TESTING OF LIGHTNING PROTECTORS FOR WIND ENERGY PLANTS

Description

Field of the invention

[0001] Exemplary embodiments of the invention relate to the inspection of lightning rods included in wind turbines, for example, whether they are damaged or not. Background of the invention

[0002] Wind turbines are equipped with a lightning protection system in the rotor blades. This system must be inspected at regular intervals due to legal requirements. According to the state of the art, this inspection consists of measuring the resistance of the lightning rod included in the lightning protection system using a measuring device. The measuring device measures between the beginning and end of the lightning rod.

[0003] Furthermore, the measurement must be conducted between various coupling points and the starting point, to access which personnel must abseil down the rotor blade surrounding the lightning rod. This is complex, dangerous, and also associated with high costs.

[0004] The disadvantage of this method is the labor and time required, as the measuring device must be attached to each blade using a cable team. The wind turbine rotor must be re-rotated for each measurement. Furthermore, the current measurement method involves a significant risk of falling.

[0005] In addition, such resistance measurements must be performed every two years. If a lightning rod is damaged or defective, this can lead to the energy introduced by a lightning strike not being able to be dissipated through the rod. Instead, the energy is conducted to nearby components, which can be severely damaged or even completely destroyed. A prior art example is known from DE102012214981A1. Summary of some exemplary embodiments of the invention

[0006] Based on this state of the art, the object of the present subject matter is to provide a solution for the inspection of lightning rods incorporated in wind turbines which makes it possible, on the one hand, to carry out the corresponding inspection with little expenditure of time and, on the other hand, while minimising the risks, in particular for the personnel carrying out an inspection of the lightning rod.

[0007] This object is achieved by a method according to the features of the independent claims.

[0008] According to a first aspect of the invention, a method is described, e.g. performed by one or more devices, the method comprising: Determining impulse response information indicative of an impulse response, wherein the impulse response information is determined based on a pulse introduced into the lightning rod, which is characterized by an electromagnetic wave, wherein the impulse response information represents at least a waveform and a propagation time determined after the introduction of the pulse based on its reflection; determining evaluation information based on the determined impulse response information, wherein the impulse response information is analyzed at least with regard to the represented waveform and the propagation time of the introduced and reflected electromagnetic wave, wherein the evaluation information is indicative of whether the lightning rod is functional or not; and outputting or causing the output of the determined evaluation information.

[0009] According to a second aspect of the invention, a device is described which is configured or comprises corresponding means for carrying out and / or controlling a method according to the first aspect. Devices of the method according to the first aspect are or comprise, in particular, one or more devices according to the second aspect.

[0010] According to the second aspect of the invention, an alternative device is also described, comprising at least one processor and at least one memory with computer program code, wherein the at least one memory and the computer program code are configured to execute and / or control at least one method according to the first aspect with the at least one processor. A processor is understood to mean, for example, a control unit, a microprocessor, a microcontrol unit such as a microcontroller, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), or a field-programmable gate array (FPGA).

[0011] For example, an exemplary device further comprises means for storing information, such as a program memory and / or a main memory. For example, an exemplary device according to the invention further comprises means for receiving and / or transmitting information via a network, such as a network interface. For example, exemplary devices according to the invention are connected and / or connectable to one another via one or more networks.

[0012] An exemplary device according to the second aspect is or includes, for example, a data processing system configured in software and / or hardware to be able to execute the respective steps of an exemplary method according to the second aspect. Examples of a data processing system are a computer, a desktop computer, a server, a thin client, and / or a portable computer (mobile device), such as a laptop computer, a tablet computer, a wearable device, a personal digital assistant, or a smartphone.

[0013] Individual method steps of the method according to the first aspect (e.g., determining the impulse response information) can be performed using a sensor device (e.g., measuring device) that also has at least one sensor element. Likewise, individual method steps (e.g., determining the evaluation information), which do not necessarily have to be performed using the sensor device, can be performed by another device that is connected, in particular, via a communication system to the device that has at least one sensor element.

