A wind turbine blade tip lightning protection circuit resistance testing device

Abstract

The application belongs to the technical field of resistance testing, and particularly relates to a wind turbine blade tip lightning protection loop resistance testing device. The traditional wind turbine blade tip lightning protection loop resistance detection requires personnel high-altitude operation, and the traditional contact type measurement cannot reflect the overall loop resistance state including the connection point, it is difficult to truly evaluate the lightning current discharge capacity, and there is a huge safety hazard and maintenance blind area. The present application proposes the following scheme, which comprises a profiling fixed support, a UAV clamping ear piece is fixedly installed at the top of the profiling fixed support, the UAV clamping ear piece is used for connecting a UAV, and a blade tip matching groove is formed in one side of the profiling fixed support. The present application solves the high-altitude installation problem through mechanical profiling and self-adaptive clamping, solves the problem of accurate measurement of the real loop resistance through constant current injection and non-contact measurement, and solves the problem of remote operation and data management through wireless communication and intelligent control.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of resistance testing, in particular to a wind turbine blade tip lightning protection circuit resistance testing device. BACKGROUND

[0002] It is known that due to the existence of wind shear, the higher the altitude, the better the resources, so many wind farms are located in high-altitude mountainous areas, and the capacity of wind turbines is getting larger and larger, and the tower and blades are also getting larger and larger, so lightning protection of wind turbines becomes an important part of safe operation of wind turbines. The general wind turbine lightning protection system mainly includes blade lightning protection, nacelle lightning protection, tower lightning protection and grounding grid, when the unit is struck by lightning, the lightning arrester arranged on the blade receives lightning current through the lightning down conductor into the nacelle, and then the nacelle is transmitted to the grounding grid through the tower, and finally flows into the ground to release the lightning current and prevent the lightning current from causing overcurrent damage to the wind turbine. Since the wind turbine blade lightning arrester is arranged at the tip of the blade, there is great difficulty in wiring the blade tip lightning arrester during loop resistance testing, and the maintenance personnel are placed on the blade tip by a safety rope to make the connection, which has great safety hazards.

[0003] Publication (announcement) No. CN111198301B discloses a wind turbine blade tip lightning protection circuit resistance testing device, and the technical solution is that the crawling device includes a crawling mechanism that crawls along the surface of the blade, a bottom plate is fixed to the upper part of the crawling mechanism, a support frame is fixedly connected to the upper part of the front end of the bottom plate, a push rod motor fixing frame is fixedly connected to the upper end of the support frame, a push rod motor is fixed to the push rod motor fixing frame, a wiring terminal is fixed to the lower end of the telescopic rod of the push rod motor, a first camera and a second camera are arranged on the crawling device, one end of a test lead is connected to the wiring terminal, and the other end of the test lead is connected to a test device.

[0004] At present, the resistance testing of the wind turbine blade tip lightning protection circuit usually adopts the following two methods:

[0005] The conventional grounding resistance tester method: the technician needs to climb to the inside of the hub, disconnect the connection point of the blade tip lightning arrester and the down conductor, and use a handheld grounding resistance tester (such as a double clamp or three electrode method) to measure. The test process needs more than two people to cooperate in the high altitude.

[0006] Loop conduction method: use the resistance scale of an ordinary multimeter to measure. This method also requires technicians to climb the tower, find the test point at the blade root junction box or in the hub to measure.

[0007] Low efficiency and high safety risk: the existing method must rely on technicians to work on the tower at high altitude. This not only consumes time and effort (wind farms are usually located in remote areas, and the tower is nearly 100 meters high), but also faces high safety risks such as high-altitude work and mechanical injury, which seriously restricts the efficiency of regular maintenance of the wind farm.

[0008] Large environmental impact on measurement accuracy, accuracy in doubt: the lightning protection circuit resistance is a low-value resistance of milliohm (mΩ). The existing method (especially the multimeter method) cannot effectively eliminate the influence of the test line resistance and contact resistance, resulting in large measurement deviation. In addition, factors such as loose connection points and metal surface oxidation in high-altitude environment will further introduce errors, and cannot truly reflect the conduction state of the lightning protection circuit, which may leave lightning hazards.

[0009] Traditional wind turbine blade tip lightning protection circuit resistance detection requires personnel to work at high altitude, which is extremely risky and inefficient. In addition, traditional contact measurement cannot reflect the overall circuit resistance state including the connection points, making it difficult to truly evaluate the lightning current discharge capacity, and there are huge safety hazards and maintenance blind spots. SUMMARY

[0010] The purpose of the present application is to solve the problems of traditional wind turbine blade tip lightning protection circuit resistance detection, which requires personnel to work at high altitude, is extremely risky and inefficient, and traditional contact measurement cannot reflect the overall circuit resistance state including the connection points, making it difficult to truly evaluate the lightning current discharge capacity, and there are huge safety hazards and maintenance blind spots. A wind turbine blade tip lightning protection circuit resistance testing device is proposed.

