An electromagnetic shielding system of an insulator detection device and an unmanned aerial vehicle-mounted insulator detection device

Abstract

The application relates to an electromagnetic shielding system of an insulator detection device and a UAV-mounted insulator detection device, the insulator detection device comprising a hanging frame, a zero-value detector mounted on the hanging frame, and a detection needle electrically connected with the zero-value detector through a signal line, the electromagnetic shielding system comprising a detector shielding assembly, a floating shielding potential equalization network, and a signal transmission shielding assembly. The detector shielding assembly comprises a movable shielding member and an inner shielding member. The movable shielding member comprises a shielding box body and a movable cover plate, the shielding box body is arranged outside the zero-value detector, the shielding box body is provided with an opening, the movable cover plate is arranged at the opening, and the movable cover plate can be switched from a storage state to a closed state to close the opening under the driving of a driving mechanism, so that the shielding box body forms a fully-closed Faraday cage. The application can solve the problem that the detection signal is submerged and distorted by noise, improve the stability and accuracy of the zero-value detection data of the insulator, and meet the high-precision detection requirement of the high-voltage live operation scene.

Description

Technical Field

[0001] This invention relates to the field of insulator testing technology, specifically to an electromagnetic shielding system for insulator testing equipment and a drone-mounted insulator testing equipment. Background Technology

[0002] Transmission line insulators are core insulating components of the power system, playing a crucial role in supporting conductor insulation and isolating high-voltage potentials. Their operating condition directly determines the safety and stability of power supply from the transmission line. Under the combined effects of long-term high-voltage electric fields, wind, sand, rain, snow, alternating temperature differences, and mechanical stress, insulators are prone to defects such as insulation aging, zero-value degradation, and flashover damage. If these defects are not promptly identified and addressed, they can easily lead to line leakage, tripping, or even large-scale power outages, seriously threatening the safe and stable operation of the power grid. Therefore, conducting routine and precise condition monitoring of transmission line insulators is a core and essential requirement of power operation and maintenance work.

[0003] Currently, drone-mounted insulator inspection equipment, with its advantages of flexible operation, no need to build operating channels, and suitability for high-altitude, long-distance line inspection, has gradually replaced traditional methods such as manual tower climbing and ground telescope inspection, becoming the mainstream technical means for detecting insulator defects in transmission lines. The applicant, in collaboration with Wuhan Lierda Digital Intelligent Testing Technology Co., Ltd. and Henan Sida Testing Technology Co., Ltd., has jointly developed a drone-mounted insulator inspection device, as detailed in Reference 1 (Chinese Patent Document with Publication No. CN121299382A).

[0004] The aforementioned testing equipment, through optimized mounting structure and the integration of drive, stabilization, and auxiliary units, achieves stable mounting and precise displacement of the testing equipment on insulator strings. This enables automated detection of zero-value defects in insulators, effectively solving the problems of low efficiency, high-risk high-altitude operations, and large errors associated with traditional manual testing. However, this equipment is primarily designed for power outage environments without strong electromagnetic interference. In actual power grid operation and maintenance scenarios, high-voltage transmission lines cover a wide area with high load density, and frequent full-line power outages for testing can severely impact regional power supply reliability. When this testing equipment is directly applied to live-line testing of high-voltage transmission lines, the following problems arise: Firstly, strong power frequency electric fields can form around live lines, continuously coupling interference to the electrical system of the testing equipment. Secondly, corona discharge between high-voltage conductors and insulator surfaces generates broadband, high-frequency electromagnetic noise, covering the core signal frequency band for insulator leakage current detection. This makes the signal easily submerged by electromagnetic noise, causing coupling distortion, ultimately leading to a significant decrease in the accuracy of zero-value insulator detection, data disorder, and even complete signal failure. Summary of the Invention

