Wind turbine blade lightning protection structure and wind turbine blade

Abstract

The wind turbine blade lightning protection structure and wind turbine blade provided by the present invention belong to the technical field of lightning protection for wind turbine blades, wherein the wind turbine blade lightning protection structure comprises: a metal blade tip, which is arranged at the tip of the blade and is electrically connected to the grounding lead in the blade; a metal probe, which is arranged on the blade with an interval from the metal blade tip and is electrically connected to the metal blade tip through a connecting wire. The wind turbine blade lightning protection structure of the present invention forms a discharge path through the metal probe, the connecting wire, the metal blade tip, and the grounding lead. Under the action of the strong electric field of the downward leader of the lightning strike, the metal probe closer to the lightning will have a higher probability of starting the upward leader than the grounding lead, and form a discharge path with the downward leader. Thereby, the induced charge around the grounding lead is effectively reduced to form a streamer discharge, and further an upward leader is formed to break through the blade, which can effectively protect the safety of the blade in a lightning strike environment.

Description

Technical Field

[0001] The present invention relates to the technical field of lightning protection for wind turbine blades, and in particular to a lightning protection structure for wind turbine blades and a wind turbine blade. Background Art

[0002] With the rapid development of economy, people's demand for electric energy is increasing, and the capacity of wind turbines and the scale of wind power generation are also expanding. As the main structure of wind turbines is tall and protruding, and they are often located in wilderness or mountainous areas, lightning strikes are one of the main factors affecting the safe operation of wind turbines, and the blades are the most vulnerable components of the entire generator set. Therefore, lightning protection of wind turbine blades has become a key issue restricting the reliable operation of wind turbines.

[0003] Chinese patent document CN102869882A discloses a wind turbine blade with a lightning protection system, including a blade tip, a lightning rod arranged near the blade tip, and a grounding lead running through the inside of the blade; when a lightning strike occurs, the lightning current is conducted through the lightning rod to the grounding lead and finally to the earth to realize a discharge path.

[0004] When the above blade structure is struck by lightning, the grounding lead will generate induced charges around the lead with a certain probability under the induction of the strong electric field of the downward leader of the lightning strike, and the charge accumulation will form a streamer discharge. The charges gathered on the grounding lead further form an upward leader, forming a discharge path with the downward leader of the lightning strike. Since the grounding lead is located inside the blade, the streamer discharge formed and the discharge path formed by the downward leader of the lightning strike are easy to break through the blade, and a large number of high-temperature lightning arcs are integrated into the breakdown position, which is easy to cause lightning damage to the blade. Summary of the invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defect of high lightning damage rate of blades caused by lightning in the prior art that, when the wind turbine blades are struck by lightning, a large amount of electric charges are easily gathered around the grounding lead under the induction of the electric field of the downward leader of the lightning strike. The large amount of gathered electric charges have a certain probability of forming a streamer discharge, further forming an upward leader, and then breaking through the blades to form a discharge path with the downward leader of the lightning strike, thereby providing a lightning protection structure for wind turbine blades that can effectively avoid starting the upward leader on the grounding lead and reduce the lightning damage rate of the blades.

[0006] The present invention also provides a wind turbine blade having the lightning protection structure.

[0007] In order to solve the above technical problems, the present invention provides a wind turbine blade lightning protection structure, comprising:

[0008] A metal blade tip, disposed at the tip of the blade and electrically connected to a ground lead in the blade;

[0009] The metal probe is arranged on the blade at a distance from the metal blade tip and is electrically connected to the metal blade tip through a connecting wire.

[0010] As a preferred solution, there are a plurality of metal probes, which are arranged in sequence along the connecting wire.

[0011] As a preferred solution, the metal probe is arranged on the blade at a position close to the blade tip and 1 / 10 of the blade length.

[0012] As a preferred solution, a plurality of the metal probes are evenly arranged on the connecting wire.

[0013] As a preferred solution, the metal probe and the connecting wire are an integrated structure.

[0014] As a preferred solution, the connecting wire is closely attached to the outer surface of the blade.

[0015] As a preferred solution, the metal probe is vertically arranged on the blade, and one end of the metal probe close to the blade is electrically connected to the connecting wire.

[0016] The wind turbine blade provided by the present invention comprises the lightning protection structure described in any one of the above solutions.

[0017] As a preferred solution, the wind turbine blade further includes:

[0018] A lightning receptor is arranged on the outer surface of the blade and is electrically connected to the grounding lead.

[0019] As a preferred solution, the metal probe of the lightning protection structure is arranged at the trailing edge of the blade.

