220kV transformer substation unmanned aerial vehicle inspection operation safety distance confirmation method

Abstract

The invention discloses a 220kV transformer substation unmanned aerial vehicle inspection operation safety distance confirmation method. The method comprises the steps that an electric field, a magnetic field and a wireless electric field of a transformer substation are analyzed and calculated to obtain field intensity, and the distribution rule of the field intensity is analyzed; establishing a simulation model of each key device of the transformer substation and setting materials and parameters; performing material and parameter setting on each structure of the unmanned aerial vehicle simulation model; performing electric field, magnetic field and wireless electric field simulation on each key device simulation model of the transformer substation and the unmanned aerial vehicle simulation model, and analyzing the sizes and distribution rules of the electric field, the magnetic field and the wireless electric field received by the unmanned aerial vehicle; meanwhile, the distribution characteristics of the field intensity in the spatial position and the attenuation rule along with the distance are analyzed; changing the spatial position and the flight attitude of the unmanned aerial vehicle, simulating the interference condition of the unmanned aerial vehicle under the actual working condition, and obtaining the electric field safety distance, the magnetic field safety distance and the wireless field safety distance of the unmanned aerial vehicle. The method can effectively avoid blind inspection caused by unclear safety distance, thereby reducing accident risk and reducing manpower waste.

Description

Technical Field

[0001] This invention relates to the field of substation inspection technology, specifically to a method for confirming the safe distance for unmanned aerial vehicle (UAV) inspection operations in 220kV substations. Background Technology

[0002] With the rapid development of drone technology, its application in substation inspection is becoming increasingly widespread. However, substations are high-voltage, strong electromagnetic field environments, and the safe distance for drone inspections is a core issue to ensure the normal operation of equipment and the safety of the drone itself. Substations contain numerous high-voltage devices that generate strong electric fields, magnetic fields, and electromagnetic radiation during operation. Non-uniform electric fields can form around high-voltage conductors, reaching extremely high values ​​at close range. Alternating currents during equipment operation generate alternating magnetic fields, which may interfere with components such as the drone's geomagnetic sensors. Furthermore, switching operations and arc discharges of high-voltage equipment generate electromagnetic pulses, which may interfere with the drone's wireless communication and navigation systems. These electromagnetic phenomena are the core factors in determining the safe distance for drones. Simultaneously, the drone's electronic systems are extremely sensitive to the electromagnetic environment. Its communication and navigation systems, which rely on wireless communication and satellite navigation, may experience signal interruptions and positioning errors due to strong electromagnetic fields. Various onboard sensors and control systems are susceptible to magnetic field interference, affecting data acquisition accuracy and flight stability. Strong electric fields can also induce electrostatic induction, leading to internal circuit breakdown or battery failure, and even safety accidents. Therefore, it is necessary to set safe distances to prevent drones from being exposed to electromagnetic environments exceeding their tolerance thresholds.

[0003] Currently, determining safe distances still faces challenges such as inconsistent standards, complex environmental influences, and individual differences among drones. To address these challenges, existing research mainly focuses on electromagnetic field simulation, drone shielding design, and dynamic distance adjustment to optimize safe distances. This research is of great significance for promoting the large-scale application of drones in the power industry. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a method for confirming the safe distance for drone inspection operations in 220kV substations. This method can find the optimal safe distance for drone inspections, effectively avoiding blind inspections caused by unclear safe distances, thereby reducing accident risks and minimizing manpower waste.

[0005] The technical solution adopted in this invention is as follows:

[0006] A method for confirming the safe distance for unmanned aerial vehicle (UAV) inspection operations at 220kV substations includes the following steps:

[0007] Step 1: Analyze the basic principles of electric field, magnetic field and radio field of substation, calculate the magnitude of electric field, magnetic field and radio field in space and analyze their distribution law;

[0008] Step 2: Establish simulation models of key components of the substation based on finite element simulation software, and set the materials and parameters of the structure of each key component of the substation;

[0009] Step 3: Establish a UAV simulation model based on finite element simulation software, and set the materials and parameters for each structure of the UAV;

[0010] Step 4: Based on the magnitudes of the electric, magnetic, and radio fields obtained in Step 1, simulate the electric, magnetic, and radio fields of the simulation models of key components in the substation and the UAV simulation model, and analyze the magnitude and distribution patterns of the electric, magnetic, and radio fields experienced by the UAV; at the same time, analyze the spatial distribution characteristics of the field strength and its attenuation with distance.

