manufacturer to better understand the failure mechanism.

[0083] In the event of a defect in the lightning protection system LPS of a wind turbine, the operator can be immediately informed via the data storage and analysis device 50 , for example by means of a text message, a corresponding application or the like.

[0084] In About Figure 5 In an alternative embodiment of the system described, the wind turbine includes a nacelle 32 as described above. Figure 4b A single condition monitoring device 10 is described.

[0085] Figures 6 to 8 The wind turbine illustrated in FIG comprises a condition monitoring system comprising a controller 111 configured to provide an input probe signal for injection into an electrical conductor system 113 of a blade 115, in particular when the respective blade 115 is aligned with a tower 117 of the wind turbine. In this example, the wind turbine comprises three blades 115. The condition monitoring system further comprises at least one measuring device 119, which may be arranged in the controller 111 and is configured to detect a response signal, which is a system response after the injection of the probe signal. The system response is generated in particular by the electrical conductor system 113 of the blade 115 and the fixed electrical conductor system 121, which is coupled to the electrical conductor system 113 via a capacitive coupling cc between the blade 115 and the tower 117, in particular when the respective blade 115 is aligned with the tower 117. The condition monitoring system is configured to provide an input detection signal for injection into the electrical conductor system of the blade 115 each time the respective blade 115 is aligned with the tower 117 or at predetermined intervals or on demand when the blade 115 is aligned with the tower 117. At least in some embodiments, alignment with the tower 117 essentially means that the blade 115 is pointing downwards, e.g. Figure 7 A is shown in FIG. A capacitive connection cc then exists between the electrical conductor system 113 of the blade 115 and a fixed electrical conductor system 121 which also extends in the tower 117 and provides a return path for the response signal to the measuring device 119 .

[0086] The detected response signals may be received by the measuring device 119. The detected response signals may be stored, for example, in the measuring device 119 and / or they may be provided to the controller 111 for further processing. Additionally or alternatively, the detected response signals may be provided to an external system, such as a Figure 5 The remote data storage and analysis device 50 shown in FIG. 5 is used for storage and / or further processing.

[0087] Additionally or alternatively, regarding providing an input probe signal for injection into the electrical conductor system of blade 115 each time a corresponding blade 115 is aligned with tower 117, or at predetermined intervals or on demand when blade 115 is aligned with tower 117, controller 111 may be configured to provide the input probe signal when the wind turbine is operating under predetermined operating conditions, such as predetermined loads on blade 115, or in a predetermined operating mode, such as idle mode, or at a predetermined generator output level. The predetermined loads on blade 115 may be measured, for example, using sensors, such as strain sensors attached to blade 115, or calculated using simulations, which may also use sensor data obtained from the sensors. In particular, controller 111 may be configured to determine the operating conditions of the wind turbine, such as the generated output level, or determine the operating conditions of the wind turbine based on the sensor data.

[0088] The analysis and fault detection based on the detected response signal can be carried out as described above with respect to FIG. Figure 5 Performed as described.

[0089] The controller 111 may include a signal generator 123 for generating a detection signal. The signal generator 123 may be separate from the measuring device 119, but as shown in FIG. Figure 8 As shown in , the signal generator 123 is electrically connected to the measuring device 119 .

[0090] The controller 111 may also include a power supply, communication hardware for communicating with components and devices of the wind turbine or with devices and systems external to the wind turbine, such as Figure 5 Controller 111 may include an electrical filter, for example, to filter the detection signal and / or the detected response signal.

[0091] The controller 111 may further include a processing unit, specifically for further processing the detected response signal. The controller 111, and in particular the processing unit, may be configured to process the response signal obtained from one blade 115 or from all three blades 115. In some embodiments, the processing unit may be included in the measurement unit 119 of the controller 111, or the processing unit may be a separate unit that is distinct from the measurement unit 119.

[0092] The controller 111 may analyze or compare response signals obtained from all blades 115, in particular such response signals obtained at least approximately during the same operating conditions of the wind turbine. Based on the detected response signals, the controller 111 may identify a change in a signal pattern in the response signals and determine at least one of the following based on the detected change in the signal pattern:

[0093] A fault in the blade 115 and / or the location of the fault, the time when the fault occurred, the type of fault.

