Method for preparing a repair of a rotor blade of a wind turbine, support structure, rotor blade system and repair method

Abstract

The present application relates to a method for preparing a repair of a damaged area (32) of a load-bearing structure of a rotor blade (2') of a wind turbine (1), wherein the method comprises: Determining a first rotor blade position, which can be a single set position or a set range, in such a way that a first mechanical load of the load-bearing structure in the first rotor blade position is smaller than a second mechanical load of the load-bearing structure in a second rotor blade position and / or that a first mechanical strength of the load-bearing structure and / or the non-load-bearing structure in the first rotor blade position is higher than a second mechanical strength of the load-bearing structure and / or a non-load-bearing structure in the second rotor blade position (S3); determining whether the first mechanical load and / or the first mechanical strength of a first condition is sufficient, such that the rotor blade (2') can remain connected (E1) ready for operation to the wind turbine (1) during the repair. The application further relates to a support structure, a rotor blade system and a repair method.

Description

[0001] Method for preparing a repair of a rotor blade of a wind turbine, support structure, rotor blade system and repair method

[0002] The application relates to a method for preparing a repair (hereinafter also referred to as preparation method) of a damaged area on a load-bearing structure of a rotor blade of a wind turbine, a support structure for supporting a repair of a damaged area on a load-bearing structure of a rotor blade of a wind turbine, a corresponding rotor blade system and a method for repairing (hereinafter also referred to as repair method) a damaged area on a load-bearing structure of a rotor blade of a wind turbine.

[0003] Wind turbines are exposed to external influences that can cause damage to various components, particularly rotor blades. For example, with the progressively increasing size of wind turbines and the corresponding increase in the length of their rotor blades, the probability of lightning strikes increases, which can cause damage to rotor blades even in the presence of a lightning protection system (e.g., if the intensity of a lightning strike or the position of the strike is outside the design parameters of the lightning protection system). Among other factors, the electrical conductivity of the load-bearing structures themselves (as described below) can contribute to damage caused by lightning strikes.

[0004] Such damage is particularly critical when it occurs in load-bearing structures of the rotor blades. Such load-bearing structures often comprise fiber-reinforced materials, advantageously in the form of pultruded materials stacked in layers and joined in parallel stacks to form belts. For example, pultruded materials made of carbon fiber-reinforced plastic (CFRP) or glass fiber-reinforced plastic (GFRP) exhibit good mechanical properties for the formation of such load-bearing belts. Load-bearing structures of this type are frequently used, especially for long rotor blades, which is associated with the increasing size of wind turbines.

[0005] It is known from the prior art to separate the affected rotor blade from the wind turbine in preparation for repairing a damaged area on such a load-bearing structure (i.e. to carry out a downtower repair) in order to be able to relieve the load on the damaged structure during the repair by suitable support. This can result in considerable effort and considerable dismantling / assembly, transport and / or downtime costs, which depend in detail on whether the wind turbine is operated on land (for example on a flat surface or on a slope) or at sea (for example on a floating or land-based platform). It is therefore desirable to provide repair and preparation processes as well as devices and systems suitable for use in such processes that can reduce such effort and costs.At the same time, it is desirable to restore the mechanical properties of the damaged load-bearing structure impaired by the damage as best as possible, which is not the case with known processes, which in the case of pultrudates, for example, may be based on the infusion of dry fibers.

[0006] In certain cases, it is also necessary to restore electrical properties impaired by damage, provided the load-bearing structures possess such properties. For example, CFRP pultrudates are electrically conductive, which is why their use in rotor blades requires either electrical isolation (through insulation and physical separation) from the wind turbine's lightning protection system or the provision of defined equipotential bonding connections with components of the lightning protection system (e.g., lightning conductor cables and / or metal mesh foils arranged on the surface of the rotor blade). If equipotential bonding connections are provided, any impairments to the electrical conductivity of the load-bearing structure and / or the associated equipotential bonding connections must be remedied during the repair.

[0007] Against the background of the prior art, the object of the application is to propose a preparation method, a support structure, a rotor blade system and a repair method which have one or more of the aforementioned properties or reduce or avoid the aforementioned problems.

[0008] To achieve this object, a preparation method according to claim 1, a support structure according to claim 6, a rotor blade system according to claim 11, and a repair method according to claim 13 are proposed. Advantageous embodiments and further developments emerge in conjunction with the features of the subclaims.

[0009] The proposed method for preparing a repair (preparation method) of a damaged area on a load-bearing structure of a rotor blade of a wind turbine, wherein the rotor blade comprises, in addition to the load-bearing structure, at least one non-load-bearing structure that is connected to the load-bearing structure or arranged close to the load-bearing structure, in particular adjacent to the load-bearing structure, comprises the following steps:

[0010] Determining a first rotor blade position, which can be a single setting position or a setting range, such that a first mechanical load on the load-bearing structure in the first rotor blade position is lower than a second mechanical load on the load-bearing structure in a second rotor blade position and / or that a first mechanical resistance of the load-bearing structure and / or the non-load-bearing structure in the first rotor blade position is higher than a second mechanical resistance of the load-bearing structure and / or the non-load-bearing structure in the second rotor blade position,

[0011] Determine whether the first mechanical load and / or the first mechanical resistance satisfies a first condition according to which the rotor blade can remain operatively connected to the wind turbine during the repair.

[0012] A rotor blade position can be defined by a set of angles, which can include a pitch angle about a rotor blade longitudinal axis and / or an azimuth angle about a rotation axis of a rotor of the wind turbine and / or a yaw angle about a tower axis of the wind turbine, in particular all three of the above-mentioned angles.

[0013] Mechanical loading here can be understood as any acting force and / or moment, as well as the resulting structural stresses, such as strains, stresses, and / or buckling loads. Mechanical resistance refers to a maximum permissible mechanical load, such as a permissible force and / or a permissible moment, e.g., buckling resistance, a permissible stress (strength), and / or permissible strain.

[0014] The damage can be caused, in particular, by a lightning strike to the rotor blade, but also (additionally or alternatively) by other influences, such as excessive mechanical stress and / or material fatigue. If the first rotor blade position is a setting range, it is also referred to below as an envelope, which can define a range of rotor blade positions that are advantageous for repair while relieving the load-bearing structure.

[0015] In addition to the load-bearing structure surrounding the damaged area, which is always referred to here and below as the load-bearing structure, the rotor blade may comprise other load-bearing structures. In addition to the non-load-bearing structure connected to the load-bearing structure or arranged near the load-bearing structure, which is always referred to here and below as the non-load-bearing structure, the rotor blade may comprise other non-load-bearing structures. Non-load-bearing structures (i.e., the non-load-bearing structure and, if applicable, other load-bearing structures) may include panels, cladding parts, etc.

[0016] By determining the first rotor blade position and, based on this, determining whether the first mechanical load satisfies the first condition, it is possible, in particular in a large number of cases, to repair the rotor blade that is connected to the wind turbine in an operational state (uptower repair), thereby avoiding the problems (effort and costs) associated with an uptower repair.

[0017] The method may include determining the type and extent of the damaged area and / or any other damage to the rotor blade by means of visual inspection and / or a measuring method. The extent may include, for example, a length and / or width and / or depth of the damaged area and / or a number of damaged load-bearing elements, in particular pultruded elements. A corresponding measuring method may include, for example, ultrasound measurements and / or thermography and / or computed tomography.

