Overhead transmission line composite insulator hydrophobicity live detection device and method

Abstract

The invention discloses an overhead transmission line composite insulator hydrophobicity live-line detection device and method, an unmanned aerial vehicle on-load platform is provided with a power supply and control module and a spraying mechanism, the power supply and control module is electrically connected with the spraying mechanism, the unmanned aerial vehicle on-load platform comprises an unmanned aerial vehicle, the unmanned aerial vehicle is provided with a mounting bracket, and the mounting bracket is electrically connected with the unmanned aerial vehicle. The spraying mechanism comprises an atomizing nozzle, a fan, a water pump and water stop valves, a water tank, the water pump and an air duct are arranged on the mounting support, the atomizing nozzle is arranged at the front end in the air duct, the fan is arranged at the rear end in the air duct, the water tank is communicated with the water pump through a water pipe, and the water pump is communicated with the atomizing nozzle through a water pipe. And water sprayed from the atomizing nozzle is blown out of the air duct from the front end of the air duct under the blowing of the fan, and is sprayed on the composite insulator in a mist form, so that hydrophobicity detection is carried out.

Description

Technical Field

[0001] The present invention relates to a technology for detecting the hydrophobicity of an insulator, and in particular to a device and method for detecting the hydrophobicity of a composite insulator of an overhead power transmission line under charge. Background Art

[0002] The Power Transmission Operation and Maintenance Center is responsible for the operation and maintenance of 510 overhead transmission lines in Zhengzhou, covering 35-220 kV voltage, totaling approximately 4,446.7 kilometers. These lines are crucial to the region's power supply, economy, and livelihoods. To protect the normal operation of the power system and ensure power supply security, regular hydrophobicity testing of composite insulators on transmission lines is necessary. Currently, hydrophobicity testing still relies on manual labor, performed while live, which is time-consuming and inefficient, and poses personal safety risks such as falls and electric shock.

[0003] According to the provincial company's requirements, the Transmission Operation and Maintenance Center is required to complete hydrophobicity testing of composite insulators on all 510 lines under its jurisdiction within a three-month window each year, inspecting over 1,000 towers. This must not impact routine maintenance and troubleshooting. Currently, the Transmission Operation and Maintenance Center has a limited number of maintenance personnel and a heavy workload. Furthermore, hydrophobicity testing of composite insulators is time-consuming and inefficient, posing a significant challenge to the team's workload.

[0004] In the existing manual inspection of the hydrophobicity of composite insulators, auxiliary work (including inspection and testing of safety tools, and organizing and storing tools, totaling 29.90 minutes) and personnel transfer at high altitude (including climbing up the tower, moving to another monitoring point, and climbing down the tower, totaling 66.23 minutes) consumes a large amount of time, accounting for 93% of the total operation time, seriously slowing down work efficiency. Therefore, the existing inspection method cannot meet the requirements of the project. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the existing technology and provide a device and method for detecting the hydrophobicity of composite insulators on overhead power transmission lines with a reasonable design and using an unmanned aerial vehicle to implement motion water spraying.

[0006] The technical solution of the present invention is: A device for detecting the hydrophobicity of composite insulators on overhead power transmission lines, comprising a drone-carrying platform, on which a power supply and control module and a spray mechanism are provided, the power supply and control module being electrically connected to the spray mechanism, the drone-carrying platform comprising a drone, on which a mounting bracket is provided, the spray mechanism comprising an atomizing nozzle, a fan, a water pump and a water stop valve, the mounting bracket being respectively provided with a water tank, a water pump and a wind tube, the front end of the wind tube being provided with the atomizing nozzle, the rear end of the wind tube being provided with the fan, the water tank and the water pump being connected as well as the water pump and the atomizing nozzle being connected via water pipes, each section of the water pipe being provided with the water stop valve, the water sprayed from the atomizing nozzle being blown out of the wind tube from the front end of the wind tube under the blowing of the fan, and sprayed onto the composite insulator in the form of mist, thereby performing a hydrophobicity test.

[0007] Furthermore, the power supply and control module is arranged above the air duct, and the power supply and control module includes a power supply and a control module. The control module is electrically connected to the power supply, the fan and the water pump respectively, and can adjust the wind force of the fan and the injection time of the water pump to improve the accuracy of hydrophobicity detection.