[0005] The purpose of this invention is to solve the above-mentioned technical problems existing in the prior art and to provide an electromagnetic shielding system for insulator testing equipment and a drone-mounted insulator testing equipment.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: An electromagnetic shielding system for an insulator testing device, the insulator testing device comprising a mounting bracket, a zero-value detector mounted on the mounting bracket, and a detection probe electrically connected to the zero-value detector via a signal line, the electromagnetic shielding system comprising: Detector shielding components; and Floating shielding potential equalization network; and Signal transmission shielding components; The detector shielding assembly includes a movable shielding component and an inner shielding component; The movable shielding component includes a shielding box and a movable cover plate. The shielding box is placed outside the zero-value detector. The shielding box has an opening, and the movable cover plate is located at the opening. The movable cover plate can switch from a retracted state to a closed state under the drive of the drive mechanism to close the opening, so that the shielding box forms a fully enclosed Faraday cage. The inner shield is disposed around the circuit board of the zero detector and at the signal line entrance; The floating shielding potential equalization network includes a high-value resistor and a small-capacity capacitor connected in parallel, which are electrically connected between the outer shielding layer and the signal ground of the zero-value detector. In high-voltage live-line testing, the testing device itself is in a high-potential floating state. If a potential difference arises between the shielding layer and the internal circuit, it may introduce greater coupling interference. Traditional fixed grounding methods are not suitable for high-potential floating conditions. It is recommended to use floating shielding potential equalization technology. Its core principle is to connect the shielding layer and the ground of the internal circuit through a high-impedance voltage divider network, so that the potential of the shielding layer follows the potential changes of the internal circuit, maintaining a constant potential difference between the two, thereby avoiding additional coupling interference caused by potential fluctuations.

[0007] This technology has been applied in the fields of electric field measurement and high voltage measurement. The key is that the shielding electrode of the measuring electrode and the shielded measuring electrode must maintain a good potential following relationship. At the same time, the RC equipotential shielding technology is used to solve the measurement accuracy problem in the 30300Hz AC high voltage environment.

[0008] The signal ground (GND) of the zero-value detector is connected to the shielding layer through a floating network consisting of a high-value resistor (approximately 110MΩ) and a small-capacity capacitor (approximately 1000pF) connected in parallel. This ensures that the potential of the shielding layer always follows the change in the signal ground potential, while also providing a path for electrostatic discharge.

[0009] The signal transmission shielding assembly includes a double-layer coaxial shielded cable and common-mode chokes disposed at both ends of the double-layer coaxial shielded cable. The double-layer coaxial shielded cable is used to connect the detection probe and the zero-value detector. The inner shielding layer of the double-layer coaxial shielded cable is grounded, and the outer shielding layer is grounded at one end.

[0010] The inner shielding layer is directly connected to the signal ground of the probe signal link (i.e., the analog ground of the zero-value detector). Its function is to provide a low-impedance return path for the main signal line while suppressing electric field coupling.

[0011] The outer shielding layer is connected to the signal ground only at one end of the cable (the end closer to the zero-value detector), while the other end (the end closer to the detection probe) is left unconnected. This single-end grounding avoids circulating currents caused by the potential difference between the two ends of the shielding layer, and at the same time, the outer shielding layer absorbs spatial electromagnetic interference and guides it to the signal ground.

[0012] As a further optimization of the electromagnetic shielding system of the insulator testing device of the present invention: the resistance of the high-value resistor is 1 to 10 MΩ, and the capacitance of the small-capacity capacitor is 1000 pF.

[0013] As a further optimization of the electromagnetic shielding system of the insulator testing device of the present invention: the shielding box is composed of a box body and a shielding layer disposed on the surface of the box body. The box body is made of engineering plastic, and the shielding layer is silver-plated copper foil or copper sheet with a thickness of 0.1mm to 0.2mm.

[0014] As a further optimization of the electromagnetic shielding system of the insulator testing device of the present invention: the inner shielding component is conductive rubber or conductive foam with a volume resistivity of less than 0.05 Ω·cm.

[0015] As a further optimization of the electromagnetic shielding system of the insulator testing device of the present invention: the shielding box is provided with wire holes for leading out signal lines, power lines and control lines.

[0016] As a further optimization of the electromagnetic shielding system of the insulator testing device of the present invention: a conductive rubber gasket or a metal braided mesh is provided on the inner edge of the wire hole.

[0017] As a further optimization of the electromagnetic shielding system of the insulator testing device of the present invention: the movable cover plate includes: A reel, rotatably mounted on the first side of the opening of the shielding box; and Flexible shielding film, wound on a spool; and A tie rod is fixedly connected to the outer edge of the flexible shielding film and extends along the width direction of the flexible shielding film; and A winding motor is located on the second side of the open end of the shielded housing, opposite to the first side; and The pull wire has one end connected to the shaft of the winding motor and the other end connected to the support rod; An elastic recovery component, located at the spool, is used to apply a restoring force to the spool to allow the flexible shielding film to be wound.