[0018] When determining the first rotor blade position and / or when determining whether the first mechanical load satisfies the first condition, external conditions, such as a wind direction and / or a wind force and / or a wave load, and / or properties of the damaged area or of the load-bearing structure comprising the damaged area, such as the previously determined type and / or the previously determined extent of the damaged area and / or an extent (length and / or width and / or depth) of a recess to be introduced into the load-bearing structure to repair the damaged area, can be taken into account.

[0019] Based on determining whether the first mechanical load satisfies the first condition, the preparation method may advantageously further comprise: arranging the rotor blade to enable the repair, wherein the rotor blade operatively connected to the wind turbine is arranged in the first rotor blade position if the first mechanical load and / or the first mechanical resistance satisfies the first condition, and / or wherein the rotor blade is arranged separately from the wind turbine if the first mechanical load and / or the first mechanical resistance does not satisfy the first condition.

[0020] Thus, an uptower repair can be performed if suitable operating conditions can be determined; only if this is not the case will a downtower repair be used. Since this can reduce the frequency of downtower repairs, a reduction in effort and costs can be achieved—at least over multiple repair processes.

[0021] To determine whether the first mechanical load satisfies the first condition, it may be necessary to determine one or more load values ​​in the first rotor blade position and compare them with one or more resistance values ​​of the load-bearing structure. Possible load values ​​include values ​​of forces and / or moments and / or mechanical stresses and / or strains. Possible resistance values, in turn, include permissible forces or moments, e.g., buckling resistances, and / or permissible stresses (strengths) and / or permissible strains.

[0022] It can be provided that the load-bearing structure comprises a fiber-reinforced material, in particular at least one pultrudate made of plastic reinforced with carbon and / or glass fibers, and the damaged area comprises damage to one or more of the fibers and / or the plastic. The load-bearing structure can in particular comprise one or more pultrudate belts, wherein each of the pultrudate belts comprises at least one, optionally several pultrudate stacks arranged parallel to one another in a fiber direction, and each of the pultrudate stacks comprises at least one, preferably several stack-shaped pultrudate elements, in particular plank-shaped pultrudate elements (pultrudate planks, also referred to here as planks for short). The damaged area can penetrate one or more of the planks completely or partially.

[0023] It can be provided that the first rotor blade position is determined by means of an aerodynamic and / or elastic and / or hydrodynamic simulation of at least one part of the wind turbine. Thus, the first rotor blade position can be determined in a simple and robust manner. For example, an aeroelastic simulation, i.e., a simulation that includes aerodynamic and elastic parameters, can be provided.

[0024] It can be provided that the first rotor blade position is adjusted according to a time profile of an external load on the rotor blade, in particular a wind and / or wave load. This allows a dynamic response to changing conditions during the preparation and / or execution of the repair. It can be provided that a warning signal is issued if a critical condition occurs, for example if a predetermined maximum wind speed and / or maximum wave load is exceeded. Based on such a warning signal, a repair can be interrupted or stopped if safe work and / or the stability of the damaged load-bearing structure can no longer be guaranteed due to the critical condition.

[0025] The preparation method may comprise: determining whether the first mechanical load and / or the first mechanical resistance satisfies a second condition according to which the operational connection of the rotor blade to the wind turbine during the repair requires a reduction of the first mechanical load and / or an increase of the first mechanical resistance by means of a support structure.

[0026] By determining whether the first mechanical load satisfies the second condition, an envelope corresponding to the first rotor blade position can be expanded, thus enabling repair within a wider range of external influences and / or properties of the damaged area. In particular, in certain cases where an uptower repair would not be possible without further measures (i.e., in particular, only by operating the wind turbine in the first rotor blade position), an uptower repair may still be possible.

[0027] The preparation method may include attaching a support structure to the rotor blade to reduce the first mechanical load. The support structure may, in particular, be a support structure of the type proposed and described below.

[0028] The preparation method may include attaching a strain gauge to the load-bearing structure surrounding the damaged area and / or to another load-bearing structure of the rotor blade. This can be used, for example, to monitor whether or ensure that the support structure enables the desired mechanical unloading. It may also be provided that the first rotor blade position is determined and / or whether the first mechanical load satisfies the first condition and / or whether the first mechanical load satisfies the second condition (see below) are determined taking into account a strain value provided by the strain gauge.

[0029] The preparation method may comprise measuring an impedance of the load-bearing structure, in particular to detect an impairment of the electrical conductivity of the load-bearing structure by the damaged area.

[0030] The preparation method may include: determining whether the repair is to be performed by accessing the damaged area from the interior of the rotor blade and / or from the exterior of the rotor blade. This determination may be made, for example, taking into account the accessibility of the damaged area and / or the position of the damaged area and / or the extent of the damaged area and / or the extent of a recess to be made in the load-bearing structure to repair the damaged area. If the repair is to be performed from the interior of the rotor blade, the preparation method may include: cutting out a window from a web of the rotor blade to allow access to the damaged area.

[0031] The preparation process may include (in the case of a repair of the interior and / or exterior of the rotor blade): removing one or more layers, in particular one or more outer layers, of the rotor blade, in particular by grinding and / or milling and / or planing and / or chiseling and / or breaking. It may be provided to reduce the spread of dust during the removal of the outer layer by vacuuming, for example using the BT-40 method, and / or by using moisture.

[0032] The proposed support structure is suitable for supporting the repair of a damaged area on a load-bearing structure of a rotor blade of a wind turbine. It is provided that the support structure is connectable or connected to the rotor blade in such a way that mechanical stress on the load-bearing structure, in particular in an area surrounding the damaged area, is reduced and / or mechanical resistance, in particular buckling resistance, of the load-bearing structure and / or the non-load-bearing structure is increased. By means of such a support structure, an uptower repair can nevertheless be enabled in certain cases where an uptower repair would not be possible without further measures (i.e., in particular, only by operating the wind turbine in the first rotor blade position). However, such a support structure can also be advantageously used for a downtower repair.

[0033] The support structure can comprise a support rod assembly that can be arranged in the interior of the rotor blade and has at least one prestressing means for exerting a prestressing force on the rotor blade such that the mechanical load on the load-bearing structure is reduced and / or the mechanical resistance of the load-bearing structure and / or the non-load-bearing structure is increased. For this purpose, the support structure can be introduced into the interior of the rotor blade through the aforementioned window—as a whole or disassembled into individual parts. The prestressing means can comprise, for example, a tensioning screw and / or a turnbuckle and / or a telescopic rod. The support rod assembly can comprise at least one transverse support rod that can be arranged in the interior of the rotor blade along a transverse direction that is angled, in particular substantially perpendicular, to a longitudinal axis of the rotor blade.Preferably, the support rod assembly comprises at least two transverse support rods spaced apart along a longitudinal direction substantially parallel to the longitudinal axis of the rotor blade, of which in particular one can be arranged at a blade tip-side end of the window, and another at a blade root-side end of the window.

[0034] The support rod assembly may comprise a longitudinal support rod that can be arranged substantially parallel to the longitudinal axis inside the rotor blade. The transverse support rod(s) is / are connected to the longitudinal support rod, for example, by rigid connections and / or joints. The joints may be or comprise ball and / or cardan joints, for example.

[0035] The support rod assembly may include additional connecting rods connecting the longitudinal support rod to the transverse support rods. For example, each transverse support rod may be connected to the longitudinal support rod by two connecting rods in a Y-shaped arrangement.

[0036] The transverse support rods and / or the longitudinal support rods and / or the connecting rods can comprise the pretensioning means or a respective pretensioning means. The pretensioning means can be adjustable to adjust the respective pretensioning force in the transverse or longitudinal direction. The pretensioning means can also be configured to adjust a length of the respective rod, and / or an additional length adjustment means can be provided to adjust the length of the respective rod.