[0011] Step 5: Based on the magnitude and distribution of the electric field, magnetic field and radio field experienced by the UAV, change the spatial position and flight attitude of the UAV to approach the key components of the substation from different angles, simulate the interference experienced by the UAV under actual working conditions, and further analyze and compare the magnitude of the field strength experienced by the UAV during the inspection operation, as well as the distribution of the electric field, magnetic field and radio field.

[0012] Step 6: Record the magnitude of the electric field strength experienced by the UAV at different spatial locations when it is inspecting key components of the substation under different flight attitudes. Based on the UAV interference threshold, determine the safe distance of the UAV's electric field, magnetic field, and radio field.

[0013] It also includes step 7, which analyzes the performance of the selected drone model, confirms its hovering error distance, and confirms the control delay distance and braking distance based on the speed of the drone during operation and its control signal delay time.

[0014] The maximum wind speed that the drone can withstand during actual inspection operations is measured, and the drone's own performance is analyzed to confirm the impact of gusts on the drone's offset distance.

[0015] It also includes step 8, which, based on steps 6 and 7, accurately calculates the safe distance for drone inspection, and based on the calculated safe distance, determines the safe range for drone inspection of each key component of the substation.

[0016] The method also includes step 9, which involves installing a shielding device on the drone to improve its safety and stability during inspection operations. The method for calculating the magnitudes of the electric, magnetic, and radio fields in space in step 1 includes:

[0017] 1.1: The method for calculating the magnitude of the electric field intensity at any point in space is as follows:

[0018] According to the superposition principle, the electric field intensity E can be expressed by its components E in the horizontal and vertical directions.x E y The expression is:

[0019]

[0020] Components E in the horizontal and vertical directions x E y The expression is:

[0021]

[0022] In equation (2): x and y are the coordinates of any point; x i y i Let L be the coordinate of conductor i; ε be the vacuum permittivity; L i ′ and L i Let ' be the distance related to point (x,y) from the i-th charged high-voltage conductor and its mirror image, respectively; Q i Let be the charge of the i-th line charge, and m be the total number of line charges participating in the superposition of the electric field.

[0023] 1.2: The method for calculating the magnitude of the magnetic field strength at any point in space is as follows:

[0024] According to the superposition principle, the magnetic induction intensity B can be composed of the components B in the horizontal and vertical directions. x B y The expression is:

[0025]

[0026] Components B in the horizontal and vertical directions x B y The expression is:

[0027]

[0028] In equation (4): μ is the free permeability; r i Let be the distance from point (x,y) to the i-th current-carrying wire; δ be the angle between the line connecting the i-th current-carrying wire and point (x,y) and the horizontal direction; and I be the magnitude of the current in the wire.

[0029] 1.3: The method for calculating the radio intensity at any point in space is shown in equations (5) to (8):

[0030] At a distance of 20m from the ground projection of the phase conductors of each key component in the substation, the interference level (dB) at a frequency of 1MHz is:

[0031]

[0032] In equation (5): g maxd represents the maximum potential gradient of the lines of each key component in the substation, in kV / cm; d is the diameter of the line, in cm.

[0033] Calculating the radio interference field strength at other frequencies requires frequency correction, which is calculated as follows:

[0034]

[0035] In equation (6): △E f This is the result of the interference field strength correction at frequency f; f is the frequency to be corrected, in MHz.

[0036] To calculate the radio interference field strength when the projected distance of the side-phase conductor of an overhead transmission line on the ground is X, a distance correction is required. The calculation method is as follows:

[0037]

[0038] In equation (7): E x The radio interference field strength is expressed in dB (uV / m) at a distance of X meters from the ground projection of the side phase conductor (X<100).

[0039] E represents the radio interference field strength at a distance of 20m from the ground projection of the side phase conductor, expressed in dB (uV / m).

[0040] X is the projected distance from the side phase conductor, in meters;

[0041] H represents the height of the side-phase conductor above the ground at the measuring point, in meters (m).

[0042] h represents the installation height of the measuring instrument's antenna, in meters (m).

[0043] k is the attenuation coefficient, expressed as:

[0044]

[0045] In equation (8): f is the frequency, in MHz.

[0046] In step 2, the parameters include transformer capacity, operating current, operating voltage, relative permeability, relative permittivity, conductivity, reference resistivity of each key component of the substation; and physical structural parameters of the internal components of each key component of the substation.

[0047] The transformer capacity is 200MVA, the operating current of each key component in the substation is 524A, and the operating voltage is 220kV. Parameters such as relative permeability, relative permittivity, conductivity, and reference resistivity are shown in Table 1 below, taking the busbar as an example.