[0014] Further devices may be provided, for example, a server and / or a part or component of a so-called computer cloud, which dynamically provides data processing resources to various users in a communications system. A computer cloud is understood, in particular, to be a data processing infrastructure according to the definition of the National Institute for Standards and Technology (NIST) for the English term "cloud computing." An example of a computer cloud is a Microsoft Windows Azure Platform.

[0015] According to the second aspect of the invention, a computer program is also described, comprising program instructions that cause a processor to execute and / or control a method according to the first aspect when the computer program is running on the processor. An exemplary program according to the invention can be stored in or on a computer-readable storage medium containing one or more programs.

[0016] According to the second aspect of the invention, a computer-readable storage medium is also described, which contains a computer program according to the second aspect. A computer-readable storage medium can be designed, for example, as a magnetic, electrical, electromagnetic, optical, and / or other type of storage medium. Such a computer-readable storage medium is preferably tangible (i.e., "tangible"), for example, it is designed as a data storage device. Such a data storage device is, for example, portable or permanently installed in a device. Examples of such a data storage device are volatile or non-volatile random access memories (RAM), such as NOR flash memories, or sequential access memories, such as NAND flash memories, and / or read-only or read-write memories (ROM). Computer-readable should be understood, for example, to mean that the storage medium can be read by a computer orcan be read and / or written by a data processing system, for example by a processor.

[0017] According to a third aspect of the invention, a system is also described, comprising a plurality of devices, in particular a server and a device for checking a lightning rod, which together carry out a method according to the first aspect.

[0018] An exemplary system according to the third aspect comprises an exemplary device, for example, a mobile device or a server, for carrying out an exemplary method according to the first aspect. Furthermore, the system can comprise, for example, a device for testing a lightning rod, the device comprising, for example, a pulse generator and a measuring device.

[0019] According to the invention, a rotor blade for a wind turbine or which is comprised by a wind turbine comprises at least one lightning rod (which is arranged, for example, internally or externally of the rotor blade) and means for checking the at least one lightning rod, wherein the means are designed and / or configured for carrying out and / or implementing a method according to the invention according to the first aspect of the present invention.

[0020] Further details and details of the present subject matter are demonstrated below using the exemplary embodiments described as examples: A lightning rod within the meaning of the invention is a device whose task is to prevent damage in the event of a lightning strike, e.g., to a device comprising the lightning rod, and also to divert the current introduced by the lightning via a defined current path. Lightning rods in wind turbines are, in particular, encompassed by at least one rotor blade of the wind turbine. Examples of such lightning rods are metal profiles, metal cables, and / or metal lines arranged inside the at least one rotor blade (also referred to as internal lightning rods).

[0021] Furthermore, such lightning rods can also be at least a mesh of copper wires (so-called meshes), which are arranged, for example, in the blade surfaces and / or at the blade edges of the rotor blade or are encompassed by the blade. Metal profiles in the blade edges of the rotor blade can also constitute such a lightning rod. If the lightning rod is not arranged within the blade and / or the blade edge, such lightning rods are also referred to as external lightning rods of a rotor blade. To define a point of impact, such lightning rods regularly comprise a receptor, e.g., a metal receptor, which is usually arranged at the outer blade tip of the rotor blade, since the blade tip (depending on the position of at least one rotor blade of the wind turbine) represents the highest point of the wind turbine. The lightning rod can, for example, be designed as a single-conductor.Furthermore, the lightning rod can be designed with or without a return conductor.

[0022] The pulse introduced into the lightning rod is characterized or represented by an electromagnetic wave.

[0023] The impulse response information is determined, for example, by determining (e.g., measuring) a response signal that can be detected (e.g., measured) in response to the impulse introduced into the lightning rod. The impulse response information then represents, for example, this measured signal (response signal). The response signal is detected, for example, after the impulse is introduced into the lightning rod, e.g., for a predefined period of time, and / or by detecting (e.g., measuring) an amplitude of the measured response signal. The impulse response information can be determined, for example, using a measuring device.