[0037] The support rod assembly can be connected to a surface of the interior of the rotor blade by means of clamping feet. The clamping feet can comprise a material with a high coefficient of friction, such as a rubber material, and / or an adhesive for bonding to the surface of the interior of the rotor blade.

[0038] The support structure can comprise at least one clamping frame that can be arranged on an exterior of the rotor blade and is configured to exert a clamping force on the rotor blade, preferably at least two clamping frames connected to one another by means of a support rod that is prestressed or can be prestressed to reduce the mechanical load on the load-bearing structure. Thus, the load-bearing structure can be relieved of stress by clamping the rotor blade on both sides of the damaged area. The clamping frames are preferably spaced apart from one another in the longitudinal direction of the rotor blade. The support structure can comprise a plurality of support rods of the specified type.

[0039] The clamping frames can have a similar structure to known load frames used, for example, in rotor blade testing to apply a load to the rotor blade. In particular, such a clamping frame can comprise a clamping chuck that is adapted or adaptable to the outer contour of the rotor blade and is arranged between at least two clamping beams. The clamping beams of each clamping frame can be connected by means of one or more clamping elements for exerting a force that can be transmitted to the rotor blade by the clamping chuck.

[0040] The clamping frames can be connected to the support rod by rigid connections and / or joints, wherein the joints can be or include, for example, ball and / or cardan joints. The support rods comprise a respective pretensioning means that can be adjustable to set a respective pretensioning force. The pretensioning means can also be configured to adjust a length of the respective support rod, and / or an additional length adjustment means can be provided to adjust the length of the respective support rod.

[0041] The support structure can comprise at least one support assembly arranged on an interior and / or exterior of the rotor blade and connected to the load-bearing structure, preferably bonded thereto, comprising one or more support planks arranged to reduce the mechanical loading of the load-bearing structure and / or one or more support profiles arranged to increase the mechanical resistance of the load-bearing structure and / or the non-load-bearing structure. One or more of the one or more support planks or support profiles can be made of a plastic material reinforced with fibers, such as glass fibers or carbon fibers, and / or of metal. The support assembly can be connected to the interior or exterior of the rotor blade by means of an adhesive connection, in particular a detachable one, for example using a thermoplastic material.The support assembly, in particular in the form of one or more support profiles, can be attached to the interior or exterior of the rotor blade by means of one or more magnets. Support profiles can, in particular, be provided as support ribs and / or stringers.

[0042] The support structure can comprise a carrier structure on which a tool for repairing the damaged area and / or a sensor for detecting at least one property of the damaged area and / or an area surrounding the damaged area is arranged, in particular movably arranged. The carrier structure can be arranged, for example, on a support rod, transverse support rod, longitudinal support rod, connecting rod, or another component of one of the described support structures. The carrier structure can be displaceable along such a rod. The tool can be configured, for example, to exert pressure on a pultrudate belt and / or a patch and / or a plaster and / or to apply an adhesive and / or another layer and / or to remove material and / or to hold a component. The sensor can, for example, comprise an image sensor, such as a camera, and / or an ultrasonic sensor and / or a temperature sensor.The support structure can be configured to allow the tool or sensor to be replaced. The support structure can comprise several support structures of the aforementioned type.

[0043] The proposed rotor blade system comprises a rotor blade of a wind turbine and a support structure of the type proposed above, wherein the rotor blade comprises a load-bearing structure with a damaged area, the load-bearing structure comprises a fiber-reinforced material, in particular at least one pultrudate made of carbon and / or glass fiber-reinforced plastic, and the damaged area comprises damage to one or more of the fibers and / or the plastic.

[0044] It is evident that the proposed support structure unfolds its effects and advantages in the context of the proposed rotor blade system; Furthermore, the preparation method proposed above and the repair method proposed below can be advantageously carried out on the rotor blade system. Accordingly, the rotor blade system, the preparation method, and the repair method can also be further developed according to optional features of the support structure, or vice versa.

[0045] Furthermore, a method (repair method) for repairing a damaged area on a load-bearing structure of a rotor blade of a wind turbine is proposed, wherein the load-bearing structure comprises a fiber-reinforced material, in particular at least one pultruded material made of carbon and / or glass fiber-reinforced plastic, and the damaged area comprises damage to one or more of the fibers and / or the plastic. The method can be performed as an uptower repair method or as a downtower repair method.

[0046] The repair method comprises removing a portion of the load-bearing structure encompassing the damaged area, thereby forming a recess in the load-bearing structure. The recess is preferably formed such that its ends are chamfered along a fiber direction at a suitable kerf angle.

[0047] Removal can be accomplished by grinding, milling, planing, chiseling, and / or breaking. During the formation of the recess, dust spread can be reduced by vacuuming, for example, using the BT-40 process, and / or by applying moisture. This can improve occupational safety, reduce environmental impact, and / or reduce the risk of leakage currents forming on the rotor blade prior to a lightning strike (streamer formation).

[0048] The repair method further comprises inserting and joining a patch comprising a fiber-reinforced material into the recess. Multiple patches can also be inserted and joined. Using the proposed method, the mechanical properties of the load-bearing structure can be advantageously and easily restored. The patch can advantageously comprise an identical fiber-reinforced material as the load-bearing structure.

[0049] Before inserting the patch, the recess may be measured and the patch provided or manufactured according to the dimensions of the recess thus determined.

[0050] The patch is preferably provided with chamfered ends along one fiber direction at a scarf angle corresponding to the scarf angle of the recess. This provides sufficient mechanical strength and resilience for the repaired damaged area.

[0051] Joining the patch may involve welding, soldering, and / or gluing the patch into the recess. The bonding may be achieved using an electrically conductive (for example, by admixing soot particles or carbon nanotubes) adhesive resin, adhesive, adhesive film, and / or pre-impregnated fabric or fabric. Joining may occur under a vacuum bag assembly installed in the area of ​​the repair site, so that the patch is pressed into the recess and excessive joining gaps are avoided.

[0052] The repair method may include applying a patch comprising a fiber-reinforced material in the transition area between the patch and the load-bearing structure. The patch further reinforces or stabilizes the repair site. The patch may advantageously comprise an identical fiber-reinforced material as the load-bearing structure.

[0053] The repair method comprises: establishing at least one electrically conductive connection between the load-bearing structure comprising the recess, in particular a pultrudate plank of the load-bearing structure, and the patch and / or between at least one further load-bearing structure of the rotor blade, in particular a pultrudate plank of the further load-bearing structure, and the patch and / or between the patch and an electrically conductive element of the rotor blade, in particular a lightning protection element, for example a grounding cable and / or a metal grid. If a patch is provided, the repair method can comprise appropriate electrical contacting of the patch. The electrically conductive connection is established in particular by means of an electrically conductive contact means. By establishing the electrically conductive connection, the required lightning protection reliability is restored.

[0054] The repair method may include curing a joining material used to join the patch using a heating means. The heating means may comprise a heated blanket and / or a hot air gun in a tent configuration. A temperature of the patch during curing may be monitored by a sensor, which may, for example, be arranged between the patch and the heating means.

[0055] The repair method may further comprise preparing the repair according to the preparation method proposed above; accordingly, the repair method may be further developed according to the optional features of the preparation method. Steps of the preparation method may be performed partly before, and partly simultaneously with, further steps of the repair method.