[0018] As a further optimization of the electromagnetic shielding system of the insulator testing device of the present invention: the elastic recovery component is a torsion spring sleeved on the reel, one end of the torsion spring is fixed to the reel, and the other end is fixed to the shielding box.

[0019] As a further optimization of the electromagnetic shielding system of the insulator testing device of the present invention: the flexible shielding film is made of conductive fabric or metallized plastic film.

[0020] As a further optimization of the electromagnetic shielding system of the insulator testing device of the present invention: the winding motor is a slow-speed DC motor, and the pull wire is nylon wire, Dyneema wire or Kevlar wire.

[0021] The present invention also provides a drone-mounted insulator testing device, including a mounting frame, a drive unit, a testing unit, a stabilization unit, and an auxiliary unit. The testing unit includes a zero-value detector mounted on an extension frame. The signal input terminal of the zero-value detector is electrically connected to a testing probe. The testing unit also includes the aforementioned electromagnetic shielding system.

[0022] The present invention has the following beneficial effects: 1. The electromagnetic shielding system of the present invention forms a fully enclosed Faraday cage through movable shielding components, and together with the inner shielding components, achieves all-round electromagnetic isolation of the zero-value detector, which can effectively shield the strong power frequency electric field and spatial stray electromagnetic interference around the high-voltage live line; the floating shielding potential equalization network adopts a high resistance-capacitance parallel structure, so that the shielding layer potential follows the internal signal ground potential dynamically and synchronously, avoiding additional coupling interference caused by the potential difference between the shielding layer and the circuit in the high-potential floating state, which can solve the problem of the detection signal being submerged and distorted by noise, improve the stability and accuracy of the zero-value detection data of the insulator, and meet the high-precision detection requirements of high-voltage live operation and maintenance scenarios; 2. The movable shielding component of the present invention adopts a lightweight design with an engineering plastic substrate coated with a shielding layer. Combined with a flexible shielding film and an electric winding drive mechanism, it can automatically switch between a retracted state and a closed shielding state (closed when encountering strong interference such as switching operation or lightning transients, and opened during routine inspection and heat dissipation or wireless communication), without manual intervention, taking into account both shielding performance and the lightweight and miniaturized requirements of UAV mounted equipment. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the shielding box structure; Figure 2 This is a structural diagram of a shielded box (in its enclosed state); Figure 3 Insulator testing equipment (perspective 1); Figure 4 Insulator testing equipment (perspective 2); Marked in the image: 1. Hanging bracket; 2. Detection components; 201. Zero-value detector; 202. Detection needle; 3. Drive unit; 4. Detector shielding assembly; 401. Shielding box; 402. Movable cover plate; 4021, Scroll; 4022, Flexible shielding film; 4023, pull rod; 4024. Winding motor; 4025, Pulling wire. Detailed Implementation

[0024] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the accompanying drawings in this application are for illustrative and descriptive purposes only and are not intended to limit the scope of protection of this application. Furthermore, it should be understood that the schematic drawings are not drawn to scale. The flowcharts used in this application illustrate operations implemented according to some embodiments of this application. It should be understood that the operations in the flowcharts may not be implemented in sequence, and steps without logical contextual relationships may be reversed or implemented simultaneously. In addition, those skilled in the art, guided by the content of this application, may add one or more other operations to the flowcharts, or remove one or more operations from the flowcharts.

[0026] Furthermore, the described embodiments are merely some, not all, of the embodiments of this application. The components of the embodiments of this application described and illustrated herein can typically be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0027] It should be noted that the term "comprising" will be used in the embodiments of this application to indicate the presence of the features declared thereafter, but does not exclude the addition of other features.

[0028] All terms related to "grounding" refer to the "signal ground" connected inside the device, i.e., the zero-potential reference point on the zero-value detector circuit board.

[0029] Example 1

[0030] An electromagnetic shielding system for an insulator testing device is disclosed, which is compatible with UAV-mounted insulator testing equipment. The testing device includes a mounting frame 1, a testing component 2 mounted on the mounting frame, and a testing needle electrically connected to the testing component 2 via a signal line. The electromagnetic shielding system consists of three parts: a detector shielding component 4, a floating shielding potential equalization network, and a signal transmission shielding component.

[0031] The detector shielding assembly 4 includes an active shield and an inner shield, which are used to achieve electromagnetic shielding of the zero-value detector body.

