A lightning strike protection device for wind turbine blades

Abstract

The invention discloses a lightning strike protection device for blades of a wind turbine generator set, comprising: a liquid transducer, arranged in a blade, containing a conductive liquid and an electrode plate, converting the energy carried by a lightning current or limiting the size of the lightning current; a first liquid slip ring, arranged in a wheel hub, connected to the liquid transducer through a liquid infusion pipeline; a second liquid slip ring, arranged in a tower, connected to the first liquid slip ring through a liquid infusion pipeline; a liquid supply and replenishment device, arranged in the tower, connected to the second liquid slip ring through a liquid infusion pipeline, and providing conductive liquid to the liquid transducer; a first lightning current slip ring, arranged in the wheel hub, conducting lightning current between the wheel hub and the base metal of the nacelle; a second lightning current slip ring, arranged in the tower, electrically connected to the base metal of the nacelle and the tower, and conducting lightning current between the base metal of the nacelle and the tower. The device converts lightning energy into thermodynamic energy and pressure energy, and weakens the damage caused by lightning current to wind turbine components.

Description

Technical Field

[0001] The present invention relates to the field of wind power generation. A wind turbine blade lightning strike protection device is proposed to prevent the wind turbine blades, bearings and transmission components from being damaged directly by lightning when the wind turbine blades are struck by lightning. The damage may occur under severe conditions without being throttled or weakened, resulting in the shutdown of the wind turbine and even blade breakage or tower collapse. Background Art

[0002] As a powerful natural force, thundercloud discharge to the ground is extremely harmful to ground facilities including wind turbines. In terms of the way of harm, it mainly manifests in two aspects: direct harm and indirect harm. In terms of direct harm, there are thermal and mechanical effects caused by lightning strikes; in terms of indirect harm, there are lightning electromagnetic induction effects and surge overvoltage effects.

[0003] Below, we will conduct a large-scale search on lightning protection measures for wind turbines, give some cases as examples, and demonstrate some lightning protection measures.

[0004] CN220636379U, wind turbine blade lightning arrester drilling and positioning device. Wind turbine blades work in high altitude or open environments such as mountains, coastal areas, and seas. They are the objects closest to the clouds on the ground and are very susceptible to lightning strikes on rainy days. Blade lightning arresters can guide lightning in a directional manner and conduct lightning current. The installation quality of lightning arresters directly affects the operating safety of blades and maintenance personnel.

[0005] CN117028175A, a variable pitch bearing lightning protection structure and method, discloses a variable pitch bearing lightning protection structure and method, the structure includes a variable pitch bearing inner gear ring, a variable pitch bearing outer gear ring, and a lightning protection device, the upper surface of the variable pitch bearing inner gear ring and the upper surface of the variable pitch bearing outer gear ring are electrically connected through the lightning protection device, and the lightning protection device is arranged above the variable pitch bearing inner gear ring and the variable pitch bearing outer gear ring.

[0006] CN220748467U, a lightning protection structure for wind turbine blades, the purpose of the utility model is to provide a lightning protection structure for wind turbine blades, by setting a lightning protection component, the impedance unit in the lightning protection component effectively blocks the current, by setting a mounting component, the fixed plate in the mounting component is quickly installed in the blade by screws, and the telescopic block can be quickly adjusted in position by a limit pin, so as to realize the lightning protection component to quickly adjust the position, which is convenient for operation. The utility model sets a lightning protection component, and a lightning receptor is set in the lightning protection component, and the lightning receptor receives lightning, and the lightning first passes through the ball for the first obstruction, and then passes through the impedance unit for the second obstruction, and the lightning protection component can be quickly plugged with the mounting component through the base, which is convenient for maintenance and replacement, and solves the above-mentioned wind turbine blade lightning protection structure, the set ring is installed on one side of the fixed frame, and the movable frame is installed on the outside of the set ring, and the adjustment rod is movably connected to the inside of the movable frame, and the position of the lightning receptor is adjusted by rotating the adjustment rod in the movable frame, and the operation of adjusting it by rotation is complicated, so it is not conducive to the problem of replacing the lightning receptor. It adopts a method of secondary obstruction of lightning current.

[0007] CN112483335B, a lightning protection assembly for the root of a wind turbine blade and its installation method, the present invention provides a lightning protection assembly for the root of a wind turbine blade and its installation method, which can ensure that the lightning protection assembly is simply and firmly bonded to the outer surface of the blade root shell while ensuring lightning conductivity. This patent document emphasizes lightning conductivity.

[0008] CN117569986A, a lightning dissipator applied to a wind turbine generator set, is an active protection device for direct lightning strikes based on energy transfer air type, and uses a dielectric intervention method to transfer energy in advance for the spatial electric field changes caused by thunderclouds, reduce the intensity of the accumulated charge at the blade tip, and make the charge density at the blade tip approach the surface of the ground, so as to reduce the probability of the wind turbine set being struck by lightning. This technology uses air-type energy transfer technology. Before the arrival of a strong lightning current, as long as there is a slight change in the spatial electric field, the lightning dissipator can timely discharge and limit the establishment of charge at the blade tip, avoiding the strong lightning current from forcibly entering the ground, and also avoiding secondary damage and losses caused by poor grounding. Emphasis is placed on timely discharge and limiting the establishment of charge at the blade tip.

[0009] In the process of realizing the present invention, the inventors discovered that in the prior art, with the increase of the capacity of a single unit and the increase of the height of the wind power generation equipment, the spatial exposure range of the fuselage is expanding, and accordingly, the probability of being directly struck by lightning is also increasing. It is necessary to convert part of the energy carried by the lightning current at the front end of the whole machine where it receives wind energy to weaken the damage of the lightning current to the equipment on the transmission path. Summary of the invention

[0010] In view of this, an embodiment of the present invention aims to provide a wind turbine blade lightning strike protection device, so as to absorb and convert part of the strong lightning current energy in advance when the wind turbine blade is directly struck by lightning. The device converts electrical energy into the thermodynamic energy of the liquid vaporization latent heat and the pressure energy carried by the liquid to transfer or release energy along with the gas and liquid, which can weaken or prevent in advance the thermal and mechanical effects that the lightning current will produce on the path it will be transmitted to the ground, and prevent direct damage to the wind turbine blades, bearings and transmission components under severe conditions where the lightning current energy is not throttled or weakened, causing the unit to shut down or even blade breakage or tower collapse accidents.

[0011] To achieve the above-mentioned object, in a first aspect, the present invention provides a lightning strike protection device for blades of a wind turbine generator set, the lightning strike protection device comprising:

[0012] The liquid transducer is arranged inside the blade and contains a conductive liquid and an electrode plate, and is used to convert the energy carried by the lightning current or limit the size of the lightning current;

[0013] A first liquid slip ring, disposed in the hub and connected to the liquid transducer via a liquid infusion pipeline;

[0014] A second liquid slip ring is arranged in the tower and connected to the first liquid slip ring through a liquid infusion pipeline;

[0015] A liquid supply and replenishment device, arranged in the tower, connected to the second liquid slip ring through a liquid infusion pipeline, and used for providing conductive liquid to the liquid transducer;

[0016] a first lightning current slip ring, arranged in the hub, electrically connected to the liquid transducer and the nacelle base metal, and used for conducting lightning current between the hub and the nacelle base metal;

[0017] The second lightning current slip ring is arranged in the tower, electrically connected to the nacelle base metal and the tower, and is used for conducting lightning current between the nacelle base metal and the tower.

