Blades and wind turbine generator sets

Abstract

This utility model provides a blade and a wind turbine generator set. The blade includes: a blade body; a lightning protection system including a lightning arrester and a down conductor connected to the lightning arrester, the down conductor being located within the inner cavity of the blade body and extending towards the root of the blade body; and a sensor disposed within the inner cavity of the blade body, with its cable extending towards the root of the blade body. The distance between any point on the sensor and its cable and the down conductor is greater than the air breakdown distance between the down conductor and that point. This ensures a sufficient safe distance between the sensor and its cable and the down conductor, effectively reducing the risk of flashover.

Description

Technical Field

[0001] This utility model relates to the field of wind power generation technology, specifically to a blade and a wind turbine generator set. Background Technology

[0002] In traditional wind turbines, to reduce the risk of lightning strikes, no metal components other than the lightning protection system are allowed inside the blades. However, with the development of wind turbines, blades are becoming longer, and blade problems are increasing. Sensors need to be installed inside the blades to monitor their condition, but there is a risk of flashover between the sensor cables and the down conductors of the lightning protection system, which can easily damage the sensors and the blade structure. Utility Model Content

[0003] Therefore, the purpose of this invention is to provide a blade and wind turbine generator set that can reduce the risk of flashover between the sensor cable and the down conductor of the lightning protection system.

[0004] One embodiment of the present invention provides a blade, the blade comprising: a blade body; a lightning protection system including a lightning arrester and a down conductor connected to the lightning arrester, the down conductor being located in the inner cavity of the blade body and extending towards the root of the blade body; a sensor disposed in the inner cavity of the blade body, the sensor cable extending towards the root of the blade body; wherein, the distance between any point on the sensor and its cable and the down conductor is greater than the air breakdown distance between the down conductor and that point.

[0005] Furthermore, in some embodiments, the minimum clearance between the cable and the down conductor is 0.3 meters.

[0006] Furthermore, in some embodiments, the blade further includes a connecting flange disposed at the root of the blade body for connection to the hub, wherein the distance between the sensor and the connecting flange in the length direction of the blade body is less than or equal to 20 meters.

[0007] Furthermore, in some embodiments, the blade also includes a connecting flange and a blade baffle disposed at the root of the blade body. The blade baffle is located on the side of the connecting flange near the blade tip of the blade body, and the distance between the cable and the down conductor between the connecting flange and the blade baffle is minimal; or the distance between the cable and the down conductor increases as it moves further away from the root of the blade body; or the cable includes a first segment near the root of the blade body and a second segment adjacent to the first segment, the portion of the first segment corresponding to the down conductor is distributed in parallel, and the distance between the second segment and the down conductor increases as it moves further away from the root of the blade body.

[0008] Furthermore, in some embodiments, the blade further includes: at least one web disposed in the inner cavity of the blade body to divide the inner cavity of the blade body into at least two cavities, with the downlead and the sensor disposed in the same cavity.

[0009] Furthermore, in some embodiments, the blade further includes an insulating septum disposed on the cavity wall or web of the blade body and located between the sensor and its cable and the downleader to prevent surface flashover between the sensor and its cable and the downleader.

[0010] Furthermore, in some embodiments, the blade also includes a blade baffle disposed at the root of the blade body, the first end of the insulating partition extends to the location of the blade baffle, and the second end of the insulating partition extends at least 1 meter beyond the sensor towards the blade tip of the blade body; and / or the insulating partition is a 10kV epoxy resin board; and / or the thickness of the insulating partition is greater than or equal to 10mm.

[0011] Furthermore, in some embodiments, the down conductor is a high-voltage insulated cable; or the outer periphery of the down conductor is fitted with a high-voltage insulated heat shrink sleeve, and the high-voltage insulated heat shrink sleeve extends from the portion of the down conductor near the root of the blade body to a position at least 3 meters beyond the sensor.

[0012] Furthermore, in some embodiments, the cable end has a plug, and at least one of the sensor, cable, and plug is covered with a high-voltage insulating heat shrink sleeve.

[0013] Furthermore, in some embodiments, the cable is a single-shielded cable or a double-shielded cable.

[0014] Furthermore, in some embodiments, the cable is a double-shielded cable, having an inner shielding layer and an outer shielding layer; the resistance per unit length of the inner shielding layer and the outer shielding layer is less than 20mΩ / m, and / or one end of the inner shielding layer is used to connect to the grounding terminal of the data acquisition unit in the electrical cabinet, and both ends of the outer shielding layer are used to connect to the grounding points of the sensor and the data acquisition unit respectively, and / or both ends of the outer shielding layer are grounded in a ring.

[0015] Furthermore, in some embodiments, the sensor includes a sensor core and a sensor housing, the sensor core being disposed within the sensor housing and electrically connected to a cable; the blade also includes a surge protector box disposed outside the sensor housing and electrically connected to a cable.

[0016] Furthermore, in some embodiments, the surge protector box has multiple varistors, and the cable has a signal line, a ground signal line, and at least one shielding layer wrapped around the signal line and the ground signal line, with a varistor connected between any two of the signal line, the ground signal line, and the at least one shielding layer.

[0017] Furthermore, in some embodiments, the blade further includes: a sensor grounding wire, one end of which is connected to the sensor and the other end of which is used to connect to the hub grounding point, and a high-voltage insulating heat shrink sleeve is provided around the outer periphery of the sensor grounding wire.

[0018] Furthermore, in some embodiments, the sensor includes a sensor core and a sensor housing, the corners of which are chamfered or rounded, or the outer side of the sensor housing is covered with a hemispherical protective cover; and / or the sensor is used to detect the vibration amplitude of the blade.

[0019] A second aspect of this utility model provides a wind turbine generator set, including blades as described in any of the above embodiments.

[0020] Furthermore, in some embodiments, the wind turbine generator set further includes: an electrical cabinet, which has a data acquisition unit electrically connected to the sensor. The data acquisition unit is used to acquire the transmitted signals of the sensor, and a surge protector is provided at the input end of the data acquisition unit.