[0011] In order to achieve the above purpose, the present application adopts the following technical scheme:

[0012] A wind turbine blade tip lightning protection circuit resistance testing device, comprising a profiling fixing support, a drone clamping ear piece is fixedly installed at the top of the profiling fixing support, the drone clamping ear piece is used to connect a drone, a blade tip matching groove is formed on one side of the profiling fixing support, an arc surface is arranged on the side of the blade tip matching groove, the blade tip matching groove is matched with the blade tip of the wind turbine, a discharge structure is installed at the front end of the profiling fixing support, a host unit is installed on the outer side of the profiling fixing support, and a ground operation unit is wirelessly connected to the host unit.

[0013] An adjusting mechanism is installed at the bottom of the profiling fixing support, and a power mechanism is installed on the adjusting mechanism.

[0014] Two non-contact signal collectors are connected with the power mechanism and are used for detecting the wind turbine down-line electric field signal.

[0015] Preferably, the discharge structure comprises a pointed discharge rod cylinder, a through hole is opened in the tip of the profiling fixed support, the pointed discharge rod cylinder is fixedly installed at the outer end of the through hole, a plurality of arc-shaped conductive rods are fixedly installed on the inner wall of the pointed discharge rod cylinder, and a sharp head is fixedly arranged at the front end of the pointed discharge rod cylinder.

[0016] Preferably, an electricity connection ear is fixedly installed on the outer side of the pointed discharge rod cylinder, and an electricity connection hole is opened in the electricity connection ear.

[0017] Preferably, the main unit comprises a shell, the inside of the shell is provided with a precise constant current source, a high-precision ADC, a microprocessor and a wireless transmission module, and a conductive cable is connected between the precise constant current source and the electricity connection ear.

[0018] The precise constant current source generates stable large direct current test current.

[0019] The high-precision ADC analog-digital converter collects weak voltage signals transmitted by the voltage induction coil.

[0020] The microprocessor MCU controls the test process, performs preliminary calculation and data packaging.

[0021] The wireless transmission module such as 4G / LoRa sends data to the ground operation unit.

[0022] The battery pack supplies power to the entire tower unit.

[0023] Preferably, the adjusting mechanism comprises a rectangular box, the rectangular box is fixedly installed at the bottom of the profiling fixed support, a servo motor is fixedly arranged in the rectangular box, the output shaft of the servo motor extends to the lower side of the rectangular box and is fixedly installed with a rotating plate, a vertical rod is fixedly installed at the bottom of the rotating plate, a vertical groove is opened at the bottom of the vertical rod, a telescopic rod is slidingly installed in the vertical groove, a linear motor is fixedly installed in the vertical groove, and the output shaft of the linear motor is fixedly installed with the telescopic rod.

[0024] Preferably, a horizontal rectangular box is fixedly installed at the bottom end of the telescopic rod, front and rear telescopic rods are slidingly installed in the horizontal rectangular box, threaded holes are opened in the front and rear telescopic rods, a threaded rod is rotatably installed in the horizontal rectangular box through a bearing, the threaded rod is screwed with the threaded holes, a rotating motor is fixedly installed at the outer end of the horizontal rectangular box, the output shaft of the rotating motor is fixedly installed with the threaded rod, and a fixed plate is fixedly installed at the front end of the front and rear telescopic rods.

[0025] The servo motor drives the rotating plate to horizontally rotate, the rotating plate drives the vertical rod to horizontally rotate, the horizontal angle of the power mechanism and the non-contact signal collector is adjusted through the transverse rectangular box and the front and rear telescopic rods, the vertical length of the telescopic rod in the vertical slot is adjusted by the linear motor, the vertical height of the power mechanism and the non-contact signal collector is adjusted through the transverse rectangular box and the front and rear telescopic rods, the front and rear telescopic rods are telescoped forward and backward through the rotation of the threaded rod driven by the rotating motor and the threaded cooperation of the threaded rod and the threaded hole, the front and rear positions of the power mechanism and the non-contact signal collector are adjusted, and multidirectional adjustment is achieved, so that the down conductor is located between the two non-contact signal collectors.

[0026] Preferably, the power mechanism comprises a protection box, the protection box is fixedly installed with the fixing plate, a driving rod and a driven rod are rotatably installed in the protection box, a first gear is sleeved on the outer side of the driving rod, a second gear is sleeved on the outer side of the driven rod, the first gear is engaged with the second gear, a worm motor is installed at the bottom of the protection box, and an output shaft of the worm motor is fixedly installed with the driving rod.

