Magnetic fault detection and electric energy recovery method based on power grid inspection

Abstract

The invention discloses a magnetic fault detection and electric energy recovery method based on power grid inspection, and belongs to the technical field of electric power inspection. The device comprises a control terminal, an unmanned aerial vehicle and a magnetic detection energy recovery device, wherein the magnetic detection energy recovery device is mounted at the lower part of the unmanned aerial vehicle; the magnetic detection electric energy recovery device is composed of three identical one-way magnetic induction coils, and every two of the three one-way magnetic induction coils are perpendicular to each other to form an omnidirectional coil. According to the unidirectional magnetic induction coil, a plurality of T-shaped ferrite arrays which are uniformly distributed and are in mirror symmetry pairwise are respectively embedded in the upper plane and the lower plane of the coil. According to the method, power line magnetic field changes are captured in real time through the magnetic detection technology, electric energy is recycled in combination with the electromagnetic induction principle, and meanwhile the recycled electric energy is used for improving the endurance of the unmanned aerial vehicle. The system can accurately judge the damage condition and the fault distance, improves the inspection distance through energy recovery, directly detects the internal problem of the line without considering the influence of the external environment, and prolongs the inspection distance of the unmanned aerial vehicle.

Description

Technical Field

[0001] The present invention belongs to the technical field of power system inspection, and in particular relates to a magnetic fault detection and electric energy recovery method based on power grid inspection. Background Art

[0002] As electricity demand continues to grow, the scale and complexity of power grids continue to increase. Manual inspection methods are often dangerous and inefficient, and can no longer meet the demands for efficient, safe, and economical management. Power grid inspection technology is gradually moving toward intelligent and automated approaches.

[0003] In existing technologies, drone-based power inspection methods have two major drawbacks:

[0004] 1. Poor environmental adaptability: Application number "CN202410178393.9" discloses a solution titled "UAV-Based Power Line Safety Inspection System and Method Based on Intelligent Image Recognition." This method uses image recognition technology and a YOLOv4 network for target detection and extraction of power line information. Due to the strong dependence of the optoelectronic and infrared devices on drones on the environment, the image recognition accuracy of this method will be significantly reduced in foggy and dusty weather conditions. Application number "CN202321649138.5" discloses a solution titled "A Method for Power Line Inspection Device Based on Infrared Detection." This method uses multiple infrared sensors to perform power line inspections. However, this method still has the problem of being dependent on the environment. In strong winds, the surface temperature of the device dissipates too quickly, affecting the accuracy of the inspection results. In hot weather, background radiation sources can also significantly affect the infrared test results.

[0005] 2. Insufficient endurance: Existing solutions do not integrate energy recovery technology, and the drone's endurance is limited, making it difficult to meet long-distance inspection needs. Summary of the Invention

[0006] The present invention proposes a magnetic fault detection and power recovery method based on power grid inspection to solve the problems of inaccurate results caused by inspection dependence on the environment and insufficient drone endurance in the existing technology.

[0007] To achieve the purpose of the present invention, the technical solution proposed in the present invention is as follows: a magnetic fault detection and power recovery system based on power grid inspection, comprising a control terminal, a drone, and a magnetic detection energy recovery device, wherein the magnetic detection power recovery device is installed at the bottom of the drone;

[0008] The magnetic detection power recovery device is composed of three identical unidirectional magnetic induction coils wound with enameled copper wires in a clockwise direction. The three unidirectional magnetic induction coils are perpendicular to each other in pairs to form omnidirectional coils.

[0009] The unidirectional magnetic induction coil is respectively embedded with an array of T-shaped ferrites that are evenly distributed and mirror-symmetrical in pairs on the upper plane and the lower plane of the coil.