[0021] Furthermore, in some embodiments, the surge protector is a three-stage surge protector.

[0022] The blade provided in this embodiment of the invention can effectively reduce the risk of flashover by ensuring that there is a sufficient safe distance between the sensor and its cable and the down conductor.

[0023] The wind turbine generator set provided in this embodiment of the present invention has the same beneficial effects as those in the above embodiment due to having the blades described above, which will not be repeated here.

[0024] Other aspects and / or advantages of the present invention will be set forth in part in the description which follows, and in part will be clear from the description or may be learned by practice of the present invention. Attached Figure Description

[0025] The above and other objects and features of this utility model will become clearer from the following description of embodiments in conjunction with the accompanying drawings, in which: Figure 1 A schematic diagram of the lightning protection system and sensor wiring on the blades of the relevant technology is shown; Figure 2 A schematic diagram illustrating the path through which the downlead wire in the blade of the related technology may break down into the sensor through air. Figure 3 A partial structural schematic diagram of a wind turbine generator set according to an embodiment of this application is shown; Figure 4 It shows Figure 3 A magnified view of a portion of point I in the middle; Figure 5 Another partial structural schematic diagram of a wind turbine generator set according to one embodiment of this application is shown; Figure 6 A schematic cross-sectional view of the blade according to the first embodiment of this application is shown; Figure 7 A cross-sectional schematic diagram of the blade according to the second embodiment of this application is shown; Figure 8 A cross-sectional schematic diagram of the blade according to the third embodiment of this application is shown; Figure 9 A cross-sectional schematic diagram of the blade according to the fourth embodiment of this application is shown; Figure 10 A cross-sectional schematic diagram of the blade according to the fifth embodiment of this application is shown; Figure 11 A schematic cross-sectional view of the lead wire according to an embodiment of this application is shown; Figure 12 A partial structural schematic diagram of a wind turbine generator set according to a second embodiment of this application is shown.

[0026] Figures 1 to 12 Explanation of icon numbers: 100 blade body; 110 connecting flange; 120 blade baffle; 200 lightning protection system; 210 lightning arrester; 220 down conductor; 230 blade lightning arrester; 300 Sensor; 301 Sensor Core; 302 Sensor Housing; 310 Cable; 311 Conductor; 312 Insulation Layer; 313 Filler Material; 314 Inner Mylar Layer; 315 Inner Shielding Layer; 316 Middle Sheath; 317 Outer Mylar Layer; 318 Outer Shielding Layer; 319 Outer Sheath; 320 Sensor Grounding Wire; 330 Hemispherical Protective Cover; 400 insulation partition; 500 web plates; 600 surge protector box; 610 varistor; 700 data collector; 800 surge protector. Detailed Implementation

[0027] The following detailed embodiments are provided to aid the reader in gaining a comprehensive understanding of the methods, apparatus, and / or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatus, and / or systems described herein will become apparent upon understanding this disclosure. For example, the order of operations described herein is merely illustrative and is not limited to those orders set forth herein, but may be changed as will become clear upon understanding this disclosure, except for operations that must occur in a specific order. Furthermore, for clarity and conciseness, descriptions of features known in the art may be omitted.

[0028] The features described herein may be implemented in different forms and should not be construed as limited to the examples described herein. Rather, the examples described herein are provided only to illustrate some of the many feasible ways of implementing the methods, apparatus, and / or systems described herein, which will become clear upon understanding the disclosure of this application.

[0029] As used herein, the term “and / or” includes any one of the associated listed items and any combination of any two or more.

[0030] Although terms such as “first,” “second,” and “third” may be used herein to describe various components, assemblies, regions, layers, or parts, these components, assemblies, regions, layers, or parts should not be limited by these terms. Rather, these terms are used only to distinguish one component, assembly, region, layer, or part from another. Thus, without departing from the teaching of the examples described herein, the first component, first assembly, first region, first layer, or first part referred to as the first component, first assembly, first region, first layer, or first part may also be referred to as the second component, second assembly, second region, second layer, or second part.

[0031] In the specification, when an element such as a layer, region, or substrate is described as being "on" another element, "connected to," or "bonded to" another element, the element may be directly "on" another element, directly "connected to," or "bonded to" the other element, or one or more other elements may be present in between. Conversely, when an element is described as being "directly on" another element, "directly connected to," or "directly bonded to" another element, no other elements may be present in between.

[0032] The terminology used herein is for the purpose of describing various examples only and is not intended to limit disclosure. Unless the context clearly indicates otherwise, the singular form is intended to include the plural form as well. The terms “comprising,” “including,” and “having” indicate the presence of the described features, quantities, operations, components, elements, and / or combinations thereof, but do not preclude the presence or addition of one or more other features, quantities, operations, components, elements, and / or combinations thereof. The term “a plurality” represents any quantity of two or more.

[0033] The directional terms such as "above" and "below" in this application are all based on the directions shown in the diagram.

[0034] Unless otherwise defined, all terms used herein, including technical and scientific terms, shall have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains after understanding the invention. Unless expressly defined herein, terms such as those defined in a general dictionary shall be interpreted as having a meaning consistent with their meaning in the context of the relevant field and in this invention, and shall not be interpreted in an idealized or overly formalistic manner.

[0035] With the rapid development of wind turbine generators, blades are becoming increasingly longer, leading to a rise in blade-related problems. Therefore, the need to install sensors within the blades to monitor their condition is becoming increasingly urgent. However, because both the sensors themselves and the cables connecting them contain metal components, the presence of metal objects other than those in the lightning protection system within the blades could potentially cause new lightning strike damage.

[0036] Lightning strike damage can be broadly categorized into the following three types: The first scenario is that lightning strikes the sensor after penetrating the blade casing from the outside. The second scenario is that after lightning strikes the lightning arrester of the lightning protection system, when it is conducted along the down conductor, a flashover channel is formed between the down conductor and the sensor, resulting in damage to the sensor and the blade structure. The third type occurs when there is no direct lightning strike or flashover, but the sensor and cables are affected by electromagnetic induction, causing damage to the sensor and electrical system.