[0094] The electrical conduction system 113 may comprise a lightning protection system LPS of the respective blade 115 . Thus, the electrical conduction system 113 may comprise a protection unit 23 comprising a down conductor 125 of the respective blade 115 .

[0095] If especially in Figure 6 and Figure 8 As shown in FIG, the down conductor 125 provides an injection site from which the insulating material 127 is removed and is used to inject the input probe signal into the electrical system 113 and to measure the response signal. The injection site 129 includes a portion of the electrical conductor, here a portion of the down conductor 125, around which the ferrite core 131 is arranged. Figure 6 In the embodiment of the present invention, the ferrite core 131 is depicted as a clamped ferrite core and is shown in an open state and a closed state for illustration purposes. In operation, the ferrite core 131 is used in the closed state. The ferrite core 131 can be easily installed when used as a clamped ferrite core. The ferrite core 131 can be composed of two half shells that can be arranged to surround an isolated portion of the down conductor 125, such as Figure 6 As shown in .

[0096] The first electrical injection line 133 is connected to the isolated portion of the electrical down conductor 125 at a first connection point 137, and the second electrical injection line 135 is connected to the portion of the down conductor 125 at a second connection point 139, and the ferrite core 131 is located between the first connection point 137 and the second connection point 139.

[0097] The first and second electrical injection lines 133 , 135 are also connected to the controller 111 via electrical connectors 141 and thus to the signal generator unit 123 and the measuring device 119 .

[0098] like Figure 8 As further illustrated in FIG, the conductor to the left of the second connection point 139 can be considered as part of the fixed electrical conductor system 121, which extends through the hub 143, the nacelle 145 and the tower 117, while the down conductor 125 to the right of the first connection point 137 extends through the rotor 147 and the blade 115. Figure 7 As shown in A and B in FIG, a conductive connection cc is obtained between the electrical conductor system in the blade 115 and the stationary conductor system in the tower 117 .

[0099] An input probe signal can be injected into the down conductor 125 at a first connection point 137 via a first electrical injection line 133 and at a second connection point 139 via a second electrical injection line 135. The ferrite core can provide a high impedance for the probe signal, thereby preventing a short circuit between the first connection point 137 and the second connection point 137. The ferrite core can provide a low impedance in the event of a lightning strike to avoid system damage.

[0100] As shown, the first and second electrical injection lines 133 and 135 are also used to detect a response signal, which can be detected by a measuring device or measuring unit 119. In some embodiments, the measuring device 119 can include a high internal resistance, such as 1 megohm. In some embodiments, the signal generating unit 123 can include a low internal resistance, such as 50 ohms.

[0101] Each blade 115 has its own connection point 133, 135, and an input detection signal can be provided independently for each blade. Correspondingly, a response signal can be detected independently for each blade 115. The signal generation unit 123 and / or the measurement unit 119 and / or other components of the control unit 111 can be provided separately for each blade 115, or at least some of the units can be used for all blades 115. However, preferably, a main control unit 149 is provided, for example, in the nacelle 145, to which all units of the unit are connected.

[0102] In particular, for each blade 115, the condition monitoring system may include a corresponding measuring device 119 dedicated to the respective blade 119. The measuring device 119 may be located at the root of the blade, at the junction between the hub 143 and the blade 115 or the rotor 147, or in the hub 143, the nacelle 145, or the tower 117. Alternatively, there may be one measuring device 119 for all blades 115, which may be located at the junction between the hub 143 and the blade 115, or in the hub 143, the nacelle 145, or the tower 117.

[0103] The at least one measuring device 119 may include a memory to at least temporarily record the detected response signal.

[0104] For example, the controller 111 including the signal generating unit 123 may be located in the hub 143 .

[0105] The controller 111 or the corresponding signal generating unit 123 may be configured to trigger the injection of a detection signal into the down conductor 125 of the blade 115 when the corresponding blade 115 is aligned with the tower 117. Figure 7As shown in Figure 1A, the tip of the blade 115 is pointed at least approximately vertically downwards, thereby ensuring that a capacitive connection cc can be obtained between the blade 115 and the tower 117, so that the response signal can be guided to the measuring device 119 via a return path established by the fixed electrical conductor system 121, which may include a grounded wire.