[0027] Preferably, the two non-contact signal collectors comprise two semicircular magnet rods, coils are wound on the outer sides of the two semicircular magnet rods, the coils are two groups, electromagnetic shielding shells are fixedly sleeved on the outer sides of the two semicircular magnet rods, turnover rods are fixedly installed on the outer sides of the two electromagnetic shielding shells, circular holes are formed in the two turnover rods, the outer sides of the driving rod and the driven rod are fixedly installed with the two circular holes, and the two groups of coils are current driving coils and voltage induction coils respectively.

[0028] The current driving coil is wound with a plurality of enameled wires with a cross-sectional area of not less than 2.5 mm 2 on the outer side of the semicircular magnet rod for 5-10 turns, has a very small direct current resistance and is used for bearing a large current.

[0029] The voltage induction coil is wound with a fine enameled wire on the outer side of the semicircular magnet rod for 100-200 turns and is finely distributed on the magnetic ring and is used for high-sensitivity voltage signal induction.

[0030] Preferably, a strip-shaped hole is formed in the protection box, the two turnover rods are in sliding connection with the inner wall of the strip-shaped hole, and an infrared sensor is embedded in the protection box.

[0031] Preferably, the two clamping mechanisms comprise two electric cylinders, output shafts of the two electric cylinders are fixedly installed with insulating clamping plates, anti-skid lines are arranged on the inner sides of the two insulating clamping plates, accommodating grooves are formed in the inner walls of the two sides of the blade tip fitting groove, and the two anti-skid lines are matched with the two accommodating grooves.

[0032] In the application, the wind turbine blade tip lightning protection circuit resistance testing device has the following beneficial effects:

[0033] 1. Extremely high safety: completely avoids the huge safety risks brought by technicians climbing the blades. All operations can be completed on the ground or through remote control, meeting the safety development requirements of modern power operation and maintenance.

[0034] 2. Accurate measurement, reflecting the real working condition: a precise constant current source is used to simulate lightning current, and the voltage drop on the down conductor is measured by a non-contact method to calculate the loop resistance. This method measures the resistance of the entire dynamic discharge loop including the lightning arrester, down conductor, connection points and grounding network, rather than just the wire resistance. The result more truly reflects the actual state during lightning current discharge, which has great engineering significance.

[0035] 3. Efficiency is greatly improved: without the need to stop operation or build complex scaffolding, the installation and testing of the device can be completed in a few minutes by a UAV. The detection time of a single wind turbine is reduced from several hours to tens of minutes, greatly reducing operation and maintenance costs and power generation losses.

[0036] 4. Intelligent and digital: integrated microprocessor and wireless transmission technology, automatic testing process, automatic data calculation, wireless transmission and report generation, easy to be included in the wind farm digital management system for state tracking and trend analysis.

[0037] 5. Strong adaptability: unique profiling support, multi-degree-of-freedom adjustment mechanism and non-contact clamp design can adapt to the installation position differences of different types of wind turbine blade tips and down conductors, with good universality.

[0038] 6. Can simulate the current injection scenario of lightning strike on the blade tip lightning arrester on the ground remotely, and collect the loop response signal non-contact through a special inductor, thereby completely avoiding personnel tower operation.

[0039] The present application solves the problem of high-altitude installation through mechanical profiling and self-adaptive clamping, solves the problem of accurate measurement of real loop resistance through constant current injection and non-contact measurement, and solves the problem of remote operation and data management through wireless communication and intelligent control. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 A structure diagram of a wind turbine blade tip lightning protection loop resistance testing device is proposed for the present application;

[0041] Figure 2 A side view structure diagram of a wind turbine blade tip lightning protection loop resistance testing device is proposed for the present application;

[0042] Figure 3 A bottom view structure diagram of a wind turbine blade tip lightning protection loop resistance testing device is proposed for the present application;

[0043] Figure 4The square fixed support, the main unit, the unmanned aerial vehicle clamping ear piece and the related part structure schematic diagram are provided for the application;

[0044] Figure 5 The square fixed support internal view structure schematic diagram is provided for the application;

[0045] Figure 6 The sharp discharge tube, the ear piece and the related part structure schematic diagram are provided for the application;

[0046] Figure 7 The sharp discharge tube internal view structure schematic diagram is provided for the application;

[0047] Figure 8 The adjustment mechanism explosion structure schematic diagram is provided for the application;

[0048] Figure 9 The adjustment mechanism bottom view structure schematic diagram is provided for the application;

[0049] Figure 10 The power mechanism, the non-contact signal collector structure schematic diagram is provided for the application;

[0050] Figure 11 The power mechanism, the non-contact signal collector bottom view structure schematic diagram is provided for the application;

[0051] Figure 12 The power mechanism structure schematic diagram is provided for the application;

[0052] Figure 13 The non-contact signal collector structure schematic diagram is provided for the application;

[0053] Figure 14 The clamping mechanism structure schematic diagram is provided for the application;

[0054] Figure 15 The clamping mechanism side view structure schematic diagram is provided for the application.