[0037] To address the above-mentioned issues, this utility model provides a blade to avoid one or more types of lightning strike damage that may occur. The following will describe... Figures 1 to 12 This invention introduces the blades and wind turbine generator sets provided by embodiments of the present invention.

[0038] like Figure 1 and Figure 3 As shown, a first aspect of the present invention provides a blade, which includes a blade body 100, a lightning protection system 200, and a sensor 300.

[0039] The lightning protection system 200 includes an air receiver 210 and a down conductor 220 connected to the air receiver 210. The air receiver 210 is typically located at or near the tip of the blade body 100, and the down conductor 220 is located inside the cavity of the blade body 100 and extends towards the root of the blade body 100. The tip of the blade body 100 is at higher risk of being struck by lightning; therefore, the air receiver 210 is installed near the tip of the blade body 100 to facilitate the reception of lightning strikes and conduction to the ground via the down conductor 220.

[0040] The number of lightning arresters 210 can be one or more. When there are multiple lightning arresters 210, all of them can be grounded through a single main lead 220 to reduce the number of cables, lower costs, and facilitate wiring.

[0041] In addition, such as Figure 1 As shown, the lightning protection system 200 may also include a blade lightning arrester 230, which is located closer to the root of the blade body 100 than the lightning arrester 210. By setting the blade lightning arrester 230, the lightning protection range can be increased. The blade lightning arrester 230 is also grounded through the aforementioned main down conductor 220.

[0042] The sensor 300 is installed inside the blade body 100, and the cable 310 of the sensor 300 extends to the root of the blade body 100. The sensor 300 monitors the blade body 100 and transmits the monitoring data to the electrical cabinet via the cable 310. This facilitates the timely detection of blade problems, provides convenience for timely repair or replacement of the blade, and also provides data support for subsequent blade improvements.

[0043] According to embodiments of this application, the distance between any point on the sensor 300 and its cable 310 and the down conductor 220 is greater than the air breakdown distance between the down conductor 220 and that point. By controlling the distance between the sensor 300 and its cable 310 and the down conductor 220 to be greater than the air breakdown distance, the flashover voltage can be increased from a physical perspective, thereby reducing the risk of flashover.

[0044] Of course, when there are multiple lightning arresters 210, and all of the multiple lightning arresters 210 are grounded through a main lead 220, the distance between any point on the sensor 300 and its cable 310 and the main lead 220 can be greater than the air breakdown distance between the main lead 220 and that point.

[0045] Specifically, the down conductor 220 is the core component of the lightning protection system 200 that conducts lightning current. When lightning strikes, the down conductor 220 carries a lightning current of tens of thousands to hundreds of thousands of amperes, creating an extremely strong electric field around it, and the down conductor 220 itself generates an extremely high instantaneous potential. If the distance between the sensor 300 or cable 310 and the down conductor 220 is less than the air breakdown distance, the strong electric field will break down the air between them, forming an arc discharge channel. The lightning current will then directly enter the sensor 300 or cable 310 through this channel, easily causing damage to the sensor 300.

[0046] by Figure 1 and Figure 2For example, sensor 300 and its cable 310 are roughly parallel to the down conductor 220. During lightning conduction, if the distance between sensor 300 and its cable 310 and down conductor 220 is close, a potential difference will be generated between down conductor 220 and sensor 300, causing a flashover (air breakdown or surface flashover) discharge from down conductor 220 to sensor 300 and its cable 310. See also... Figure 2 The two wavy lines in the diagram represent an air breakdown path, with the wavy line extending roughly laterally between the two webs 500 and the wavy line extending along one web 500 representing another surface flashover path.

[0047] In this embodiment, the distance between the sensor 300 and its cable 310 and the down conductor 220 is greater than the air breakdown distance. This reduces the probability of air breakdown and prevents lightning current from directly impacting the precision components of the sensor 300 (such as the piezoelectric chip for vibration detection, signal amplification circuit, etc.) and the insulation layer 312 of the cable 310. This prevents hardware damage such as burnout of the sensor 300 and insulation breakdown of the cable 310, and prevents direct lightning strike damage caused by air breakdown.

[0048] Furthermore, when lightning current passes through the down conductor 220, it can cause two major hazards: first, a strong alternating magnetic field is generated around it, which may induce overvoltage on the cable 310 of the sensor 300 through electromagnetic induction; second, the high potential of the down conductor 220 will create a significant potential difference between the sensor 300 and its cable 310, triggering electrostatic induction. In this embodiment, a larger distance is maintained between the sensor 300 and its cable 310 and the down conductor 220, which significantly reduces the magnetic field strength generated by the down conductor 220 (magnetic field strength is inversely proportional to distance), reduces the induced surge voltage on the cable 310, and prevents the induced voltage from exceeding the withstand threshold of the sensor 300 signal port, thus preventing signal distortion or port damage. Moreover, even if a potential difference exists between the down conductor 220 and the sensor 300 or cable 310, it will not cause electrostatic discharge due to an excessively large potential difference, avoiding pulse interference from discharge that could affect the analog signal transmission of the sensor 300, ensuring the accuracy of data acquisition, and weakening electromagnetic induction and potential difference interference.

[0049] It should be noted that the air breakdown distance is related to the extension length of the downlead 220. Taking the flange root of the blade body 100 as the starting point, the longer the extension length of the downlead 220, the greater the voltage drop on the downlead 220, and the greater the air breakdown distance between the downlead 220 and the cable 310 of the sensor 300.

[0050] According to one aspect of the embodiments of this application, the blade also includes a connecting flange 110 and a blade baffle 120 disposed at the root of the blade body 100. The blade baffle 120 is located on the side of the connecting flange 110 near the blade tip of the blade body 100, so that the distance between the cable 310 and the down conductor 220 between the connecting flange 110 and the blade baffle 120 is minimized. On the side of the blade baffle 120 facing the blade tip, the distance between the cable 310 and the down conductor 220 is larger as it gets closer to the blade tip of the blade body 100, which is beneficial to ensure that the distance between the cable 310 and the down conductor 220 at each position in the blade span is greater than the air breakdown distance.