[0032] The movable shielding component includes a shielding box 401 and a movable cover 402. The shielding box 401 covers the outside of the zero-value detector 201, and has a rectangular structure with an opening on one side.

[0033] The shielding box 401 is composed of a box body and a shielding layer. The box body is made of ABS engineering plastic injection molding, and the shielding layer is 0.15mm thick silver-plated copper foil, which is tightly attached to the inner and outer surfaces of the box body with conductive adhesive.

[0034] like Figure 1 and 2 As shown, the movable cover plate 402 is located at the opening of the shielding box 401 and consists of a roller 4021, a flexible shielding film 4022, a pull rod 4023, a winding motor 4024, a pull wire 4025, and an elastic recovery assembly.

[0035] The spool 4021 is rotatably mounted on the left side of the open end of the shielding box 401. The flexible shielding film 4022 is made of nickel-plated conductive fabric and is wound on the spool 4021.

[0036] The pull rod 4023 is fixed along the width direction of the outer end of the flexible shielding film 4022 to ensure that the film is unfolded flat. The winding motor 4024 is a slow-speed DC motor, which is installed on the right side of the opening of the shielding box 401 and is set opposite to the winding shaft 4021.

[0037] The shielding box 401 is provided with a limiting head at one end of the roller 4021 for limiting the pull rod 4023. The limiting head limits the extreme position of the pull rod 4023 so that it is located on one side of the open end of the shielding box 401 in the initial state.

[0038] The pull wire 4025 is made of Kevlar wire, with one end connected to the shaft of the winding motor 4024 and the other end connected to the pull rod 4023.

[0039] The elastic recovery component is a torsion spring sleeved on the reel 4021. One end of the torsion spring is fixed to the reel 4021 and the other end is fixed to the shielding box 401, providing winding recovery force under normal conditions.

[0040] During operation, in the equipment moving / attaching phase, the winding motor is not working; the torsion spring drives the winding shaft to rotate, and the flexible shielding film is wound and stored, opening the opening. During the testing phase, the winding motor rotates forward, pulling the lever via a cable to unfold the flexible shielding film, closing the opening and forming a fully enclosed Faraday cage within the shielding box, achieving electromagnetic shielding. After testing is completed, the winding motor reverses, and the torsion spring assists in automatically winding and storing the flexible shielding film, restoring the open state.

[0041] Specifically, it closes when encountering strong interference such as switching operations or lightning strikes, and opens during routine heat dissipation inspections or wireless communication.

[0042] The control method for the movable cover can be one of the following two: Electric field strength threshold trigger: Set up a flat plate electric field sensor, and automatically trigger the closure when a sudden change in electric field strength is detected (which is a sign of transient high electromagnetic load).

[0043] Command trigger: The pilot can switch with one button on the ground remote controller, or link it with the detection steps (the shielding layer will automatically close 1 second before the detection probe is connected, and will automatically open to send data after the detection is completed).

[0044] The inner shielding component is made of conductive rubber with a volume resistivity of 0.03Ω・cm. It is cut into a suitable shape and pasted around the gaps of the zero-value detector circuit board, the signal line entrance, and the seams of the inner wall of the shielding box. It fills the gaps in the shielding cavity, prevents electromagnetic leakage, and at the same time plays a role in buffering and shock absorption, protecting the circuit board components.

[0045] The shielded box has three wire-through holes on its side wall, which are used to lead out signal lines, power lines, and control lines, respectively. Conductive rubber gaskets are embedded in the inner edge of the wire-through holes to ensure that the cables are electrically connected to the shielding layer when they pass through, and to prevent electromagnetic leakage from the holes.

[0046] The floating shielding potential equalization network consists of a 5MΩ high-value resistor and a 1000pF small-capacity capacitor connected in parallel. One end is electrically connected to the silver-plated copper foil shielding layer of the shielding box, and the other end is electrically connected to the signal ground (GND) of the zero-value detector circuit board.

[0047] During high-voltage live testing, the equipment is in a high-potential floating state. The high-value resistor provides a high-impedance path, allowing the shielding layer potential to dynamically change with the internal signal ground potential, maintaining a constant potential difference between the two and avoiding coupling interference caused by the potential difference. The small-capacity capacitor provides a low-impedance discharge path for high-frequency interference, filtering out high-frequency noise. At the same time, the parallel network can slowly discharge the static electricity of the shielding layer to the signal ground, preventing static electricity accumulation from damaging the equipment.