[0048] Table 1. Busbar Material Parameter Settings

[0049]

[0050] Physical structural parameters of key components in the substation:

[0051] 1. Busbar structural parameters: total height is 7500mm, outer diameter is 110mm, inner diameter is 100mm, and the height of the post insulator is 2500mm.

[0052] 2. Current transformer structural parameters: The total height of the calculated model is 6500mm, including 2000mm for the cement support, 300mm for the metal flange, 3700mm for the composite insulator support, and 500mm for the head shielding layer.

[0053] 3. Circuit breaker structural parameters: The total height of the calculated model is 11,500 mm, of which the metal support is 3,000 mm high, the arc-extinguishing chamber is 2,500 mm high, and the composite insulator is 3,500 mm high.

[0054] Key components of a substation include busbars, circuit breakers, current transformers, gantry frames, and transformers.

[0055] In step 2, when establishing simulation models of key components of the substation based on finite element simulation software, including circuit breakers, current transformers, and busbars, the methods for applying excitation conditions in the simulation experiment include:

[0056] 2.1: Apply operating voltage, operating current, and electromagnetic field values ​​to the circuit breaker conductors; set the calculation boundary conditions: when the circuit breaker is in the conducting state, the moving and stationary contacts in the arc-extinguishing chamber are connected and both are at high potential, and the actual operating voltage is applied; the support column and the ground are grounded at low potential to achieve simulation; apply excitation to the circuit breaker according to the actual situation of the substation, specifically as follows... Figure 13 As shown.

[0057] 2.2: Apply operating voltage, operating current, and electromagnetic field values ​​to the current transformer conductors; calculate boundary conditions: apply the actual operating voltage to the secondary winding, conductive rod, and high-potential casing; apply zero potential to the shielding cover, cement support, and ground to achieve simulation; apply excitation to the current transformer according to the actual substation conditions, specifically as follows... Figure 14 As shown.

[0058] 2.3: Apply operating current and actual operating voltage to the busbar, while applying zero potential to the support insulators, cement supports, and ground, thus achieving simulation; apply excitation to the busbar according to the actual conditions of the substation, specifically as follows... Figure 15 As shown. In step 3, the parameters include relative permeability, relative permittivity, conductivity, reference resistivity, and physical structural parameters of each component of the UAV.

[0059] UAV structural parameters: The UAV is a small quadcopter with overall dimensions of 220mm × 220mm × 90mm. The material properties required for electromagnetic field calculations of the UAV are shown in Table 2.

[0060] Table 2 Material property parameters of UAVs

[0061]

[0062] In step 3, the materials and parameters of each structure of the UAV model are set:

[0063] The brushless DC motors at the ends of the four arms of the drone, the gimbal, and the camera housing are all made of electrically suspended metal, while the remaining outer shell is made of composite plastic. The metal present at the edges of the actual drone is mainly the motor housing, while the metal screws used to secure the motors are located at the bottom of the motors and embedded in the plastic motor base; therefore, there is no obvious protrusion, and they can be disregarded in the simulation. The material properties required for the drone's electromagnetic field calculations are shown in Table 3.

[0064] Table 3 Material property parameters of UAVs

[0065]

[0066] In step 4, the electric field, magnetic field, and radio field are simulated on the simulation models of key components in the substation and the UAV simulation model, and the magnitude and distribution of the electric field, magnetic field, and radio field experienced by the UAV are analyzed; specifically as follows:

[0067] The magnitudes of the electric, magnetic, and radio fields experienced by a drone decrease rapidly with distance; the attenuation decreases with increasing distance. The maximum electric field observed by the drone is mainly distributed on the surface of its brushless motor; the maximum magnetic and radio fields also occur at the brushless motor. For other parts of the drone, the closer to key components in the substation, the stronger the field strength.

[0068] Step 4 analyzes the spatial distribution characteristics of the electric field strength and its attenuation law with distance; specifically as follows:

[0069] The electric, magnetic, and radio fields of a substation are non-uniformly distributed around the high-voltage equipment, and they decay rapidly with distance, with the decay rate decreasing as the distance increases.