[0051] Of course, since both cable 310 and downleader 220 need to pass through blade baffle 120 and extend towards the hub, to prevent cable 310 and downleader 220 from twisting significantly as the blades rotate, cable 310 and downleader 220 will be placed as close as possible to the center of blade baffle 120. Therefore, the distance between cable 310 and downleader 220 can be minimized at the point where they pass through blade baffle 120, and larger at other points.

[0052] According to some embodiments of this application, such as Figure 3 As shown, the cable 310 of the sensor 300 includes a first segment near the root of the blade body 100 and a second segment adjacent to the first segment. The portion of the first segment corresponding to the downlead 220 is distributed in parallel, and the distance between the second segment and the downlead 220 increases as it moves further away from the root of the blade body 100. Because the first segment is closer to the root of the blade body 100, the air breakdown distance between any point on the first segment and the downlead 220 is very small. Therefore, the portion of the first segment corresponding to the downlead 220 can be distributed in parallel, facilitating wiring.

[0053] Table 1 shows the relationship between voltage drop and air breakdown distance on the down conductor 220 at different distances from the blade root flange in a specific embodiment. Table 1:

[0054] As shown in Table 1, starting from the flange position at the blade root, when the downlead 220 extends for 1 meter, the air breakdown distance between this position and the cable 310 of the sensor 300 is 0.057 m. This allows the distance between them to be greater than 0.057 m, thus reducing the probability of air breakdown. Similarly, when the downlead 220 extends for 3 meters, the distance between the cable 310 of the sensor 300 and the downlead 220 can be greater than 0.17 m, further reducing the probability of air breakdown. The same principle applies to subsequent applications.

[0055] In one example, within 5 meters of the blade root flange, the distance between the downlead 220 and the cable 310 of the sensor 300 can be 0.57m, 0.6m, or 0.7m, with them parallel to each other, maintaining a sufficient safety distance. Beyond 5 meters of the blade root flange, the distance between the downlead 220 and the cable 310 of the sensor 300 increases as the distance from the blade root flange increases, facilitating wiring.

[0056] In other examples, instead of using a partial parallel arrangement, the distance between the downlead 220 and the cable 310 of the sensor 300 can be increased as it moves further away from the blade root flange.

[0057] According to other embodiments of this application, the minimum clearance between the cable 310 and the down conductor 220 can also be 0.3 meters to meet relevant requirements and reduce the risk of flashover.

[0058] The cable 310 and the down conductor 220 can be partially parallel or partially intersecting in space. In this case, the minimum parallel clearance between the cable 310 and the down conductor 220 can be 0.3 meters, and the minimum intersecting clearance can also be 0.3 meters.

[0059] In one example, the minimum parallel clearance between cable 310 and downleader 220 can be 0.9 meters, 1 meter, etc., and the minimum crossing clearance can be 0.5 meters.

[0060] Additionally, it should be noted that the air breakdown distance varies with the environment. When the electric field around the down conductor 220 is non-uniform, the actual air breakdown distance will be shorter. In high humidity and high altitude environments, the air breakdown electric field strength will decrease, and the air breakdown distance will also be shorter. Therefore, the distance between the sensor 300 and its cable 310 and the down conductor 220 needs to be further increased to ensure a sufficient safety distance.

[0061] like Figure 4 As shown, H represents the distance between any point on the sensor 300 and its cable 310 and the downlead 220. Assuming an ideal, uniform electric field, for example, the downlead 220 is 1 × 70 mm. 2 In the case of copper cables, it is possible to Where d is the length of the lead-down line 220 extending along the blade span, starting from the blade flange position. As an example, when determining the dimension of d, the position of the lead-down line 220 along the blade span can be determined by the cross-section of the sensor 300 or cable 310, and this position can be projected onto the chord direction of the blade. Then, starting from the blade flange position, the distance between the corresponding position of the aforementioned point along the blade chord direction and the blade flange can be determined, in meters.

[0062] In actual operating conditions, the electric field at the location of the down conductor 220 is usually a non-uniform electric field. According to another embodiment of this application, it can be made... .

[0063] Furthermore, considering that lightning pulses (such as 10 / 350μs waveforms) have stronger breakdown capabilities, their breakdown voltage is about 20-30% lower than that of power frequency AC (due to the faster rise time, which makes ionization more likely). Therefore, it can also make This ensures that there is a sufficient safe distance between the sensor 300 and its cable 310 and the down conductor 220, reducing the risk of flashover.

[0064] Of course, to ensure absolute safety or increase security, it is also possible to... or make , The larger the value of H, the better the security.

[0065] Furthermore, in some embodiments, such as Figure 3 As shown, the blade also includes a connecting flange 110, which is located at the root of the blade body 100 and is used to connect with the hub. The distance L1 between the sensor 300 and the connecting flange 110 in the length direction of the blade body 100 is less than or equal to 20 meters.

[0066] Because the blades have a lightning protection system 200, a certain lightning shielding area can be formed. Using the down conductor 220 as a virtual lightning rod, its protection range is 9.2 meters along the blade length from the connecting flange, and 3 meters at a distance of 1 meter from the down conductor. Therefore, when the sensor 300 is installed 1 meter from the down conductor, and within 3 meters of the connecting flange, there is no risk of direct lightning strike. When the sensor 300 is between 3 and 9.2 meters from the connecting flange, the risk of direct lightning strike is low. When the sensor 300 is more than 9.2 meters from the connecting flange 110, the risk of direct lightning strike is relatively high, and when it exceeds 20 meters, the risk of direct lightning strike is extremely high.

[0067] Table 2 shows the lightning strike risk when the sensor 300 is at different distances from the connecting flange 110.

