A lightning eliminator applied to a wind turbine generator system

Abstract

This invention relates to a lightning dissipator for wind turbine generator sets, comprising a substrate, within which are disposed a first reactance consisting of a receiving electrode and a first electrode, and a second reactance consisting of a releasing electrode and a second electrode. The receiving electrode is connected to the down conductor of the wind turbine blade, and the releasing electrode is connected to the grounding terminal of the wind turbine blade. The first and second electrodes are connected in series, and the impedance of the second reactance is greater than that of the first reactance. The lightning dissipator for wind turbine generator sets of this invention, with its series-connected first and second reactances, ensures that when the charge on the second reactance reaches a certain value, it will discharge charge before the first reactance. This reduces the charge density across the first reactance, causing the potential at the tip of the wind turbine blade to approach the ground potential, eliminating the conditions for lightning attraction caused by charge accumulation or opposite charges in thunderclouds, thus fundamentally eliminating the probability of lightning strikes.

Description

Technical Field

[0001] This invention relates to the field of wind power equipment technology, and more specifically to a lightning dissipator applied to wind turbine generator sets. Background Technology

[0002] When a thundercloud forms above a wind farm, the induced charges generated on the ground create a highly non-uniform electric field between the wind turbine blades and the thundercloud. Simultaneously, the length of the wind turbine blades and the height of the tower act as a large-curvature electrode, causing ionization of the surrounding air and creating conditions for self-sustaining discharge. All electrons in the air leak into the ground through the root of the discharge channel. This discharge channel gradually forms a continuously elongating leader, which continuously strengthens the electric field ahead. Eventually, when the field strength is high enough, a lightning discharge channel is generated. The powerful lightning current can cause the wind turbine blades to break down. The secondary hazards caused by the powerful lightning current, including lightning induction, lightning electromagnetic induction, lightning wave intrusion, and lightning electromagnetic pulse, are self-evident.

[0003] The current main direct lightning strike protection products are shown in the table below:

[0004]

[0005] Patent application number 201520256564.1, entitled "Experimental Device for Simulating Lightning Attraction on Wind Turbine Blades," discloses a traditional lightning protection design for wind turbine blades. The technical solution involves installing lightning arresters on the wind turbine blades, embedded at the blade tips, middle sections, etc., with the arrester disc flush with the blade surface, bridging the down conductor inside the blade. Since both the wind turbine blades and nacelle are rotating, the electrical connection of the lightning current along the down conductor is achieved through various conductors, connectors, and lightning protection brushes. This can easily lead to poor current conduction, not only failing to properly discharge the lightning current to the ground but also increasing the path impedance and amplifying the thermal and mechanical destructive effects of the lightning current.

[0006] Furthermore, due to the limited distribution of wind energy resources, most wind farms are located in areas with complex geological conditions and high soil resistivity, making it difficult to meet grounding resistance requirements. Even with the deployment of numerous artificial grounding electrodes and the use of resistance-reducing agents, a good grounding effect cannot be achieved. This is especially true in cold, high-altitude regions where the thick permafrost layer and high soil resistivity further complicate the grounding resistance of wind turbine units. This can lead to poor electrical connections, making the blades more susceptible to lightning strikes, and the grounding resistance of the discharge channel may not meet design requirements, ultimately increasing losses caused by lightning strikes. Summary of the Invention

[0007] This invention provides a lightning depletion device for wind turbine generators. It is based on an energy transfer air-type direct lightning active protection device and uses a dielectric intervention method to transfer the energy of spatial electric field changes caused by thunderclouds in advance, reducing the intensity of charge accumulation at the blade tips and making the blade tip charge density closer to the ground surface, thereby reducing the probability of wind turbine generators being struck by lightning.

[0008] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0009] A lightning dissipator for use in wind turbine generator sets includes a substrate. The substrate contains a first reactance consisting of a receiving electrode and a first electrode, and a second reactance consisting of a releasing electrode and a second electrode. The receiving electrode is externally connected to the down conductor of the wind turbine blade, and the releasing electrode is externally connected to the grounding terminal of the wind turbine blade. The first electrode and the second electrode are connected in series, and the impedance of the second reactance is greater than the impedance of the first reactance.

[0010] Furthermore, the impedance of the second reactance is at least 25% greater than the impedance of the first reactance.

[0011] Furthermore, the first electrode is a disk-shaped structure, the receiving electrode is a ring-shaped structure sleeved on the outside of the first electrode, and a first gap is provided between the first electrode and the receiving electrode.

[0012] Furthermore, the outer edge of the first electrode is serrated.

[0013] Furthermore, the second electrode has a disc-shaped structure, and the release electrode has a ring-shaped structure fitted outside the second electrode, with a second gap between the second electrode and the release electrode.