[0055] In the figure: 1, profiling fixed support; 11, unmanned aerial vehicle clamping ear piece; 12, tip matching groove; 121, arc surface; 13, through hole; 14, containing groove; 2, discharge structure; 21, tip discharge rod cylinder; 22, sharp head; 23, arc conductive rod; 24, ear contact; 25, contact hole; 3, main unit; 31, conductive cable; 32, shell; 4, adjusting mechanism; 41, rectangular box; 42, servo motor; 43, rotating plate; 44, vertical rod; 441, vertical groove; 45, telescopic rod; 46, linear motor; 47, transverse rectangular box; 48, front and rear telescopic rod; 481, threaded hole; 49, rotating motor; 410, threaded rod; 411, fixed plate; 5, power mechanism; 51, protection box; 52, worm motor; 53, driving rod; 54, driven rod; 55, first gear; 56, second gear; 57, strip-shaped hole; 6, non-contact signal collector; 61, semicircular magnet rod; 62, coil; 63, electromagnetic shielding shell; 64, turnover rod; 65, circular hole; 7, clamping mechanism; 71, electric cylinder; 72, insulating clamping plate; 73, anti-skid pattern; 8, infrared sensor. DETAILED DESCRIPTION

[0056] The technical solutions in the embodiments will be described clearly and completely below in combination with the drawings in the embodiments. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0057] Embodiment one

[0058] Reference Figures 1-15 A wind turbine blade tip lightning protection circuit resistance testing device, comprising a profiling fixed support 1, an adjusting mechanism 4 and two non-contact signal collectors 6, the top of the profiling fixed support 1 is fixedly installed with an unmanned aerial vehicle clamping ear piece 11, the unmanned aerial vehicle clamping ear piece 11 is used for connecting an unmanned aerial vehicle, facilitating the unmanned aerial vehicle hook or mechanical arm to grasp and transport, and is a key interface to realize unmanned aerial vehicle automatic operation, one side of the profiling fixed support 1 is provided with a tip matching groove 12, the side of the tip matching groove 12 is provided with an arc surface 121, the tip matching groove 12 is matched with the wind turbine blade tip, the front end of the profiling fixed support 1 is installed with a discharge structure 2, the outer side of the profiling fixed support 1 is installed with a main unit 3, the main unit 3 is wirelessly connected with a ground operation unit, the adjusting mechanism 4 is installed at the bottom of the profiling fixed support 1, the adjusting mechanism 4 is installed with a power mechanism 5, two non-contact signal collectors 6 are connected with the power mechanism 5, and are used for detecting the wind turbine down-line electric field signal.

[0059] Specifically, the ground operation unit is a handheld terminal device (such as a ruggedized tablet computer or a special handheld device), which is provided with a special software.

[0060] Function: Receive the wireless data sent by the tower unit, and perform final calculation, display, storage and judgment of test results (pass / fail). At the same time, it can send start test, stop test and other instructions to the tower unit.

[0061] Specifically, the profiled support 1 has an inner contour matched with the shape of the blade tip, and can be temporarily fixed beside the blade tip lightning receptor by a quick clamping mechanism (such as a ratchet strap or a vacuum chuck). A liftable / adjustable metal discharge rod is arranged at the front end of the support, and the material and tip shape of the metal discharge rod are consistent with those of the actual lightning receptor.

[0062] Function: Simulate the actual blade tip lightning receptor to provide a reliable injection point for the test current.

[0063] In this embodiment, the discharge structure 2 includes a tip discharge rod cylinder 21, a through hole 13 is formed in the tip of the profiled fixed support 1, the tip discharge rod cylinder 21 is fixedly installed at the outer end of the through hole 13, a plurality of arc-shaped conductive rods 23 are fixedly installed on the inner wall of the tip discharge rod cylinder 21, a sharp head 22 is fixedly arranged at the front end of the tip discharge rod cylinder 21, an electricity receiving ear 24 is fixedly installed on the outer side of the tip discharge rod cylinder 21, and an electricity receiving hole 25 is formed in the electricity receiving ear 24.

[0064] Specifically, the tip discharge rod cylinder 21 and the arc-shaped conductive rods 23 are made of brass or stainless steel, and the surfaces thereof are plated with chromium to prevent oxidation.

[0065] The plurality of arc-shaped conductive rods 23 are designed to be flexible and can adapt to blade tip lightning receptors of different diameters. When the lightning receptor is inserted, these conductive rods can ensure that a large-area, low-resistance electrical connection is formed with the surface of the lightning receptor, which is a key to successful injection of the current.