[0056] The repair method may optionally comprise various rework steps, such as measuring an impedance of the load-bearing structure, in particular to determine whether an impairment of the electrical conductivity of the load-bearing structure has been remedied by the damaged area, and / or reinserting or closing a previously removed window and / or reapplying removed layers and / or removing a previously attached support device and / or attaching a web foot to a web of the rotor blade connected to the load-bearing structure.

[0057] Embodiments of the subject matter of the application are explained below with reference to drawings, which show, schematically,

[0058] Fig. 1 is a flowchart of a repair method comprising a preparation method, Fig. 2 is a perspective view of a wind turbine,

[0059] Fig. 3 shows a cross-section of a rotor blade along the section line AA shown in Fig. 3,

[0060] Fig. 4 is a longitudinal section of the rotor blade according to Fig. 3 along the section line BB shown in Fig. 4,

[0061] Fig. 5 and Fig. 6 Detailed views of various examples of area A from Fig. 4,

[0062] Fig. 7 to Fig. 9 Examples of pultrudate stacks with a respective damaged area in perspective view,

[0063] Fig. 10 a cross-section of a pultrudate belt,

[0064] Fig. 11 and Fig. 12 a cross-section (along the section line Dl-Dl) and a longitudinal section (along the section line CC) of a rotor blade system with a support rod,

[0065] Fig. 13 shows a longitudinal section of a rotor blade system with a support rod according to another example,

[0066] Fig. 14 a longitudinal section of a rotor blade system with a support assembly,

[0067] Fig. 15 and Fig. 16 show a cross-section (along the section line D2-D2) and a longitudinal section (along the section line C2-C2) of a rotor blade system with a support structure comprising two clamping frames,

[0068] Fig. 17 and Fig. 18 show a cross-section (along the section line D3-D3) and a longitudinal section (along the section line Cl-Cl) of a rotor blade with a support rod according to another example,

[0069] Fig. 19 and Fig. 20 show a cross-section (along the section line D4-D4) and a longitudinal section (along the section line C4-C4) of a rotor blade with a support assembly according to another example,

[0070] Fig. 21 shows a cross-section of a rotor blade with a support assembly according to another example,

[0071] Fig. 22 shows a cross-section (along the section line El-El shown in Fig. 23) of part of a rotor blade system with a support assembly,

[0072] Fig. 23 is a plan view of the part according to Fig. 22,

[0073] Fig. 24 shows a cross-section (along the section line E2-E2 shown in Fig. 25) of a part of a rotor blade system with a support assembly according to a further example,

[0074] Fig. 25 is a plan view of the part according to Fig. 24,

[0075] Fig. 26 to Fig. 29 cross-sections of further examples of a part of a rotor blade system with a support composite,

[0076] Fig. 30 to Fig. 33 Longitudinal sections of a pultrudate stack during different steps of a repair process in different examples,

[0077] Fig. 34 shows a cross-section (along the section line E3-E3 shown in Fig. 35) of a part of a rotor blade system with a support assembly according to a further example,

[0078] Fig. 35 is a plan view of the part according to Fig. 34,

[0079] Fig. 36 shows a cross-section of another example of a part of a rotor blade system with a support composite.

[0080] Recurring and similar features are provided with identical alphanumeric reference numerals in the figures. Fig. 1 shows a possible sequence of steps of an exemplary repair method, with the steps above S9 (i.e., steps S1 to S8.1 or S8.2) representing an exemplary preparation method. In the example shown, the repair method comprises preparing a repair according to the preparation method. The preparation method can also be carried out independently, in whole or in part. Likewise, the repair method can be carried out independently, in whole or in part.

[0081] The preparation method serves to prepare a repair of a damaged area 32 on a load-bearing structure of a rotor blade 2 of a wind turbine 1. The wind turbine 1 and components of the wind turbine 1 are shown in various views, examples and configurations in Fig. 2 to Fig. 10.

[0082] As shown in Fig. 2, the wind turbine 1 comprises a tower 5, a nacelle 4 rotatably mounted on the tower, and a rotor with a plurality of rotor blades 2, 2' attached to a hub 3, wherein the hub 3 is rotatably connected to the nacelle. The wind turbine 1 is arranged on a base 6. At least one of the rotor blades 2, 2' is a damaged rotor blade 2' with a damaged area 32, which can be caused in particular by a lightning strike to the rotor blade 2', but also (additionally or alternatively) by other influences, such as excessive mechanical stress and / or material fatigue.

[0083] Fig. 2 shows various angles that define a rotor blade position of the damaged rotor blade 2', namely a pitch angle 11 about a longitudinal axis 11' of the rotor blade 2', an azimuth angle 9 about a rotation axis 9' of the rotor (i.e. measured in a rotor plane 10 defined by the rotor blades 2, 2', in particular relative to the 12 o'clock position 9") and a yaw angle 8 about a tower axis 8' of the wind turbine 1.

[0084] As shown in Fig. 3 and 4, the rotor blade 2' comprises load-bearing primary structures, here in the form of pultrudate stacks 14, 14', including the damaged pultrudate stack 14', and webs 15, 15', as well as non-load-bearing secondary structures in the form of a fairing connected to the load-bearing primary structures, comprising in particular panels 16A and 16B adjacent to the damaged load-bearing structure on the leading edge side (i.e. oriented towards a leading edge 17 of the rotor blade 2') and on the trailing edge side (i.e. oriented towards a trailing edge 18 of the rotor blade 2') (hereinafter also simply referred to as non-load-bearing structure).

[0085] Fig. 5 to Fig. 10 illustrate details of the load-bearing structure comprising the damaged area 32 (hereinafter referred to simply as the load-bearing structure). The load-bearing structure comprises one or more pultrudate belts 30, 30', comprising in particular the damaged pultrudate belt 30'. Each of the pultrudate belts 30, 30' comprises at least one (Fig. 5, Fig. 7 to Fig. 9), optionally several (Fig. 6, Fig. 10) pultrudate stacks 14, 14' arranged parallel to one another in a fiber direction, including the damaged pultrudate stack 14'. Each of the pultrudate stacks 14, 14' comprises at least one, and in the examples shown, several, plank-shaped pultrudate elements (pultrudate planks 12) arranged in a stack. The pultruded planks 12 are formed as pultruded products, i.e., by pultrusion, from a plastic reinforced with carbon fibers. Alternatively, a plastic reinforced with glass fibers can be provided.

[0086] The damaged area 32 comprises damage to one or more of the carbon fibers and / or the plastic within one or more of the pultrudate planks 12 of the damaged pultrudate belt 30'. The damaged area 32 may penetrate one or more of the planks 12 in whole or in part.

[0087] Fig. 8 to Fig. 10 show some aspects of prior art lightning protection devices of the wind turbine 1 in the area of ​​a damaged pultrudate stack 14'. According to Fig. 8, a collared end 33 of a pultrudate plank 12 is connected to a metal grid and / or another pultrudate belt 30 by means of an electrically conductive contact means 34. Here, the damaged area 32 can be caused or exacerbated, for example, by contact corrosion, a jump in electrical resistance, or poor manufacturing quality. Fig. 9 shows a further variant in which an electrically conductive contact means 34' is provided for connection to a grounding cable by means of a connecting cable 35, wherein the contact means 34' advantageously contacts all carbon fiber ends accessible at the collared end 33. Fig.Figure 7, on the other hand, shows a configuration in which no electrically conductive connection to a lightning protection element is provided on the pultrudate stack 14'; here, the damaged area 32 may have been caused, for example, by flashover to a grounding cable.