[0008] Furthermore, the water stop valve is a spring water stop valve, which has different characteristics in two flow directions. When the water flow is reversed, the spring water stop valve cuts off the water path in one direction.

[0009] Furthermore, the mounting bracket is a distributed bracket, including a UAV extension bracket and a ball head gimbal. The UAV extension bracket is arranged on the UAV, and the ball head gimbal is installed on the upper part of the UAV extension bracket, and the ball head gimbal is used as the base of the wind tube and connected to the wind tube, so that the angle of the wind tube can be adjusted as needed.

[0010] Furthermore, the fan adopts an axial flow fan, which has strong wind force and good water mist spraying effect. The wind tube is frustum-shaped, and its front end diameter is small, which improves the spraying force.

[0011] Furthermore, the water pump adopts a diaphragm water pump, which has a high water pressure density. When the load weight of the UAV is limited, the diaphragm water pump has a higher water pressure and better operability.

[0012] Furthermore, the atomizing nozzle adopts a centrifugal nozzle, which has a small mist particle diameter, a high degree of atomization fineness, and better operability.

[0013] Furthermore, the power supply is a plug-in power supply, the battery in the power supply adopts a Sony VTC5A power lithium battery, the charging module of the power supply adopts a 2S lithium battery balance charging module, and the plug connector adopts an XT60H-F / M plug.

[0014] Furthermore, the drone is DJI Mavic 3 Pro.

[0015] Furthermore, the control module is provided with an integrated module combination circuit, which includes a 12V DC boost module, a temperature control switch, a remote control switch, an isolating switch and a high-power MOSFET. One end of the temperature control switch is connected to the positive electrode of the lithium battery, and the other end is connected to the manual switch. The other end of the manual switch is connected to the 12V DC boost module. A power indicator is also provided between the manual switch and the 12V DC boost module. The other end of the 12V DC boost module is connected to the diaphragm water pump after passing through the remote control switch, and is connected to the fan after passing through the high-power MOSFET. The circuit between the remote control switch and the diaphragm water pump is connected to the isolating switch. The other end of the isolating switch is connected to the axial flow fan through the fan control board. The remote control switch is connected to the line between the 12V DC boost module and the high-power MOSFET.

[0016] The control module needs to control the working status of the fan and water pump, and receive and process signals from the remote control to achieve remote control of the measuring device. Therefore, the control module is a hybrid circuit with both "signal circuit" and "power circuit".

[0017] A method for detecting the hydrophobicity of composite insulators on overhead transmission lines, comprising the following steps: (1) Preparation: Install the nozzle, fan, water pump, water tank, water stop valve, power supply, and control module onto the drone through the mounting bracket; inject pure water into the water tank; (2) Flight test operations: Start the drone and the remote controller, fly the drone to a certain height, and then issue a command to make the water pump spray water into the air duct and start the fan at the same time. Check whether there is water mist spraying out. If there is water mist spraying out, the device is normal. If there is no water mist spraying out, the device is abnormal and you need to find the cause and solve the problem. (3) Flight operations; After the equipment is normal, control the drone to take off through the remote control and fly to the tower head to be inspected; (4) Water mist spraying and taking photos: The remote-controlled drone flies to a distance of 2-3 meters from the insulator to be tested, activates the spray mechanism, and then uses the drone's built-in camera to photograph the morphology of water droplets on the insulator surface. The photographed water droplet morphology is compared with the standard water droplet morphology to determine the insulator's hydrophobicity. (5) Operation recovery: Control the drone to return, dismantle the spray mechanism, and return it to the warehouse for use.

[0018] Furthermore, in steps (1) and (2), the time for installing the spray mechanism on the drone is controlled within 30 seconds through a simple and reliable connection mechanism; while injecting water, the power of the drone is turned on, and considering the startup time of the drone, the total preparation time can be controlled within 50 seconds.

[0019] Furthermore, the connecting mechanism includes a spring clamp and a cable tie, the cable tie is used to fix the spring clamp on the mounting bracket, and then the spring clamp is used to fix the components in the spray mechanism.

[0020] Furthermore, in step (3), the take-off point of the drone should be within 50 meters of the horizontal position of the tower to be tested; the height of the composite insulator is generally 20-70 meters, so the straight-line distance between the drone take-off point and the test position should not exceed 86 meters. Since the drone carries an additional load, considering safety and control performance, the flight speed of the drone should be 2-4m / s, so the time it takes for the drone to fly to the tower head can be controlled within 43s.