[0066] The electricity receiving ear 24 is used as a current input terminal and is connected with the host unit through a power supply wire 31 to receive a large test generated by a precision constant current source.

[0067] In the current example, the host unit 3 includes a shell 32, and the inside of the shell 32 is provided with a precision constant current source, a high-precision ADC, a microprocessor and a wireless transmission module. The precision constant current source is connected with the electricity receiving ear 24 through a conductive cable 31. The flexible copper cable with a large wire diameter (such as AWG 6) and low resistance is covered with a wear-resistant insulating layer to reduce the loss of the test current caused by the resistance of the cable itself.

[0068] The precision constant current source generates a stable large DC test current.

[0069] The high-precision ADC analog-to-digital converter collects the weak voltage signal transmitted by the voltage sensing coil.

[0070] The microprocessor MCU controls the test process, performs preliminary calculation and data packaging.

[0071] Wireless transmission module such as 4G / LoRa: send data to the ground operation unit.

[0072] Battery pack: power supply for the entire tower unit.

[0073] More specifically, the host unit 3 includes:

[0074] Housing 32: IP67 protection level of engineering plastic box, with portable handle and mounting point, can be tied and fixed.

[0075] Internal circuit board:

[0076] Master MCU: 32-bit ARM Cortex-M series processor, responsible for process control.

[0077] Precise programmable DC constant current source: core component. Adopting closed-loop feedback control technology, it can output and stabilize multiple selectable DC current values such as 10A, 20A, 30A, etc., with precision better than ±0.5%. Even if the downlead resistance and contact resistance change, it can also ensure the stability of the current I.

[0078] High-precision differential ADC module: 24-bit Σ-Δ analog-to-digital converter, with a front-end instrument amplifier, specially used for amplifying and collecting microvolt-level (μV) DC voltage signals ΔV.

[0079] Power management: built-in large-capacity lithium-ion battery pack (such as 12V 20Ah), with battery management system (BMS) and fast charging interface.

[0080] Wireless communication module: LoRa (Long Range Radio) module, which is very suitable for the complex radio environment inside and outside the fan tower due to its strong penetration and ultra-long transmission distance (>3km).

[0081] In this embodiment, the adjusting mechanism 4 comprises a rectangular box 41 fixedly installed at the bottom of the profiling fixed support 1, a servo motor 42 fixedly installed in the rectangular box 41, the output shaft of the servo motor 42 extending to below the rectangular box 41 and fixedly installing a rotating plate 43, a vertical rod 44 fixedly installed at the bottom of the rotating plate 43, a vertical slot 441 being formed at the bottom of the vertical rod 44, a telescopic rod 45 slidingly installed in the vertical slot 441, a linear motor 46 fixedly installed in the vertical slot 441, the output shaft of the linear motor 46 being fixedly installed with the telescopic rod 45, a horizontal rectangular box 47 fixedly installed at the bottom end of the telescopic rod 45, a front and rear telescopic rod 48 slidingly installed in the horizontal rectangular box 47, a threaded hole 481 being formed on the front and rear telescopic rod 48, a threaded rod 410 rotatably installed in the horizontal rectangular box 47 through a bearing, the threaded rod 410 being screwed with the threaded hole 481, a rotating motor 49 fixedly installed at the outer end of the horizontal rectangular box 47, the output shaft of the rotating motor 49 being fixedly installed with the threaded rod 410, and a fixed plate 411 fixedly installed at the front end of the front and rear telescopic rod 48.

[0082] The servo motor 42 drives the rotating plate 43 to horizontally rotate, the rotating plate 43 drives the vertical rod 44 to horizontally rotate, the horizontal rectangular box 47 and the front and rear telescopic rod 48 drive the power mechanism 5 and the non-contact signal collector 6 to horizontally adjust the angle, the linear motor 46 drives the telescopic rod 45 to vertically adjust the length in the vertical slot 441, the horizontal rectangular box 47 and the front and rear telescopic rod 48 drive the power mechanism 5 and the non-contact signal collector 6 to vertically adjust the height, the rotating motor 49 drives the threaded rod 410 to rotate, the threaded rod 410 is screwed with the threaded hole 481 to drive the front and rear telescopic rod 48 to extend forward and backward, the front and rear positions of the power mechanism 5 and the non-contact signal collector 6 are adjusted, and multidirectional adjustment is achieved so that the down conductor is located between the two non-contact signal collectors 6.