[0024] The response signal is determined, for example, by detecting (e.g. measuring) a reflected electromagnetic wave or several reflected electromagnetic waves, which are the result of the introduced pulse or the several introduced pulses in the case that several pulses are introduced into the lightning rod. The response signal corresponds, for example, to an output signal of a system comprising the lightning rod, in which the pulse at the input is, for example, a Dirac pulse or a pulse approximating a Dirac pulse, in which the pulse is fed to this system with the highest possible amplitude in the shortest possible time. The introduced pulse is therefore, for example, a signal (e.g. electromagnetic wave) with the (highest possible) amplitude over the (shortest possible), i.e. limited, period of time.

[0025] The evaluation information is determined based on the determined impulse response information, whereby the impulse response information is analyzed at least with regard to the represented waveform and the propagation time (e.g., signal propagation length of the response signal) of the introduced and then reflected electromagnetic wave (pulse). After the analysis has been completed, the evaluation information represents whether the lightning rod is functional or not. The response signal reflected based on the introduced pulse is, for example, altered in particular by disturbances, e.g., its propagation time is altered (e.g., extended). This can be caused, for example, in particular by external disturbances to which the introduced pulse may be subjected during the reflection until the response signal is detected.These can be, for example, disturbances such as open and / or (un)shielded conductors, atmospheric coupling, or the like, to name just a few non-limiting examples.

[0026] The specific evaluation information is then output, or its output is initiated, or a corresponding output can be triggered. A user can then carry out an action based on the specific evaluation information. For example, if the evaluation information represents a non-functional lightning rod, the user can be informed of this through the output and can then, for example, carry out a repair. Alternatively or additionally, in one embodiment of the method, the evaluation information can be output to a further entity, e.g. a server. For example, the evaluation information can represent whether the lightning rod is functional or not. The server can, for example, store this evaluation information. If the server stores a large amount of such evaluation information, a user orThe user can gain an overview of which lightning rods, for example, are functional or not, within wind turbines. It is also conceivable that the output of the evaluation information could automatically trigger an action, such as initiating a repair.

[0027] The method according to the invention can, for example, be carried out regularly, e.g. at predefined time intervals. Alternatively or additionally, the method according to the invention can be carried out after an event has occurred, e.g. a lightning strike on the wind turbine. As a result, it can be determined promptly whether a lightning rod is functional or not. In the event that, for example, a large number of such lightning rods are checked using the method according to the invention, it becomes apparent immediately after the method has been carried out whether the lightning rod is functional or not. Depending on the frequency with which the method according to the invention is carried out, it can therefore be determined very quickly whether one or more lightning rods, which are included, for example, in one or more wind turbines, are functional or not.

[0028] In this way, it is now possible to carry out the inspection of the lightning rod, which is comprised, for example, of a wind turbine, at least partially automatically. The device according to the second aspect of the present invention can for this purpose be comprised, for example, of the wind turbine. In particular, such a device has an operative connection, e.g. via a hub, to which rotor blades of the wind turbine are connected to a generator of the wind turbine, to the respective lightning rods comprised by the rotor blades. The device can then introduce a pulse into one of the lightning rods via this connection and determine the pulse response information using the method according to the first aspect of the present invention. The costly deployment of personnel on site to inspect the lightning rods comprised by the rotor blades of the wind turbine can be eliminated.

[0029] This leads to a cost advantage, as the personnel and time required for the measurement are significantly reduced. It also eliminates the risk of falls or injuries to personnel or the rope team, which offers a significant advantage from a health and safety perspective.

[0030] According to the invention, determining the evaluation information comprises a comparison of the waveform and / or runtime represented by the impulse response information with at least one reference information.

[0031] According to the invention, the at least one piece of reference information is indicative of impulse response information of an undamaged lightning rod. Accordingly, the at least one piece of reference information can be determined or ascertained, for example, prior to the method according to the first aspect of the invention. To determine the at least one piece of reference information, for example, a pulse is introduced into the undamaged lightning rod, and the signal response is subsequently determined (e.g., measured). To ensure that the lightning rod is undamaged, a further measurement of the lightning rod is carried out according to the invention, in particular according to an alternative measuring method, so that it can be ensured that the lightning rod is undamaged.Alternatively or additionally, the lightning rod can be used, for example, immediately after its manufacture to determine the at least one piece of reference information, so that it can again be ensured that an undamaged lightning rod is used to determine the at least one piece of reference information. Alternatively or additionally, it can be ensured, for example, by a manual inspection, whether the lightning rod is undamaged or whether the at least one piece of reference information is determined or ascertained.