[0014] Furthermore, the outer edge of the second electrode is serrated.

[0015] Furthermore, the distance between the receiving electrode and the releasing electrode is no less than three times the distance between the receiving electrode and the first electrode.

[0016] Furthermore, an insulating fixing body is provided between the first electrode and the second electrode, and a connecting body is provided on the outside of the insulating fixing body.

[0017] Furthermore, a number of uniformly distributed insulating support columns are provided between the receiving electrode and the releasing electrode.

[0018] Furthermore, the substrate includes an upper cover and a base. The upper cover is fastened onto the base, forming a cavity in the middle to accommodate the first reactance and the second reactance. The upper cover is provided with a first external electrode connected to the receiving electrode. The outer end of the first external electrode is connected to the lead wire of the fan blade. The base is provided with a second external electrode connected to the release electrode. The outer end of the second external electrode is connected to the grounding terminal of the fan blade.

[0019] The embodiments of the present invention have the following advantages:

[0020] The lightning dissipator for wind turbine generators described in this invention comprises a first reactor and a second reactor connected in series. Since the impedance of the second reactor is greater than that of the first reactor, when the charge of the second reactor reaches a certain value, it will discharge charge before the first reactor. Preferably, the electric field strength of the charge discharge by the second reactor is ≤25Kv / m, which is equivalent to a reduction of 100 times compared to the electric field strength of lightning. This leads to a decrease in the charge density at both ends of the first reactor, resulting in the simultaneous discharge of charge by the first and second reactors. This causes the potential at the tip of the wind turbine blades to approach the potential of the ground, eliminating the conditions for charge accumulation at high tips and the generation of lightning by opposite charges in thunderclouds, thus fundamentally eliminating the probability of lightning generation. Attached Figure Description

[0021] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0022] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0023] Figure 1 A product structure diagram of a lightning dissipator applied to a wind turbine generator set provided in an embodiment of the present invention;

[0024] Figure 2 for Figure 1 Internal structure diagram; Figure 3 This is a graph showing actual test data of the lightning dissipator applied to a wind turbine generator set in this embodiment.

[0025] In the picture:

[0026] 1. Receiving electrode; 2. First electrode; 3. Releasing electrode; 4. Second electrode; 5. First gap; 6. Second gap; 7. Insulating fixing body; 8. Connecting body; 9. Insulating support column; 10. Through hole; 11. Top cover; 12. Base; 13. First external electrode; 14. Second external electrode. Detailed Implementation

[0027] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] like Figure 1 As shown, a lightning dissipator for wind turbine generator sets includes a substrate. The substrate contains a first reactance consisting of a receiving electrode 1 and a first electrode 2, and a second reactance consisting of a releasing electrode 3 and a second electrode 4. The receiving electrode 1 is externally connected to the down conductor of the wind turbine blade, and the releasing electrode 3 is externally connected to the grounding terminal of the wind turbine blade. The first electrode 2 and the second electrode 4 are connected in series to realize the series connection of the first reactance with the second reactance. The impedance of the second reactance is greater than the impedance of the first reactance.

[0029] The capacitive reactor composed of the first and second reactors has the characteristics of capacitance (absorbing charge) and the ability to release charge at any time. Changes in the spatial electric field and the movement of the blades will cause changes in the induced charge of the lightning protection conductor (wire). That is, the induced charge at both ends of the first and second reactors will be discharged on its own in a very short time, that is, the induced current tends to 0, so that the tip potential of the wind turbine blades tends to the ground potential.

[0030] When a slight change occurs in the electric field, a micro-current generated by charge exchange immediately appears in the first and second reactances. This micro-current is neutralized by itself and discharged to the ground through the circuit. That is, the micro-current flows to the ground through the grounding terminal of the blade.

[0031] When the external electric field continues to rise to the point that lightning clouds form, an electric field with an intensity of several hundred kV / m or even higher is generated between the lightning cloud and the ground, satisfying the lightning occurrence condition of electric field intensity ≥ 25 kV / cm. At this time, lightning is easily generated. In this technology, since the first reactance and the second reactance are two capacitive dielectrics with a high degree of insulation, the electric field generated between the capacitive dielectrics under the action of a strong external electric field forms a strong potential difference. Charges move in the electric field due to the force. The first electrode and the second electrode are designed as toothed electrodes to accelerate the charge exchange rate and improve the reaction rate, thereby enhancing the electron exchange energy transfer process. In the relatively highly insulating capacitive dielectric, molecules in the state of overlapping positive and negative electron centers will experience separation of positive and negative electron centers, thus generating energy transfer in the form of electron exchange.