[0068] Table 2:

[0069] As shown in the table above, making the distance L1 between the sensor 300 and the connecting flange 110 in the length direction of the blade body 100 less than or equal to 20 meters can reduce the risk of direct lightning strikes.

[0070] Of course, the distance between the sensor 300 and the connecting flange 110 in the length direction of the blade body 100 can be further made between 3 meters and 9.2 meters, which reduces the risk of direct lightning strikes. Moreover, the sensor 300 is placed closer to the area of ​​the blade body 100 that is prone to vibration and fatigue, which is more conducive to the sensor 300 monitoring the blade.

[0071] Furthermore, in some embodiments, such as Figures 6 to 10 As shown, the blade also includes at least one web 500 disposed within the inner cavity of the blade body 100 to divide the inner cavity of the blade body 100 into at least two cavities, with the downlead 220 and the sensor 300 disposed within the same cavity. This design prevents flashover breakdown of the web 500 and protects the blade structure from damage.

[0072] As an example, such as Figure 6 and Figure 7 As shown, the web 500 can be a single unit. In this case, the downlead 220 and the sensor 300 can be set in... Figure 6 and Figure 7 in the cavity shown.

[0073] As an example, such as Figures 8 to 10 As shown, the web 500 can also be two; in this case, the downlead 220 and the sensor 300 can be set in... Figures 8 to 10 in the cavity shown.

[0074] Furthermore, in some embodiments, such as Figure 3 and Figure 4 As shown, the blade also includes an insulating partition 400, which is disposed on the cavity wall or web 500 of the blade body 100 and located between the sensor 300 and its cable 310 and the down conductor 220. This partition prevents surface flashover between the sensor 300 and its cable 310 and the down conductor 220, and also prevents air breakdown. By adding the insulating partition 400, physical isolation and insulation protection can be achieved, weakening the electric / magnetic field interference generated by the lightning current of the down conductor 220, while blocking the formation path of the air breakdown arc, thus compensating for the protection shortcomings when the spacing is insufficient.

[0075] As an example, the insulating partition 400 can be a 10kV epoxy resin board with good insulation performance.

[0076] As an example, the insulation partition 400 has a thickness of 10 mm or more, such as 12 mm or 14 mm, which is sufficient to provide good protection against breakdown.

[0077] Furthermore, such as Figure 3As shown, the blade may also include a blade baffle 120 disposed at the root of the blade body 100. The first end of the insulating partition 400 extends to the location of the blade baffle 120, and the second end of the insulating partition 400 extends beyond the sensor 300 at least 1 meter beyond the sensor 300 towards the blade tip of the blade body 100. This design helps the insulating partition 400 to better block the electric field, arc, and environmental interference generated by the lightning current of the down conductor 220 from spreading to the sensor 300 body, preventing the sensor 300 from being damaged by edge discharge, magnetic field diffraction, or foreign object intrusion, thus ensuring its detection accuracy and operational stability.

[0078] As an example, the distance L2 from the second end of the insulating partition 400 to the blade tip of the blade body 100 beyond the sensor is 1.2 meters, 1.5 meters, or 2 meters.

[0079] Furthermore, in some embodiments, the down conductor 220 is a high-voltage insulated cable; or the outer periphery of the down conductor 220 is fitted with a high-voltage insulating heat shrink sleeve, which can improve the insulation level and avoid the risk of breakdown.

[0080] Furthermore, with a high-voltage insulating heat-shrink sleeve fitted around the outer periphery of the downlead 220, the high-voltage insulating heat-shrink sleeve can extend from the part of the downlead 220 near the root of the blade body 100 to a position at least 3 meters beyond the sensor. This design helps the high-voltage insulating heat-shrink sleeve to better block the electric field, arc, and environmental interference generated by the lightning current of the downlead 220 from spreading to the sensor body 300.

[0081] As an example, in the blade root area where sensor 300 is installed, the downlead 220 uses a 35kV high-voltage insulating heat shrink sleeve.

[0082] Furthermore, in some embodiments, the end of the cable 310 of the sensor 300 has a plug, and at least one of the sensor 300, the cable 310 and the plug is wrapped with a high-voltage insulating heat shrink sleeve to avoid the risk of breakdown.

[0083] As an example, the cable 310 of sensor 300 uses a 10kV or higher high-voltage insulating heat shrink sleeve to enhance the insulation of cable 310.

[0084] Furthermore, in some embodiments, the cable 310 of the sensor 300 uses a single-layer shielded cable or a double-layer shielded cable, which can reduce the influence of electromagnetic induction. Moreover, single-layer shielded cables are low in cost, flexible, and easy to bend and wire. Double-layer shielded cables provide more comprehensive shielding performance and have stronger resistance to complex electromagnetic interference.

[0085] In one specific embodiment, the cable 310 of the sensor 300 is a double-shielded cable. For example... Figure 11As shown, the cable 310 includes a plurality of conductors 311, an insulation layer 312 wrapped around each conductor 311, a filler material 313 filling the periphery of the insulation layer 312, an inner Mylar layer 314 located on the periphery of the insulation material, and an inner shielding layer 315, a middle sheathing layer 316, an outer Mylar layer 317, an outer shielding layer 318, and an outer sheathing layer 319 distributed sequentially from the inside to the outside.

[0086] Furthermore, the resistance per unit length of both the inner shielding layer 315 and the outer shielding layer 318 can be less than 20 mΩ / m. This reduces current loss during transmission through the shielding layers, minimizes signal attenuation and phase distortion caused by excessively high shielding layer impedance, and ensures the integrity of long-distance signal transmission. Moreover, the low resistance allows both shielding layers to possess excellent conductivity. When external electromagnetic interference exists, it can quickly conduct and disperse the induced current generated by the interference, preventing current from accumulating locally within the shielding layers and forming new interference sources, thus improving the electromagnetic interference shielding effect.

[0087] Furthermore, such as Figure 5 As shown, one end of the inner shielding layer 315 can also be used to connect to the grounding terminal of the data acquisition unit 700 in the electrical cabinet, and both ends of the outer shielding layer 318 can be used to connect to the grounding points of the sensor 300 and the data acquisition unit 700, respectively.