[0010] Furthermore, in the above-mentioned magnetic detection power recovery device, the T-type ferrite material array includes 4 pairs of evenly distributed and mirror-symmetrical T-type ferrites, wherein the T1 ferrite is symmetrical with the T5 ferrite, wherein the T2 ferrite is symmetrical with the T6 ferrite, wherein the T3 ferrite is symmetrical with the T7 ferrite, and wherein the T4 ferrite is symmetrical with the T8 ferrite.

[0011] Furthermore, the above-mentioned line fault determination method of the magnetic fault detection and power recovery method based on power grid inspection includes the following steps: the inspection task is started, the control terminal sends an inspection instruction, and the drone that receives the instruction takes off. During the inspection process, the magnetic detection energy recovery device simultaneously performs energy recovery; if a fault is found, the controller sends the fault location data to the control terminal, and continues to cruise after the sending is completed. If the sending is not completed, the control terminal finds the problem and resends the inspection instruction to the new drone; if no fault is found, magnetic detection and energy recovery are continued during the cruise until the inspection task is completed.

[0012] Furthermore, the actual magnetic flux of the magnetic detection energy recovery device is:

[0013]

[0014] Fault diagnosis is performed based on changes in magnetic flux.

[0015] Furthermore, the above-mentioned method for fault judgment based on magnetic flux change is the absolute threshold method |ΔΦ op (t)∣≥Φ th , when the magnetic flux change exceeds the preset threshold Φ th When the error message is displayed, it is judged as a fault.

[0016] Furthermore, the method for fault judgment based on the above magnetic flux change is the relative change rate method. When ∈ op (t)≥∈ th , it is determined to be a fault state.

[0017] Furthermore, the magnetic detection energy recovery device is an omnidirectional coil that can cut the magnetic field in every dimension. During the shaking, there is always one dimension that can cut the magnetic flux lines. Based on Faraday's law of electromagnetic induction, the converted electrical energy is stored in the drone battery after being stabilized by the DC-DC module, thereby increasing the inspection distance. The induced electromotive force in the coil is:

[0018]

[0019] Furthermore, the equivalent area A of the omnidirectional coil all The energy conversion efficiency is:

[0020]

[0021] Furthermore, the above-mentioned UAV starts to take off in the designated inspection area after receiving the command from the control terminal. When the UAV inspects along the cable, its GPS coordinates or relative displacement are recorded: x(t)=x0+v d t(where v d is the inspection speed of the drone), and at the same time, the amplitude of the magnetic flux change is monitored, and the point with the largest amplitude change is determined as the fault point:

[0022]

[0023] Compared with the existing method, the present invention has the following beneficial effects:

[0024] 1. The present invention can effectively solve the problems of image information loss and inaccurate infrared recognition under conditions of heavy fog, dust and high temperature. During the power grid inspection process, the magnetic detection power recovery device uses the relative change rate of the current cable's magnetic flux as the fault judgment standard. By comparing image recognition and infrared detection, since the material medium of the same cable is the same, the current flowing over a period of time is constant, and the relative change rate of the detected magnetic flux is small. If a cable fault occurs, the corresponding cable current will change, and the relative change rate of the detected magnetic flux will be large. Magnetic fault detection can focus on damage to the power system line and eliminate interference from other factors. It can accurately detect the cable's magnetic flux in different environments, thereby judging the cable's fault condition, ignoring the influence of heavy fog, dust and high temperature in the environment, making the application range of this method wider. In this method, the magnetic detection power recovery device uses an omnidirectional coil of T-type ferrite, and the magnetic field is effectively concentrated, which increases the magnetic flux. Therefore, the same current produces a larger magnetic flux change, making it easier to detect small anomalies, improving detection sensitivity and the accuracy of fault judgment.

[0025] 2. The present invention can effectively improve the endurance of drones. This device uses an omnidirectional coil of T-shaped ferrite. Compared with ferrites and coils of other shapes, this structure has a smaller volume and lighter weight under the same magnetic flux conditions. The symmetrical arrangement of two coils effectively increases the effective area of the magnetic detection power recovery device. The omnidirectional coils provided can cut the magnetic field in each dimension, and energy recovery can be achieved within the magnetic field range of the power system line. This feature greatly simplifies the inspection operation, allowing drones to operate efficiently even in complex environments. At the same time, the continuous energy supply ensures that the drone can monitor for a longer period of time, cover a wider area, and improve the efficiency and reliability of inspections.