[0106] Units in wind turbines or external units, such as Figure 5 The remote device 50 shown in FIG, and in particular the controller 111, can be configured to compare one or more detected response signals with at least one predetermined fingerprint signal. The fingerprint signal may be based on the same detection signal and may have been determined during known operating conditions of the wind turbine. Furthermore, if a deviation between the detected response signal and the predetermined fingerprint signal is detected, for example, if the deviation exceeds a threshold level, an alarm can be set, which may include notifying the operator of the wind turbine.

[0107] The controller may be configured to determine a time delay between injection of the detection signal and detection of the corresponding response signal.If the time delay exceeds a threshold, an alarm may be output.

[0108] In operation, an input probe signal can be injected into the downconductor 125 of each blade 115, particularly when the corresponding blade 115 is aligned with the tower 117. Each blade 115 has an individual response in the form of at least one response signal that travels backward through the tower 117, which is coupled to the blade 115 via a capacitive coupling cc. Each impedance change in blade 115 results in a partial reflection included in the response signal. Repeated measurements after installation of the wind turbine provide each blade with a signature of a good blade. Such measured response signals can be used as fingerprint signals for the corresponding blade 115. In the event of damage, changes in impedance will result in changes in the detected response signals. Therefore, defects in blade 115 can be determined based on a comparison between the fingerprint signal of the corresponding blade 115 and the detected response signals.

[0109] like Figure 7 As illustrated at B in FIG, the condition monitoring system 111 may be located in the hub 143 and connected to the ferrite core 131 in the blade root via a coaxial cable 151 .

[0110] At least in some embodiments, Figures 6 to 8 The method for operational monitoring of a wind turbine shown in may comprise the following steps:

[0111] injecting at least one detection signal into the electrical conductor system 113 of the blade 115 when the corresponding blade is aligned with the tower 117,

[0112] Detecting at least one response signal, which is a system response after the injection of the probe signal, wherein the system response is obtained from the electric conductor system 113 of the blade and the fixed electric conductor system 121, wherein the fixed conductor system 121 is coupled to the electric conductor system 113 via a capacitive coupling cc between the blade 115 and the tower 117, in particular when the blade 115 is aligned with the tower 117.

[0113] The injecting step of at least one probe signal may comprise providing an input probe signal for injection into the electrical conductor system 113 of the blade 115 whenever the blade 115 is aligned with the tower 117 or at predetermined intervals or on demand when the blade 115 is aligned with the tower 117 .

[0114] The step of injecting at least one detection signal may be performed only when the wind turbine is operating under predetermined operating conditions, such as a predetermined load on the blades, or in a predetermined operating mode, such as an idle mode, or at a predetermined generator output level. Thus, the condition monitoring system may be configured to provide the input detection signal only when the wind turbine is operating under predetermined operating conditions.

[0115] In some embodiments, the method includes comparing a response signal detected from the blade 115 to a predetermined fingerprint signal of the blade 115 , and detecting a defect in the blade based on the comparison of the response signal to the fingerprint signal.

[0116] In some embodiments, the method includes determining a fingerprint signal of the blade 115 after the blade 115 is installed on the wind turbine by detecting at least one response signal in response to injecting at least one input detection signal.

[0117] Reference numerals

[0118] 10 Condition monitoring device

[0119] 11 Signal generating unit

[0120] 11a Signal sensing device

[0121] 11b waveguide coupler

[0122] 12 measurement units

[0123] 13 Control Unit

[0124] 20 blades

[0125] 21 blade shell

[0126] 22 CFRP structural elements connected to protection units

[0127] 23 Protection unit (down conductor)

[0128] 24 Electrical Conductors

[0129] 25 Protection unit (tip receiver)

[0130] 26 Protection unit (side receiver)