[0088] Fig. 10 shows several parallel stacks of pultrudate elements 12. Electrically insulating insulation elements 37 are arranged between pultrudate planks 12 arranged one above the other and side by side; a defined electrical connection between the pultrudate planks 12 is established by potential equalization elements 36. In this way, for example, inhomogeneous electrical contact can be avoided, which could arise, for example, from different distances between the planks due to a curvature of the rotor blade 2'.

[0089] The method illustrated in Fig. 1 comprises determining the type and extent of the damaged area 32 by means of visual inspection (step S1). The extent can include, for example, a length and / or width and / or depth of the damaged area and / or a number of damaged pultrudate planks 12. Alternatively or additionally, an inspection can be performed using a measuring method, such as ultrasound measurements and / or thermography and / or computed tomography.

[0090] The method further comprises determining a dimension of a recess 38 to be introduced into the load-bearing structure for repairing the damaged area 32 (step S2), as shown in Fig. 30. The dimension may include a length 39, a depth 40, and a width (not shown).

[0091] The method further comprises determining an envelope of rotor blade positions advantageous for a repair, first rotor blade positions, as the first rotor blade position of the rotor blade 2' such that a first mechanical load on the load-bearing structure in the first rotor blade position is lower than a second mechanical load on the load-bearing structure in a second rotor blade position and / or that a first mechanical resistance of the load-bearing structure and / or the non-load-bearing structure in the first rotor blade position is higher than a second mechanical resistance of the load-bearing structure and / or the non-load-bearing structure in the second rotor blade position (step S3).

[0092] The method further comprises determining whether the first mechanical load satisfies a first condition according to which the rotor blade 2' can remain operatively connected to the wind turbine 1 during the repair (step E1).

[0093] When determining the first rotor blade position (step S3) and when determining whether the first mechanical load satisfies the first condition (step E1), external conditions are taken into account in addition to the properties determined in steps S1 and S2. Relevant external conditions include, for example, a wind direction (represented in Fig. 1 by wind direction vector 7), a wind force and / or a wave load, as well as a mechanical load on the load-bearing structure caused by gravity (represented in Fig. 3 and Fig. 4 by the gravitational vector 13).

[0094] An exemplary first rotor blade position for a repair by accessing the damaged area 32 from the interior of the rotor blade can comprise, for example, a yaw angle 8 of 90° to the wind direction vector 7 and an azimuth angle 9 of 90° (3 o'clock position) or 270° (9 o'clock position), so that only low aerodynamic forces act on the rotor blade 2'. Another exemplary first rotor blade position can comprise, for example, a pitch angle 11 at which an angle of attack of the wind direction vector 7 does not generate any lift. Provision can be made to fix the azimuth angle 9 during the repair in order to enable or simplify the implementation of the repair. If the damaged area 32 is located in the region of an aerodynamic pressure side 20 (cf. Fig. 3) of the rotor blade 2', an azimuth angle 9 of approximately 270° can be advantageous. If there is damage on an aerodynamic suction side 19 (see Fig. 3) of the rotor blade 2', an azimuth angle of approximately 90° may be advantageous.An exemplary first rotor blade position for a repair by accessing the damaged area 32 from an exterior of the rotor blade can include, for example, a yaw angle 8 of 180° to the wind direction vector 7 and an azimuth angle 9 of 180° (6 o'clock position), so that only slight aerodynamic forces act on the rotor blade 2' to be repaired. The first rotor blade position is determined in S3, for example, using an aeroelastic simulation of the wind turbine 1, but can also be determined, for example, using an aerodynamic and / or elastic and / or hydrodynamic simulation of at least part of the wind turbine 1.To determine whether the first mechanical load and / or the first mechanical resistance satisfies the first condition (El), load values ​​of the load-bearing structure in the first rotor blade position (in particular forces and / or moments and / or mechanical stresses and / or strains) are determined and compared with one or more resistance values ​​(in particular permissible forces or moments, e.g. buckling resistances, and / or permissible stresses and / or permissible strains).

[0095] The method further comprises positioning the rotor blade 2' to facilitate the repair. The rotor blade 2', which is connected to the wind turbine 1 in an operationally ready state, is positioned in the first rotor blade position (step S4) if the first mechanical load satisfies the first condition (step E1). Thus, an uptower repair is prepared.

[0096] The initial rotor blade position is continuously adjusted over the course of the process according to the time course of the external conditions considered in E1, allowing for dynamic responses to changing conditions during the preparation and execution of the repair. If a critical condition occurs, for example, if a specified maximum wind speed and / or maximum wave load is exceeded, a warning signal can also be issued, based on which the further repair procedure can be adjusted if necessary.

[0097] When arranging the rotor blade 2' to enable the repair, the rotor blade 2 is further arranged separately from the wind turbine 1 if the first mechanical load does not satisfy the first condition. Thus, a downtower repair is prepared. In this case, the subsequent steps S4 to S7 are omitted, and step E3 described below follows next. When preparing the uptower repair, the method further comprises determining whether the first mechanical load satisfies a second condition, according to which the operational connection of the rotor blade 2' to the wind turbine 1 during the repair requires a reduction of the first mechanical load by means of a support structure and / or an increase of the first mechanical resistance by means of a support structure (step E2).In this step, the properties determined in steps S1 and S2 as well as the external conditions taken into account in steps S3 and E1 can be taken into account again and an aerodynamic and / or elastic and / or hydrodynamic simulation of at least part of the wind turbine 1 can be used.

[0098] If a support structure is not required, the following steps S5 and S6 are skipped and step S7 described below follows.

[0099] If a support structure is required, the method may include attaching a strain gauge to the load-bearing structure encompassing the damaged area 32 and / or to another load-bearing structure of the rotor blade 2' (step S5). This allows monitoring to determine whether the support structure enables the desired mechanical relief. Attaching the strain gauge is only provided in the case of a repair with a support structure in the described example, but in other examples, it is also conceivable in connection with a repair without a support structure.

[0100] If a support structure is required, the method includes attaching a support structure to the rotor blade 2' to reduce the first mechanical load and / or to increase the first mechanical resistance (step S6). Examples of such support structures are described further below. In the described example, relief by a support structure is only provided in the case of an uptower repair, but in other examples, it is also conceivable in connection with a downtower repair.

[0101] The method may include measuring an impedance of the load-bearing structure, in particular to detect any impairment of the electrical conductivity of the load-bearing structure due to the damaged area (step S7). The method further includes determining whether the repair is to be performed by accessing the damaged area 32 from an interior of the rotor blade and / or from an exterior of the rotor blade (E3). This determination is made taking into account an accessibility of the damaged area 32 and / or a position of the damaged area 32 and / or an extent of the damaged area 32 and / or an extent of a recess 38 to be introduced into the load-bearing structure to repair the damaged area 32.

[0102] If the repair is to be carried out starting from the interior of the rotor blade 2', the method comprises cutting out a window 21 (cf. Fig. 12 / 13 / 14 / 16) from a web of the rotor blade 2' to allow access to the damaged area 32 (step S8.1).

[0103] If the repair is to be carried out starting from the exterior of the rotor blade 2', the method comprises removing one or more outer layers of the rotor blade 2' (step S8.2), in particular by grinding and / or milling and / or planing and / or chiseling and / or breaking. During the removal of the outer layer, it is intended to reduce the spread of dust by suction, for example using the BT-40 method, and / or by using moisture. The outer layers can be, for example, cladding layers and / or components of a lightning protection system, in particular a metal mesh foil.