[0026] 3. The present invention has multiple functions: the magnetic detection power recovery device is fixed to the drone. During the inspection process, the real-time data detected by the magnetic detection power recovery device can be sent to the control terminal 1. The feedback data is processed through calculation, and the GPS module of the drone is used to analyze the accurate power line fault point, and notify the maintenance personnel of the specific maintenance location. At the same time, the inspection distance can be effectively extended, and the GPS system of the drone can be used to locate the precise fault point, thereby improving the detection efficiency of the power system line, improving the inspection efficiency and maintenance feedback. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the architecture diagram of the magnetic detection power grid drone inspection system;

[0028] Figure 2 This is a three-dimensional structural diagram of the magnetic detection power recovery device;

[0029] Figure 3 Schematic diagram of symmetrically arranged T-shaped ferrite unidirectional coils;

[0030] Figure 4 This is a schematic diagram of the inspection scene of the magnetic detection power recovery device;

[0031] Figure 5 It is an inspection flow chart, which includes three stages: "fault detection → energy recovery → data return".

[0032] The reference numerals are as follows:

[0033] 1-control terminal, 2-drone, 3-magnetic detection energy recovery device, 11-unidirectional magnetic induction coil, 12-unidirectional magnetic induction coil, 13-unidirectional magnetic induction coil. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is described clearly and completely below in conjunction with the specific embodiments of the present invention and the accompanying drawings.

[0035] The power cable will generate a certain stable magnetic field around it due to the flow of current. When the drone 2 moves above the power line, the magnetic detection power recovery device 3 will judge the damage and abnormal status of the current power line based on the current magnetic field changes, and at the same time, it will cut the magnetic lines of force during the movement to recover power.

[0036] See also Figures 1-4 The present invention proposes a magnetic detection-based energy recovery device for power grid drone inspections, comprising a control terminal 1, a drone 2, and a magnetic detection energy recovery device 3. The drone 2 is equipped with a magnetic detection energy recovery device 3 and a controller. The control terminal 1 can be located in a ground control center or a mobile control cabin.

[0037] See also Figure 2 The magnetic detection power recovery device 3 is composed of three identical unidirectional magnetic induction coils, each with N turns, an inner diameter r, and an outer diameter R, wound clockwise around an enameled copper wire. The three unidirectional magnetic induction coils are arranged perpendicular to each other to form an omnidirectional coil. The unidirectional magnetic induction coils are arranged in an orthogonal X / Y / Z configuration, with unidirectional magnetic induction coil 11 serving as the XY plane, unidirectional magnetic induction coil 12 serving as the XZ plane, and unidirectional magnetic induction coil 13 serving as the YZ plane. Unidirectional magnetic induction coil 11 is perpendicular to unidirectional magnetic induction coil 12, unidirectional magnetic induction coil 12 is perpendicular to unidirectional magnetic induction coil 13, and unidirectional magnetic induction coil 11 is perpendicular to unidirectional magnetic induction coil 13.

[0038] See also Figure 3 The unidirectional magnetic induction coil is embedded with evenly distributed, mirror-symmetrical T-shaped ferrite arrays on the upper and lower surfaces of the coil. The T-shaped ferrite array includes four pairs of evenly distributed, mirror-symmetrical T-shaped ferrites. The eight T-shaped ferrites are fixed to the upper and lower surfaces of the unidirectional magnetic induction coil using non-magnetic insulating tape. The T1 ferrite is symmetrical with the T5 ferrite, the T2 ferrite is symmetrical with the T6 ferrite, the T3 ferrite is symmetrical with the T7 ferrite, and the T4 ferrite is symmetrical with the T8 ferrite.