[0018] In some possible implementations, the electrical lead wires of the electrical busbar of the metal frame disposed inside the blade are electrically connected to the electrode plate lead wires of the liquid transducer.

[0019] In some possible implementations, the liquid transducer includes:

[0020] The enclosure is an insulating shell containing a conductive liquid;

[0021] An electrode plate is arranged inside the insulating shell of the enclosure structure and submerged in the conductive liquid;

[0022] An electrical insulation isolation plate is arranged inside the insulating shell of the enclosure structure and submerged in the conductive liquid, and is used to implement electrical insulation isolation on two directions of the plate surface of the electrode plate;

[0023] A safety valve is arranged on the insulating shell of the enclosure structure;

[0024] The liquid injection interface is connected to the liquid injection pipeline from the first liquid slip ring.

[0025] In some possible implementations, the liquid transducer further includes:

[0026] A buffer explosion-proof device tightly surrounds the insulating shell of the enclosure structure, and an insulating resin is poured to fill the gap between the joint surface of the buffer explosion-proof device and the insulating shell of the enclosure structure, so as to prevent the insulating shell of the enclosure structure from exploding;

[0027] The outer periphery of the safety valve is integrally connected with the buffer explosion-proof device, and the gap between the outer periphery of the safety valve and the joint surface of the buffer explosion-proof device is filled with insulating resin casting;

[0028] The liquid injection interface adopts a check valve structure made of non-metallic materials, and the conductive liquid can only enter but not exit;

[0029] The conductive liquid includes deionized water or a mixture of deionized water and ethylene glycol;

[0030] The ethylene glycol mixture is used for antifreeze;

[0031] The conductive liquid is used to limit the value of the lightning current and convert the lightning energy into latent heat and vaporization latent heat of the conductive liquid;

[0032] The safety valve is used to protect the insulating shell of the enclosure structure and perform buffer exhaust when the pressure generated by the expansion of the conductive liquid inside the insulating shell of the enclosure structure exceeds the pressure that the insulating shell of the enclosure structure is allowed to withstand.

[0033] In some possible embodiments, the exhaust structure of the safety valve is a Rafale nozzle structure; the buffer explosion-proof device is a hollow cavity structure that tightly embraces the insulating shell of the enclosure structure; the cross-section of the buffer explosion-proof device is a rectangular cross-section, a circular cross-section, or a trapezoidal cross-section; the insulating shell of the enclosure structure is fixed to the inner cavity of the blade by electrical insulating support fasteners.

[0034] In some possible implementations, the electrode plate has a lead-out end portion, the lead-out end portion is wrapped with an electrical insulating material or poured with a liquid insulating material, the lead-out end portion is led out from the inside of the insulating shell of the enclosure structure, and is connected to the metal lead-out wire of the electrode plate;

[0035] An insulating seal is formed between the lead-out end and the insulating shell of the enclosure structure, and the pressure that the insulating seal withstands to prevent leakage is greater than the value set for the action pressure of the safety valve.

[0036] In some possible implementations, the number of the electrode plates is two or more than three;

[0037] Wherein, the metal lead wire of an electrode plate and its electrical insulation protection are connected to the electrical bus connection lead wire of the metal frame of the blade and / or the metal mesh belt bus;

[0038] The metal lead wire of the other electrode plate and its electrical insulation protection are connected to the metal lead wire of the first lightning current slip ring in the hub for conducting lightning current.

[0039] In some possible implementations, the electrode plate is arranged in a circular ring shape to constitute a ring-shaped plate electrode of the liquid transducer;

[0040] The electrical insulation isolation plate is arranged in a circular ring shape around both sides of the inner and outer circumference of the annular plate electrode, constituting an electrode electrical insulation isolation annular plate of the liquid transducer;

[0041] The height of the electrode electrical insulation isolation annular plate is higher than the height of the annular plate electrode.

[0042] In some possible implementations, the liquid feeding and rehydration device includes: a water feeding pump, a drive motor, a liquid infusion pipeline, a pressure sensor, and a liquid feeding and rehydration controller;

[0043] The pressure sensor is arranged at the outlet of the water supply pump, and is used to feed back the detected current liquid pressure signal of the outlet of the water supply pump to the liquid supply and replenishment controller;

[0044] The liquid supply and replenishment controller is used to judge the liquid supply operation or the liquid replenishment operation according to the current liquid pressure signal at the outlet of the water supply pump, and control the start or stop of the water supply pump.

[0045] In some possible implementations, the fluid feeding and replenishment controller is specifically used to:

[0046] If the current liquid pressure signal at the outlet of the water supply pump indicates that the pressure is constant but has not reached the set target value, a control signal for continuing operation is input to the drive motor; wherein the set target value is the pressure when the cavity containing the liquid in the insulating shell of the enclosure structure of the liquid transducer is full;

[0047] If the current liquid pressure signal at the outlet of the water supply pump indicates that the pressure has reached the set target value and an upward inflection point has appeared, a shutdown control signal is input to the drive motor;

[0048] If the current liquid pressure signal at the outlet of the water supply pump indicates that the pressure is constant but the liquid supply time has exceeded, a shutdown control signal is input to the drive motor.

[0049] In some possible implementations, the fluid supply and rehydration device further includes:

[0050] The wireless image sensor disposed in the blade of the wind turbine is used to monitor and obtain image information of whether the liquid transducer is damaged, whether there is liquid leakage, or whether there is lightning current burn; and transmit the image information to the liquid supply and replenishment controller;

[0051] The liquid supply and replenishment controller is also used to determine whether the water supply pump performs infusion or replenishment to the liquid transducer based on the image information.

[0052] In a second aspect, a liquid transducer in a wind turbine blade is provided, wherein the liquid transducer is arranged inside the wind turbine blade and is used to perform lightning protection and current limiting on the wind turbine blade, and the liquid transducer comprises:

[0053] An insulating housing of the enclosure structure, wherein the insulating housing of the enclosure structure contains a conductive liquid;

[0054] A first electrode plate is arranged inside the insulating shell of the enclosure structure, submerged in the conductive liquid, and electrically connected to the metal skeleton inside the blade;

[0055] A second electrode plate is arranged inside the insulating shell of the enclosure structure, submerged in the conductive liquid, and electrically connected to a first lightning current slip ring in the hub for conducting lightning current;

[0056] The first electrode plate, the second electrode plate and the conductive liquid form a capacitor with a dielectric to limit, absorb or transform the energy carried by the lightning current;

[0057] A first set of electrical insulation isolation plates, arranged inside the insulating shell of the enclosure structure, submerged in the conductive liquid, and spaced apart on both sides of the first electrode plate, for electrically insulating and isolating the plate surface of the first electrode plate in two directions;

[0058] A second set of electrical insulation isolation plates, arranged inside the insulating shell of the enclosure structure, submerged in the conductive liquid, and spaced apart on both sides of the second electrode plate, for electrically insulating and isolating the plate surface of the second electrode plate in two directions;

[0059] A safety valve is arranged on the insulating shell of the enclosure structure;

[0060] The liquid injection interface is connected to the liquid injection pipeline of the first liquid slip ring arranged in the hub.

[0061] In some possible implementations, the liquid transducer further includes:

[0062] A buffer explosion-proof device tightly surrounds the insulating shell of the enclosure structure, and an insulating resin is poured to fill the gap between the joint surface of the buffer explosion-proof device and the insulating shell of the enclosure structure, so as to prevent the insulating shell of the enclosure structure from exploding;

[0063] The outer periphery of the safety valve is integrally connected with the buffer explosion-proof device, and the gap between the outer periphery of the safety valve and the joint surface of the buffer explosion-proof device is filled with insulating resin casting;

[0064] The liquid injection interface adopts a check valve structure made of non-metallic materials, and the conductive liquid can only enter but not exit;

[0065] The conductive liquid includes deionized water or a mixture of deionized water and ethylene glycol.