[0104] The steps of the preparatory process described so far are followed by the actual repair of the damaged area (step S9). Details of this repair are illustrated by way of example in Figs. 30 to 33.

[0105] The repair method comprises removing a portion of the load-bearing structure encompassing the damaged area 32, so that a recess 38 is formed in the load-bearing structure, more specifically, in the damaged pultrudate stack 14'. As shown in Fig. 30, forming the recess 38 creates weakened pultrudate planks 12" or a weakened pultrudate stack 14" encompassing these weakened pultrudate planks 12". The recess 38 is formed such that its ends are chamfered at a suitable shank angle 41 along a fiber direction of the pultrudate stack 14". The recess has a length 39, a depth 40, and a width (not shown).

[0106] The removal of the part of the load-bearing structure encompassing the damaged area 32 can be accomplished, for example, by grinding and / or milling and / or planing and / or chiseling and / or breaking. When forming the recess 38, provision can be made to reduce the spread of dust by vacuuming, for example, using the BT-40 method, and / or by using moisture.

[0107] The repair method further comprises (as shown in Fig. 30 and Fig. 31): introducing and joining at least one patch 31 comprising a fiber-reinforced material into the recess 38. In the example, several patches 31 are introduced and joined. The patches 31 advantageously comprise an identical fiber-reinforced material as the load-bearing structure; in particular, the patches 31 are formed as pultrudate plank sections. The patches 31 are provided with ends chamfered along the fiber direction at a scarf angle corresponding to the scarf angle 41 of the recess 38.

[0108] Joining the patches 31 involves gluing the patches 31 into the recess 38 using electrically conductive joining elements 42, in this case in the form of adhesive films. Joining takes place under a vacuum bag assembly (not shown) mounted in the area of ​​the repair site, so that the patch 31 is pressed into the recess 38 and excessive joining gaps are avoided.

[0109] By inserting the patches 31 into the recess 38 of the weakened pultrudate planks 12", the planks are repaired (repaired pultrudate planks 12"' of the repaired pultrudate stack 14"'). In the example shown, the recess 38 is arranged on an inner rotor blade surface 46. However, it can also be arranged on an outer rotor blade surface 47.

[0110] The repair method further comprises applying patches 44, comprising an identical fiber-reinforced material as the load-bearing structure, in the region of transitions between the patches 31 and the weakened 12" pultrudate planks of the load-bearing structure. The patches 44 further reinforce or stabilize the repair site. The ends of the patches 44 are preferably chamfered at a suitable patch angle 43.

[0111] The repair method comprises establishing electrically conductive connections between the load-bearing structure encompassing the recess (in particular the repaired planks 12''') and the patches 31 and / or between the patches 31 and an electrically conductive lightning protection element of the rotor blade 2' by means of electrically conductive contact means 34, 34'. The patches 44 are also connected to the load-bearing structure and / or the patches 31 and / or the lightning protection element by means of the contact means 34, 34'. Examples of such electrical contacts are shown in Fig. 32 and Fig. 33. In this case, as in Fig. 8 / 9, contact means 34 for connecting to a metal grid and / or another pultrudate belt 30 and / or contact means 34' for connecting to an earthing cable can be provided. The contact means 34, 34' are advantageously provided at the shouldered ends of the patches 31 and 31, respectively.the patches 44 and may optionally also comprise common connections of patches 31 and patches 44, as shown in Fig. 33.

[0112] The method comprises curing a joining material used to join the patch using a heating means (step S10). The heating means may comprise a heated blanket and / or a hot air blower in a tent arrangement. A temperature of the patch during curing may be monitored by a sensor, which may be arranged, for example, between the patch and the heating means.

[0113] Heating the repair area with the heating medium leads to a reduction in stiffness and strength. In the case of an uptower repair, curing can therefore be performed with the rotor blade positioned at an azimuth angle of 180° (6 o'clock position). In this position, mechanical material stresses are reduced compared to an azimuth angle of 90° or 270°, which also allows for a higher curing temperature (approximately 70°C instead of 60°C). After curing, the rotor blade can be returned to its original position, for example, to perform rework.

[0114] The method ultimately comprises various rework steps. If the repair was performed starting from the interior of the rotor blade 2', the removed window 21 is reinserted (step S11.1); it may also be necessary to attach a web base 29 (Fig. 5 / 6) to a web 15' of the rotor blade 2' that is connected to the load-bearing structure. If the repair was performed starting from the exterior of the rotor blade 2', any removed outer layers are reapplied (step S11.2). The impedance measurement according to step S7 is repeated to determine whether any impairment of the electrical conductivity of the load-bearing structure caused by the damaged area 32 was remedied during the repair (step S12). If the repair was performed using a support device, the support device is removed or attached (step S13).

[0115] The support structures shown in Fig. 11 to Fig. 29 and Fig. 34 to Fig. 36 are particularly suitable for supporting the repair method described above. In each case, it is provided that the support structure can be or is connected to the rotor blade 2' in such a way that mechanical loading of the load-bearing structure, in particular in an area surrounding the damaged area 32, is reduced or avoided and / or mechanical resistance of the load-bearing structure and / or the non-load-bearing structure is increased. In this way, a rotor blade system of the proposed type is formed in each case. Different types of support structures can be used individually or combined with one another. For example, a support assembly (with support planks and / or support profiles) can be combined with a support rod assembly and / or a support structure with a clamping frame and / or a support rod assembly can be combined with a support structure with a clamping frame.

[0116] The support structure shown in Fig. 11 and Fig. 12 consists of a support rod assembly 25 arranged in the interior of the rotor blade 2', comprising two transverse support rods 24 spaced apart along a longitudinal direction substantially parallel to the longitudinal axis of the rotor blade 2', one of which is arranged at a blade-tip end of the window 21, and another at a blade-root end of the window 21, such that each of the transverse support rods 24' is arranged in the interior of the rotor blade 2' along a transverse direction substantially perpendicular to a longitudinal axis of the rotor blade 2'. The support rod assembly 25 further comprises a longitudinal support rod 24' that can be arranged substantially parallel to the longitudinal axis in the interior of the rotor blade 2'. The transverse support rods 24 are connected to the longitudinal support rod 24' by ball and / or universal joints 27.

[0117] The transverse support rods 24 and the longitudinal support rod 24' comprise respective prestressing means (indicated as a thinner section of the respective rod) for exerting a prestressing force 26 in the transverse direction and a prestressing force 26' in the longitudinal direction on the rotor blade 2' such that the mechanical stress, in particular strain, on the load-bearing structure is reduced. The prestressing means are adjustable for adjusting the respective prestressing force 26, 26' in the transverse and longitudinal directions, respectively, and are simultaneously configured for adjusting a length of the respective rod. The prestressing means can comprise, for example, clamping screws and / or turnbuckles and / or telescopic rods.

[0118] The support rod 25 is connected to the inner rotor blade surface 46 by means of clamping feet 23 arranged on foot adapters 22 (for two clamping feet each). The clamping feet 23 can comprise a material with a high coefficient of friction, for example, a rubber material, and / or an adhesive for frictionally and / or firmly bonding to the surface of the interior of the rotor blade 2'. Additionally or alternatively, roughening of the inner rotor blade surface 46 can be provided.

[0119] The required preload force 26 in the transverse direction can result, for example, from a necessary thrust transmission force between the clamping base 23 and the inner rotor blade surface 46, whereby the required thrust transmission force results from a required value of the preload force 26' in the longitudinal direction, which in turn results from the required unloading. The setting of the preload force 26' can be adjusted, for example, based on a strain value determined by the strain gauge.