[0088] Here, both the outer shielding layer 318 and the inner shielding layer 315 are grounded. The induced current generated by interference can be quickly discharged to the ground through both shielding layers, and a "shielding cavity" is formed between the two shielding layers, which weakens the penetration of high-frequency signals and enhances the shielding effectiveness against high-frequency electric field interference. Furthermore, in the event of lightning surges or transient overvoltages in the power grid, grounding both shielding layers effectively adds an extra electrostatic discharge channel, allowing the induced electrostatic charge on the surface and inside of the cable 310 to be discharged to the ground more quickly, preventing the accumulation of static electricity that could lead to a high potential difference and spark discharge. For instantaneous large currents such as lightning surges, the double-grounded shielding layers can divert some of the surge current, reducing the impact of the surge on the core insulation layer 312 and connected equipment. Moreover, grounding one end of the inner shielding layer 315 and both ends of the outer shielding layer 318, compared to grounding both ends of the inner and outer shielding layers, can prevent the shielding layers from forming a closed conductive loop. This avoids the induced voltage on the inner and outer shielding layers when current flows through the core wire, thus preventing the cable 310 from overheating due to a large amount of circulating current and improving the service life of the cable 310.

[0089] Furthermore, both ends of the outer shielding layer 318 can be grounded in a ring, and one end of the inner shielding layer 315 can be grounded in a ring. This can maximize the grounding reliability and current discharge efficiency of the shielding layers, while reducing the risk of shielding failure caused by poor grounding contact.

[0090] As an example, when the cable connects the sensor 300 and the data acquisition unit 700, the inner shielding layer 315 is grounded at one end and is only connected to the grounding terminal of the data acquisition unit 700. The outer shielding layer 318 is grounded at both ends. 360-degree surround grounding is achieved at the sensor 300 end through a connector, and surround grounding is achieved at the data acquisition unit 700 end through a grounding clip.

[0091] Furthermore, to address the problem of damage to the sensor 300 and its electrical system caused by electromagnetic induction, in some embodiments, such as... Figure 5 As shown, surge protectors 800 can be installed at the sensor end and the electrical cabinet connection end of cable 310 to prevent lightning surges from intruding and affecting the system.

[0092] In a specific embodiment, such as Figure 12 As shown, the sensor 300 includes a sensor core 301 and a sensor housing 302. The sensor core 301 is disposed within the sensor housing 302 and is electrically connected to the cable 310. The blade also includes a surge protector 600, disposed on the outside of the sensor housing 302 and electrically connected to the cable 310. By connecting the sensor 300 to the surge protector 600, surge protection can be enhanced, preventing lightning surges from entering the sensor 300 and causing damage.

[0093] In addition, such as Figure 5 As shown, the wind turbine generator set also includes an electrical cabinet, which contains a data acquisition unit 700 electrically connected to the sensor 300. The data acquisition unit 700 is used to acquire the transmitted signals from the sensor 300, and a surge protector 800 is installed at the input terminal of the data acquisition unit 700. By connecting an external surge protector to the data acquisition unit 700, surge protection can be strengthened, preventing lightning surges from entering the electrical cabinet and causing damage to it.

[0094] Of course, if the surge protector 600 and surge protector 800 are installed simultaneously and distributed at both ends of the cable 310 of the sensor 300, surge protection can be achieved for the entire cable 310 link, blocking the intrusion of lightning surge energy in both directions, and greatly reducing the risk of damage to the sensor 300 and the electrical cabinet.

[0095] Furthermore, such as Figure 12 As shown, the surge protection box 600 may have multiple varistors 610, and the cable 310 has a signal line, a ground signal line, and at least one shielding layer wrapped around the signal line and the ground signal line. A varistor 610 is connected between any two of the signal line, the ground signal line, and the at least one shielding layer.

[0096] This design employs a comprehensive varistor layout to effectively address both differential-mode and common-mode overvoltages that may occur in cables. Furthermore, while a single varistor discharges surge energy, it often leaves a relatively high residual voltage. If this residual voltage exceeds the equipment's tolerance range, it can still damage the equipment. In this design, multiple varistors 610 work collaboratively, effectively distributing surge current and energy across multiple paths simultaneously. Experiments show that a structure with multiple varistors 610 connected in parallel or in multiple locations significantly reduces residual voltage compared to a single varistor, suppressing surge voltage to within the equipment's safe voltage range and greatly reducing the risk of high residual voltage impacting precision components. Moreover, lightning-induced surge energy is extremely high, and a single varistor has limited energy absorption and current-carrying capacity, making it susceptible to burnout and failure under strong surges. In this design, each varistor 610 only bears a portion of the surge energy, and the overall energy tolerance increases with the number of varistors 610, enhancing the reliability of the surge protector 600 in the face of strong surge impacts.

[0097] As an example, such as Figure 12 As shown, when the cable 310 of the sensor 300 is a double-shielded cable, having an outer shielding layer 318, an inner shielding layer 315, a signal line, and a grounding signal line, the surge protector 600 can have four varistors 610, with the first varistor 610 connected between the signal line and the grounding signal line. Figure 12 The upper middle varistor 610), the second varistor 610 is connected between the signal line and the outer shielding layer 318 ( Figure 12 The third varistor 610 is connected between the ground signal line and the outer shielding layer 318. Figure 12 The second varistor from the left in the lower center is 610. The fourth varistor 610 is connected between the inner shielding layer 315 and the outer shielding layer 318. Figure 12 The varistor 610 is located at the bottom right of the center.

[0098] The following table compares the results of adding a surge protector box 600 with and without adding a surge protector box 600:

[0099] After installing the surge protector box 600, the withstand voltage of sensor 300 increased from 5kV to 7kV, an increase of 40%; the surge withstand value increased from 4kV to 7kV, an increase of 75%, and both indicators exceeded the technical requirements. Clearly, the surge protector box 600 enhances the sensor 300's resistance to high-voltage surges and lightning surges, effectively expanding the safe operating boundaries of sensor 300 in complex electrical environments.