[0020] The technical solution of the present invention has the following advantages:

[0021] 1. The wind turbine blade lightning protection structure provided by the present invention comprises a metal blade tip arranged at the tip of the blade and a metal probe arranged on the blade, wherein the metal blade tip is electrically connected to the grounding lead in the blade, the metal probe is arranged at a distance from the metal blade tip, and is electrically connected to the metal blade tip through a connecting wire; in this way, the metal probe, the connecting wire, the metal blade tip, and the grounding lead form a discharge path, and under the action of the strong electric field of the downward leader of the lightning strike, the metal probe closer to the lightning will have a higher probability of starting the upward leader than the grounding lead, and form a discharge path with the downward leader. This effectively reduces the induced charge around the grounding lead to form a streamer discharge, and further forms an upward leader to break through the blade, which can effectively protect the safety of the blade in a lightning strike environment.

[0022] 2. The wind turbine blade lightning protection structure provided by the present invention has multiple metal probes, which are arranged in sequence along the connecting wire. The multiple metal probes work together to improve the lightning protection capability of the blade.

[0023] 3. The wind turbine blade lightning protection structure provided by the present invention has a metal probe arranged on the blade at a position close to the blade tip at 1 / 10 of the blade length, which can reduce the conduction time of the lightning current and enable it to be quickly conducted to the metal blade tip.

[0024] 4. In the wind turbine blade lightning protection structure provided by the present invention, multiple metal probes are evenly arranged on the connecting wire, which is conducive to the sequential diversion and conduction of lightning current and effectively reduces the charge accumulation phenomenon.

[0025] 5. In the lightning protection structure for wind turbine blades provided by the present invention, the metal probe and the connecting conductor are an integrated structure, which is conducive to the rapid conduction of lightning current through the connecting conductor.

[0026] 6. The lightning protection structure for wind turbine blades provided by the present invention has a connecting wire that is closely attached to the outer surface of the blade, so that the metal probe can form an exposed electrode on the outer surface of the blade.

[0027] 7. In the lightning protection structure for wind turbine blades provided by the present invention, a metal probe is vertically arranged on the blade, and one end of the metal probe close to the blade is electrically connected to the connecting wire, so that only the top of the metal probe is affected by the lightning strike, thereby avoiding damage to the metal probe itself by the lightning current, thereby avoiding affecting the conduction of the lightning current and ultimately causing the blade to be punctured.

[0028] 8. The wind turbine blade provided by the present invention has the advantages of any one of the above solutions because it has the lightning protection structure of any one of the above solutions.

[0029] 9. The wind turbine blade provided by the present invention also includes: a lightning rod arranged on the outer surface of the blade and electrically connected to the grounding lead, so that the grounding lead connects the metal blade tip and the lightning rod in series to form a complete discharge path. When lightning occurs, the lightning attachment point will hit the lightning rod, and a large amount of lightning current can be transferred to the grounding lead through the lightning rod and introduced into the earth.

[0030] 10. In the wind turbine blade provided by the present invention, the metal probe of the lightning protection structure is arranged at the trailing edge of the blade, which will not damage the aerodynamic performance of the blade. By gathering lightning to the trailing edge of the blade, the lightning breakdown damage to other parts of the blade is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 It is a schematic diagram of the three-dimensional structure of a wind turbine blade according to the present invention;

[0033] Figure 2 for Figure 1 Enlarged schematic diagram of the middle lobe tip;

[0034] Figure 3 This is the front view of the connecting wire and the metal probe.

[0035] Description of reference numerals:

[0036] 1. Blade; 2. Connecting wire; 3. Metal probe; 4. Metal blade tip; 5. Lightning arrester; 6. Grounding lead. DETAILED DESCRIPTION

[0037] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0039] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0041] like Figure 1 , Figure 2 As shown, this embodiment provides a wind turbine blade having a lightning protection structure, which includes a metal blade tip 4 arranged at the tip of the blade, and a connecting wire 2 and a metal probe 3 connecting the metal blade tip. The metal blade tip 4 is arranged at the tip of the blade 1 and is electrically connected to the grounding lead 6 inside the blade 1, so that the lightning current can be conducted to the grounding lead 6 through the metal blade tip 4, and then transmitted to the ground.

[0042] The connecting wire 2 is closely attached to the outer surface of the blade 1 near the blade tip and is electrically connected to the metal blade tip 4. The connecting wire 2 extends from the metal blade tip 4 toward the blade root.

[0043] The metal probe 3 is arranged on the connecting wire 2 and electrically connected to the connecting wire 2. There are multiple metal probes 3, which are evenly distributed on the connecting wire 2 and perpendicular to the outer surface of the blade 1. The metal probes are arranged vertically, and the exposed electrodes at their free ends can make the metal probes 3 contact with lightning earlier, so that lightning is conducted toward the metal blade tip 4 through the metal probes 3, so that under the induction of the electric field of the downward leader of the lightning strike, a large amount of charge is gathered near the metal probes 3, thereby greatly reducing the circuit passing through the blade during the upward leader, and reducing the lightning damage rate of the blade.