[0021] Furthermore, in step (4), according to the requirements of the hydrophobicity test, the spraying duration is 20-30 seconds, and the shooting is completed within 10 seconds after the spraying ends; according to the experience of the department's drone pilots, the drone position adjustment time for each insulator measurement point is about 10 seconds; the number of insulators per tower is 3-6 strings; therefore, the detection time is within 180-360 seconds.

[0022] Furthermore, in step (5), the water storage device becomes lighter when the drone returns, and the flight speed can be 3-5 m / s; the time for disassembling the spray mechanism can be controlled within 20 seconds, so the operation recovery time is within 48 seconds.

[0023] The beneficial effects of the present invention are: 1. The present invention uses drones to replace manpower in the live hydrophobicity test of composite insulators, and the performance is good. It reduces the on-site hydrophobicity test time of a composite insulator from the original 104.27 minutes to 8.35 minutes. The device is portable and safe to operate, and the production efficiency is increased by 92%.

[0024] 2. The present invention integrates a drone and a spray mechanism to deliver pure water and a water mist release device to an appropriate location in the sky. The spray mechanism's directional, long-distance water mist spraying enables unmanned, automatic spray inspection of composite insulators, ultimately replacing manpower with machines and improving operational efficiency.

[0025] 3. The present invention adopts a centrifugal nozzle, which has a smaller mist particle diameter, that is, a higher degree of atomization fineness, better operability, and meets the water mist requirements of hydrophobicity testing. The diameter of the mist particles generated by the nozzle should be less than 1mm, and the smaller the mist particle diameter, the easier it is to reflect the hydrophobicity of the insulator and the better the operability.

[0026] 4. The present invention adopts an axial flow fan. The greater the wind speed generated by the fan, the farther the mist particles can fly. On the one hand, it is more conducive to long-distance measurement. On the other hand, it can also withstand greater environmental wind force, thereby having better operability.

[0027] 5. The present invention is applicable to overhead transmission lines of different voltage levels. Although the detection time of different towers varies due to different tower heights, the number and layout of insulators, the average hydrophobicity live detection time per tower is 8.35 minutes, which is less than the target value of 20 minutes. The goal has been achieved! 6. The present invention utilizes drones to realize liquid transportation and remote automatic spraying, thereby achieving the purpose of improving work efficiency. At the same time, it also ensures detection safety, so that workers no longer need to climb towers, and eliminates the risk of people falling from heights from the root, effectively protecting the personal safety of workers, and is easy to promote, with good economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a principle block diagram of a device for detecting the hydrophobicity of composite insulators on overhead transmission lines; Figure 2 This is a diagram showing the optimal components of a device for detecting the hydrophobicity of composite insulators on overhead power transmission lines; Figure 3 A rendering of a device for detecting the hydrophobicity of composite insulators on overhead transmission lines; Figure 4 This is a product diagram of a device for detecting the hydrophobicity of composite insulators on overhead transmission lines; Figure 5 This is a diagram showing the use of a device for detecting the hydrophobicity of composite insulators on overhead transmission lines; Figure 6 This is a product image of a drone extension bracket used in a device for detecting the hydrophobicity of composite insulators on overhead power transmission lines. Figure 7 This is a product image of a ball head pan / tilt head used in a device for detecting the hydrophobicity of composite insulators on overhead power transmission lines. Figure 8 This is a distribution diagram of the centroids of various components on a drone in a device for detecting the hydrophobicity of composite insulators on overhead power transmission lines. Figure 9 This is a circuit diagram of a control module in a device for detecting the hydrophobicity of composite insulators on overhead power transmission lines; Figure 10 The present invention provides the operating steps of a live detection method for the hydrophobicity of composite insulators of overhead transmission lines.