[0032] In a capacitive series circuit, each reactor carries the same amount of charge. Therefore, reactors with larger capacitance receive a lower voltage, and reactors with smaller capacitance receive a higher voltage. Utilizing this characteristic, with the first and second reactors having equal terminal charges and voltage distribution opposite to capacitance, in a series circuit, the second reactor has a smaller capacitance than the first. This causes the second reactor to discharge its surface charge earlier, reducing the terminal charge of the first reactor, and consequently, the charge at the blade tip. Under the same external electric field conditions, when the charge of the second reactor reaches a certain value, it discharges charge before the first reactor, lowering the charge density at the first reactor's terminals. This also lowers the potential at the blade tip, limiting the establishment of an external electric field at the tip.

[0033] This technology, based on the uniform electric field formula E=U / d, where E is the electric field strength, U is the voltage, and d is the distance between the two electrodes along the electric field lines, designs a second reactor with a fixed distance between the two electrodes. By controlling the voltage of the two electrodes, the electric field strength of the second reactor can be controlled. Preferably, the electric field strength for charge discharge of the second reactor is ≤25Kv / m. The electric field strength of the second reactor is equivalent to 100 times less than the electric field strength of lightning. This allows the first and second reactors to discharge charge simultaneously when the external electric field continues to rise to a certain level, causing the potential at the tip of the wind turbine blades to approach the potential of the ground. This eliminates the conditions for charge accumulation at tall tips and the generation of lightning by opposite charges in thunderclouds, fundamentally eliminating the probability of lightning generation.

[0034] This technology utilizes air-based energy transfer technology. Before a powerful lightning current arrives, as long as there is a slight change in the electric field, the lightning depletion device can promptly discharge the current and limit the accumulation of charge at the blade tip, thus preventing the powerful lightning current from forcibly entering the ground and avoiding secondary damage and losses caused by poor grounding.

[0035] In this embodiment, the impedance of the second reactance is at least 25% greater than the impedance of the first reactance, and preferably greater than 25% of the impedance of the first reactance. According to the capacitive reactance formula: Zc = 1 / (2πfC), where f is the frequency of change (e.g., 50Hz for the State Grid), and C is the capacitance of the first or second reactance. Capacitive reactance is inversely proportional to capacitance and also inversely proportional to frequency. If the distance between the receiving electrode 1 and the first electrode 2 is determined, then the capacitance C1 of the first reactance is a fixed quantity. Similarly, if the distance between the releasing electrode 3 and the second electrode 4 is determined, then the capacitance C2 of the second reactance is a fixed quantity. Furthermore, based on capacitance, the distance between the two electrodes is inversely proportional to the capacitance. Therefore, the distance between the releasing electrode 3 and the second electrode 4 is less than the distance between the receiving electrode 1 and the first electrode 2.

[0036] Both the first electrode 2 and the second electrode 4 are disc-shaped structures. The receiving electrode 1 is a ring-shaped structure fitted around the first electrode 2. A first gap 5 is provided between the first electrode 2 and the receiving electrode 1. The releasing electrode 3 is a ring-shaped structure fitted around the second electrode 4. A second gap 6 is provided between the second electrode 4 and the releasing electrode 3. The second gap 6 is smaller than the first gap 5, which is used to ensure that the impedance of the first reactance is greater than the impedance of the second reactance. Both the first electrode 2 and the second electrode 4 are planar structures. The planar structures form a capacitive reactance, which is equivalent to a capacitor, and is used for charge accumulation.

[0037] The outer edges of both the first electrode 2 and the second electrode 4 are serrated, and the serrated electrodes facilitate the release of charge.

[0038] The distance between the receiving electrode 1 and the releasing electrode 3 is not less than three times the distance between the receiving electrode and the first electrode.

[0039] An insulating fixing body 7, such as an insulating fixing bolt, is provided between the first electrode 2 and the second electrode 4. A connecting body 8 is fitted on the outside of the insulating fixing body 7. The insulating fixing body 7 is used for the fixed connection between the first electrode 2, the connecting body 8 and the second electrode 4. In this embodiment, since both the first electrode 2 and the second electrode 4 are disc-shaped structures, the insulating fixing body 7 passes through the center of the first electrode 2, the connecting body 8 and the second electrode 4 in sequence and perpendicularly. This makes the forces on the first electrode 2 and the second electrode 4 more balanced, less prone to tilting, and makes the first electrode 2 and the second electrode 4 parallel to each other. This ensures the balance of the electric field around the first electrode 2 and the second electrode 4. Only the distance between the two needs to be designed to meet the technical requirements, realize the miniaturization of the equipment, and save costs.