[0131] 30 Tower conduction unit

[0132] 31 Tower

[0133] 32 Cabin

[0134] 50 (remote) data storage and analysis device

[0135] 60 waveguide chassis

[0136] 61RF connector

[0137] 62 Transition Elements

[0138] 63 Insulator

[0139] 65 Chassis ground

[0140] L Destructive lightning impulse current

[0141] S1 detection signal

[0142] S2 response signal

[0143] LPS Lightning Protection System

[0144] cc capacitor connection

[0145] 111 Controller

[0146] 113 Electrical conductor systems

[0147] 115 blades

[0148] 117 Tower

[0149] 119 Measuring device

[0150] 121 Fixed electrical conductor systems

[0151] 123 signal generation unit

[0152] 125 Downlink

[0153] 127 Insulation Materials

[0154] 129 Injection site

[0155] 131 ferrite core

[0156] 133 First electrical injection line

[0157] 135 Second electric injection line

[0158] 137 First connection point

[0159] 139 Second connection point

[0160] 141 Electrical Connectors

[0161] 143 Hub

[0162] 145 Cabin

[0163] 147 Rotator

[0164] 149 Main Control Unit

[0165] 151 coaxial cable

Claims

1. A condition monitoring system for a wind turbine, in, The wind turbine comprises a tower, a nacelle, a hub and wind turbine blades attached to the hub, wherein each blade comprises an electrical conductor system, in particular a lightning protection system, wherein the tower, the nacelle and the hub comprise a fixed electrical conductor system, in particular the fixed electrical conductor system comprises an electrical grounding system of the wind turbine, Wherein, the condition monitoring system includes: a controller configured to provide an input detection signal for injection into the electrical conductor system of a blade when the corresponding blade is aligned with the tower, and at least one measuring device configured to detect a response signal, the response signal being a system response after the injection of the detection signal, wherein the system response is generated by the electrical conductor system of the blade and the fixed electrical conductor system, the fixed electrical conductor system being coupled to the electrical conductor system via a capacitive coupling between the blade and the tower, in particular when the blade is aligned with the tower, and Therein, the condition monitoring system is configured to provide the input detection signal for injection into the electrical conductor system of the blade whenever the blade is aligned with the tower or at predetermined intervals or on demand when the blade is aligned with the tower.

2. The condition monitoring system according to claim 1, in, The at least one measuring device is configured to provide the detected response signal to the controller for further processing.

3. A condition monitoring system for a wind turbine, in particular a condition monitoring system according to any one of the preceding claims, for a wind turbine. in, The wind turbine comprises a tower, a nacelle, a hub and wind turbine blades attached to the hub, wherein each blade comprises an electrical conductor system, in particular a lightning protection system, wherein the tower, the nacelle and the hub comprise a fixed electrical conductor system, in particular the fixed electrical conductor system comprises an electrical grounding system of the wind turbine, Wherein, the condition monitoring system includes: a controller configured to provide an input detection signal for injection into the electrical conductor system of a blade when the respective blade is aligned with the tower, at least one measuring device configured to detect a response signal, the response signal being a system response after the injection of the detection signal, wherein the system response is generated by the electrical conductor system of the blade and the fixed electrical conductor system, the fixed electrical conductor system being coupled to the electrical conductor system via a capacitive coupling between the blade and the tower, in particular when the blade is aligned with the tower, and Therein, the condition monitoring system is configured to provide the input detection signal when the wind turbine is operating under predetermined operating conditions, such as a predetermined load on the blades or in a predetermined operating mode, such as an idle mode, or at a predetermined generator output level.

4. The condition monitoring system according to any one of the preceding claims, in, The controller is configured to determine an operating condition of the wind turbine.

5. The condition monitoring system according to any one of the preceding claims, in, The controller, in particular the measurement unit of the controller, is configured to process the response signals from all blades, and / or wherein the condition monitoring system is configured to inject a response signal into each blade and to detect the response signal of each blade, wherein, optionally, the system, in particular the controller, is configured to compare the measurement values ​​from all blades and to indicate a fault in said one blade if a deviation is detected in said measurement values ​​from one blade in view of said measurement values ​​from the rest of said blades.