[0100] Furthermore, the surge protector 800 can be a three-stage surge protector 800. The input signal of the sensor 300 adopts three-stage surge protection, which discharges surge energy and clamps voltage step by step, and finally limits the residual voltage to a safe range that the data acquisition unit 700 can withstand, so as to fully resist surges without interfering with the normal signal transmission of the sensor 300.

[0101] As an example, the first level of protection consists of a varistor and a gas discharge tube, serving as the main discharge path for surge current. The second level of protection uses varistors and gas discharge tubes with smaller current-carrying capacity, and the impact of increased leakage current of the varistor on the signal needs to be considered during commissioning. The third level mainly performs interference filtering and TVS (Transient Voltage Suppressor) surge protection.

[0102] During surge protection testing, the signal port of the data acquisition unit 700 must be tested according to the requirements for power supply ports. This significantly raises the surge protection acceptance threshold for this signal port.

[0103] In addition, the data acquisition unit 700 is installed inside the cabinet, and the main surge protection design may also include protection for the power supply input and protection for the external communication interface (Profibus-DP or CANOpen).

[0104] Furthermore, in some embodiments, such as Figure 5 As shown, the blade also includes a sensor grounding wire 320, one end of which is connected to the sensor 300, and the other end is used to connect to the hub grounding point. This helps to reduce the resistance value of the sensor 300 to ground.

[0105] In addition, the high-voltage insulating heat shrink sleeve is fitted around the outer periphery of the sensor grounding wire 320, which can improve the insulation level and avoid the risk of breakdown.

[0106] As an example, in addition to grounding through the shielding layer, sensor 300 can be further grounded by adding a separate 1×1.5mm² grounding cable connected to the hub grounding point to accelerate electrostatic discharge, as demonstrated by comparative testing. The DC resistance of the 1×1.5mm² grounding cable is 14mΩ / m.

[0107] Further, in some embodiments of the design of sensor 300, sensor 300 includes sensor core 301 and sensor housing 302. The corners of sensor housing 302 are chamfered or rounded, or the outer side of sensor housing 302 is covered with a hemispherical protective cover 330, which can reduce electric field distortion.

[0108] Specifically, the relative rate of change of electric field intensity at any point in an electric field along the direction of the field is inversely proportional to the radius of curvature of the equipotential surface at that point. Therefore, the electric field intensity is smaller where the radius of curvature of the conductor surface is large, and the electric field intensity is larger where the radius of curvature is small. Thus, the surface charge density at the tip of the conductor is naturally the greatest, and the electric field intensity nearby is also naturally very strong. A strong electric field causes ions in the air to move violently. When they collide with air molecules, they ionize the molecules, making the air more conductive—that is, the air is broken down. Therefore, using a rounded corner design for the sensor housing 302 or adding a hemispherical protective cover 330 can avoid the risk of charge accumulation and tip discharge during lightning strikes.

[0109] Furthermore, sensor 300 can be used to detect blade vibration amplitude. Abnormal blade vibration amplitude (such as a sudden increase in amplitude or a shift in vibration frequency) is often a precursor to structural failures such as cracks, adhesive layer delamination, lightning strike damage, and blade tip cracking. Sensor 300 can capture these abnormal signals in real time, issuing early warnings in the early stages of a fault, preventing serious accidents such as blade breakage and detachment due to continued damage. Moreover, in traditional operation and maintenance, blade inspection often relies on periodic manual inspections (such as high-altitude climbing and drone inspections), which can easily lead to problems of "over-maintenance" (frequent maintenance when there are no faults) or "under-maintenance" (faults have occurred but have not been detected in time). By using sensor 300 to monitor vibration data in real time, the health status of the blades can be accurately determined, and targeted maintenance can be arranged only when vibration indicators are abnormal, reducing unnecessary disassembly and maintenance operations and minimizing secondary damage to the blades during maintenance.

[0110] Furthermore, in some embodiments, the number of sensors 300 may be one or at least two.

[0111] Furthermore, in some embodiments, the sensor 300 is fixed to an insulating plate by screws, and the insulating plate is attached to the inner wall of the blade body 100, which can increase the surface flashover path and reduce the probability of surface flashover.

[0112] As an example, the insulation board can be an epoxy resin board with a thickness of not less than 10mm.

[0113] As an example, the closest distance between the fixed screw and the edge of the insulating board is 5mm, which can prevent the electric field concentration at the edge of the screw from causing the risk of discharge and prevent the screw from contacting external conductors.

[0114] A second aspect of this utility model provides a wind turbine generator set, including blades as described in any of the above embodiments.

[0115] The wind turbine generator provided in this embodiment has the blades of any of the above embodiments, and thus has the beneficial effects of any of the above embodiments, which will not be repeated here.

[0116] To prevent lightning strikes, the blade provided in this embodiment of the invention allows for the definition of the sensor 300's installation position, ensuring it is within a certain range from the blade root and sufficiently isolated from the down conductor 220 to improve flashover voltage. By designing the sensor 300's housing with chamfered edges or providing additional circular housing protection, electric field distortion can be reduced. Furthermore, placing the sensor 300 and down conductor 220 within the same chamber of the blade avoids damage to the blade structure. Using a high-voltage insulated cable or a high-voltage insulated heat-shrink sleeve for the down conductor 220, and a high-voltage insulated heat-shrink sleeve for the sensor 300's cable 310, improves the insulation level and avoids the risk of breakdown. Adding an insulating partition 400 prevents surface flashover. Furthermore, using a single-layer shielded cable or a double-layer shielded cable for the sensor 300's cable 310 reduces electromagnetic induction effects. Additionally, adding a grounding wire 320 reduces the sensor 300's resistance to ground. A surge protector 800 is installed at the sensor end and the electrical cabinet connection end to prevent lightning surge intrusion.