[0032] The at least one piece of reference information can, for example, represent or include identification information indicative of a type, type, and / or at least one property that uniquely characterizes the lightning rod (e.g., length, number of coupling points, or the like, to name only a few non-limiting examples) or corresponding identification information. The at least one piece of reference information can, for example, optionally be determined or ascertained depending on the initiated pulse.

[0033] For example, the at least one piece of reference information associated with the undamaged lightning rod can be a signal response to an applied pulse, such as a Dirac pulse, a predefined amplitude, and / or the trailing edge of an applied pulse, to name just a few non-limiting examples. It goes without saying that for comparability, the lightning rod should subsequently be tested with an identical pulse.

[0034] The pulse introduced can, for example, be a rectangular pulse. Alternatively, instead of a single pulse, a sequence of pulses comprising at least two pulses can be introduced into the lightning rod.

[0035] If the (cable) parameters of the lightning rod are known, the at least one piece of reference information can also be entered directly. This is particularly recommended in cases where determining the at least one piece of reference information is otherwise not possible.

[0036] If the lightning rod is defective, i.e. the conductor is damaged in any way or even completely broken, the shape of the reflected electromagnetic wave, which is represented by the impulse response information, changes.

[0037] According to an exemplary embodiment of all aspects of the invention, the evaluation information is determined on the basis of one or more of the following parameters i) to ii): i) propagation times of the introduced pulse; and ii) character of the reflected electromagnetic wave.

[0038] The propagation time of the introduced pulse (signal), which is represented by the impulse response information, is, for example, the time difference between the entry of a signal (in this case the pulse introduced into the lightning rod) into the lightning rod and the exit (reflection and / or decay of the introduced pulse) after its reflection and / or (complete) decay.

[0039] For example, a lightning rod has an open cable end. A pulse introduced into the lightning rod, which has an open cable end, oscillates back and forth between the ends of the lightning rod, with the intensity (i.e., amplitude) of the introduced pulse gradually decreasing. For the purposes of the present subject matter, this is also referred to as pulse decay.

[0040] The character of the reflected electromagnetic wave (also referred to as signal character) represented by the impulse response information is, for example, indicative of one or more reflection characteristics. For example, the signal character can form a voltage wave with exponentially decreasing characteristics in lightning rods where parallel losses predominate. For example, the signal character can form a voltage wave with exponentially increasing characteristics in lightning rods where series losses predominate. Accordingly, it can be determined, for example, whether the lightning rod is functioning properly or functionally based on the losses that occur. For example, in lightning rods with an open end, only pulses and their reflections of the same polarity occur, with the amplitude of the reflections continuously decreasing.This can, for example, be represented by the signal character that a signal response, represented by the impulse response information, can exhibit in response to a pulse introduced into the lightning rod. The signal character can, for example, further represent one or more capacitive, resistive, and / or inductive characteristics of the reflection of the pulse introduced into the lightning rod.

[0041] The differences, for example in the shape and travel time of the electromagnetic waves, therefore serve as an indicator of a defective lightning rod.

[0042] According to an exemplary embodiment of all aspects of the invention, the at least one reference information item is determined based on an undamaged lightning rod, which is comprised, for example, of a rotor blade, by determining a corresponding impulse response information item that characterizes the undamaged lightning rod.

[0043] Alternatively or additionally, known parameters, which are available, for example, if a similar lightning rod has already been measured, can be entered directly so that at least one piece of reference information can be determined. This can also be done, for example, if (other) parameterization is not possible.

[0044] According to an exemplary embodiment of all aspects of the invention, the impulse response information is characterized as a function in the time domain.

[0045] The impulse response information as such a function comprises, for example, multiple values, e.g., amplitudes, mapped over a time range, e.g., for a duration of zero to five seconds. The multiple values ​​are recorded, for example, discretely or continuously.

[0046] According to an exemplary embodiment of all aspects of the invention, the lightning rod has at least one coupling point (also referred to as coupling point) at one end of the lightning rod, wherein the pulse (e.g. generated by a pulse or step function generator) is introduced into the lightning rod via the at least one coupling point.