[0066] In some possible embodiments, the exhaust structure of the safety valve is a Rafale nozzle structure; the buffer explosion-proof device is a hollow cavity structure that tightly embraces the insulating shell of the enclosure structure; the cross-section of the buffer explosion-proof device is a rectangular cross-section, a circular cross-section, or a trapezoidal cross-section; the insulating shell of the enclosure structure is fixed to the inner cavity of the blade by electrical insulating support fasteners.

[0067] In some possible implementations, the electrode plate has a lead-out end portion, the lead-out end portion is wrapped with an electrical insulating material or poured with a liquid insulating material, the lead-out end portion is led out from the inside of the insulating shell of the enclosure structure, and is connected to the metal lead-out wire of the electrode plate;

[0068] An insulating seal is formed between the lead-out end and the insulating shell of the enclosure structure, and the pressure that the insulating seal withstands to prevent leakage is greater than the value set for the action pressure of the safety valve.

[0069] In some possible implementations, the metal lead wires of the electrode plates are wrapped with electrical insulating materials or cast with liquid insulating materials, and the metal lead wires of the electrode plates are led out from the inside of the insulating shell of the enclosure structure and connected to the electrical bus connection lead wires of the metal skeleton and / or metal mesh belt bus of the blades;

[0070] An insulating seal is formed between the metal lead wire of the electrode plate and the insulating shell of the enclosure structure, and the pressure that the insulating seal withstands to prevent leakage is greater than the value set by the action pressure of the safety valve.

[0071] In some possible implementations, the metal lead wires of the first electrode plate and their electrical insulation protection are connected to the electrical bus connection lead wires of the metal skeleton of the blade and / or the metal mesh belt bus;

[0072] The metal lead wire of the second electrode plate and its electrical insulation protection are connected to the metal lead wire of the first lightning current slip ring in the hub for conducting lightning current.

[0073] In some possible implementations, the first electrode plate and the second electrode plate are both arranged in a circular ring shape, constituting a first ring-shaped plate electrode and a second ring-shaped plate electrode of the liquid transducer;

[0074] The first group of electrically insulating isolation plates are arranged in a circular ring shape around the inner and outer sides of the circumference of the first annular plate electrode, forming the first group of electrode electrically insulating isolation annular plates of the liquid transducer; the height of the first group of electrode electrically insulating isolation annular plates is higher than the height of the first annular plate electrode;

[0075] The second group of electrically insulating isolation plates are arranged in a circular ring shape around the inner and outer sides of the circumference of the second annular plate electrode, constituting the second group of electrode electrically insulating isolation annular plates of the liquid transducer; the height of the second group of electrode electrically insulating isolation annular plates is higher than the height of the second annular plate electrode.

[0076] In some possible embodiments, the distance between the first electrode plate and the second electrode plate can be adjusted; the overlapping area between the first electrode plate and the second electrode plate can be adjusted; the degree to which the conductive liquid submerges the first electrode plate or the second electrode plate can be adjusted; the height difference between the first group of electrodes of electrically insulating isolation ring plates and the first ring plate electrode can be adjusted; the height difference between the second group of electrodes of electrically insulating isolation ring plates and the second ring plate electrode can be adjusted.

[0077] The above technical solution has the following beneficial effects:

[0078] With the increase of the capacity of a single unit and the increase of the height of the unit, the spatial exposure range of the fuselage is expanding. Correspondingly, the probability of being directly struck by lightning is also increasing. It is necessary to dispose and convert part of the energy carried by the lightning current at the front end of the whole unit to receive wind energy. The present invention provides a lightning strike protection device for wind turbine blades. When the blades of the wind turbine are directly struck by lightning, it absorbs and converts part of the strong lightning current energy in advance. The device converts electrical energy into the thermodynamic energy of the latent heat of liquid vaporization and the pressure energy carried by the liquid to transfer or release energy along with the gas and liquid, which can weaken or prevent the thermal and mechanical effects of the lightning current on the path of its transmission into the ground in advance, and prevent direct damage to the wind turbine blades, bearings and transmission parts, and the lightning current energy is not throttled or weakened in the severe case of component damage, causing the unit to stop operating or even blade breakage or tower collapse accidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. It is obvious that the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0080] Figure 1 It is a general diagram of the arrangement of liquid supply and liquid replenishment transmission after a blade lightning protection device is provided in a traditional wind turbine generator set according to an embodiment of the present invention;

[0081] Figure 2 2. It is a diagram of a liquid supply and replenishment device of a liquid transducer in a blade according to an embodiment of the present invention;

[0082] Figure 3 It is a diagram of the lead wires of the metal skeleton electrical bus connection or the electrical bus connection containing the metal mesh belt in the blade and the arrangement of the liquid transducer arranged in the blade in the embodiment of the present invention;

[0083] Figure 4 It is a diagram showing the internal and external parts of a liquid transducer having a cylindrical space structure and its material transport connection relationship in an embodiment of the present invention (a side view when the cylindrical axis is horizontal);

[0084] Figure 5 It is a diagram showing the internal and external parts of a liquid transducer having a cylindrical space structure and its material transport connection relationship in an embodiment of the present invention (an axial view when the cylindrical axis is horizontal);

[0085] Figure 6 It is a schematic diagram of the structural decomposition of the lightning protection device of an embodiment of the present invention.

[0086] Description of Figure Numbers:

[0087] 100. Wind turbine; 200. Lightning protection device;

[0088] 110, blade; 120, hub; 130, generator; 140, nacelle; 150, tower;

[0089] 115. Metal frame; 116. Connection and mounting surface of blade and bearing; 125. Wind deflector; 145. Wind vane and anemometer; 151. Tower door; 152. Equipment platform;

[0090] 210, liquid transducer; 220, first liquid slip ring; 230, second liquid slip ring; 240, liquid supply and replenishment device; 250, first lightning current slip ring; 260, second lightning current slip ring;

[0091] 211. Insulating shell of enclosure structure; 212. Conductive liquid; 213. Electrode plate; 214. Electrical insulation isolation plate; 215. Safety valve; 216. Liquid injection interface; 217. Buffer explosion-proof device;

[0092] 218, first electrode plate lead wire; 219, second electrode plate lead wire;

[0093] 213a', an annular plate electrode on the blade side; 214a', an annular plate for electrically insulating and isolating the electrode on the blade side;

[0094] 213b', an annular plate electrode on the hub side; 214b', an annular plate for electrically insulating and isolating the electrode on the hub side;

[0095] 241. Water supply pump; 242. Drive motor; 243. Infusion pipeline; 244. Pressure sensor; 245. Liquid supply and replenishment controller; 246. Wireless image sensor. DETAILED DESCRIPTION

[0096] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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.

[0097] The idea and solution proposed in this application based on electrothermal conversion and releasing (carrying heat energy discharge) part of the lightning current energy by means of liquid absorption or throttling has not been found in the existing literature. The inventor was the first to realize that with the increase of single machine capacity and the increase of unit height, the spatial exposure range of the fuselage is expanding, and accordingly, the probability of direct lightning strike is also increasing, and it is necessary to dispose of and convert part of the energy carried by the lightning current at the front end of the whole machine receiving wind energy.