[0040] The connector 8 is a rust-resistant and corrosion-resistant conductor. On the one hand, it is used to limit the distance between the first electrode 2 and the second electrode 4, ensuring that the first electrode 2 and the second electrode 4 are parallel and co-core, thus playing a supporting and limiting role. On the other hand, it is used to realize the series connection between the first electrode 2 and the second electrode 4.

[0041] A plurality of evenly distributed insulating support columns 9 are provided between the receiving electrode 1 and the releasing electrode 3 to fix the receiving electrode 1 and the releasing electrode 3 into a whole. On the one hand, this is used to fix the distance between the two, balance the forces around the first electrode 2 and the second electrode 4, and increase the stability of the system. On the other hand, it allows the releasing electrode 3 to be free from connection to the housing, thus avoiding leakage.

[0042] The base includes an upper cover 11 and a base 12. The upper cover 11 is fastened onto the base 12, forming a cavity in the middle to accommodate a first reactance and a second reactance. The upper cover 11 has a first external electrode 13 connected to the receiving electrode 1. The inner end of the first external electrode 13 is connected to the receiving electrode 1, and the outer end of the first external electrode 13 is connected to the down conductor of the fan blade. The upper cover 11 and the first external electrode 13 are insulated from each other, or the upper cover 11 is an insulator. The base 12 has a second external electrode 14 connected to the release electrode 3. The inner end of the second external electrode 14 is connected to the release electrode 3, and the outer end of the second external electrode 14 is connected to the grounding terminal of the fan blade. The base 12 and the second external electrode 14 are insulated from each other, or the base 12 is an insulator. The base has several through holes 10 for air circulation, adapting to different geographical environments and providing good working conditions for the lightning dissipator.

[0043] The table below compares the lightning dissipator applied to wind turbine generators in this embodiment with existing lightning protection devices that use wind turbine blades as lightning rods:

[0044]

[0045] The following figure shows the actual test data of the lightning dissipator applied to wind turbine generators in this embodiment:

[0046]

[0047] like Figure 3 As shown in the figure, the vertical axis represents voltage, the horizontal axis represents time, the curve represents the trend of induced voltage change over time, and the current unit is μA.

[0048] The conclusion in the figure is that when the electric field changes, the terminal voltage of the lightning dissipator initially rises, which is a charge accumulation process. Then the current is quickly released over time, which is the lightning dissipation process.

[0049] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A lightning dissipator for use in wind turbine generator sets, characterized in that: The device includes a substrate, within which a first reactance consisting of a receiving electrode and a first electrode is provided, and a second reactance consisting of a releasing electrode and a second electrode is provided. The receiving electrode is externally connected to the down conductor of the fan blade, and the releasing electrode is externally connected to the grounding terminal of the fan blade. The first electrode and the second electrode are connected in series, and the impedance of the second reactance is greater than the impedance of the first reactance.

2. The lightning dissipator for wind turbine generators according to claim 1, characterized in that: The impedance of the second reactance is at least 25% greater than the impedance of the first reactance.

3. The lightning dissipator for wind turbine generators according to claim 1, characterized in that: The first electrode is a disk-shaped structure, and the receiving electrode is a ring-shaped structure sleeved on the outside of the first electrode. A first gap is provided between the first electrode and the receiving electrode.

4. The lightning dissipator for wind turbine generators according to claim 3, characterized in that: The outer edge of the first electrode is serrated.

5. The lightning dissipator for wind turbine generators according to claim 1, characterized in that: The second electrode has a disk-shaped structure, and the release electrode has a ring-shaped structure fitted outside the second electrode. A second gap is provided between the second electrode and the release electrode.

6. The lightning dissipator for wind turbine generators according to claim 5, characterized in that: The outer edge of the second electrode is serrated.

7. The lightning dissipator for wind turbine generators according to claim 1, characterized in that: The distance between the receiving electrode and the releasing electrode is no less than three times the distance between the receiving electrode and the first electrode.

8. The lightning dissipator for wind turbine generators according to claim 1, characterized in that: An insulating fixing body is provided between the first electrode and the second electrode, and a connecting body is provided on the outside of the insulating fixing body.

9. The lightning dissipator for wind turbine generators according to claim 1, characterized in that: A number of evenly distributed insulating support columns are provided between the receiving electrode and the releasing electrode.

10. The lightning dissipator for wind turbine generators according to claim 1, characterized in that: The base includes an upper cover and a base. The upper cover is fastened onto the base, forming a cavity in the middle to accommodate a first reactance and a second reactance. The upper cover is provided with a first external electrode connected to the receiving electrode. The outer end of the first external electrode is connected to the lead wire of the fan blade. The base is provided with a second external electrode connected to the release electrode. The outer end of the second external electrode is connected to the grounding terminal of the fan blade.

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