[0029] In the figure, 1-UAV, 2-distributed bracket, 3-centrifugal nozzle, 4-axial flow fan, 5-air duct, 6-diaphragm water pump, 7-water tank, 8-ball head, 9-water pipe, 10-spring water check valve, 11-plug-in power supply, 12-integrated module combination circuit, A-12V DC boost module, B-temperature control switch, C-remote control switch, D-isolating switch, E-high-power MOSFET, F-lithium battery, G-manual switch, H-battery indicator, I-fan control board, O-center of mass of UAV + mounting bracket, N-center of mass of water tank, X-center of mass of air duct and power supply, Y-center of mass of diaphragm water pump. DETAILED DESCRIPTION

[0030] Example 1: See Figures 1-9 , A device for detecting the hydrophobicity of composite insulators on overhead power transmission lines is disclosed. The device comprises an unmanned aerial vehicle (UAV) carrying platform, wherein the UAV carrying platform comprises a UAV 1 and a mounting bracket. The UAV 1 is a DJI Mavic 3 Pro UAV 1. The mounting bracket is a distributed bracket 2. The distributed bracket 2 comprises a UAV extension bracket and a ball head 8. The UAV extension bracket is fixed to the UAV 1. A power supply and control module and a spray mechanism are respectively arranged on the UAV carrying platform, and the power supply and control module and the spray mechanism are electrically connected.

[0031] The spraying mechanism includes an atomizing nozzle, a fan, a water pump and a water stop valve.

[0032] The atomizing nozzle uses a centrifugal nozzle 3. This type of nozzle produces small mist droplets, a fine mist, and improved operability. In this embodiment, a copper-tipped, adjustable, four-point nozzle is used. To meet the water mist requirements for hydrophobicity testing, the nozzle's mist droplets should have a diameter of less than 1 mm. The smaller the droplet diameter, the more easily the insulator's hydrophobic properties are demonstrated, and the better the operability.

[0033] The fan adopts an axial flow fan 4, which has strong wind force and good water mist spraying effect. The dimensions of the axial flow fan 4 in this embodiment are: 45mm in length, 29.5mm in diameter, and the meter parameters are: rated voltage: 8.4V; rated power: 250W; the greater the wind speed generated by the fan, the farther the mist particles can fly, which is more conducive to long-distance measurement on the one hand, and can also withstand greater environmental wind force on the other hand, thereby having better operability.

[0034] The axial flow fan 4 is arranged in the air tube 5. In this embodiment, the air tube 5 has the following dimensions: 193 mm long and 39 mm inner diameter at the widest opening. The air tube 5 is truncated cone-shaped with a small diameter at the front end to improve the spraying force.

[0035] The water pump uses a diaphragm pump 6, which has a high water pressure density. Given the limited payload of the drone 1, the diaphragm pump 6 provides greater water pressure and improved operability. The diaphragm pump 6 has a drive voltage of 5-12V, a drive current of ≤2A, and an interface outer diameter of 6.5-5.6mm.

[0036] The water tank 7 and the water pump are placed on the UAV extension bracket, and the corresponding spring clamps are fixed respectively with binding straps, and the spring clamps are used to quickly fix and remove the water tank 7 and the diaphragm water pump 6.

[0037] A ball head 8 is mounted on the top of the drone extension bracket and connected to the wind tube 5 as the base, allowing the angle of the wind tube 5 to be adjusted as needed. The ball head 8 is located at the rear end of the wind tube 5, on the side with the largest diameter. The fan is fixed to the inside of the largest diameter of the wind tube 5 by a grid plate and is located to the right of the ball head 8.

[0038] A centrifugal nozzle 3 is provided at the front end of the interior of the air duct 5, i.e., at the small diameter of the air duct 5. The water tank 7 and the water pump, as well as the water pump and the centrifugal nozzle 3 are connected through a water pipe 9. The atomizing nozzle needs to be coaxially suspended at the center of the front end of the air duct 5. In this embodiment, a hard water pipe 9 is used to support its suspension, and a 4 / 7 type PE capillary tube is preferably used as the water pipe 9 directly connected to the atomizing nozzle.

[0039] Each section of the water pipe 9 is provided with a water stop valve, which is a spring-loaded water stop valve 10. The spring-loaded water stop valve 10 has different characteristics in two flow directions. When the water flow is reversed, the spring-loaded water stop valve 10 cuts off the waterway in one direction.

[0040] The water sprayed from the atomizing nozzle is blown out of the wind tube 5 from the front end under the blowing of the fan and sprayed onto the composite insulator in the form of mist, thereby performing the hydrophobicity test.