[0070] In step 4, since the operating current of each key component in the substation is three-phase AC, the interference experienced by the UAV during inspection of the side phases and the middle phases differs. The UAV is placed around the middle phase and the side phases respectively to determine the difference in the electric field strength experienced by the UAV. Based on this difference in electric field strength, the electric field concentration and magnetic focusing phenomena of the UAV's brushless DC motor are further analyzed. Specifically:

[0071] Electric field concentration phenomenon: When drones inspect high-voltage equipment in substations, they are affected by the electric and magnetic fields of the equipment. Under the influence of the electric field, induced charges and induced electric fields usually appear on the metal parts of the drone, distorting the original spatial electric field distribution. The electric field around the motor is approximately 2 to 3 times stronger than the original electric field. This electric field distortion is mainly concentrated on the surface of the drone's brushless motor. Specifically... Figure 7 As shown.

[0072] Magnetic concentrating phenomenon: Drones exhibit magnetic concentrating under the influence of a magnetic field. This is due to the magnetically conductive material inside the motor. The permeability of this material is much higher than that of air, making it a preferential channel for magnetic flux. Magnetic flux naturally converges towards the region of least magnetic reluctance. Since the path reluctance formed by the magnetically conductive material is much lower than that of the air gap and non-magnetically conductive components, this directly leads to the concentration of magnetic flux at key locations within the magnetically conductive material. Specifically... Figure 8 As shown.

[0073] In step 5, the spatial position and flight attitude of the UAV are changed to approach the key components of the substation from different angles, simulating the interference experienced by the UAV under actual working conditions. Further analysis and comparison are then conducted on the magnitude of the field strength experienced by the UAV during inspection operations, as well as the distribution patterns of electric, magnetic, and radio fields. Specifically, the following is a detailed analysis:

[0074] Analysis of the magnitude of electric field interference experienced by drones during inspection operations: Changing the spatial position and flight attitude of a drone significantly affects the electric, magnetic, and radio field interference it experiences during substation inspections. When the drone's spatial position remains unchanged, attitude 4 experiences the strongest electric, magnetic, and radio field interference. Attitude 1 experiences the weakest electric, magnetic, and radio field interference.

[0075] Distribution patterns of electric, magnetic, and radio fields: The attenuation of the magnetic field is greatest with increasing distance, while the attenuation of the radio field is smallest. Specifically... Figure 16 As shown.

[0076] In step 6, the magnitude of the electric field force experienced by the UAV at different spatial locations during its inspection of key components of the substation under different flight attitudes is recorded, as follows:

[0077] While maintaining the drone's flight attitude, its spatial position is continuously adjusted, and the magnitude of the electric field experienced by the drone at different spatial positions under different flight attitudes is recorded. Taking the electric field as an example, the specific results are as follows: Figure 17 As shown.

[0078] Based on the drone interference threshold, the safe distances for the drone's electric field, magnetic field, and radio field are determined.

[0079] Taking electric field as an example: The core of electric field interference threshold is the critical electric field strength before the gap between the drone and the high-voltage equipment discharges. When the drone gets too close to the substation equipment, the electric field strength will exceed the threshold, which may cause gap discharge and damage the drone. Therefore, confirming the safe distance of the drone electric field is the premise for ensuring the safe operation of the drone. The electric field safe distance of this invention refers to the experimental results in reference [1] Cai Huanqing, Fu Jing, Yang Ning, Shao Guiwei, Wen Zhike, Tan Jiaying. Safe distance of drone inspection operation in 500kV substation [J]. High Voltage Engineering, 2024, 50(07):3199-3208. The electric field safe distance is 3kV / cm. The specific results are as follows Figure 18 As shown.

[0080] In step 7, the performance of the selected drone model is analyzed to determine its hovering error distance; specifically as follows:

[0081] The hovering error distance of a drone is strongly correlated with its positioning system (such as visual positioning or RTK positioning), flight control performance, and fuselage design. Consumer-grade and industrial-grade models with different positioning accuracies show significant differences. If a drone is equipped with an RTK positioning system, its hovering error distance can be reduced to the centimeter level (10cm).

[0082] Based on the drone's operating speed and its control signal delay time, determine the control delay distance and braking distance; specifically as follows:

[0083] Control delay distance: During the control signal delay, the drone typically maintains its current operational speed and flies at a constant speed. Therefore, it can be directly calculated using the formula for constant speed flight distance, as shown below:

[0084] d2=v×t d ;

[0085] Where d2 is the control delay distance in meters (m); v is the UAV operating speed in meters per second (m / s); t d The delay time for controlling the signal is measured in seconds (s).