[0039] To find the optimal distribution of ferrites within the coil, simulations were performed using COMSOL physics simulation software. The work was conducted as follows: simulation comparisons of a full-coverage ferrite coil with a symmetrical T-shaped ferrite coil; simulation comparisons of a symmetrical rectangular ferrite coil with a symmetrical T-shaped ferrite coil; simulation comparisons of a symmetrical cross-shaped ferrite coil with a symmetrical T-shaped ferrite coil; and simulation comparisons of 8 symmetrical T-shaped ferrite coils with 4 symmetrical T-shaped ferrite coils, 12 symmetrical T-shaped ferrite coils, and 16 symmetrical T-shaped ferrite coils, ranging from 4 to 16 ferrites. The simulation results show that, under the same frequency and material, a larger coverage area does not necessarily result in a higher magnetic flux density. Among ferrite coils of varying shapes, T-shaped ferrites have the best magnetic flux density. For coils with 4 to 16 ferrite coils, the flux density of eight symmetrical T-shaped ferrite coils is greater than that of 12 symmetrical T-shaped ferrite coils, greater than that of 16 symmetrical T-shaped ferrite coils, and greater than that of four symmetrical T-shaped ferrite coils. Simulations show that eight symmetrical T-shaped ferrite coils are the optimal configuration, and the magnetic flux detected by eight symmetrically arranged T-shaped ferrite coils is approximately twice that of a coil without ferrite.

[0040] A power grid drone inspection energy recovery device based on magnetic detection, wherein a lightweight carbon fiber insulation plate is installed on the bottom of the drone 2, and a hole is punched in the center of the carbon fiber insulation plate for fixing the controller. The controller includes a control circuit and a communication transmission circuit. The communication transmission circuit uses a serial port to connect to the drone's data transmission system to transmit the obtained data information back to the control terminal 1. The magnetic detection energy recovery device 3 is fixed 60 cm below the carbon fiber insulation plate through a metal tube. The line is connected to the control circuit and transmission circuit through the metal tube. The magnetic field detection and energy recovery are realized through the differential amplifier circuit, filter circuit and DC-DC voltage regulation. The actual magnetic flux of the magnetic detection energy recovery device 3 is:

[0041]

[0042] Using the absolute threshold method |ΔΦ op (t)∣≥Φ th Fault judgment is performed on the magnetic flux change. When the magnetic flux change exceeds the preset threshold Φ th When the error message is displayed, it is judged as a fault.

[0043] The effective surface area of the detection power recovery device by symmetrically arranging the T-shaped ferrites is increased, and the energy conversion efficiency is:

[0044]

[0045] This shows that the energy recovery efficiency is improved as the coil becomes omnidirectional.

[0046] See also Figure 5 A line fault determination method based on a magnetic fault detection and power recovery method for power grid inspection includes the following steps: when the inspection task is started, the control terminal 1 sends an inspection instruction, and the drone 2 that receives the instruction takes off. During the inspection process, the magnetic detection energy recovery device 3 simultaneously recovers energy; if a fault is found, the controller sends the fault location data to the control terminal 1, and continues to cruise after the sending is completed. If the sending is not completed, the control terminal 1 finds a problem and resends the inspection instruction to a new drone 2; if no fault is found, magnetic detection and energy recovery are continued during the cruise until the inspection task is completed.

[0047] The magnetic detection power recovery device 3 performs energy recovery. Under normal working conditions, the current I n (t) will produce a uniform magnetic field. The unidirectional coil placed near the center of the cable at a distance r detects the magnetic flux along its normal vector direction as follows:

[0048]

[0049] When the coil faces the magnetic field (cosθ=1), the sensitivity is highest.