6. The condition monitoring system according to any one of the preceding claims, in, The controller is configured to analyse or compare the response signals from all blades, wherein optionally the controller is configured to analyse or compare only response signals obtained during at least approximately the same operating conditions of the wind turbine.

7. The condition monitoring system according to any one of the preceding claims, in, The controller is configured to determine at least one of the following based on the detected response signal and in particular according to the detection of a change in a signal pattern in the response signal: at least the approximate location of the fault, The time when the fault occurs, The type of fault in question.

8. The condition monitoring system according to any one of the preceding claims, in, An injection device is electrically connected to the controller and is configured to receive a probe pulse from the controller and to inject the probe pulse into the electrical conductor system of the blade when the blade is aligned with the tower, wherein optionally the injection device is comprised in the measuring device.

9. The condition monitoring system according to any one of the preceding claims, in, For each blade, the condition monitoring system comprises a measuring device dedicated to the respective blade, wherein optionally the measuring device is located at the root of the blade, at the junction between the hub and the blade, or in the hub, the nacelle or the tower.

10. The condition monitoring system according to any one of claims 1 to 8, in, The condition monitoring system comprises one measuring device for all blades, wherein, optionally, the measuring device is located at the junction between hub and blade, or in the hub, nacelle or tower.

11. The condition monitoring system according to any one of the preceding claims, in, The at least one measuring device is configured to record the detected response signal.

12. The condition monitoring system according to any one of the preceding claims, in, The controller includes a signal generating unit configured to generate the input detection signal.

13. The condition monitoring system according to any one of the preceding claims, in, The controller is located in the hub, in particular in a cabinet.

14. The condition monitoring system according to any one of the preceding claims, in, The controller is configured to trigger injection of the detection signal into the electrical conductor system of the blade when the respective blade is aligned with the tower.

15. The condition monitoring system according to any one of the preceding claims, in, The controller is configured to compare the response signal with a predetermined fingerprint signal and, optionally, set an alarm if the response signal deviates from the fingerprint signal.

16. The condition monitoring system according to any one of the preceding claims, in, The controller is configured to determine a time delay between injection of a detection signal and detection of a corresponding response signal, wherein, optionally, an alarm is output if the time delay exceeds a threshold.

17. The condition monitoring system according to any one of the preceding claims, in, The electrical conductor system of the blade comprises at least one electrical conductor, in particular a down conductor, located in the blade, the electrical conductor providing an injection site for injecting the input detection signal, wherein the injection site comprises a portion of the electrical conductor and at least one ferrite core arranged around the portion of the electrical conductor, wherein the input detection signal is injected into the electrical conductor system via a first electrical injection line and a second electrical injection line, wherein the first electrical injection line is connected to the portion of the electrical conductor at a first connection point and the second electrical injection line is connected to the portion of the electrical conductor at a second connection point, wherein the at least one ferrite core is located between the first connection point and the second connection point.

18. The condition monitoring system according to claim 17, in, The first electrical injection line and the second electrical injection line are further used to detect a response signal.

19. A wind turbine comprising at least one condition monitoring system according to any one of the preceding claims.

20. A method for operational monitoring of a wind turbine, preferably by means of a condition monitoring system according to any one of claims 1 to 18, wherein: The method comprises the following steps: injecting at least one detection signal into the electrical conductor system of a blade of the wind turbine when the respective blade is aligned with the tower of the wind turbine, detecting at least one response signal, which is a system response after the injection of the probing signal, wherein the system response is obtained from the electrical conductor system of the blade and a fixed electrical conductor system of the tower, the nacelle and the hub of the wind turbine, wherein the fixed conductor system is coupled to the electrical conductor system via a capacitive coupling between the blade and the tower, in particular when the blade is aligned with the tower, wherein injecting the at least one probe signal comprises providing the input probe signal for injection into the electrical conductor system of the blade whenever the blade is aligned with the tower or at predetermined intervals or on demand when the blade is aligned with the tower, and / or Therein, the at least one input detection signal is injected when the wind turbine is operating under predetermined operating conditions, such as a predetermined load on the blades or in a predetermined operating mode, such as an idle mode, or at a predetermined generator output level.

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