[0086] Braking distance: The braking distance is the distance a drone travels from receiving a braking command to a complete stop at maximum deceleration. The specific formula is as follows:

[0087]

[0088] Where d3 is the braking distance in meters (m); v is the drone's operating speed in meters per second (m / s); a max This represents the maximum deceleration of the drone, expressed in m / s². 2 .

[0089] The maximum wind speed that the drone can withstand during actual inspection operations was measured, and combined with the drone's own performance analysis, to confirm the impact of gusts on the drone's offset distance. Details are as follows:

[0090] The impact of gusts on drone drift distance: The effect of gusts on drone drift is essentially the lateral drift caused by the lateral force of the wind. Short-duration gusts can be simplified to a uniform lateral wind interference model, as shown in the following formula:

[0091]

[0092] Where d4 is the distance offset by the gust, in meters; v w The lateral wind speed of the gust is expressed in m / s; t r The disturbance rejection response time of the flight control system, measured in seconds; a w The lateral acceleration of the drone caused by gusts of wind is expressed in m / s². 2 .

[0093] In step 8, the safe distance for drone inspection is accurately calculated. The calculation formula for the safe distance confirmation method for drone inspection operations is as follows:

[0094] d y =max(d E ,d B ,d db )+(d1+d2+d3+d4)(9);

[0095] In equation (9): Hovering error distance d1: The stability of the UAV in maintaining a specified three-dimensional spatial position (horizontal X, Y axis, vertical Z axis) without deviation when there is no manual control intervention; the deviation between the actual position and the preset target position. Control delay distance d2: The buffer distance caused by the delay of the remote control signal.

[0096] Braking distance d3: The distance required for the drone to come to a complete stop from the start of braking.

[0097] Gust-affected distance d4: The offset of the drone caused by gusts.

[0098] d E d represents the safe distance in an electric field. B d represents the safe distance for magnetic fields. db The safe distance for radio fields is represented by max(d). E ,d B ,d db ) indicates taking the maximum value of the three.

[0099] In step 8, based on the calculated safe distance, the safe range for drone inspection of key components in the substation is determined:

[0100] After determining the safe distance for drone inspections based on the above formula, the space around the key equipment in the substation is divided into three parts:

[0101] (1) Core no-fly zone (high-risk area adjacent to the main equipment, drones are strictly prohibited from entering), the red area in Figure 11(a);

[0102] (2) Risk warning zone (a transitional area between no-fly zone and safe zone, where drones still face the risk of strong field interference from substation equipment during inspection due to the performance of the drones themselves and the influence of external wind speed) in the yellow area of ​​Figure 11(a);

[0103] (3) Normal safety zone (low-risk area far away from the main equipment, where the drone can stably perform inspection tasks) Green area in Figure 11(a).

[0104] This invention provides a method for confirming the safe distance during unmanned aerial vehicle (UAV) inspection operations at 220kV substations. The technical advantages are as follows:

[0105] 1) This invention establishes simulation models of key components and inspection drones in a 220kV substation through finite element simulation. By simulating the physical fields of electric field, magnetic field and radio field, it studies the distribution characteristics of the spatial electric field, spatial magnetic field and spatial radio field generated by the components in the substation, which can provide a reference for determining the inspection area of ​​the drone and optimizing the structure of the drone shielding device.

[0106] 2) This invention uses a method to confirm the safe distance for drone inspections of 220kV substations. By approaching the key components of the substation from different angles, it simulates the interference experienced by the drone under actual working conditions and analyzes and compares the magnitude of the field strength and the distribution patterns of electric, magnetic and radio fields. This method can accurately determine the optimal safe distance for drone inspections, laying the foundation for subsequent confirmation of the optimal safe range for 220kV drone inspections.

[0107] 3) This invention can find the optimal safe inspection range for 220kV substation drone inspections, which is of great significance for promoting technological progress in the power industry and the intelligent development of substation inspections. Attached Figure Description

[0108] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0109] Figure 1 This is the overall flowchart of the present invention.

[0110] Figure 2(a) is a three-dimensional model diagram of each key component (busbar) of the 220kV substation in this invention;

[0111] Figure 2(b) is a three-dimensional model of each key component (circuit breaker) in the 220kV substation of this invention;

[0112] Figure 2(c) is a three-dimensional model of each key component (current transformer) in the 220kV substation of this invention;

[0113] Figure 2(d) shows the three-dimensional model of each key component (gantry frame) of the 220kV substation in this invention.

[0114] Figure 3 This is a 3D model of the 220kV substation inspection drone in this invention.

[0115] Figure 4 This is a diagram showing the electric field distribution around key components of a 220kV substation in this invention (taking a busbar as an example).