[0050] The unidirectional coil is improved to an omnidirectional coil. The omnidirectional coil consists of three orthogonal units arranged along the x, y, and z axes, which can capture magnetic fields in all directions in space. Assuming that the parameters of each unit are the same, the equivalent effective area is defined as:

[0051]

[0052] Where μ0 is the vacuum permeability, N and A are the number of turns and effective area of the unidirectional coil, and θ is the angle between the normal vector of the unidirectional coil and the direction of the magnetic field.

[0053] Then the actual magnetic flux detected by the magnetic detection energy recovery device 3 is:

[0054]

[0055] Compared to unidirectional coils, the omnidirectional design of the magnetic detection energy recovery device 3 responds to magnetic fields in any direction, providing more comprehensive detection. This design typically captures magnetic field information more comprehensively in real-world environments, improving the robustness of fault detection. However, during power cable inspections, the magnetic detection energy recovery device 3 must maintain a certain safe distance from the cables, which reduces its detection accuracy. To ensure both inspection safety and fault detection accuracy, the upper and lower surfaces of the unidirectional magnetic induction coils of the present invention are each embedded with evenly distributed, mirror-symmetrical T-shaped ferrite arrays.

[0056] Compared to ferrites of other shapes, the T-shaped ferrite has a smaller volume and lighter weight under the same magnetic flux conditions. The array-type arrangement effectively increases the area of the ferrite. The T-shaped ferrite array used in this embodiment is mirror-symmetrical, with a total of 48 T-shaped ferrites evenly embedded in the omnidirectional coil.

[0057] After the T-type ferrite is arranged in a ring inside the omnidirectional coil, the magnetic field is effectively concentrated and the magnetic permeability is increased from μ0 to:

[0058] μ op =μ0Λ=μ0[1+κ(μ r -1)]

[0059] where μ r is the relative magnetic permeability of ferrite. It can be seen that after ferrite is enhanced, the magnetic flux increases by a factor of Λ, thereby improving the detection sensitivity and the accuracy of fault judgment. The actual magnetic flux after adding ferrite is:

[0060]

[0061] Assume that the current in normal state is I n (t), the current in the fault state is I f(t). After the omnidirectional coil is enhanced by ferrite, the magnetic flux in the two states is

[0062]

[0063] The change in magnetic flux is used to determine the fault

[0064]

[0065] When judging a fault, you can set the following two criteria:

[0066] 1. Absolute threshold method |ΔΦ op (t)∣≥Φ th , when the magnetic flux change exceeds the preset threshold Φ th When the error message is displayed, it is judged as a fault.

[0067] 2. Relative rate of change method When ∈ op (t)≥∈ th It can also be judged as a fault state.

[0068] At the same time, according to Faraday's law, the induced electromotive force in the omnidirectional coil is:

[0069]

[0070] Abnormal changes can also serve as an auxiliary basis for fault detection. The function of ferrite is to concentrate the original magnetic flux, increasing the magnetic flux. Therefore, the same current produces a larger magnetic flux change, making it easier to detect small abnormalities.

[0071] The magnetic flux data detected by the magnetic detection power recovery device 3 is converted into digital form and transmitted through the control circuit and communication transmission circuit. The communication transmission circuit uses a serial port to connect to the data transmission system of the drone 2 to transmit the obtained data information back to the control terminal 1. Finally, the current power system inspection information is returned to the control terminal 1 through the drone 2 data transmission system. During the drone 2's inspection process, the magnetic detection power recovery device 3 converts kinetic energy into electrical energy.

[0072] The idea of the present invention to provide electric energy recovery is:

[0073] Drone 2 is stationary above power lines for inspection. During movement, the unidirectional coils vibrate, increasing the cost of stabilization equipment. However, the omnidirectional coils, with their X, Y, and Z dimensions perpendicular to each other, can cut through the magnetic field in each dimension. This ensures consistent access to magnetic flux lines during movement, ensuring stable and balanced energy recovery. Based on Faraday's law of electromagnetic induction, the magnetic detection energy recovery device 3 converts the electrical energy, stabilizes it with a DC-DC module, and stores it in the drone's battery, extending the inspection range.