[0120] The support rod 25 comprises a support structure 48 on which a tool for repairing the damaged area is arranged. Alternatively or additionally, a sensor for detecting at least one property of the damaged area and / or an area surrounding the damaged area can be arranged on the support structure 48. The support structure 48 is slidably arranged on the longitudinal support rod 24'. The support structure can also be arranged elsewhere on the support rod 25.

[0121] Compared to the example according to Fig. 11 / 12, the support rod 25 shown in Fig. 13 comprises additional connecting rods 24", which connect the longitudinal support rod 24' to the transverse support rods 24 by means of support rod adapters 28 in a Y-shaped arrangement.

[0122] The support structure shown in Fig. 15 and Fig. 16 comprises two clamping frames 52 arranged on an exterior of the rotor blade 2' and configured to exert a clamping force on the rotor blade 2'. The clamping frames 52 are connected to one another by means of a longitudinal support rod 24' prestressed to reduce the mechanical load, in particular strain, on the load-bearing structure. Thus, the load-bearing structure can be relieved of stress by clamping the rotor blade 2' on both sides of the damaged area. The clamping frames 52 are spaced apart from one another in the longitudinal direction of the rotor blade 2'.

[0123] The clamping frames 52 have a similar structure to known load frames used, for example, in rotor blade testing to apply a load to the rotor blade 2'. Each of the clamping frames 52 comprises a clamping chuck 51 adapted to an outer contour of the rotor blade 2', which is arranged between two clamping beams 50. The clamping beams 50 of each clamping frame 52 are connected by means of two clamping elements 49 for exerting a force that can be transmitted to the rotor blade 2' by the clamping chuck 51.

[0124] The clamping frames 52 are connected to the longitudinal support rod 24' by ball or cardan joints 27. The longitudinal support rods comprise a respective preloading means as described above in connection with Fig. 11 / 12.

[0125] The support structure shown in Fig. 17 and Fig. 18 consists of a support rod assembly arranged inside the rotor blade 2' with a transverse support rod 24 for increasing the mechanical resistance (here, in particular, the buckling resistance) of the load-bearing structure. For this purpose, the transverse support rod 24 is connected to the leading edge-adjacent panel 16A (alternatively, for example, to the trailing edge-adjacent panel 16B) by means of a clamping foot 23, secured by means of the clamping foot adapter 22' (for a clamping foot). By means of further clamping feet 23 (on the clamping foot adapter 22), the transverse support rod 24 is connected to an opposite panel and to the web 15' arranged above the damaged pultrudate stack 14'.

[0126] The transverse support rod 24 comprises a prestressing means prestressing force 26 in the transverse direction on the rotor blade 2' such that the buckling resistance is increased by supporting the buckling field of the leading edge adjacent panel 16A (and thus also the damaged pultrudate stack 14' of the adjacent load-bearing structure).

[0127] Fig. 14, Fig. 19 to Fig. 29, and Fig. 34 to Fig. 35 show various examples of support assemblies 45 arranged on the interior or exterior of the rotor blade 2' and connected to the load-bearing structure as support structures. In general, each of the support assemblies 45 comprises one or more support planks 45' arranged to reduce the mechanical loading of the load-bearing structure (Fig. 14, Fig. 22 to Fig. 29, Fig. 34 / 39) or one or more support profiles 45" arranged to increase the mechanical resistance (in particular buckling resistance) of the load-bearing structure and / or the non-load-bearing structure, also referred to as stringers (Fig. 19 to Fig. 21), wherein one or more of the one or more support planks 45' or support profiles 45" are made of a plastic material reinforced with fibers, such as glass fibers or carbon fibers, and / or of metal. Fig. 19 to Fig. 21 show support profiles with an S-shaped cross-section.Other cross-sections are possible, such as T-shaped, C-shaped or L-shaped cross-sections.

[0128] In most examples, the support assemblies are connected to the interior or exterior of the rotor blade 2' by means of a detachable adhesive bond, for example, using a thermoplastic material. In the example shown in Fig. 21, a magnet arrangement 53 is provided for a simple, reversible, and repositionable connection.

[0129] In some examples (Fig. 14, Fig. 21, Fig. 26 to Fig. 29, Fig. 34 to Fig. 36) the support assemblies 45 are arranged on the outside of the rotor blade 2'. According to Fig. 14, Fig. 21, Fig. 26, Fig. 27 and Fig. 36, a repair with access from the interior of the rotor (through a window 21) can be provided, wherein relief is provided by an external support composite 45 opposite the recess 38 on the weakened pultrudate belt 14". A repair with access from the exterior of the rotor blade 2' can also be provided with an external support composite 45 (Fig. 28, Fig. 29, Fig. 34). The support composite 45 can in both cases be arranged on the outer rotor blade surface 47 (Fig. 14, Fig. 21, Fig. 28, Fig. 29, Fig. 34 / 30) and / or on external pultrudate planks 12 / 12' / 12" (Fig. 26, Fig. 27, Fig. 36). In the case of support profiles (Fig.21) an arrangement can be provided on the buckling field of the non-load-bearing structure, here the panel 16A adjacent to the leading edge.

[0130] The example according to Fig. 34 / 30 shows a geometry for a repair with external access, with an external damaged area and an external support composite 45, in which the application of patches 44 during the repair is not possible. In order to still achieve sufficient rigidity, the patches 31 are designed to be wider than the pultrudate planks 12, thereby increasing the adhesive surfaces and reducing stresses. This is only possible if the damaged pultrudate stack is directly adjacent to the adjacent panels 16A, 16B. This is not the case in the example according to Fig. 36. Here, a repair with internal access is provided with a recess penetrating the entire pultrudate stack 14", with relief provided by an external support composite arranged on adjacent pultrudate stacks 14.

[0131] In other examples (Fig. 19 to Fig. 20, Fig. 22 to Fig. 25), the support assemblies 45 are arranged on the interior of the rotor blade 2', which is typically associated with a repair with access from the interior of the rotor blade 2', but can also (if necessary in conjunction with additional external support assemblies) be associated with a repair with access from the exterior of the rotor blade 2'. The support assembly 45 can be arranged in particular on the inner rotor blade surface 46 (Fig. 22 / 23) and / or on internal pultrudate planks 12 / 12' / 12" (Fig. 24 / 25). In the examples shown with support planks 45', two support assemblies 45 run parallel to the weakened pultrudate stack 14" on both sides, which enables good and even load relief; However, other numbers and / or arrangements of support assemblies 45 may also be provided. In the case of support profiles (Fig.19 / 20) an arrangement can again be provided on the buckling field of the non-load-bearing structure, here the panel 16A adjacent to the leading edge.