[0047] The lightning rod can, for example, have at least one coupling point for initiating the pulse. This coupling point can, for example, also be used to determine the impulse response information, for example by operatively connecting or linking a corresponding measuring device to this coupling point. The lightning rod can also have a defined point of impact for lightning, which, for the purposes of the present subject matter, is to be distinguished from the at least one coupling point for initiating the pulse.

[0048] According to an exemplary embodiment of all aspects of the invention, a total impedance information indicative of a total impedance of the lightning rod is determined, wherein the determination of the evaluation information is further carried out at least partially based on the total impedance information.

[0049] The total impedance of the lightning rod can be determined retrospectively, for example, based on the propagation time of the pulse (the electromagnetic wave) and its shape.

[0050] The total impedance of the lightning rod results, among other things, from the characteristics of the lightning rod enclosed by a rotor blade of a wind turbine. These include, for example, the length of the rotor blade, the length of the lightning rod (e.g., a single-conductor version), and the number of defined strike points at which lightning electrically connects with the lightning rod, to name just a few non-limiting examples. Furthermore, these can include the length and type of lightning rod, the specific resistance of the lightning rod, the number of receptors in the lightning rod, and / or the connection of the receptors. All of the aforementioned characteristics can be defined by the rotor blade enclosed by the wind turbine, which in turn includes the lightning rod.

[0051] According to an exemplary embodiment of all aspects of the invention, the total impedance information is determined based on the determined propagation time of the pulse, its shape, each represented by the determined impulse response information, and the specific resistance of the lightning rod.

[0052] The total impedance of the lightning rod can be determined by the signal propagation length represented by the impulse response information (e.g. the measured propagation time of the electromagnetic wave or its reflection), its represented shape and the specific resistance (which depends, for example, on the temperature and material of the lightning rod).

[0053] According to an exemplary embodiment of all aspects of the invention, the impulse response information is determined by means of at least one tap at the beginning or at the end of the lightning rod.

[0054] The tap can, for example, be identical to the coupling point for introducing the pulse into the lightning rod or be operatively connected at the same point. The at least one tap can, in particular, be arranged at the end of the lightning rod that is adjacent to a hub of a wind turbine, on which, for example, a rotor blade that encompasses the lightning rod is arranged, i.e., rotatably mounted.

[0055] According to an exemplary embodiment of all aspects of the invention, the method is carried out by means of a time domain reflectometry device, wherein the time domain reflectometry device comprises at least one pulse generator for introducing the pulse and a measuring device for determining the pulse response.

[0056] The measuring device is, for example, an oscilloscope or comprises one or more functionalities of an oscilloscope. The reflection or multiple reflections of one or more introduced pulses (represented by the impulse response information) determined (e.g. measured) by means of the measuring device can, for example, be analyzed. For example, the one or more determined reflections can be compared with the pulse introduced into the lightning rod or, in the event that a sequence comprising at least two pulses is introduced into the lightning rod, with the respective ones from the sequence of pulses. In this case, the reflections can, for example, be analyzed for the presence of one or more signal characteristics, or these can be determined at least partially based on a difference between the introduced pulse and its reflection or between the introduced pulses and their reflections.

[0057] Using time-domain reflectometry, for example, the propagation lengths and reflection characteristics of electromagnetic waves and signals can be determined and analyzed. Using a pulse or step function generator, an electromagnetic wave is sent into the lightning rod at the beginning of the lightning protection system's line. This wave is reflected at the end of the lightning protection system and sent back to its source. The shape of the reflected wave, as well as its travel time, are recorded and evaluated. If the lightning rod is defective—i.e., the conductor of the lightning protection system is damaged in any way or is completely broken—the shape of the reflected wave changes as a result.

[0058] The above-described embodiments and exemplary configurations of all aspects of the present invention, which initially stand alone in principle, are also to be understood as disclosed in all combinations with one another.