[0074] According to Faraday's law of electromagnetic induction, the induced electromotive force in the coil is

[0075]

[0076] If the cable current is assumed to be a sinusoidal AC signal:

[0077] I(t)=I0sin(ωt)

[0078] but

[0079]

[0080] The effective value (RMS value) of the induced electromotive force is

[0081]

[0082] If this voltage is passed through a matching load R L If energy recovery is performed, the output power is

[0083]

[0084] In magnetic energy recovery, the available energy can be estimated by using the magnetic field power density.

[0085]

[0086] Its energy flux density

[0087]

[0088] Then, through the equivalent area A of the omnidirectional coil all The captured magnetic field power is

[0089]

[0090] Energy conversion efficiency is defined as the ratio of recovered electrical energy to the energy available in the magnetic field

[0091]

[0092] Substitute P into the above formula out and have to

[0093]

[0094] Energy conversion efficiency during inspection and equivalent effective area A of omnidirectional coil allThe larger the area, the more magnetic energy is captured. The symmetrical array arrangement effectively increases the equivalent effective area of the ferrite omnidirectional coil, which further improves the energy conversion efficiency and increases the inspection distance of the drone. L Inversely proportional, load matching optimization is crucial for energy conversion. The enameled copper wire used in the present invention comprehensively considers the production cost and the more appropriate impedance R L , which significantly improves the energy conversion efficiency.

[0095] Control terminal 1 and fault location principle are as follows:

[0096] After receiving the command from the control terminal 1, the drone 2 starts to take off in the designated inspection area. When the drone 2 inspects along the cable, its GPS coordinates or relative displacement can be recorded: x(t) = x0 + v d t(where v d is the inspection speed of the drone), and at the same time monitor the abnormal value of magnetic flux. The fault point can be determined by finding the spatial location of the magnetic flux anomaly:

[0097]

[0098] That is, in the inspection data, the point with the largest flux change amplitude is taken as the fault location.

[0099] After UAV 2 locates the fault point using the magnetic detection device, it sends the location information to the control center to notify the fault repair. This greatly reduces the time required for manual inspections and allows for accurate inspection of the fault location.

[0100] The control terminal 1 serves as the control center for the inspection by the drone 2, responsible for emergency response, controlling the drone's flight status, and providing feedback on the inspection progress. The control terminal 1 can complete regular power system line inspections on schedule, receive magnetic detection data transmitted back by the drone 2, calculate the precise power line fault point based on real-time feedback from the drone's flight duration, and notify maintenance personnel of the specific repair location, thereby improving the efficiency of power line inspections and ensuring worker safety.

[0101] In this embodiment, a DJI Mavic series drone 2 was selected, taking into account its payload, endurance, and data transmission capabilities. A lightweight insulating plate was installed on the bottom of the drone 2, with a hole punched in the center to house the controller for the magnetic detection power recovery device 3. This controller includes control circuitry and communication transmission circuitry. This communication transmission circuitry uses a serial port to connect to the drone 2's data transmission system, transmitting data back to the control terminal 1. The magnetic detection power recovery device 3 was secured 40 cm below the plate via a metal tube, with wiring connected to the control and transmission circuits within the metal tube.

[0102] The data detected by the magnetic detection power recovery device 3 is transmitted through the control circuit and the communication transmission circuit. The communication transmission circuit uses a serial port to connect to the data transmission system of drone 2 and transmits the obtained data information back to the control terminal 1. Finally, the current power system inspection information is returned to the control terminal 1 through the drone 2 data transmission system. During the inspection process, the kinetic energy generated by drone 2 during the inspection is converted into electrical energy and stored.

[0103] The above description is an explanation of the specific implementation of the present invention, rather than a limitation of the present invention. Those skilled in the relevant technical field can also make various equivalent technical solutions without departing from the scope of the present invention, so all equivalent technical solutions should be included in the scope of protection of the present invention.