[0098] As the capacity of a single unit increases and the height of the wind turbine 100 increases, the spatial exposure range of the fuselage is expanding, and accordingly, the probability of being directly struck by lightning is also increasing, and part of the energy carried by the lightning current needs to be processed and converted at the front end of the whole machine where it receives wind energy.

[0099] The embodiment of the present invention discloses a device for absorbing and converting part of the powerful lightning current energy in advance when the blades 110 of the wind turbine 100 are struck by direct lightning. The lightning current energy device converts electrical energy into the thermodynamic energy of the latent heat of liquid vaporization and the pressure energy carried by the liquid to transfer or release energy along with the gas and liquid, and can weaken or prevent in advance the thermal and mechanical effects that the lightning current will produce on the path of its transmission into the ground, and prevent direct damage to the wind turbine blades, bearings and transmission components under severe conditions where the lightning current energy is not throttled or weakened, causing the wind turbine 100 to shut down or even blade breakage or tower collapse accidents.

[0100] It should be briefly explained that when there is material migration between moving parts and stationary parts, including power transmission, fluid transmission or migration of solid particles or powdered materials, the transfer can be undertaken with the help of collector ring devices, liquid slip ring devices, gas slip ring devices or other equipment or functional devices called adapters that can perform this function.

[0101] like Figure 1 As shown, in the wind power equipment, the root of the blade 110 of the wind turbine or wind turbine is connected to the hub 120 of its wind turbine. According to the energy flow path of wind energy conversion, the hub 120 is further connected to the transmission chain or the mechanical gearbox for speed increase at the downstream of the transmission system. The high-speed output end of the mechanical gearbox is connected to the shaft of the generator 130, or the above-mentioned hub 120 is directly connected to the shaft of the generator 130, forming a transmission system for directly driving the motor 242 (referred to as direct drive method).

[0102] The stationary part of the generator 130, such as the stator and its fixed axis, needs to be connected to the nacelle 140 of the wind power generation equipment. In the above two transmission methods, there is structural migration of the above-mentioned material between the rotating parts of the hub 120 of the blade 110 and the non-rotating space in the nacelle 140. At this time, the material transfer and transportation function from the moving space to the static space can be completed with the help of a device called a slip ring or adapter.

[0103] In addition, when the wind turbine and its generator 130 are in operation and need to absorb wind energy to the maximum extent, the axis of the wind turbine or the wind deflector 125 in front of the wind turbine needs to face the upwind flow to implement real-time wind process control. The wind turbine together with the gear box or the shaft system linkage nacelle 140 of the generator 130 will rotate in the same plane, or it is called performing yaw control operation.

[0104] At this time, the cabin 140 and the tower 150 of the supporting structure or other supporting structures are connected by a yaw bearing. When the space in the cabin 140 in a rotating state is transferred or transported with the space of the tower 150 of the supporting structure, a device called a slip ring or adapter is also required.

[0105] Figure 1 This is a general diagram of the liquid supply and liquid replenishment transmission arrangement after the blade 110 lightning protection device 200 is set in the wind turbine 100 in an embodiment of the present invention. Figure 1 As shown, the wind turbine set 100 includes a tower 150, wind turbine blades 110, a hub 120, a generator 130, a nacelle 140, a fairing 125, and a wind vane anemometer 145. The tower 150 includes a tower door 151 and an equipment platform 152 inside the tower door 151.

[0106] The lightning protection device 200 includes: a liquid transducer 210, which is arranged in the blade 110, and contains a conductive liquid 212 and an electrode plate 213, which is used to convert the energy carried by the lightning current or limit the size of the lightning current; a first liquid slip ring 220, which is arranged in the hub 120 and connected to the liquid transducer 210 through a liquid infusion pipeline 243; a second liquid slip ring 230, which is arranged in the tower 150 and connected to the first liquid slip ring 220 through a liquid infusion pipeline 243; a liquid supply and replenishment device 240, which is arranged in the tower 150 and connected to the second liquid slip ring 230 through a liquid infusion pipeline 243, which is used to Provide conductive liquid 212 to the liquid transducer 210; the first lightning current slip ring 250 is arranged in the hub 120, electrically connected to the liquid transducer 210 and the cabin base metal, and is used to conduct lightning current between the hub 120 and the cabin base metal, and the lightning current is a lightning current that is throttled, weakened, limited or transduced; the second lightning current slip ring 260 is arranged in the tower 150, electrically connected to the cabin base metal and the tower 150, and is used to conduct lightning current between the cabin base metal and the tower 150, and the lightning current is a lightning current that is throttled, weakened, limited or transduced. Specifically, the liquid supply and replenishment device 240 is arranged on the equipment platform 152 in the tower door 151.

[0107] Each liquid transducer 210 is electrically connected to a first lightning current slip ring 250 in the hub 120 for conducting lightning current, and a liquid delivery pipeline 243 is provided between each liquid transducer 210 and the first liquid slip ring 220 (i.e., the liquid slip ring in the hub 120). The first liquid slip ring 220 is connected to the second liquid slip ring 230 (i.e., the liquid slip ring in the tower 150) through a connecting pipeline between the slip rings.

[0108] A first lightning current slip ring 250 for conducting lightning current is provided in the hub 120, and a second lightning current slip ring 260 is provided in the tower 150. The first lightning current slip ring 250 is electrically connected to the second lightning current slip ring 260, and the second lightning current slip ring 260 is electrically connected to the wall of the tower 150. Specifically, the first lightning current slip ring 250 is electrically connected to the second lightning current slip ring 260 through the metal of the nacelle base. The electrode plate lead wire of the liquid transducer 210 is electrically connected to the electrical lead wire after being connected to the electrical bus of the metal frame provided inside the blade 110.

[0109] The liquid transducer 210 is used to receive the conductive liquid 212 or conductive medium provided by the liquid supply and replenishment device 240, which is previously transferred and transported by the first liquid slip ring 220 in the hub 120 through the second liquid slip ring 230 in the tower 150. In specific use, if the lowest temperature throughout the year in the local history is above zero degrees Celsius, deionized water can be used. If the wind farm area is below zero degrees Celsius and will freeze, deionized water and ethylene glycol mixture can be used. Then, ethylene glycol can be proportioned according to the degree to which the winter temperature of the wind farm is below zero degrees Celsius, so that the deionized water and ethylene glycol mixture will not be frozen when there is no wind turbine in the wind farm. Thereby, the automatic control operation of the liquid supply and replenishment can be realized. The ethylene glycol mixture is used for antifreeze; the conductive liquid 212 is used to limit the value of the lightning current and convert the lightning energy into the latent heat and / or vaporization latent heat of the conductive liquid 212.

[0110] Figure 1 It is also shown in the figure that the lightning current is converted into energy by the electrode plate 213 and the conductive liquid through the liquid transducer 210, the lightning current energy is absorbed by the liquid, and even released by the throttling of the gas-liquid mixture, and after the current is limited, it flows into the ground through the first lightning current slip ring 250 in the hub 120 for conducting lightning current (used to make electrical connections and conduction between the wind turbine hub 120 and the base metal of the nacelle 140) and the second lightning current slip ring 260 of the nacelle 140 connecting the tower 150 (used to make electrical connections and conduction between the base metal of the nacelle 140 and the metal tower 150), the tower 150 body, and the tower 150 foundation grounding device. The whole process is limited to the liquid transducer 210 in the blade 110, and the gas-liquid mixture released by the leakage can be discharged to the atmosphere from the gap between the root of the blade 110 and the guide cover 125, so the pressure in the above-mentioned liquid transducer 210 is reduced, as shown in FIG. Figure 2 As shown, the pressure sensor 244 notifies the liquid replenishment controller 245 after sensing it. The liquid replenishment controller 245 starts the drive motor 242 according to the outlet pressure signal fed back by the pressure sensor 244, and controls the drive motor 242 to drag the water supply pump 241 to replenish liquid into the liquid transducer 210 until the replenishment stops, so as to cope with the next conversion of lightning current.