[0116] Figure 5 This is a magnetic field distribution diagram around key components of a 220kV substation in this invention (taking a busbar as an example).

[0117] Figure 6 This is a radio field distribution diagram around key components of a 220kV substation in this invention (taking a busbar as an example).

[0118] Figure 7 This is a diagram showing the electric field interference distribution experienced by the UAV of this invention (taking a busbar as an example).

[0119] Figure 8 This is a distribution diagram of magnetic field interference experienced by the UAV of this invention (taking the busbar as an example).

[0120] Figure 9 This is a distribution diagram of radio field interference experienced by the UAV of this invention (taking a busbar as an example).

[0121] Figure 10 This is a schematic diagram of different flight attitudes of the UAV during inspection of the present invention (taking a busbar as an example).

[0122] Figure 11(a) is a schematic diagram of the inspection safety distance of the present invention (taking a busbar as an example);

[0123] Figure 11(b) is a schematic diagram of the inspection safety range of the present invention (taking a busbar as an example);

[0124] Figure 12 This is a schematic diagram of the drone shielding device of the present invention.

[0125] Figure 13 This is a schematic diagram of applying excitation to a circuit breaker.

[0126] Figure 14 This is a schematic diagram of applying excitation to a current transformer.

[0127] Figure 15 This is a schematic diagram of applying excitation to the busbar.

[0128] Figure 16 This is a diagram showing the distribution patterns of electric, magnetic, and radio fields.

[0129] Figure 17 The results show the magnitude of the electric field force experienced by a drone in different spatial positions under different flight attitudes, taking an electric field as an example.

[0130] Figure 18 The results show the safe distance of a UAV from the electric field under different flight attitudes, taking the electric field as an example.

[0131] Figure 19 This is a diagram showing the distribution patterns of electric, magnetic, and radio fields. Detailed Implementation

[0132] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0133] A method for confirming safe distances during drone inspections of 220kV substations is proposed. First, finite element method (FEM) simulation technology is used to construct simulation models of key components in the substation and conduct electric, magnetic, and radio field interference simulations. This in-depth study of the distribution patterns of electric, magnetic, and radio fields around the main components of the substation lays the foundation for analyzing interference affecting the drone. Then, by combining numerical calculations and the FEM simulation results of the key components, the safe electric, magnetic, and radio field distances for drone inspection operations are determined. Simultaneously, based on the drone's performance, the hovering error distance, control delay distance, and braking distance are calculated, and the impact distance of gusts on the drone is determined by considering the actual operating conditions of the drone. Finally, using the proposed method for confirming safe distances for drone operations, the safe distances for drone inspections are accurately determined, ensuring the safety and reliability of drones in 220kV substation inspection operations.

[0134] like Figure 1 As shown, a method for confirming the safe distance during unmanned aerial vehicle (UAV) inspection operations at a 220kV substation includes the following steps:

[0135] Step 1: Analyze the basic principles of electric field, magnetic field and radio field of substation, calculate the magnitude of electric field, magnetic field and radio field in space and analyze their distribution law;

[0136] Step 2: Use the finite element simulation software COMSOL to establish simulation models of each key component of the substation, and set the materials and parameters for each structure of the simulation model of each key component of the substation. The parameters include transformer capacity, operating current, operating voltage, relative permeability, relative permittivity, conductivity, reference resistivity, and physical structural parameters of internal components of each main component simulation model of the substation.

[0137] like Figures 2(a) to 2(d)As shown, the constructed model is a three-dimensional model of each key component of the 220kV substation in this invention;

[0138] Step 3: Use the finite element simulation software COMSOL to build a simulation model of the UAV and set the materials and parameters for each structure of the UAV model. The parameters include relative permeability, relative permittivity, conductivity, Young's modulus, Poisson's ratio, and physical structural parameters of each component of the UAV.

[0139] like Figure 3 As shown, the constructed model is a 3D model of the 220kV substation inspection drone in this invention;

[0140] Step 4: Based on the calculation method of electric field, magnetic field and radio field magnitude in Step 1, simulate the electric field, magnetic field and radio field of each key component model of the substation and the three-dimensional model of the UAV. Analyze the magnitude and distribution law of the electric field, magnetic field and radio field experienced by the UAV. At the same time, compare the distribution characteristics of field strength in spatial location and the attenuation law with distance.