[0041] The power supply and control module is fixed above the air duct 5, and includes a power supply and a control module.

[0042] The power supply in this embodiment is a plug-in power supply 11. The battery in the power supply adopts Sony VTC5A power lithium battery F, the charging module of the power supply adopts 2S lithium battery F balance charging module, and the plug connector adopts XT60H-F / M plug.

[0043] In this embodiment, the power supply is placed in the power supply box and bonded to the upper part of the wind tube 5. The power supply can also be fixed by other fixing methods, and the control module can be bonded or fixed by other fixing methods on the upper part of the power supply box.

[0044] The control module is provided with an integrated module combination circuit 12, which includes a 12V DC boost module A, a temperature control switch B, a remote control switch C, an isolating switch D and a high-power MOSFET E. One end of the temperature control switch B is connected to the positive electrode of the lithium battery F, and the other end is connected to the manual switch G. The other end of the manual switch G is connected to the 12V DC boost module A. A power indicator H is also provided between the manual switch G and the 12V DC boost module A. The other end of the 12V DC boost module A is connected to the diaphragm water pump 6 through the remote control switch C, and the other end is connected to the axial flow fan 4 through the high-power MOSFET E. The circuit between the remote control switch C and the water pump is connected to the isolating switch D. The other end of the isolating switch D is connected to the fan through the fan control board I. The circuit between the 12V DC boost module A and the high-power MOSFET E is connected to the remote control switch C.

[0045] The control module needs to control the working status of the fan and water pump, and receive and process signals from the remote control to realize remote control of the measuring device. Therefore, the control module is a hybrid circuit that combines "signal circuit" and "power circuit".

[0046] The control module is electrically connected to the power supply, the fan and the water pump respectively, and can adjust the wind force of the fan and the spraying time of the water pump to improve the accuracy of the hydrophobicity detection.

[0047] During operation, install and fix the centrifugal nozzle 3, axial flow fan 4, diaphragm water pump 6, water tank 7, spring water stop valve 10, plug-in power supply 11, control module, and air duct 5 on the drone 1 through the distributed bracket 2; and inject pure water into the water tank 7; then start the drone 1 and the remote control power supply, make the drone 1 fly a little height first, and then issue a command to make the diaphragm water pump 6 spray water into the air duct 5 while starting the axial flow fan 4, and check whether there is water mist spraying. If there is water mist spraying, the equipment is normal, if there is no water mist spraying, , the equipment is abnormal and the cause needs to be found and solved. After the equipment is normal, the remote control is used to control the drone 1 to take off and fly to the tower head of the tower to be tested. The drone 1 is further remotely controlled to fly to 2-3 meters away from the insulator to be tested, and the spray mechanism is activated. The camera on the drone 1 is then used to photograph the water droplet shape on the insulator surface. The staff compares the photographed water droplet shape with the standard water droplet shape based on the photos sent back to determine the hydrophobicity of the insulator. After all operations are completed, the drone 1 is controlled to return, the spray mechanism is disassembled, and the device is returned to the warehouse for use.

[0048] Example 2: See Figure 1-10 A method for detecting the hydrophobicity of composite insulators on overhead transmission lines. This embodiment is basically the same as the first embodiment, and the similarities are not repeated. The differences are as follows: A method for detecting the hydrophobicity of composite insulators on overhead transmission lines, comprising the following steps: (1) Preparation: Install and secure the centrifugal nozzle 3, axial flow fan 4, diaphragm water pump 6, water tank 7, spring check valve 10, plug-in power supply 11, control module, and air duct 5 to the drone 1 via the distributed bracket 2; inject purified water into the water tank 7; (2) Flight test operations: Start the drone 1 and the remote controller, make the drone 1 fly to a certain height, then issue a command to make the water pump spray water into the air duct 5 and start the fan at the same time, and check whether there is water mist spraying out. If there is water mist spraying out, the device is normal. If there is no water mist spraying out, the device is abnormal and you need to find the cause and solve the problem. (3) Flight operations; After the equipment is normal, control the drone 1 to take off through the remote control and fly to the tower head to be inspected; (4) Water mist spraying and taking photos: The remote-controlled drone 1 flies to a distance of 2-3 meters from the insulator to be tested, activates the spray mechanism, and then uses the camera on the drone 1 to photograph the morphology of water droplets on the insulator surface. The photographed morphology of water droplets is compared with the standard morphology of water droplets to determine the hydrophobicity of the insulator. (5) Operation recovery: Control UAV 1 to return home, dismantle the spray mechanism, and return it to the warehouse for use.