[0059] Further advantageous exemplary embodiments of the invention can be found in the following detailed description of some exemplary embodiments of the present invention, particularly in conjunction with the figures. However, the figures appended to the application are intended only for the purpose of illustration and not to define the scope of the invention. The accompanying drawings are not necessarily to scale and are intended merely to reflect the general concept of the present invention by way of example. In particular, features contained in the figures should in no way be considered a necessary part of the present invention. Short description of the characters

[0060] They show: Fig. 1 is a schematic representation of an exemplary embodiment of a system according to the present invention; Fig. 2 is a flowchart of an exemplary embodiment of a method according to the first aspect of the present invention; and Fig. 3 is a schematic representation of an exemplary embodiment of an apparatus according to the present invention. Detailed description of some exemplary embodiments of the invention

[0061] Fig. 1is a schematic representation of an exemplary embodiment of a system 100 according to the present invention. The system 100 comprises a server 110, an optional database 120, a lightning rod 130, which in this case is comprised of a schematically illustrated rotor blade 170 of a wind turbine, and a device 160 for checking the lightning rod 130. This device 160 can be used to check whether the lightning rod 130 is functional or not.

[0062] The device 160 may be a time-domain reflectometry device and may, for example, comprise a pulse generator or step function generator 140, as well as a measuring device 150 (e.g., a measuring device configured as an oscilloscope). The device 160 is particularly suitable for a wind turbine (in Fig. 1not shown), which also includes the rotor blade 170 comprising the lightning rod 130. Advantageously, the device 160, or the entities 140 and 150 included in the device 160, are operatively connected (e.g., electrically) to a coupling point of the lightning rod 130. The lightning rod 130 has such a coupling point, in particular at one end, in particular at the end of the lightning rod 170 facing a hub to which, for example, the rotor blade 170 is also connected to a wind turbine.

[0063] The output of the specific evaluation information (see step 240 of the Fig. 2 ) is carried out, for example, to the server 110 by transmitting the evaluation information to the server 110, for example via a communication network (e.g. the Internet).

[0064] The server 110 is, for example, further operatively connected to an optional database 120, or the server 110 comprises, for example, the optional database 120. The database 120 has, for example, a memory in which, for example, one or more reference information (cf. optional step 210 of the Fig. 2 ), or at least temporarily one or more impulse response information and / or evaluation information can be stored.

[0065] Fig. 3 shows a schematic representation of an exemplary embodiment of a device 300 that can be used in the context of the present invention.

[0066] The device 300 can, for example, be the device 160 according to Fig. 1 represent (and then, for example, the method of flowchart 200 after Fig. 2 The device 300 may, for example, also instruct the server 110 to Fig. 1represent (and then, for example, together with the device 160 according to Fig. 1 the process of flowchart 200 according to Fig. 2 carry out).

[0067] Device 300 comprises a processor 310 with associated memory 340 and program memory 320. Processor 310 executes, for example, program instructions stored in program memory 320. The program instructions execute and / or control the method according to the first aspect of the invention. Thus, program memory 320 contains a computer program according to an exemplary aspect of the invention and represents a computer program product for storing it. Device 300 represents an example of a device according to the second aspect of the invention.

[0068] The program memory 320 can, for example, be persistent memory, such as a read-only memory (ROM). The program memory 320 can, for example, be permanently connected to the processor 310, but can alternatively also be detachably connected to the processor 310, for example, as a memory card, floppy disk, or optical data storage medium (e.g., a CD or DVD). Additional information can also be stored in the program memory 320 or in a separate memory.

[0069] The main memory 340 is used, for example, to store temporary results during the processing of the program instructions; this is, for example, a volatile memory, such as a random access memory (RAM).

[0070] The processor 310 is further operatively connected to a communication interface 330, which, for example, allows information to be exchanged with other devices (see, for example, the arrows between the interfaces used by the system 110 according to Fig. 1 entities included).

[0071] The device 300 may also contain or include further components. If the device 300 comprises a detection unit (e.g., measuring device 150 according to Fig. 1 ), e.g., to determine impulse response information (see step 201 after Fig. 2), in particular, a detection means for detecting the impulse response is provided, which is configured, for example, for signal detection (e.g., measuring) in the form of a measuring device 312 (e.g., a measuring device) as a structural and / or functional unit and is operatively connected to the processor 310 or is comprised by it. The device 300, in particular the processor 310, may further comprise a pulse generator 311 (or alternatively, a step function generator) as a structural and / or functional unit. The pulse generator 311 may, for example, be configured to input a pulse into a lightning rod (e.g., lightning rod 130 according to Fig. 1 ) (see also step 221 of the Fig. 2 ).