[0044] The connecting wire 2 and the metal probe 3 are an integrated structure, and the connecting wire 2 and the metal probe 3 are located at 1 / 10 of the blade length near the blade tip and at the trailing edge of the blade, so as not to affect the aerodynamic performance of the blade. By concentrating lightning at the trailing edge of the blade, the breakdown damage of lightning to other parts of the blade can be reduced.

[0045] The metal probe 3, connecting wire 2, metal blade tip 4 and grounding lead 6 of this embodiment are connected in sequence to form a discharge circuit. When lightning contacts the metal probe 3, the metal probe 3 quickly conducts the lightning to the metal blade tip 4 through the connecting wire 2. Under the induction of the strong electric field of the downward leader of the lightning strike, induced charges will exist around the metal probe 3. The charge accumulation will form a column discharge, and further form an upward leader, so that the lightning will at most damage the metal probe 3; in this way, the charge accumulation is transferred from the area around the grounding lead 6 to the area around the metal probe 3, avoiding the upward leader circuit generated by the charge accumulation from breaking through the blade.

[0046] like Figure 3As shown, the metal probes 3 are evenly arranged on the connecting wires 2, and the size of the metal probes can be set to: 4mm in diameter, 50mm in height, and 500mm in spacing; the size of the connecting wires 2 can be set to: 4mm in diameter, and 1 / 10 of the blade radius in length. In addition, the metal probes and the connecting wires 2 can also be in other conventional forms and sizes, and other sizes are within the protection scope of this patent.

[0047] like Figure 1 , Figure 2 As shown, the lightning protection structure of the wind turbine blade of this embodiment may also include: a lightning receptor 5, which is arranged on the outer surface of the blade 1 near the metal blade tip 4, and another discharge path formed by the grounding lead 6 inside the wind turbine blade; when lightning occurs, after the lightning hits the lightning receptor, a large amount of lightning current can be transferred to the grounding lead through the lightning receptor and introduced into the earth. The lightning protection structure of the wind turbine blade provided in this embodiment does not conflict with other facilities of the existing installed blades, so it can be used for lightning strike modification of the existing installed wind turbine blades, and the installation and construction are simple and convenient.

[0048] Working principle:

[0049] The metal probe 3, the connecting wire 2, the metal blade tip 4 and the grounding lead 6 form a discharge path. The process is: when lightning occurs, the lightning attachment point will first hit the metal probe 3, so that the lightning current is conducted from the metal probe 3 to the metal blade tip 4 through the connecting wire 2, and then the metal blade tip 4 transmits the lightning current to the ground through the grounding lead 6, forming a discharge path. The above is an ideal circuit for lightning current discharge. The actual situation is that under the induction of the strong electric field of the downward leader of the lightning strike, there will be induced charges around the metal probe 3. The charge accumulation will form a column discharge, and further form an upward leader, so that the lightning will at most damage the metal probe; in this way, the charge accumulation is transferred from the surrounding of the grounding lead 6 to the surrounding of the metal probe 3, reducing the probability of the upward leader circuit generated by the charge accumulation breaking through the blade.

[0050] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A wind turbine blade characterized by: include: A blade (1), wherein a metal blade tip (4) is provided at the tip of the blade (1), and the metal blade tip (4) is electrically connected to a grounding lead (6) inside the blade (1); A metal probe (3) is arranged at the trailing edge of the blade (1); the metal probe (3) is arranged on the blade (1) at a distance from the metal blade tip (4) and is electrically connected to the metal blade tip (4) via a connecting wire (2); the connecting wire (2) is closely attached to the outer surface of the blade (1); there are a plurality of metal probes (3), which are arranged in sequence along the connecting wire (2); The metal probe (3), the connecting wire (2), the metal blade tip (4) and the grounding lead (6) are connected in sequence to form a discharge circuit; A lightning receptor (5) is provided on the outer surface of the blade (1), and the lightning receptor (5) is electrically connected to the grounding lead (6).

2. The wind turbine blade according to claim 1, characterized in that: The metal probe (3) is arranged on the blade (1) at a position close to the blade tip and 1 / 10 of the blade length.

3. The wind turbine blade lightning protection structure according to claim 1, characterized in that: A plurality of the metal probes (3) are evenly arranged on the connecting wire (2).

4. The wind turbine blade according to claim 1, characterized in that: The metal probe (3) and the connecting wire (2) are an integrated structure.

5. The wind turbine blade according to any one of claims 1 to 4, characterized in that: The metal probe (3) is vertically arranged on the blade (1), and one end of the metal probe (3) close to the blade (1) is electrically connected to the connecting wire (2).

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