[0049] In this embodiment, the time for installing the spray mechanism on the drone 1 is controlled within 30 seconds through a simple and reliable connection mechanism; the connection mechanism includes a spring clamp and a cable tie, and the cable tie is used to fix the spring clamp to the mounting bracket, and then the spring clamp is used to fix the components in the spray mechanism.

[0050] While injecting water, turn on the power of the drone 1. Considering the startup time of the drone 1, the total preparation time can be controlled within 50 seconds.

[0051] In this embodiment, the take-off point of the drone 1 should be within 50 meters of the horizontal position of the tower to be tested; the height of the composite insulator is generally 20-70 meters, so the straight-line distance between the take-off point of the drone 1 and the detection position does not exceed 86 meters. Since the drone 1 carries an additional load, considering safety and controllability, the flight speed of the drone 1 should be 2-4m / s. Therefore, the time it takes for the drone 1 to fly to the tower head can be controlled within 43s.

[0052] In this embodiment, according to the requirements of hydrophobicity testing, the spraying duration is 20-30 seconds, and the shooting is completed within 10 seconds after the spraying ends. According to the experience of the department's drone 1 pilot, the time required to adjust the position of drone 1 at each insulator measurement point is approximately 10 seconds. The number of insulators per tower is 3-6 strings; therefore, the detection time is within 180-360 seconds.

[0053] In this embodiment, the water storage device becomes lighter when the drone 1 returns, and the flight speed can be 3-5m / s; the time for disassembling the spray mechanism can be controlled within 20s, so the operation recovery time is within 48s.

[0054] The present invention uses a drone 1 to replace manpower in the live hydrophobicity detection of composite insulators, integrates the drone 1 and a spray mechanism, and realizes the transportation of pure water and a water mist release device to an appropriate position at high altitude; utilizes the directional long-distance water mist spraying of the spray mechanism to realize unmanned automatic spraying detection of composite insulators, and finally realizes the replacement of manpower by machines. The use situation is good, and the on-site hydrophobicity detection time of a composite insulator is reduced from the original 104.27 minutes to 8.35 minutes. In addition, the device is portable and safe to operate, and the production efficiency is improved by 92%. At the same time, the detection safety is guaranteed, so that the operators no longer need to climb the pole tower, and the risk of people falling from high altitude is eliminated from the root, which effectively protects the personal safety of the operators. It is easy to promote and has good economic and social benefits.

[0055] The above are only preferred embodiments of the present invention and do not limit the present invention in any form. Any simple modifications made according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A device for detecting the hydrophobicity of composite insulators on overhead power transmission lines, comprising an unmanned aerial vehicle (UAV) carrying platform, characterized by: The UAV carrying platform is provided with a power supply and control module and a spraying mechanism, and the power supply and control module is electrically connected to the spraying mechanism. The UAV carrying platform includes a UAV, and a mounting bracket is provided on the UAV. The spraying mechanism includes an atomizing nozzle, a fan, a water pump and a water stop valve. The mounting bracket is respectively provided with a water tank, a water pump and a wind tube. The atomizing nozzle is provided at the front end of the wind tube, and the fan is provided at the rear end. The water tank and the water pump, as well as the water pump and the atomizing nozzle are connected by water pipes. The water stop valve is provided on each section of the water pipe. The water sprayed from the atomizing nozzle is blown out of the wind tube from the front end of the wind tube under the blowing of the fan, and sprayed onto the composite insulator in the form of mist, and then the hydrophobicity test is performed.

2. The device for detecting hydrophobicity of composite insulators for overhead power transmission lines according to claim 1, wherein: The power supply and control module is arranged above the air duct, and includes a power supply and a control module. The control module is electrically connected to the power supply, the air blower and the water pump respectively.

3. The device for detecting hydrophobicity of composite insulators for overhead power transmission lines according to claim 1, wherein: The water stop valve is a spring water stop valve, which has different characteristics in two flow directions. When the water flow is reversed, the spring water stop valve cuts off the water path in one direction.