[0141] like Figures 4-6 The diagram shows the electric field distribution, magnetic field distribution, and radio field distribution of key components in the 220kV substation of this invention. From... Figures 4-6 It is clearly visible that the maximum values ​​of the electric field, magnetic field, and radio field of key components in a 220kV substation all occur around the charged body. The field strength decreases rapidly with increasing distance, and the attenuation decreases with increasing distance. Specifically... Figure 19 As shown.

[0142] Step 5: Based on the different magnitudes and attenuation laws of the electric, magnetic, and radio fields experienced by the UAV, change the position and flight attitude of the UAV to approach the key components of the substation from different angles, simulate the interference situation experienced by the UAV under actual working conditions, and further analyze and compare the magnitude of the field strength and the distribution laws of electric, magnetic, and radio fields experienced by the UAV during the inspection operation.

[0143] like Figures 7-9 As shown, the diagram illustrates the distribution of electric, magnetic, and radio field interference experienced by the UAV of this invention. Figures 7-9It can be seen that the maximum field strength experienced by the drone occurs at the drone motor. However, the physical characteristics and mechanisms of electric, magnetic, and radio fields differ, resulting in significant differences in their interference paths, effects, and risk levels. The impact of electric fields on drones is concentrated in corona formation and discharge phenomena, directly threatening the electrical safety of the equipment. In contrast, the core interference of magnetic and radio fields focuses on the flight control system, communication system, and inspection system, indirectly disrupting operational stability by affecting the normal operation of internal electronic components and sensors. Comparatively, their interference effect on the drone motor is not significant. Therefore, when studying the interference of magnetic and radio fields on drones, the primary focus should be on the interference experienced by the drone's fuselage.

[0144] Step 6: Record the magnitude of the electric field experienced by the UAV at different spatial locations during its inspection of key components in the substation under different flight attitudes. Record the safe electric field distance, magnetic field distance, and radio field distance of the UAV at different angles for different flight attitudes, based on the UAV interference threshold. Take the maximum safe distance at each angle as the safe electric field distance, magnetic field distance, and radio field distance of the UAV.

[0145] like Figure 10 The diagram shows different flight attitudes of the UAV during inspection according to the present invention;

[0146] Step 7: Analyze the performance of the selected drone model to confirm its hovering error distance. Based on the drone's operating speed and control signal delay time, confirm the control delay distance and braking distance. Measure the maximum wind speed the drone can withstand during actual inspection operations, and analyze this in conjunction with the drone's performance to confirm the drone's offset distance affected by gusts.

[0147] Step 8: Based on steps 6 and 7, the safe distance for drone operation is determined using the method for confirming the safe distance of drone operation proposed in this invention. Based on the obtained safe distance, the safe range for drone inspection of each key component of the substation is determined.

[0148] Figures 11(a) and 11(b) illustrate the safety distance and safety range for busbar inspection, a key component of this invention. As clearly seen in Figures 11(a) and 11(b), this invention employs a layered and zoned strategy based on distance quantification for the safety management of busbar inspection. By dividing the space surrounding key equipment in the substation into a core no-fly zone, a risk warning zone, and a normal safety zone, and combining critical distance and early warning distance, the safety boundary of busbar inspection is visualized and made operable, ensuring the safety of UAV inspections.

[0149] Step 9: To improve the safety and stability of drone inspection operations, install shielding devices on the drones. For example... Figure 12 As shown, Figure 12 This is a schematic diagram of the UAV shielding device of the present invention. The core function of the UAV shielding device is to resist radio and magnetic field interference from substations, ensure the stable operation of the UAV's flight control, positioning, and communication systems through electromagnetic shielding, and reduce the risk of equipment damage, thus building a solid defense for the safety and stability of inspection operations.

Claims

1. A method for confirming the safe distance during unmanned aerial vehicle (UAV) inspection operations at a 220kV substation, characterized in that... Includes the following steps: Step 1: Analyze the basic principles of electric field, magnetic field and radio field of substation, calculate the magnitude of electric field, magnetic field and radio field in space and analyze their distribution law; Step 2: Establish simulation models of key components in the substation, and set the materials and parameters for the structure of each key component. Step 3: Establish a UAV simulation model and set the materials and parameters for each structure of the UAV; Step 4: Based on the magnitudes of the electric, magnetic, and radio fields obtained in Step 1, simulate the electric, magnetic, and radio fields of the simulation models of key components in the substation and the UAV simulation model, and analyze the magnitude and distribution patterns of the electric, magnetic, and radio fields experienced by the UAV; at the same time, analyze the spatial distribution characteristics of the field strength and its attenuation with distance. Step 5: Based on the magnitude and distribution of the electric field, magnetic field and radio field experienced by the UAV, change the spatial position and flight attitude of the UAV to approach the key components of the substation from different angles, simulate the interference experienced by the UAV under actual working conditions, and further analyze and compare the magnitude of the field strength experienced by the UAV during the inspection operation, as well as the distribution of the electric field, magnetic field and radio field. Step 6: Record the magnitude of the electric field strength experienced by the UAV at different spatial locations when it is inspecting key components of the substation under different flight attitudes. Based on the UAV interference threshold, determine the safe distance of the UAV's electric field, magnetic field, and radio field.