Claims

1. A magnetic fault detection and power recovery system based on power grid inspection, characterized by: The invention comprises a control terminal (1), an unmanned aerial vehicle (2), and a magnetic detection energy recovery device (3), wherein the magnetic detection electric energy recovery device (3) is installed at the lower part of the unmanned aerial vehicle (2); The magnetic detection electric energy recovery device (3) is mainly composed of three identical unidirectional magnetic induction coils wound with enameled copper wires in a clockwise direction, and the three unidirectional magnetic induction coils are perpendicular to each other in pairs to form omnidirectional coils; The unidirectional magnetic induction coil is respectively embedded with an array of T-shaped ferrites that are evenly distributed and mirror-symmetrical in pairs on the upper plane and the lower plane of the coil.

2. The magnetic fault detection and power recovery system based on power grid inspection according to claim 1, characterized in that: The magnetic detection electric energy recovery device (3) comprises four pairs of evenly distributed and mirror-symmetrical T-shaped ferrites, wherein the T1 ferrite is symmetrical with the T5 ferrite, the T2 ferrite is symmetrical with the T6 ferrite, the T3 ferrite is symmetrical with the T7 ferrite, and the T4 ferrite is symmetrical with the T8 ferrite.

3. The line fault determination method of the magnetic fault detection and power recovery method based on power grid inspection according to claim 1 is characterized in that: The invention comprises the following steps: the inspection task is started, the control terminal (1) sends an inspection instruction, the unmanned aerial vehicle (2) receiving the instruction takes off, and during the inspection process, the magnetic detection energy recovery device (3) simultaneously recovers energy; if a fault is found, the controller sends the fault location data to the control terminal (1), and the cruise is continued after the sending is completed; if the sending is not completed, the control terminal (1) finds the problem and resends the inspection instruction to the new unmanned aerial vehicle (2); if no fault is found, the magnetic detection and energy recovery are continued during the cruise until the inspection task is completed.

4. The line fault determination method of the magnetic fault detection and power recovery method based on power grid inspection according to claim 3 is characterized in that: The actual magnetic flux of the magnetic detection energy recovery device (3) is: Fault diagnosis is performed based on changes in magnetic flux.

5. The line fault determination method of the magnetic fault detection and power recovery method based on power grid inspection according to claim 3 is characterized in that: The method for fault judgment based on the change of magnetic flux is: absolute threshold method |ΔΦ op (t)∣≥Φ th , when the magnetic flux change exceeds the preset threshold Φ th When the error message is displayed, it is judged as a fault.

6. The line fault determination method of the magnetic fault detection and power recovery method based on power grid inspection according to claim 3 is characterized by: The method for fault judgment based on the change of magnetic flux is the relative change rate method. When ∈ op (t)≥∈ th , it is determined to be a fault state.

7. The line fault determination method of the magnetic fault detection and power recovery method based on power grid inspection according to claim 3 is characterized in that: The magnetic detection power recovery device (3) is an omnidirectional coil that can cut the magnetic field in every dimension. During the shaking, there is always one dimension that can cut the magnetic flux line. Based on Faraday's law of electromagnetic induction, the converted electric energy is stored in the battery of the drone (2) after being stabilized by a DC-DC module, thereby increasing the inspection distance. The induced electromotive force in the coil is:

8. The line fault determination method of the magnetic fault detection and power recovery method based on power grid inspection according to claim 3 is characterized in that: The equivalent area A of the omnidirectional coil all The energy conversion efficiency is:

9. The method for determining fault distance of a magnetic fault detection and power recovery method based on power grid inspection according to claim 3, characterized in that: After receiving the command from the control terminal (1), the drone (2) starts to take off in the designated inspection area. When the drone (2) inspects along the cable, its GPS coordinates or relative displacement are recorded: x(t) = x0 + v d t(where v d is the inspection speed of the drone (2), and at the same time, the amplitude of the magnetic flux change is monitored, and the point with the largest amplitude change is determined as the fault point:

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