4. The device for detecting hydrophobicity of composite insulators for overhead power transmission lines according to claim 2, wherein: The mounting bracket is a distributed bracket, including a UAV extension bracket and a ball head gimbal. The UAV extension bracket is arranged on the UAV, and the ball head gimbal is installed on the upper part of the UAV extension bracket, and the ball head gimbal is used as the base of the wind tube and connected to the wind tube. The fan adopts an axial flow fan; the water pump adopts a diaphragm water pump; the atomizing nozzle adopts a centrifugal nozzle; and the power supply is a plug-in power supply.

5. The device for detecting hydrophobicity of composite insulators for overhead power transmission lines according to claim 2, wherein: The control module is provided with an integrated module combination circuit, which includes a 12V DC boost module, a temperature control switch, a remote control switch, an isolating switch and a high-power MOSFET. One end of the temperature control switch is connected to the positive electrode of the lithium battery, and the other end is connected to the manual switch. The other end of the manual switch is connected to the 12V DC boost module. A power indicator is also provided between the manual switch and the 12V DC boost module. The other end of the 12V DC boost module is connected to the diaphragm water pump after passing through the remote control switch, and is connected to the axial flow fan after passing through the high-power MOSFET. The circuit between the remote control switch and the water pump is connected to the isolating switch. The other end of the isolating switch is connected to the fan through the fan control board. The remote control switch is connected to the circuit between the 12V DC boost module and the high-power MOSFET.

6. A method for detecting the hydrophobicity of a composite insulator of an overhead transmission line when it is charged, using the device for detecting the hydrophobicity of a composite insulator of an overhead transmission line when it is charged, comprising the following steps: (1) Preparation: Install the nozzle, fan, water pump, water tank, water stop valve, power supply, and control module onto the drone through the mounting bracket; inject pure water into the water tank; (2) Flight test operations: Start the drone and the remote controller, fly the drone to a certain height, and then issue a command to make the water pump spray water into the air duct and start the fan at the same time. Check whether there is water mist spraying out. If there is water mist spraying out, the device is normal. If there is no water mist spraying out, the device is abnormal and you need to find the cause and solve the problem. (3) Flight operations; After the equipment is normal, control the drone to take off through the remote control and fly to the tower head to be inspected; (4) Water mist spraying and taking photos: The remote-controlled drone flies to a distance of 2-3 meters from the insulator to be tested, activates the spray mechanism, and then uses the drone's built-in camera to photograph the morphology of water droplets on the insulator surface. The photographed water droplet morphology is compared with the standard water droplet morphology to determine the insulator's hydrophobicity. (5) Operation recovery: Control the drone to return, dismantle the spray mechanism, and return it to the warehouse for use.

7. The method for detecting the hydrophobicity of composite insulators of overhead power transmission lines according to claim 6 is characterized in that: In steps (1) and (2), the time for installing the spray mechanism on the drone is controlled within 30 seconds through the connecting mechanism; while injecting water, the power of the drone is turned on. Considering the startup time of the drone, the total preparation time can be controlled within 50 seconds.

8. The method for detecting the hydrophobicity of composite insulators of overhead power transmission lines according to claim 6 is characterized in that: In step (3), the take-off point of the drone is set within 50 meters of the horizontal position of the tower to be tested; the height of the composite insulator is generally 20-70 meters, so the straight-line distance between the drone take-off point and the test position does not exceed 86 meters. Since the drone carries an additional load, considering safety and control performance, the drone flight speed should be 2-4m / s, so the time it takes for the drone to fly to the tower head can be controlled within 43s.

9. The method for detecting the hydrophobicity of composite insulators of overhead power transmission lines according to claim 6, wherein: In step (4), according to the requirements of the hydrophobicity test, the spraying duration is 20-30 seconds, and the shooting is completed within 10 seconds after the spraying ends. According to the experience of the department's drone pilots, the drone position adjustment time for each insulator measurement point is about 10 seconds. The number of insulators per tower is 3-6 strings; therefore, the detection time is within 180-360 seconds.

10. The method for detecting the hydrophobicity of composite insulators of overhead power transmission lines according to claim 6, wherein : In step (5), the water storage device becomes lighter when the drone returns, and the flight speed can be 3-5m / s; the time for disassembling the spray mechanism can be controlled within 20s, so the operation recovery time is within 48s.

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