[0072] If device 300 represents a detection unit, means for determining evaluation information may be operatively connected to processor 310. Alternatively, the determination of the evaluation information may be performed directly by processor 310.

[0073] Fig. 2 illustrates a flowchart 200 of an exemplary embodiment of a method used by a device 160 in the context of the present invention for testing a lightning rod, e.g., lightning rod 170 according to Fig. 1 can be executed.

[0074] In an optional first step 210, at least one reference information item is determined. The at least one reference information item is determined, for example, by a pulse generator (or alternatively a step function generator), e.g., pulse generator 140 according to Fig. 1. The device 160 or the pulse generator 140 directs a generated pulse into the lightning rod (e.g. lightning rod 130 to Fig. 1 ), e.g. via a coupling point to which the device 160 or the pulse generator 140 is operatively connected.

[0075] In a second step 220, impulse response information is determined. Step 220 further comprises step 221, after which an impulse is introduced into the lightning rod. Furthermore, step 220 here comprises step 222, which is carried out following step 221, and after which a signal response is measured. The signal response measured in step 222 is subsequently represented, for example, by the impulse response information. The impulse response information is determined, for example, by a measuring device (e.g., measuring device 150 according to Fig. 1 ). The measuring device 150 is, for example, from the device 160 according to Fig. 1 The device 160 or the measuring device 150 is, for example, operatively connected to a coupling point that is comprised by the lightning rod. In the event that the measuring device 150 is comprised by the device 160, the measuring device 150 can be used to determine (e.g., measure) one or more reflections that are carried out as a signal response based on a pulse or multiple pulses introduced into the lightning rod 130. The pulse or multiple pulses introduced into the lightning rod 130 can be generated, for example, by a pulse generator (e.g., pulse generator 140 according to Fig. 1 ] and introduced into the lightning rod accordingly, in the event that a corresponding pulse generator is included in the device 160.

[0076] In a third step 230, evaluation information is determined. Step 230 includes an optional comparison of the impulse response information (cf. step 220) with the at least one reference information (cf. step 210) in the event that optional step 210 was executed by the flowchart. The evaluation information can alternatively also be determined by a server remote from the device 160, for example, connected via a communication network (e.g., Internet) (e.g., server 110 according to Fig. 1 ). For this purpose, the impulse response information must first be transmitted, for example, from device 160 to server 110.

[0077] In a fourth step 240, the determined evaluation information is output. The evaluation information is, for example, sent from the device 160 to a server (e.g., server 110 according to Fig. 1). The output evaluation information can then be further processed, for example in a database (e.g. database 120 according to Fig. 1 ) and / or output, e.g., to a user. The output can, for example, be such that the evaluation information is presented to a user, e.g., visually and / or acoustically by means of a device designed for the visual and / or acoustic reproduction of information (e.g., a display and / or loudspeaker).

[0078] In the event that the evaluation information is provided by a server (e.g. server 110 after Fig. 1 ), the output is sent to another server, for example, the network control center of a power grid into which the wind turbine, for example, including the lightning rod, feeds. Alternatively or additionally, the output can be sent to a user in a similar way to the output described above.

[0079] Steps 220, 230, and 240 can be repeated, for example, at regular intervals, e.g., predefined intervals, and / or depending on an event, e.g., a lightning strike. This is schematically illustrated in flowchart 200 by arrow 250, which leads back to step 220.