[0111] A liquid supply and replenishment device 240 is provided on a platform below the tower 150 for operating platform equipment and personnel to work on, and the liquid supply and replenishment device 240 realizes the transfer and transportation of the conductive liquid through two liquid slip rings. Figure 2 is a schematic diagram of the structure of the liquid feeding and replenishing device 240 according to an embodiment of the present invention, which is Figure 1 A graphic description of the fluid supply and replenishment device 240 and its automated feedback control is shown in FIG. Figure 2 As shown, the liquid replenishing device specifically includes:

[0112] The water supply pump 241 and its driving motor 242, the infusion pipeline 243 (also called the infusion pipeline, the liquid supply pipeline, or the supply pipeline, which is the name of a pipeline in different situations), the pressure sensor 244 arranged at the outlet of the water supply pump 241, the liquid supply and liquid replenishment controller 245 and the liquid level sensor-free control algorithm running in the liquid supply and liquid replenishment controller 245, the liquid supply and liquid replenishment controller 245 is electrically connected to the pressure sensor 244 and the driving motor 242 respectively.

[0113] The outlet of the water supply pump 241 is provided with a liquid infusion pipeline 243, and a pressure sensor 244 is provided on the liquid infusion pipeline 243. The pressure sensor 244 is used to feed back the pressure signal of the conductive liquid at the outlet of the water supply pump 241 to the liquid supply and replenishment controller 245;

[0114] The liquid supply and replenishment controller 245 is used to obtain the current liquid pressure signal at the outlet of the water supply pump 241 from the pressure sensor 244 at the outlet of the water supply pump 241, and input a control signal to the drive motor 242 according to the current conductive liquid pressure signal at the outlet of the water supply pump 241;

[0115] Specifically, the liquid supply and replenishment controller 245 is specifically used to: if the current liquid pressure signal at the outlet of the water supply pump 241 indicates that the pressure is constant but has not reached the set target value, input a continue operation control signal to the drive motor 242; wherein the set target value is the pressure when the cavity containing the liquid in the insulating shell 211 of the enclosure structure of the liquid transducer 210 is full, that is, the static pressure or total pressure formed when it is full; if the current liquid pressure signal at the outlet of the water supply pump 241 indicates that the pressure has reached the set target value and an upward inflection point appears, input a stop control signal to the drive motor 242; if the current liquid pressure signal at the outlet of the water supply pump 241 indicates that the pressure is constant but the liquid supply time has exceeded, input a stop control signal to the drive motor 242.

[0116] Specifically, the liquid feeding and replenishing controller 245 can be used to:

[0117] When feeding or replenishing liquid to the liquid transducer 210 according to the test and calculation, the pressure when the cavity containing the liquid in the insulating shell 211 of the enclosure structure of the liquid transducer 210 is full is obtained (this is equivalent to the trend of the instantaneous value of the flow meter decreasing to zero);

[0118] The pressure at which the pressure sensor 244 (or the pressure gauge installed on site) begins to gradually increase after the test chamber is filled with liquid (i.e., the pressure value has an inflection point) is used as the criterion of the control algorithm for the water supply pump 241 to stop delivering liquid (this is equivalent to the trend of the instantaneous value of the flow meter decreasing to zero);

[0119] During the continuous infusion or fluid replacement process, when the pressure has not reached the rising inflection point (equivalent to the instantaneous value of the flow meter being always non-zero), that is, as the criterion for the control algorithm that the infusion pipeline 243 is leaking or the insulating shell 211 of the enclosure structure of the liquid transducer 210 is leaking, the water pump 241 stops delivering.

[0120] Figure 3 Schematic diagram of the metal bus structure of the blade 110 according to an embodiment of the present invention. Figure 3 As shown, the metal bus structure of the blade 110 includes:

[0121] The metal frame 115 and the optional metal mesh belt disposed inside the wind turbine blade 110, the electrical bus connection of the metal frame 115 or the electrical bus connection containing the metal mesh belt are electrically connected to the lead wires of the electrode plate 213 of the liquid transducer 210, that is, the first electrode plate lead wire 218; in some embodiments, the metal mesh belt may not be disposed; and,

[0122] The liquid transducer 210 is arranged inside the blade 110 and is located at the connection and mounting surface 116 between the blade and the bearing. The outside of the liquid transducer 210 is fixedly connected and load-bearingly connected to the inner exposed surface of the open space at the root of the blade 110.

[0123] The metal frame 115 in the blade 110 of the wind turbine 100 is electrically connected, or the blade 110 contains a metal mesh belt for lightning protection, and the manufacturing process of the electrical bus is also used to set the metal bus lead wire as an electrical connection connector for fastening or welding connection.

[0124] The main part of the electrode plate 213 is installed and fixed in the shell structure of the liquid transducer 210, and one end (the lead-out end) of the electrode plate 213 is wrapped with electrical insulation material or poured with liquid insulation material, and then passed through the insulating shell 211 of the enclosure structure. In addition, insulation sealing is implemented between the lead-out end of the electrode plate 213 of the passing link and the insulating shell of the enclosure structure to achieve no seepage and pressure bearing capacity, and the pressure that can withstand no leakage is greater than the value set by the action pressure of the safety valve 215.

[0125] Figure 4 1 is a diagram showing the interior and exterior of a liquid transducer 210 having a cylindrical spatial structure and its material transport connection relationship (a side view when the cylindrical axis is horizontal) according to an embodiment of the present invention. Figure 5 It is a diagram showing the internal and external parts of a liquid transducer 210 having a cylindrical spatial structure and its material transport connection relationship in an embodiment of the present invention (an axial view when the cylindrical axis is horizontal). Figure 6 Schematic diagram of the structure of the lightning protection device according to the embodiment of the present invention. Figure 4 , Figure 5 and Figure 6 As shown, the internal structure of the liquid transducer 210 includes: an enclosure structure insulating shell 211 (i.e., an electrical insulating enclosure structure of a closed cavity shell), a conductive liquid 212, an electrode plate 213, and an electrical insulating isolation plate 214 for electrically insulating the plate surface of the electrode plate 213 in two directions or on both sides. The electrode plate 213 and its electrical insulating isolation plate 214 are submerged in the conductive liquid 212, which includes deionized water or a mixture of deionized water and ethylene glycol. Due to the existence of the electrical insulating isolation plate 214, the discharge path of the lightning current passing through the two electrode plates 213 and the conductive liquid 212 is lengthened, so that the adjacent electrode plates 213 are not directly discharged and short-circuited, and the root of the electrode plate 213 is provided with an electrical insulating material wrapped and passing through the above-mentioned enclosure structure insulating shell 211. The enclosure structure insulating shell 211 is used to accommodate the electrode plate 213, the deionized water or the mixture of deionized water and ethylene glycol, and the electrical insulating isolation plate 214 of the electrode plate 213. The insulating shell 211 of the enclosure structure can be made of glass fiber reinforced plastic with a rubber layer inside. The insulating shell 211 of the enclosure structure is fixed to the inner cavity of the wind turbine blade 110 by electrical insulating support fasteners.