[0083] In this embodiment, the power mechanism 5 comprises a protection box 51 fixedly installed with the fixed plate 411, a driving rod 53 and a driven rod 54 rotatably installed in the protection box 51, a first gear 55 sleeved on the outer side of the driving rod 53, a second gear 56 sleeved on the outer side of the driven rod 54, the first gear 55 being engaged with the second gear 56, a worm motor 52 installed at the bottom of the protection box 51, and the output shaft of the worm motor 52 being fixedly installed with the driving rod 53.

[0084] In this embodiment, the two non-contact signal collectors 6 include two half-circular magnet rods 61, the outer sides of the two half-circular magnet rods 61 are each wound with a coil 62, the coil 62 is two groups, the outer sides of the two half-circular magnet rods 61 are each fixedly sleeved with an electromagnetic shielding shell 63, the outer sides of the two electromagnetic shielding shells 63 are each fixedly installed with a turnover rod 64, the two turnover rods 64 are each provided with a circular hole 65, the two circular holes 65 are fixedly installed with the outer sides of the driving rod 53 and the driven rod 54, and the two groups of coils 62 are respectively a current driving coil and a voltage sensing coil;

[0085] The current driving coil is wound with a plurality of enameled wires with a cross-sectional area not less than 2.5 mm 2 on the outer side of the half-circular magnet rod 61 for 5-10 turns, has a very small direct current resistance, and is used to bear a large current;

[0086] The voltage sensing coil is wound with a fine enameled wire on the outer side of the half-circular magnet rod 61 for 100-200 turns, is finely distributed on the magnetic ring, and is used to sensitively sense a voltage signal.

[0087] The current driving coil is used to receive a test current signal from a host, and generate a primary magnetic field around a down conductor; and the voltage sensing coil is used to detect a secondary induced voltage in the down conductor due to the test current.

[0088] The entire magnetic ring coil assembly is packaged in a metal shielding shell, only leaving a jaw position, to effectively suppress external electromagnetic interference and ensure the purity of signal acquisition.

[0089] The magnetic core adopts a nanocrystalline alloy material with high saturation magnetic induction intensity, and has a shape of an openable and closable rectangle or a circle, so as to ensure that the down conductor with different diameters can be easily clamped. A precise mechanical locking device is arranged at the opening of the magnetic ring to prevent accidental opening during testing.

[0090] In this embodiment, a strip-shaped hole 57 is formed in the protection box 51, the two turnover rods 64 are in sliding connection with the inner wall of the strip-shaped hole 57, and the protection box 51 is embedded with an infrared sensor 8.

[0091] In this embodiment, the two clamping mechanisms 7 include two electric cylinders 71, the output shafts of the two electric cylinders 71 are each fixedly installed with an insulating clamping plate 72, the inner sides of the two insulating clamping plates 72 are each provided with an anti-skid pattern 73, the inner walls of the two sides of the blade tip fitting groove 12 are each provided with a containing groove 14, and the two anti-skid patterns 73 are matched with the two containing grooves 14.

[0092] Specifically, the clamping mechanism 7 (the electric cylinder 71 and the insulating clamping plate 72) provides an active clamping force, cooperates with the profiling structure, and firmly fixes the device on the blade tip, so as to prevent movement or falling during testing or due to wind force, and ensures operation safety.

[0093] Working mode: when in use, the technician completes the charging of the main unit 3, cable connection and other work on the ground.

[0094] The drone picks up the ear piece 11 or the whole tower unit is transported to the blade tip by the aerial work platform. First, the profiling fixed support 1 is firmly fixed beside the blade tip lightning arrester, the profiling fixed support 1 is sleeved outside through the blade tip fitting groove 12, the two clamping mechanisms 7 work to clamp and fix the blade tip, the blade tip lightning arrester is inserted into the inside of the discharge structure 2 through the through hole 13, and is extruded and connected through the plurality of arc-shaped conductive rods 23, so that the conductive effect is formed.

[0095] Then, the driving rod 53 is rotated clockwise by the worm motor 52, the driving rod 53 drives the first gear 55 to rotate, the first gear 55 drives the driven rod 54 to rotate counterclockwise through the second gear 56, the driving rod 53 and the driven rod 54 drive the two turnover rods 64 to turn outward, so that the two electromagnetic shielding shells 63 are away from each other, the purpose of opening the jaws of the two non-contact signal collectors 6 is achieved, the two non-contact signal collectors 6 are controlled to be close to the down conductor through the adjusting mechanism 4, so that the down conductor is located between the two non-contact signal collectors 6, the worm motor 52 is controlled in reverse, the two non-contact signal collectors 6 are closed tightly and clamped at the predetermined down conductor position, and the locking device is locked.

[0096] Test work can be carried out

[0097] First, the test instruction is issued:

[0098] The ground personnel select test parameters (such as test current I=10A) on the ground operation unit, and click "start test". The instruction is uploaded to the tower main unit 3 through the LoRa wireless network. Constant current injection and loop establishment (simulate lightning process): after the main MCU receives the instruction, the precise programmable direct current constant current source is started.