[0080] The exemplary embodiments of the present invention described in this specification are to be understood as disclosed both individually and in all combinations with one another. In particular, the description of a feature encompassed by an embodiment should not be understood in this case - unless explicitly stated otherwise - to mean that the feature is essential or essential for the function of the embodiment. The sequence of the method steps described in this specification in the individual flow diagrams is not mandatory; alternative sequences of the method steps are conceivable. The method steps can be implemented in various ways; for example, an implementation in software (by program instructions), hardware, or a combination of both is conceivable for implementing the method steps.Terms used in the claims such as "comprise," "have," "include," or the like do not exclude further elements or steps. The phrase "at least partially" encompasses both "partially" and "fully." The phrase "and / or" is intended to indicate that both the alternative and the combination are disclosed, thus "A and / or B" means "(A) or (B) or (A and B)." A plurality of units, persons, or the like, in the context of this specification, means multiple units, persons, or the like. The use of the indefinite article does not exclude a plurality. A single device may perform the functions of multiple units or devices recited in the claims. Reference numerals indicated in the claims are not to be construed as limitations on the means and steps employed.

Claims

1. Method for checking a lightning conductor (130) of a lightning protection system comprised by a rotor blade (170) of a wind turbine, wherein the wind turbine comprises a device (160) for checking the lightning conductor (130) and the rotor blade (170) comprising the lightning conductor (130), wherein the device (160) for checking the at least one lightning conductor (130) is designed and / or configured to carry out and / or to execute the method, and wherein the device (160) is a time domain reflectometry device and comprises at least one pulse generator (140) for introducing a pulse and a measuring device (150) for determining (220) the pulse response, the method comprising: - determining (220), by the measuring device (150), a pulse response information indicative of a pulse response, wherein the pulse response information is determined based on an pulse introduced into the lightning conductor (130) characterized by an electromagnetic wave, wherein the pulse response information represents at least a waveform and a propagation time determined on the basis of the reflection of the pulse after it has been introduced; - determining (230), by the device (160), an evaluation information based on the determined pulse response information, wherein the pulse response information is analyzed at least with regard to the represented waveform and the runtime of the introduced and reflected electromagnetic wave, wherein the evaluation information is indicative of whether the lightning conductor (130) is functional or not; and - outputting or causing an output (240), by the device (160), of the determined evaluation information; wherein determining (230) the evaluation information comprises a comparison of the waveform and / or propagation time represented by the pulse response information with at least one reference information indicative of a pulse response information of an undamaged lightning conductor, and a further measuring of the lightning conductor (130) to ensure that the lightning conductor (130) is undamaged.

2. Method according to claim 1, wherein the determining (230) of the evaluation information is based on one or more of the following parameters i) to ii): i) durations of the introduced pulse; and ii) character of the reflected electromagnetic wave.

3. Method according to claim 1 or claim 2, wherein the at least one reference information is obtained based on an undamaged lightning conductor (130) which is comprised by a rotor blade (170), by determining a corresponding pulse response information characterizing the undamaged lightning conductor (130).

4. Method according to one of the preceding claims, wherein the pulse response information is characterized as a function in the time domain.

5. Method according to one of the preceding claims, wherein the lightning conductor (130) has at least one coupling point at one end of the lightning conductor (130), wherein the pulse is introduced into the lightning conductor (130) via the at least one coupling point.

6. Method according to one of the preceding claims, wherein a total impedance information indicative of a total impedance of the lightning conductor (130) is determined, wherein the determination (230) of the evaluation information is further carried out at least partially based on the total impedance information.

7. Method according to claim 6, wherein the total impedance information is determined based on the determined propagation time of the pulse, the shape of which is represented by the determined pulse response information, and the specific resistance of the lightning rod (130).

8. Method according to one of the preceding claims, wherein the pulse response information is determined by means of at least one tap at the beginning or at the end of the lightning conductor (130).

9. Device (160, 300) configured to execute and / or control the method according to one of claims 1 to 8 or comprising respective means for executing and / or controlling the steps of the method according to one of claims 1 to 8, wherein the device is comprised by a wind turbine.

10. Rotor blade (170) for a wind turbine comprising at least one lightning conductor (130) and means (160) for checking the at least one lightning conductor (130), wherein the means (160) are designed and / or configured to execute and / or carry out a method according to one of claims 1 to 8.

11. System (100) comprising one or more devices (160, 300) according to claim 9, which are configured to carry out and / or control the method according to any one of claims 1 to 8 or comprise means (160) for carrying out and / or controlling the steps of the method according to any one of claims 1 to 8.