[0048] The signal transmission shielding assembly includes a double-layer coaxial shielded cable and two common-mode chokes for electromagnetic shielding of signal transmission between the detection probe and the zero-value detector.

[0049] The double-coaxial shielded cable features an inner copper mesh shield and an outer aluminum foil shield. The inner shield is connected to the signal ground of the zero-value detector throughout, providing a low-impedance return path for the main signal line and suppressing electric field coupling interference. The outer shield is connected to the signal ground only at the end near the zero-value detector, leaving the end near the detection probe unconnected to prevent circulating current caused by potential difference between the two ends of the shield. It also absorbs spatial electromagnetic interference and directs it to the signal ground. Common-mode chokes are connected in series at both ends of the double-coaxial shielded cable (detection probe end and zero-value detector end) to effectively suppress common-mode interference during signal transmission.

[0050] Example 2

[0051] like Figure 3 and 4 As shown, a drone-mounted insulator testing device includes a specially designed mounting frame 1 as its main body. The mounting frame 1 is quickly attached to a dedicated mounting component carried by the drone, enabling aerial deployment and precise positioning of the testing equipment. Operators can remotely control the drone from the ground to smoothly move and mount the entire mounting frame 1 onto the insulator string to be inspected. After successful mounting, the integrated drive unit 3, stabilization unit, and auxiliary unit of the mounting frame 1 work together. The drive unit 3 provides the power to move along the insulator string; the stabilization unit ensures that the device does not tilt or shake during movement; and the auxiliary unit further enhances positioning and also provides cleaning functionality. The coordinated operation of these three units ensures that the mounting frame 1 can perform displacement operations on the insulator string with extremely high stability. Ultimately, the goal is to enable the testing component 2 installed on the mounting frame 1 to sequentially and accurately position each key node of the insulator string, thereby performing non-destructive testing of the insulation resistance of each individual insulator in the string.

[0052] The overall structure of the insulator testing equipment is no different from existing technologies, and will not be described in detail here.

[0053] The shielding box is fixedly installed on the outer frame of the mounting bracket 1, and completely encloses the power supply and signal detection and transmission parts of the entire zero-value detector 201 inside it.

[0054] Around the circuit board of the zero detector 201, a layer of conductive rubber pad (volume resistivity <0.05Ω·cm) is attached to any location where components or signal lines pass through the shielded area. This conductive rubber pad serves as both local shielding and buffering material for the circuit board. A conductive rubber sheath is also provided at the entrance where the signal line (the signal line connecting the detection probe) enters the housing of the zero detector 201 from the outside to suppress electromagnetic interference from being conducted along the signal line into the circuit board.

[0055] After the device is hoisted by a drone and straddles the energized insulator string, the system operates according to the following procedure: The outer shielding layer's movable cover is in the open position (the flexible shielding film is wound on a spool) to allow the pilot to perform initial parameter configuration and status checks via wireless signal. The inner shielding layer remains closed. The drive motor shielding assembly and signal transmission shielding assembly are always operational.

[0056] When the device begins to move along the insulator string and requires precise testing, the control system issues a command, the winding motor rotates forward, the pull wire pulls the support rod, the flexible shielding film unfolds and covers the opening of the box, and the outer shielding layer forms a fully enclosed Faraday cage. In this state, external power frequency electric fields, corona discharge noise, and switching transient interference are effectively blocked. The testing device moves piece by piece under the drive unit. Whenever it reaches the target insulator, the flip motor 203 drives the detection pin 202 to connect with both ends of the insulator for testing.

[0057] A simple flat-plate electric field sensor is added to the mounting bracket 1. When a sudden change in electric field intensity is detected, the control system automatically keeps the shielding box closed and suspends the detection action until the electric field returns to stability before resuming detection.

[0058] After each string of insulators is tested, the device transmits the data back to the ground station via a wireless module. At this point, the control system instructs the winding motor to release the tension wire, and the flexible shielding film automatically rewinds under the action of a torsion spring, opening to ensure effective wireless signal transmission and natural heat dissipation of the internal circuitry. Once the data transmission is complete, the outer shielding layer closes again, and subsequent tests continue.

[0059] After the inspection is completed, the drone will lift the device away from the insulator string, keeping the outer shielding layer open (or closed according to ground instructions), and the device will be powered off.