[0117] While the embodiments of the present invention have been described in detail above, those skilled in the art can make various modifications and variations to the embodiments of the present invention without departing from the spirit and scope thereof. It should be understood that, to those skilled in the art, these modifications and variations will still fall within the spirit and scope of the embodiments of the present invention as defined in the claims.

Claims

1. A blade, characterized in that, The blade includes: Blade body (100); The lightning protection system (200) includes a lightning arrester (210) and a down conductor (220) connected to the lightning arrester (210), the down conductor (220) being located in the inner cavity of the blade body (100) and extending toward the root of the blade body (100); A sensor (300) is disposed in the inner cavity of the blade body (100), and a cable (310) of the sensor (300) extends toward the root of the blade body (100). The distance between any point on the sensor (300) and its cable (310) and the down conductor (220) is greater than the air breakdown distance between the down conductor (220) and that point.

2. The blade according to claim 1, characterized in that, The minimum clearance between the cable (310) and the down conductor (220) is 0.3 meters.

3. The blade of claim 1, wherein The blade also includes: A connecting flange (110) is provided at the root of the blade body (100) for connection to the hub. The distance between the sensor (300) and the connecting flange (110) in the length direction of the blade body (100) is less than or equal to 20 meters.

4. The blade according to claim 1, characterized in that, The blade also includes a connecting flange (110) and a blade baffle (120) disposed at the root of the blade body (100). The blade baffle (120) is located on the side of the connecting flange (110) near the blade tip of the blade body (100). The distance between the cable (310) and the downlead (220) between the connecting flange (110) and the blade baffle (120) is minimized. The distance between the cable (310) and the downlead (220) increases the further away from the root of the blade body (100); or The cable (310) includes a first segment near the root of the blade body (100) and a second segment adjacent to the first segment. The portion of the first segment corresponding to the down conductor (220) is distributed in parallel. The distance between the second segment and the down conductor (220) is greater the further away from the root of the blade body (100).

5. The blade of claim 1, wherein The blade also includes: At least one web (500) is disposed in the inner cavity of the blade body (100) to divide the inner cavity of the blade body (100) into at least two cavities, wherein the downlead (220) and the sensor (300) are disposed in the same cavity.

6. The blade of claim 5, wherein The blade also includes: An insulating partition (400) is disposed on the cavity wall of the inner cavity of the blade body (100) or on the web plate (500), and is located between the sensor (300) and its cable (310) and the down conductor (220) to prevent surface flashover between the sensor (300) and its cable (310) and the down conductor (220).

7. The blade according to claim 6, characterized in that, The blade also includes a blade baffle (120) disposed at the root of the blade body (100), a first end of the insulating partition (400) extending to the location of the blade baffle (120), and a second end of the insulating partition (400) extending at least 1 meter beyond the sensor (300) toward the blade tip of the blade body (100); and / or The insulating partition (400) is a 10kV epoxy resin board; and / or The thickness of the insulating partition (400) is greater than or equal to 10 mm.

8. The blade according to any one of claims 1 to 7, characterized in that, The down conductor (220) is a high-voltage insulated cable; or The outer periphery of the down conductor (220) is fitted with a high-voltage insulating heat shrink sleeve, and the high-voltage insulating heat shrink sleeve extends from the portion of the down conductor (220) near the root of the blade body (100) to a position at least 3 meters beyond the sensor (300).

9. The blade according to any one of claims 1 to 7, characterized in that, The cable (310) has a plug at one end, and at least one of the sensor (300), the cable (310) and the plug is covered with a high-voltage insulating heat shrink sleeve.

10. The blade according to claim 1, characterized in that, The cable (310) is a single-layer shielded cable (310) or a double-layer shielded cable (310).

11. The blade according to claim 1, characterized in that, The cable (310) is a double-shielded cable (310), having an inner shielding layer (315) and an outer shielding layer (318). The inner shielding layer (315) and the outer shielding layer (318) have a resistance value per unit length of less than 20 mΩ / m, and / or One end of the inner shielding layer (315) is used to connect to the grounding terminal of the data acquisition unit (700) in the electrical cabinet, and both ends of the outer shielding layer (318) are used to connect to the grounding points of the sensor (300) and the data acquisition unit (700) respectively, and / or Both ends of the outer shielding layer (318) are grounded in a ring.

12. The blade according to claim 10 or 11, characterized in that, The sensor (300) includes a sensor core (301) and a sensor housing (302). The sensor core (301) is disposed in the sensor housing (302) and is electrically connected to the cable (310). The blade also includes a lightning protection box (600), which is disposed on the outside of the sensor housing (302) and electrically connected to the cable (310).

13. The blade according to claim 12, characterized in that, The surge protection box (600) has a plurality of varistors (610), and the cable (310) has a signal line, a ground signal line and at least one shielding layer wrapped around the signal line and the ground signal line. Any two of the signal line, the ground signal line and the at least one shielding layer are connected to a varistor (610).

14. The blade according to any one of claims 1 to 7, characterized in that, The blade also includes: The sensor grounding wire (320) has one end connected to the sensor (300) and the other end connected to the hub grounding point. The outer periphery of the sensor grounding wire (320) is covered with a high-voltage insulating heat shrink sleeve.

15. The blade according to any one of claims 1 to 7, characterized in that, The sensor (300) includes a sensor core (301) and a sensor housing (302), wherein the edges and corners of the sensor housing (302) are chamfered or rounded, or the outer side of the sensor housing (302) is further covered with a hemispherical protective cover (330); and / or The sensor (300) is used to detect the amplitude of blade vibration.

16. A wind power unit, characterized in that include: The blade as described in any one of claims 1 to 15.

17. The wind power plant according to claim 16, characterized in that The wind turbine generator set also includes: An electrical cabinet is provided, which contains a data acquisition unit (700) electrically connected to the sensor (300). The data acquisition unit (700) is used to acquire the transmission signal of the sensor (300). A surge protector (800) is provided at the input terminal of the data acquisition unit (700).

18. The wind turbine generator set according to claim 17, characterized in that, The surge protector (800) is a level three surge protector.

Images