[0126] The electrode plate 213 and the electrical insulation isolation plate 214 are submerged in deionized water or a mixture of deionized water and ethylene glycol. The electrode plate 213 is used for convergence, and the part through which the liquid transducer 210 passes is wrapped, poured, and sealed with electrical insulation materials, and passes through the insulating shell 211 of the lead-out enclosure structure, and the shell of the passing link is subjected to an insulation sealing process.

[0127] In this embodiment, at least two electrode plates 213 are contained, wherein the metal lead wire of one electrode plate 213 (i.e., the first electrode plate lead wire 218) and its electrical insulation protection are connected to the metal skeleton 115 of the wind turbine blade 110 or the metal bus lead wire of the metal mesh belt bus; the metal lead wire of the other electrode plate 213 (i.e., the second electrode plate lead wire 219) and its electrical insulation protection are connected to the metal lead wire of the first lightning current slip ring 250 for conducting lightning current in the hub 120 of the wind turbine blade 110.

[0128] The electrode plate 213 can be arranged in a circular ring shape to constitute the circular plate electrode of the liquid transducer 210; the electrical insulation isolation plate 214 for electrically insulating and isolating the plate surface of the electrode plate 213 in two directions can also be arranged in a circular ring shape around the inner and outer sides of the circumference of the electrode plate 213 to constitute the electrode electrical insulation isolation circular plate of the liquid transducer 210. The height of the electrode electrical insulation isolation circular plate of the liquid transducer 210 is higher than the height of the circular plate electrode.

[0129] like Figure 4 and Figure 5 As shown, two blade-side electrode electrically insulating and isolating annular plates 214a' are concentrically arranged on the inner and outer sides of the annular plate electrode 213a' on the blade side. Two hub-side electrode electrically insulating and isolating annular plates 214b' are concentrically arranged on the inner and outer sides of the annular plate electrode 213b' on the hub side. The distance between the inner blade-side electrode electrically insulating and isolating annular plates 214a' and the central rotation axis of the insulating shell of the enclosure structure is greater than the distance between the outer hub-side electrode electrically insulating and isolating annular plates 214b' and the central rotation axis of the insulating shell of the enclosure structure.

[0130] like Figure 4 As shown, in some embodiments, the bottom ends of the annular plate electrode 213a' on the blade side and the electrode electrically insulating and isolating annular plates 214a' on the two blade sides are connected to the bottom end or bottom wall (the first axial end face) of the insulating shell 211 of the enclosure structure, and have a first gap and a second gap with the top end or top wall (the second axial end face) of the insulating shell 211 of the enclosure structure, respectively, and the first gap is larger than the second gap. The bottom ends of the annular plate electrode 213b' on the hub side and the electrode electrically insulating and isolating annular plates 214b' on the two hub sides are connected to the top end or top wall (the second axial end face) of the insulating shell 211 of the enclosure structure, and have a third gap and a fourth gap with the bottom end or bottom wall (the first axial end face) of the insulating shell 211 of the enclosure structure, respectively, and the third gap is larger than the fourth gap.

[0131] The conductive liquid 212 or conductive medium between the equally spaced electrode plates 213 and the two electrode plates 213 constitute an equivalent parallel transducer and capacitor function. The function of the transducer is to convert the lightning current through it into the thermal energy of the liquid, that is, to exert the essential function of the Joule heating effect. The conductive liquid 212 absorbs enough thermal energy to exceed the latent heat of vaporization and then continues to be converted into gas, storing more thermal energy, and converts the energy carried by the lightning current twice. After the safety valve 215 of the liquid transducer 210 is actuated, the unbearable gas-liquid mixture medium is released, and the gas-liquid mixture medium carries huge thermal energy out of the cavity of the liquid transducer 210, which is equivalent to the third throttling transfer and releases the energy carried by the lightning current, greatly reducing the destructive effect of the lightning current on the equipment on the energy transfer path of the wind turbine 100.

[0132] Furthermore, after the conductive liquid 212 is filled between the electrode plates 213, they function as capacitors and can store a certain amount of electric charge, including the charge induced between the clouds, humid air and the earth on the blades 110, which helps prevent the charge from transferring downstream and corroding the wind power equipment.

[0133] In addition, the distance between the electrode plates 213, the corresponding area between the electrode plates 213, the type of conductive liquid 212 (liquid medium other than water) and the scale of the submerged electrode plates 213, as well as the relative height relationship between the electrically insulating isolation plate and the electrode plates 213 can also be adjusted to achieve the purpose of changing the equivalent resistance value and the equivalent capacitance value to meet the requirements of lightning protection in different regions.

[0134] The liquid transducer 210 also includes a safety valve 215, which is used to protect the insulating shell of the enclosure structure and open or open for buffer exhaust when the pressure generated by the expansion of the conductive liquid inside the insulating shell of the enclosure structure exceeds the pressure it can withstand. When the internal pressure drops to a safe range or is within the pressure range it can withstand, the safety valve 215 is closed again. The exhaust structure of the safety valve 215 is a nozzle structure named after the French engineer Lafar. The flow channel of the nozzle structure adopts a variable cross-section zoom structure, that is, a Lafar nozzle, which is used on the flow heat conversion component of a steam turbine or a gas turbine. The Lafar nozzle structure is conducive to accelerating the discharge of the gas-liquid mixture after overpressure and can sound a whistle alarm at a long distance. The variable cross-section zoom structure is conducive to accelerating the discharge of the gas-liquid mixture formed when the lightning current passes through the shell after exceeding the pressure it is designed to withstand, and can sound a whistle alarm at a long distance to the operation duty room, informing that the energy carried by the lightning current is absorbed by the liquid inside the liquid transducer 210 by the form conversion. Part of the energy or all of the energy is absorbed by the liquid inside the liquid transducer 210.

[0135] The liquid transducer 210 disposed in the blade 110 may also include a buffer explosion-proof device 217, which is used to prevent the expansion of the liquid in the enclosure structure insulation shell 211 of the liquid transducer 210, which is constructed of glass fiber reinforced plastic and an inner rubber layer, when a lightning current passes through it, so as to protect the enclosure structure insulation shell 211, prevent the enclosure structure insulation shell 211 from exploding, and fasten the enclosure structure insulation shell 211. The buffer explosion-proof device 217 may be a hollow cavity structure that tightly embraces the enclosure structure insulation shell 211, and its cross-section adopts a rectangular cross-section structure, a circular cross-section structure, or a trapezoidal cross-section structure, so as to prevent the enclosure structure insulation shell 211 from exploding. In one embodiment, the buffer explosion-proof device 217 tightly surrounds the enclosure structure insulation shell 211, and fills the gap between the joint surfaces with insulating resin. The material of the buffer explosion-proof device 217 is glass fiber reinforced plastic or electrical insulating material, for example, a resin material or a cast steel ring, or a wrapped steel ring, or a wound steel ring, or a welded connection, or a structure with a clamp connection to tighten the above-mentioned enclosure structure insulation shell 211. The outer periphery of the safety valve 215 provided in the enclosure structure insulation shell 211 is fastened and connected to the buffer explosion-proof fastening device to form a whole, and the gap between the joint surfaces of the two is filled with insulating resin.

[0136] The liquid transducer 210 provided in the blade 110 contains deionized water or a mixture of deionized water and ethylene glycol for the electrode plate 213. In specific use, if the lowest annual temperature in the local area is above zero degrees Celsius, deionized water can be used. If the wind farm area is below zero degrees Celsius and will freeze, deionized water and ethylene glycol mixture can be used. Ethylene glycol can be mixed according to the degree to which the winter temperature of the wind farm is below zero degrees Celsius, so that the deionized water and ethylene glycol mixture will not be frozen when there is no wind turbine in the wind farm.