[0132] List of reference symbols:

[0133] 1 wind turbine,

[0134] 2 rotor blades,

[0135] 2' damaged rotor blade,

[0136] 3 hub,

[0137] 4 gondolas,

[0138] 5 tower,

[0139] 6 Underground,

[0140] 7 Wind direction vector,

[0141] 8 yaw angle,

[0142] 8' tower axis,

[0143] 9 azimuth angles,

[0144] 9' rotation axis,

[0145] 9" 12 o'clock position,

[0146] 10 rotor level,

[0147] 11 pitch angle,

[0148] 11' longitudinal axis,

[0149] 12 pultrudate planks,

[0150] 12" weakened pultrudate plank,

[0151] 12'" repaired pultruded plank,

[0152] 13 Gravitational vector,

[0153] 14 pultrudate stacks,

[0154] 14' damaged pultrudate stack,

[0155] 14" weakened pultrudate stack,

[0156] 14'" repaired pultrudate stack,

[0157] 15 jetty,

[0158] 15' bridge above the damaged pultrudate stack,

[0159] 16A leading edge adjacent panel,

[0160] 16B trailing edge adjacent panel, 17 leading edge,

[0161] 18 trailing edge,

[0162] 19 suction side,

[0163] 20 printed pages,

[0164] 21 windows,

[0165] 22 foot adapters for 2 clamp feet,

[0166] 22' foot adapter for a clamp foot,

[0167] 23 clamping foot,

[0168] 24 cross support rod,

[0169] 24' longitudinal support bar,

[0170] 24" connecting stands,

[0171] 25 support rods,

[0172] 26 Pre-tensioning force in transverse direction, 26' Pre-tensioning force in longitudinal direction,

[0173] 27 ball or cardan joint,

[0174] 28 support rod adapters,

[0175] 29 bridge foot,

[0176] 30 pultrudate belt,

[0177] 30' damaged pultrudate belt,

[0178] 31 Patches,

[0179] 32 Damaged area,

[0180] 33 dealt end,

[0181] 34, 34' contact agent,

[0182] 35 connection cables,

[0183] 36 equipotential bonding element,

[0184] 37 insulation element,

[0185] 38 recess,

[0186] 39 length,

[0187] 40 depth,

[0188] 41 shank angle,

[0189] 42 joining element,

[0190] 43 Paving shank angle,

[0191] 44 plasters,

[0192] 45 support composite,

[0193] 45' support plank,

[0194] 45" support profile, 46 inner rotor blade surface,

[0195] 47 outer rotor blade surface,

[0196] 48 support structure,

[0197] 49 clamping element, 50 clamping bar,

[0198] 51 clamping chuck,

[0199] 52 clamp frames,

[0200] 53 Magnet arrangement.

Claims

Patent claims 1. A method for preparing a repair of a damaged area (32) on a load-bearing structure of a rotor blade (2') of a wind turbine (1), wherein the rotor blade (2') comprises, in addition to the load-bearing structure, at least one non-load-bearing structure which is connected to the load-bearing structure or arranged close to the load-bearing structure, in particular adjacent to the load-bearing structure, the method comprising: Determining a first rotor blade position, which can be a single setting position or a setting range, such that a first mechanical load on the load-bearing structure in the first rotor blade position is lower than a second mechanical load on the load-bearing structure in a second rotor blade position and / or that a first mechanical resistance of the load-bearing structure and / or the non-load-bearing structure in the first rotor blade position is higher than a second mechanical resistance of the load-bearing structure and / or the non-load-bearing structure in the second rotor blade position (S3), Determining whether the first mechanical load and / or the first mechanical resistance satisfies a first condition according to which the rotor blade (2') can remain connected to the wind turbine (1) in an operational manner during the repair (El).

2. Method according to claim 1, wherein the load-bearing structure comprises a fiber-reinforced material, in particular at least one pultrudate (12, 12”, 12'”) made of carbon and / or glass fiber-reinforced plastic, and the damaged area (32) comprises damage to one or more of the fibers and / or the plastic.

3. Method according to one of the preceding claims, comprising arranging the rotor blade (2') to enable the repair, wherein the rotor blade (2') connected to the wind turbine (1) in an operative manner is in the first rotor blade position if the first mechanical load and / or the first mechanical resistance satisfies the first condition (S4), and / or wherein the rotor blade (2') is arranged separately from the wind turbine (1) if the first mechanical load and / or the first mechanical resistance does not satisfy the first condition.

4. Method according to one of the preceding claims, wherein the first rotor blade position is determined by means of an aerodynamic and / or elastic and / or hydrodynamic simulation of at least part of the wind turbine (1) and / or wherein the first rotor blade position is adjusted according to a time course of an external load on the rotor blade (2'), in particular a wind and / or wave load.

5. Method according to one of the preceding claims, comprising determining whether the first mechanical load and / or the first mechanical resistance satisfies a second condition according to which the operational connection of the rotor blade (2') to the wind turbine (1) during the repair requires a reduction of the first mechanical load and / or an increase of the first mechanical resistance by means of a support structure (E2).

6. Support structure for supporting a repair of a damaged area (32) on a load-bearing structure of a rotor blade (2') of a wind turbine (1), wherein the support structure is connectable or connected to the rotor blade (2') in such a way that a mechanical load on the load-bearing structure, in particular in an area surrounding the damaged area (32), is reduced and / or a mechanical resistance, in particular a buckling resistance, of the load-bearing structure and / or the non-load-bearing structure is increased.

7. Support structure according to claim 6, comprising a support rod (25) which can be arranged in an interior of the rotor blade (2') and has at least one prestressing means for exerting a prestressing force (26, 26') on the rotor blade (2') such that the mechanical load on the load-bearing structure is reduced and / or the mechanical resistance of the load-bearing structure and / or the non-load-bearing structure is increased.

8. Support structure according to claim 6 or 7, comprising at least one clamping frame (52) which can be arranged on an exterior of the rotor blade (2') and is designed to exert a clamping force on the rotor blade (2'), preferably at least two clamping frames (52) connected to one another by means of a support rod (24') which is prestressed or can be prestressed to reduce the mechanical loading of the load-bearing structure.

9. Support structure according to one of claims 6 to 8, comprising at least one support composite (45) arranged on an interior and / or exterior of the rotor blade (2') and connected, preferably integrally connected, to the load-bearing structure, comprising one or more support planks (45') arranged to reduce the mechanical loading of the load-bearing structure and / or one or more support profiles (45") arranged to increase the mechanical resistance of the load-bearing structure and / or the non-load-bearing structure.

10. Support structure according to one of claims 6 to 9, comprising a carrier structure on which a tool for repairing the damaged area (32) and / or a sensor for detecting at least one property of the damaged area (32) and / or of an area surrounding the damaged area (32) is arranged, in particular movably arranged.

11. Rotor blade system, comprising a rotor blade (2') of a wind turbine (1) and a support structure according to one of claims 6 to 10, wherein the rotor blade (2') comprises a load-bearing structure with a damaged area (32), the load-bearing structure comprises a fiber-reinforced material, in particular at least one pultrudate (12, 12", 12'") made of plastic reinforced with carbon and / or glass fibers, and the damaged area (32) comprises damage to one or more of the fibers and / or the plastic.

12. The method according to claim 5, further comprising attaching a support structure according to one of claims 6 to 10 to the rotor blade (2') for reducing the first mechanical load (S6).

13. A method for repairing a damaged area (32) on a load-bearing structure of a rotor blade (2') of a wind turbine (1), wherein the load-bearing structure comprises a fiber-reinforced material, in particular at least one pultrudate (12, 12", 12'") made of carbon and / or glass fiber-reinforced plastic, and the damaged area (32) comprises damage to one or more of the fibers and / or the plastic, the method comprising: Removing a part of the load-bearing structure comprising the damaged area (32) so that a recess (38) is formed in the load-bearing structure, Inserting and joining a patch comprising a fiber-reinforced material into the recess (38), Producing at least one electrically conductive connection between the load-bearing structure comprising the recess (38) and the patch and / or between the patch and an electrically conductive element of the rotor blade (2'), in particular a lightning protection element, for example an earthing cable and / or a metal grid.

14. The method of claim 13, further comprising preparing the repair according to the method of any one of claims 1 to 5 or 12.

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