[0099] The constant current source generates a stable and accurate 10A direct current I, which flows to the tip discharge rod cylinder 21 of the simulated lightning arrester through 31.

[0100] The current is released from the discharge rod tip of the discharge structure 2, and seeks to be introduced into the ground. At this time, the inherent capacitance of the whole fan blade, hub and tower cylinder and the grounding network forms a transient discharge loop. The key is that the path of the test current is highly consistent with the path of the real lightning current through the blade tip lightning arrester→down conductor→blade root→hub→main shaft→tower cylinder→grounding network into the ground. Therefore, the device measures the resistance of the whole dynamic loop including all connection points, not just the resistance of the down conductor material itself, and the result is more engineering significance.

[0101] Second, non-contact voltage signal sampling:

[0102] When 10A current I flows through the down conductor, according to Ohm's law (V=I*R), a small voltage drop ΔV will be generated on the conductor (for example, if the resistance is 50 mΩ, then ΔV=10A*0.05Ω=0.5V).

[0103] According to the law of electromagnetic induction and the principle of transformer, the current I flowing through the down conductor will generate a magnetic field proportional to I in the magnetic ring of the signal collector. This magnetic field induces an alternating voltage signal proportional to ΔV in the voltage induction coil (although the source current is direct current, due to the air gap and non-ideal magnetic circuit of the clamp structure, a weak alternating signal is usually induced, which is more conducive to amplification and processing).

[0104] The induced voltage signal is sent to the high-precision differential ADC module inside the host unit. The differential measurement mode can effectively suppress common-mode interference, and the instrument amplifier amplifies it to a suitable sampling range, and the ADC converts it to a digital signal.

[0105] Data processing and wireless transmission: the MCU reads the digital value of the ADC, and combines the known coil turn ratio and circuit calibration coefficient to convert the real voltage drop ΔV.

[0106] The MCU calculates the resistance value R of the loop according to the formula R=ΔV / I.

[0107] The calculation result is packaged with the original data by the LoRa wireless module and sent to the ground.

[0108] Third, result presentation and diagnosis:

[0109] After the ground operation unit receives the data, it not only clearly displays "Resistance value: XX.XX mΩ" on the screen, but also compares it with the preset safety threshold (such as 50 mΩ).

[0110] If the result exceeds the standard, the software will alarm in red font, and may prompt "Warning: loop resistance is too large, which may indicate loose connection or corrosion".

[0111] All data is time-stamped, fan number, blade number, etc. and can generate a standardized report with one key, which can be used for equipment status tracking and maintenance decision-making.

[0112] Example two

[0113] Example two is the same as the rest of example one, except that a high-definition wide-angle camera and a laser pointer are integrated at the end of the device body and the mechanical arm.

[0114] The ground operator can observe the tip-shedding device condition, the down conductor position and the clamping process in real time through the first view, and realize the "what you see is what you get" remote precise operation. Video data can be recorded synchronously, used to establish a blade file, and visually analyze the appearance state such as corrosion and crack. In the present application, all the structural shapes, sizes and materials of the first embodiment can be selected and adjusted to meet specific use conditions. The drawings are schematic structural diagrams, and the actual sizes can be adjusted appropriately.

[0115] The above merely describes the preferred specific implementation of the present embodiment, but the protection scope of the present embodiment is not limited thereto. Any person skilled in the art can make equivalent replacements or changes to the technical solution and the inventive concept of the present embodiment within the technical range disclosed by the present embodiment, which should be covered within the protection scope of the present embodiment.