[0137] The liquid transducer 210 also includes a liquid injection interface 216 for injecting liquid into the internal space. The liquid injection interface 216 is connected to the liquid injection pipeline from the first liquid slip ring 220. The liquid injection interface 216 of the liquid transducer 210 is made of non-metallic materials and is a check valve structure for controlling the direction of the conveying fluid, that is, a one-way flow structure, and liquid can only enter but not exit.

[0138] The first electrode plate lead wire 218 of the liquid transducer 210 is connected to the bus lead wire of the metal frame 115 inside the wind turbine blade 110, and the second electrode plate lead wire 219 of the liquid transducer 210 is connected to the electrical conduction connection wire of the first lightning current slip ring 250 inside the wind turbine hub 120 for conducting lightning current.

[0139] The lightning strike protection device of the wind turbine 100 can further realize digital monitoring, including pattern recognition function to realize intelligent operation and maintenance. If the prime mover of the wind turbine 100 is a three-blade 110 or two-blade 110 wind turbine, a wireless image sensor 246 is set in each blade 110 of the wind turbine to monitor and obtain image information of whether each liquid transducer 210 in the blade 110 is damaged, whether there is conductive liquid leakage, or whether it is burned by lightning current; and transmit the above image information to the liquid supply and replenishment controller 245 in the liquid supply and replenishment device 240, and the liquid supply and replenishment controller 245 is used to determine whether the water supply pump 241 is infusing or replenishing the liquid transducer 210 according to the image information.

[0140] In one embodiment, a plurality of miniature wireless cameras are installed inside the blades. These cameras can be waterproof, dustproof, shockproof, and can remain stable when the blades rotate. The wireless cameras should cover the key parts of the liquid transducer 210. The liquid replenishment controller 245 has a built-in image analysis module and is equipped with AI image recognition software, which can automatically analyze the received images. The AI ​​image recognition software is trained to identify the following situations: leakage of conductive liquid, which detects abnormal conductive liquid traces or liquid level drops based on image information. Physical damage, which detects cracks, depressions or deformations on the surface of the transducer based on image information. Lightning strike traces, which detect burn marks or signs of metal melting based on image information.

[0141] The liquid supply and replenishment controller is also used for: when it is detected that the liquid transducer is only slightly damaged, controlling the water supply pump to replenish liquid to the liquid transducer; when it is detected that the liquid transducer is moderately damaged, controlling the water supply pump to replenish liquid to the liquid transducer and issuing a fault alarm; after issuing the fault alarm, reducing the replenishment rate to 50% of the normal replenishment rate, and increasing the monitoring frequency of the pressure or liquid level of the liquid transducer; when it is detected that the liquid transducer is seriously damaged, stopping the replenishment operation of the water supply pump and issuing a maintenance signal.

[0142] Moderate damage indicates that the liquid transducer can still operate, but there are potential risks. Continued refilling is to maintain the basic functions and pressure of the system and prevent the liquid transducer from completely failing. Reducing the refill rate can reduce the possibility of conductive liquid leaking through the damage. A lower refill rate means that the pressure in the liquid transducer increases more slowly, and the additional stress on the damaged part is also less. By reducing the refill rate, the emergency operation time of the system can be extended, which provides more time for maintenance personnel to rush to the scene for maintenance. Reducing the refill rate allows the system to have more opportunities to monitor changes in the damage while replenishing the necessary fluid. This balance helps prevent the damage from further deteriorating. Although the damage is moderate, the situation may worsen. Reducing the refill rate is a preventive measure that can respond quickly when the situation suddenly deteriorates, minimizing potential fluid loss and equipment damage.

[0143] The liquid supply and replenishment controller is also used to: when a slight leakage of the liquid transducer is detected, control the water supply pump to completely replenish the leaked liquid; when a medium leakage of the liquid transducer is detected, control the water supply pump to partially replenish the leaked liquid and issue a fault alarm; after the fault alarm is issued, limit the replenishment amount to 70% of the leakage amount, and increase the monitoring frequency of the leakage point of the liquid transducer; when a large leakage of the liquid transducer is detected, stop the replenishment operation of the water supply pump and issue a maintenance signal.

[0144] The liquid supply and replenishment controller is also used for: when a slight lightning current burn is detected on the liquid transducer, controlling the water supply pump to replenish liquid to the liquid transducer; when a moderate lightning current burn is detected on the liquid transducer, controlling the water supply pump to replenish liquid to the liquid transducer and issuing a fault alarm; after issuing the fault alarm, reducing the replenishment rate to 50% of the normal replenishment rate and increasing the monitoring frequency of lightning current burns on the liquid transducer; when a serious lightning current burn is detected on the liquid transducer, stopping the replenishment operation of the water supply pump and issuing a maintenance signal.

[0145] The liquid supply and replenishment controller is also used for: when slight damage and trace leakage of the liquid transducer are detected at the same time, controlling the water supply pump to replenish liquid to the liquid transducer; when moderate damage and moderate leakage of the liquid transducer are detected at the same time, controlling the water supply pump to replenish liquid to the liquid transducer and issuing a fault alarm; after the fault alarm is issued, limiting the replenishment volume to 60% of the capacity of the liquid transducer, and increasing the monitoring frequency of the pressure or liquid level of the liquid transducer; when serious damage or large leakage of the liquid transducer is detected, stopping the replenishment operation of the water supply pump and issuing a maintenance signal.

[0146] The liquid supply and replenishment controller is also used for: when slight damage and slight lightning current burns are detected on the liquid transducer at the same time, controlling the water supply pump to replenish liquid to the liquid transducer; when moderate damage or moderate lightning current burns are detected on the liquid transducer, controlling the water supply pump to replenish liquid to the liquid transducer and issuing a fault alarm; after issuing the fault alarm, reducing the replenishment rate to 50% of the normal rate and increasing the monitoring frequency of the liquid transducer; when serious damage or serious lightning current burns are detected on the liquid transducer, stopping the replenishment operation of the water supply pump and issuing a maintenance signal.

[0147] The liquid supply and replenishment controller is also used for: when damage, liquid leakage and lightning current burns of the liquid transducer are detected at the same time, and all of them are minor, controlling the water supply pump to replenish liquid to the liquid transducer; when any one of the damage, liquid leakage or lightning current burns of the liquid transducer is detected to be moderate, controlling the water supply pump to replenish liquid to the liquid transducer and issuing a fault alarm; after the fault alarm is issued, limiting the liquid replenishment volume to 50% of the capacity of the liquid transducer, reducing the liquid replenishment rate to 50% of the normal liquid replenishment rate, and increasing the monitoring frequency of the pressure, liquid level, lightning current burns and physical damage of the liquid transducer; when any one of the damage, liquid leakage or lightning current burns of the liquid transducer is detected to be severe, stopping the liquid replenishment operation of the water supply pump and issuing a maintenance signal.

[0148] The 50% refill strikes a balance between maintaining the basic functions of the liquid transducer and ensuring safety. It allows the liquid transducer to continue to operate while reserving space for emergencies. Filling the liquid transducer to half capacity significantly reduces the internal pressure, relieves the pressure at the fault site, and prevents the problem from further deteriorating. The 50% refill is a compromise that can accommodate a variety of fault conditions such as breakage, leakage and burns, providing protection for a variety of possible fault types. Lower liquid levels make it easier for technicians to diagnose and repair faults, while creating favorable conditions for maintenance work. Reducing the liquid transducer capacity to 50% makes any further abnormal changes easier to detect, while giving operators greater flexibility to respond to different situations.