[0060] The electromagnetic shielding system of this invention can be directly integrated into existing UAV-mounted insulator testing equipment without significant modifications to the main structure of the equipment. It is suitable for live-line testing of insulators on transmission lines of various voltage levels, eliminating the need for a complete power outage, significantly reducing outage time, and ensuring the reliability of regional power supply. It replaces traditional manual tower climbing and ground inspection methods, avoids the safety risks of high-altitude operations, significantly improves the efficiency of power grid operation and maintenance, and provides reliable technical support for the safe and stable operation of transmission lines.

Claims

1. An electromagnetic shielding system for an insulator testing device, the insulator testing device comprising a mounting frame, a zero-value detector mounted on the mounting frame, and a detection probe electrically connected to the zero-value detector via a signal line, characterized in that, Electromagnetic shielding systems include: Detector shielding components; and Floating shielding potential equalization network; and Signal transmission shielding components; The detector shielding assembly includes a movable shielding component and an inner shielding component; The movable shielding component includes a shielding box and a movable cover plate. The shielding box is placed outside the zero-value detector. The shielding box has an opening, and the movable cover plate is located at the opening. The movable cover plate can switch from a retracted state to a closed state under the drive of the drive mechanism to close the opening, so that the shielding box forms a fully enclosed Faraday cage. The inner shield is disposed around the circuit board of the zero detector and at the signal line entrance; The floating shielding potential equalization network includes a high-value resistor and a small-capacity capacitor connected in parallel, which are electrically connected between the outer shielding layer and the signal ground of the zero-value detector. The signal transmission shielding assembly includes a double-layer coaxial shielded cable and common-mode chokes disposed at both ends of the double-layer coaxial shielded cable. The double-layer coaxial shielded cable is used to connect the detection probe and the zero-value detector. The inner shielding layer of the double-layer coaxial shielded cable is grounded, and the outer shielding layer is grounded at one end.

2. The electromagnetic shielding system of an insulator testing device as described in claim 1, characterized in that: The high-value resistor has a resistance of 1 to 10 MΩ, and the small-capacity capacitor has a capacitance of 1000 pF.

3. The electromagnetic shielding system of the insulator testing equipment as described in claim 1, characterized in that: The shielding box consists of a box body and a shielding layer disposed on the surface of the box body. The box body is made of engineering plastic, and the shielding layer is silver-plated copper foil or copper sheet with a thickness of 0.1mm to 0.2mm.

4. The electromagnetic shielding system of an insulator testing device as described in claim 1, characterized in that: The inner shielding component is made of conductive rubber or conductive foam, with a volume resistivity of less than 0.05 Ω·cm.

5. The electromagnetic shielding system of an insulator testing device as described in claim 1, characterized in that: The shielding box is provided with wire holes for leading out signal lines, power lines and control lines, and the inner edge of the wire holes is provided with conductive rubber gaskets or metal braided mesh.

6. The electromagnetic shielding system of an insulator testing device as described in claim 1, characterized in that: The movable cover plate includes: A reel, rotatably mounted on the first side of the opening of the shielding box; and Flexible shielding film, wound on a spool; and A tie rod is fixedly connected to the outer edge of the flexible shielding film and extends along the width direction of the flexible shielding film; and A winding motor is located on the second side of the open end of the shielded housing, opposite to the first side; and The pull wire has one end connected to the shaft of the winding motor and the other end connected to the support rod; An elastic recovery component, located at the spool, is used to apply a restoring force to the spool to allow the flexible shielding film to be wound.

7. The electromagnetic shielding system of an insulator testing device as described in claim 6, characterized in that: The elastic recovery component is a torsion spring sleeved on the reel, with one end of the torsion spring fixed to the reel and the other end fixed to the shielding box.

8. The electromagnetic shielding system of an insulator testing device as described in claim 6, characterized in that: The flexible shielding film is made of conductive fabric or metallized plastic film.

9. The electromagnetic shielding system of an insulator testing device as described in claim 6, characterized in that: The winding motor is a slow-speed DC motor, and the pull wire is nylon wire, Dyneema wire, or Kevlar wire.

10. A UAV-mounted insulator testing device, comprising a mounting frame, a drive unit, a testing unit, a stabilization unit, and an auxiliary unit, wherein the testing unit includes a zero-value detector mounted on an extension frame, and the signal input terminal of the zero-value detector is electrically connected to a testing probe, characterized in that: The detection unit further includes an electromagnetic shielding system as described in any one of claims 1-9.

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