Claims

1. A wind turbine blade tip lightning protection circuit resistance testing device, comprising a profiling fixing support (1), a top of the profiling fixing support (1) is fixedly provided with a drone clamping lug (11) for connecting a drone, characterized in that, The side of the profiling fixed support (1) is provided with a blade tip matching groove (12), the side of the blade tip matching groove (12) is provided with an arc surface (121), the blade tip matching groove (12) is matched with the blade tip of the wind driven generator, the front end of the profiling fixed support (1) is provided with a discharge structure (2), the outer side of the profiling fixed support (1) is provided with a main unit (3), the main unit (3) is wirelessly connected with a ground operation unit, and the discharge structure (2) further comprises: An adjusting mechanism (4) is installed at the bottom of the profiling fixed support (1), and a power mechanism (5) is installed on the adjusting mechanism (4); Two non-contact signal collectors (6) are connected with the power mechanism (5) and used for detecting the electric field signal of the wind driven generator; The discharge structure (2) comprises a tip discharge rod cylinder (21), the tip of the profiling fixed support (1) is provided with a through hole (13), the tip discharge rod cylinder (21) is fixedly installed at the outer end of the through hole (13), a plurality of arc conductive rods (23) are fixedly installed on the inner wall of the tip discharge rod cylinder (21), the arc conductive rods (23) have elasticity and can adapt to blade tip lightning arresters with different diameters, when the lightning arresters are inserted, the arc conductive rods (23) can ensure that a large-area and low-resistance electrical connection is formed with the surface of the lightning arresters, and a sharp head (22) is fixedly arranged at the front end of the tip discharge rod cylinder (21); An electricity receiving lug (24) is fixedly installed on the outer side of the tip discharge rod cylinder (21), and an electricity receiving hole (25) is formed in the electricity receiving lug (24); The power mechanism (5) comprises a protection box (51), the protection box (51) is fixedly installed with a fixed plate (411), a driving rod (53) and a driven rod (54) are rotatably installed in the protection box (51), a first gear (55) is sleeved on the outer side of the driving rod (53), a second gear (56) is sleeved on the outer side of the driven rod (54), the first gear (55) is engaged with the second gear (56), a worm motor (52) is installed at the bottom of the protection box (51), and the output shaft of the worm motor (52) is fixedly installed with the driving rod (53); The two non-contact signal collectors (6) comprise two semicircular magnet rods (61), coils (62) are wound on the outer sides of the two semicircular magnet rods (61), the coils (62) are two groups, electromagnetic shielding shells (63) are fixedly sleeved on the outer sides of the two semicircular magnet rods (61), flip rods (64) are fixedly installed on the outer sides of the two electromagnetic shielding shells (63), circular holes (65) are formed in the two flip rods (64), the two circular holes (65) are fixedly installed on the outer sides of the driving rod (53) and the driven rod (54), and the two groups of coils (62) are current driving coils and voltage sensing coils respectively; The current driving coil is made of a plurality of enameled wires with a cross-sectional area of not less than 2.5 mm² and is wound on the outer side of the semicircular magnet rod (61) for 5-10 turns, and the direct current resistance thereof is extremely small and is used for bearing large current. Voltage sensing coil, 100-200 turns of fine enamel wire are wound outside the semicircular magnet rod (61), and are finely distributed on the magnetic ring, which is used for high sensitivity induction of voltage signal; The magnetic core is made of nanocrystalline alloy material with high saturation magnetic induction intensity, and has an openable and closable rectangular or circular shape, which can easily clamp different diameter down conductors; The protection box (51) is provided with a strip-shaped hole (57), and two turnover rods (64) are slidably connected with the inner wall of the strip-shaped hole (57).

2. A wind turbine blade tip lightning circuit resistance testing device according to claim 1, wherein, The host unit (3) includes a shell (32), and the inside of the shell (32) is provided with a precise constant current source, a high-precision ADC, a microprocessor and a wireless transmission module.

3. A wind turbine blade tip lightning circuit resistance testing device according to claim 1, wherein, The adjusting mechanism (4) includes a rectangular box (41) fixedly installed at the bottom of the profiling fixed support (1), a servo motor (42) fixedly installed in the rectangular box (41), an output shaft of the servo motor (42) extending to the lower side of the rectangular box (41) and fixedly installed with a rotating plate (43), a vertical rod (44) fixedly installed at the bottom of the rotating plate (43), a vertical groove (441) formed at the bottom of the vertical rod (44), a telescopic rod (45) slidably installed in the vertical groove (441), and a linear motor (46) fixedly installed in the vertical groove (441).

4. A wind turbine blade tip lightning circuit resistance testing device according to claim 3, wherein, A horizontal rectangular box (47) is fixedly installed at the bottom end of the telescopic rod (45), a front-rear telescopic rod (48) is slidably installed in the horizontal rectangular box (47), a threaded hole (481) is formed in the front-rear telescopic rod (48), a threaded rod (410) is rotatably installed in the horizontal rectangular box (47) through a bearing, the threaded rod (410) is in threaded connection with the threaded hole (481), a rotary motor (49) is fixedly installed at the outer end of the horizontal rectangular box (47), an output shaft of the rotary motor (49) is fixedly installed with the threaded rod (410), and a fixed plate (411) is fixedly installed at the front end of the front-rear telescopic rod (48).

5. A wind turbine blade tip lightning circuit resistance testing device according to claim 1, wherein, The two clamping mechanisms (7) include two electric cylinders (71), and the output shafts of the two electric cylinders (71) are fixedly installed with two insulating clamping plates (72), the inner sides of the two insulating clamping plates (72) are provided with anti-skid patterns (73), and the inner walls of the two sides of the blade tip fitting groove (12) are provided with accommodating grooves (14), and the two anti-skid patterns (73) are matched with the two accommodating grooves (14).

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