[0149] A wind turbine blade lightning protection device provided in an embodiment of the present invention can absorb and convert part of the powerful lightning current energy in advance when the wind turbine blade is directly struck by lightning. The device converts electrical energy into the thermodynamic energy of the liquid vaporization latent heat and the pressure energy carried by the liquid to transfer or release energy along with the gas and liquid, thereby weakening or preventing in advance the thermal and mechanical effects that the lightning current will produce on the path it will be transmitted to the ground, and preventing direct damage to wind turbine blades, bearings and transmission components under severe conditions where the lightning current energy is not throttled or weakened, thereby causing the wind turbine to shut down or even blade breakage or tower collapse accidents.

[0150] The above is only a specific implementation of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present disclosure should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A lightning strike protection device for wind turbine blades, characterized in that: The lightning protection device comprises: The liquid transducer is arranged inside the blade and contains a conductive liquid and an electrode plate, and is used to convert the energy carried by the lightning current or limit the size of the lightning current; A first liquid slip ring, disposed in the hub and connected to the liquid transducer via a liquid infusion pipeline; A second liquid slip ring is arranged in the tower and connected to the first liquid slip ring through a liquid infusion pipeline; A liquid supply and replenishment device, arranged in the tower, connected to the second liquid slip ring through a liquid infusion pipeline, and used for providing conductive liquid to the liquid transducer; a first lightning current slip ring, arranged in the hub, electrically connected to the liquid transducer and the nacelle base metal, and used for conducting lightning current between the hub and the nacelle base metal; A second lightning current slip ring is arranged in the tower, electrically connected to the nacelle base metal and the tower, and is used to conduct lightning current between the nacelle base metal and the tower; The liquid transducer comprises: The enclosure is an insulating shell containing a conductive liquid; An electrode plate is arranged inside the insulating shell of the enclosure structure and submerged in the conductive liquid; An electrical insulation isolation plate is arranged inside the insulating shell of the enclosure structure and submerged in the conductive liquid, and is used to implement electrical insulation isolation on two directions of the plate surface of the electrode plate; A safety valve is arranged on the insulating shell of the enclosure structure; The liquid injection interface is connected to the liquid injection pipeline from the first liquid slip ring.

2. The wind turbine blade lightning protection device according to claim 1, characterized in that: The electrode plate lead wire of the liquid transducer is electrically connected to the electrical lead wire of the metal frame arranged inside the blade after being connected to the electrical bus.

3. The wind turbine blade lightning protection device according to claim 1, characterized in that: The liquid transducer also includes: A buffer explosion-proof device tightly surrounds the insulating shell of the enclosure structure, and an insulating resin is poured to fill the gap between the joint surface of the buffer explosion-proof device and the insulating shell of the enclosure structure, so as to prevent the insulating shell of the enclosure structure from exploding; The outer periphery of the safety valve is integrally connected with the buffer explosion-proof device, and the gap between the outer periphery of the safety valve and the joint surface of the buffer explosion-proof device is filled with insulating resin casting; The liquid injection interface adopts a check valve structure made of non-metallic materials, and the conductive liquid can only enter but not exit; The conductive liquid includes deionized water or a mixture of deionized water and ethylene glycol; The ethylene glycol mixture is used for antifreeze; The conductive liquid is used to limit the value of the lightning current and convert the lightning energy into latent heat and / or vaporization latent heat of the conductive liquid; The safety valve is used to protect the insulating shell of the enclosure structure and perform buffer exhaust when the pressure generated by the expansion of the conductive liquid inside the insulating shell of the enclosure structure exceeds the pressure that the insulating shell of the enclosure structure is allowed to withstand.

4. The wind turbine blade lightning protection device according to claim 3, characterized in that: The exhaust structure of the safety valve is a Rafale nozzle structure; The buffer explosion-proof device is a hollow cavity structure tightly surrounding the insulating shell of the enclosure structure; The cross section of the buffer explosion-proof device is a rectangular cross section, a circular cross section, or a trapezoidal cross section; The insulating shell of the enclosure structure is fixed to the inner cavity of the blade by electrical insulating support fasteners.

5. The wind turbine blade lightning protection device according to claim 1, characterized in that: The electrode plate has a lead-out end portion, the lead-out end portion is wrapped with electrical insulating material or poured with liquid insulating material, the lead-out end portion is led out from the inside of the insulating shell of the enclosure structure, and is connected to the metal lead-out wire of the electrode plate; An insulating seal is formed between the lead-out end and the insulating shell of the enclosure structure, and the pressure that the insulating seal withstands to prevent leakage is greater than the value set for the action pressure of the safety valve.

6. The wind turbine blade lightning protection device according to claim 1, characterized in that: The number of the electrode plates is two or more than three; Wherein, the metal lead wire of an electrode plate and its electrical insulation protection are connected to the electrical bus connection lead wire of the metal frame of the blade and / or the metal mesh belt bus; The metal lead wire of the other electrode plate and its electrical insulation protection are connected to the metal lead wire of the first lightning current slip ring in the hub for conducting lightning current.

7. The wind turbine blade lightning protection device according to claim 4, characterized in that: The electrode plate is arranged in a circular ring shape to constitute a ring-shaped plate electrode of the liquid transducer; The electrical insulation isolation plate is arranged in a circular ring shape around both sides of the inner and outer circumference of the annular plate electrode, constituting an electrode electrical insulation isolation annular plate of the liquid transducer; The height of the electrode electrical insulation isolation annular plate is higher than the height of the annular plate electrode.

8. The wind turbine blade lightning protection device according to claim 1, characterized in that: The liquid supply and replenishment device comprises: Water supply pump, drive motor, infusion pipeline, pressure sensor and liquid supply and rehydration controller; The pressure sensor is arranged at the outlet of the water supply pump, and is used to feed back the detected current liquid pressure signal of the outlet of the water supply pump to the liquid supply and replenishment controller; The liquid supply and replenishment controller is used to judge the liquid supply operation or the liquid replenishment operation according to the current liquid pressure signal at the outlet of the water supply pump, and control the start or stop of the water supply pump.

9. The wind turbine blade lightning protection device according to claim 8, characterized in that: The liquid feeding and replenishing controller is specifically used for: If the current liquid pressure signal at the outlet of the water supply pump indicates that the pressure is constant but has not reached the set target value, a control signal for continuing operation is input to the drive motor; wherein the set target value is the pressure when the cavity containing the liquid in the insulating shell of the enclosure structure of the liquid transducer is full; If the current liquid pressure signal at the outlet of the water supply pump indicates that the pressure has reached the set target value and an upward inflection point has appeared, a shutdown control signal is input to the drive motor; If the current liquid pressure signal at the outlet of the water supply pump indicates that the pressure is constant but the liquid supply time has exceeded, a shutdown control signal is input to the drive motor.

10. The wind turbine blade lightning protection device according to claim 9, characterized in that: The liquid supply and replenishment device also includes: The wireless image sensor disposed in the blade of the wind turbine is used to monitor and obtain image information of whether the liquid transducer is damaged, whether there is liquid leakage, or whether there is lightning current burn; and transmit the image information to the liquid supply and replenishment controller; The liquid supply and replenishment controller is also used to determine whether the water supply pump performs infusion or replenishment to the liquid transducer based on the image information.

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