2. The method for confirming the safe distance for unmanned aerial vehicle (UAV) inspection operations in a 220kV substation according to claim 1, characterized in that: It also includes step 7, which analyzes the performance of the selected drone model, confirms its hovering error distance, and confirms the control delay distance and braking distance based on the speed of the drone during operation and its control signal delay time. The maximum wind speed that the drone can withstand during actual inspection operations is measured, and the drone's own performance is analyzed to confirm the impact of gusts on the drone's offset distance.

3. The method for confirming the safe distance for unmanned aerial vehicle (UAV) inspection operations in a 220kV substation according to claim 2, characterized in that: It also includes step 8, which, based on steps 6 and 7, accurately calculates the safe distance for drone inspection, and based on the calculated safe distance, determines the safe range for drone inspection of each key component of the substation.

4. The method for confirming the safe distance for unmanned aerial vehicle (UAV) inspection operations in a 220kV substation according to claim 1, characterized in that: In step 1, the methods for calculating the magnitudes of the electric field, magnetic field, and radio field in space include: 1.1: The method for calculating the magnitude of the electric field intensity at any point in space is as follows: According to the superposition principle, the electric field intensity E consists of components E in the horizontal and vertical directions. x E y The expression is: Components E in the horizontal and vertical directions x E y The expression is: In equation (2): x and y are the coordinates of any point; x i y i Let L be the coordinate of conductor i; ε be the vacuum permittivity; L i ′ and L i Let ' be the distance related to point (x,y) from the i-th charged high-voltage conductor and its mirror image, respectively; Q i Let be the charge of the i-th line charge, and m be the total number of line charges participating in the superposition of the electric field; 1.2: The method for calculating the magnitude of the magnetic field strength at any point in space is as follows: According to the superposition principle, the magnetic induction intensity B consists of components B in the horizontal and vertical directions. x B y The expression is: Components B in the horizontal and vertical directions x B y The expression is: In equation (4): μ is the free permeability; r i Let be the distance from point (x,y) to the i-th current-carrying wire; δ be the angle between the line connecting the i-th current-carrying wire and point (x,y) and the horizontal direction; I be the magnitude of the current in the wire. 1.3: The method for calculating the radio intensity at any point in space is shown in equations (5) to (8): At a distance of 20m from the ground projection of the phase conductors of each key component in the substation, the interference level (dB) at a frequency of 1MHz is: In equation (5): g max d represents the maximum potential gradient of the lines of each key component in the substation; d is the diameter of the line.

5. The method for confirming the safe distance for unmanned aerial vehicle (UAV) inspection operations in a 220kV substation according to claim 4, characterized in that: Calculating the radio interference field strength at other frequencies requires frequency correction, which is calculated as follows: In equation (6): △E f The result is the correction for the interference field strength at frequency f; f is the frequency that needs to be corrected, in MHz; To calculate the radio interference field strength when the projected distance of the side-phase conductor of an overhead transmission line on the ground is X, a distance correction is required. The calculation method is as follows: In equation (7): E x The value represents the radio interference field strength at a distance of X meters from the ground projection of the side phase conductor, where X < 100. E represents the radio interference field strength at a distance of 20m from the ground projection of the side phase conductor; X is the projected distance from the side phase conductor; H is the height of the side phase conductor above the ground at the measuring point; h is the installation height of the measuring instrument antenna; k is the attenuation coefficient, expressed as: In equation (8): f is the frequency.

6. The method for confirming the safe distance for unmanned aerial vehicle (UAV) inspection operations in a 220kV substation according to claim 1, characterized in that: In step 2, when establishing simulation models of key components of the substation based on finite element simulation software, the components include circuit breakers, current transformers, and busbars. Methods for applying excitation conditions in simulation experiments include: 2.1: Apply operating voltage, operating current, and electromagnetic field values ​​to the circuit breaker conductors; set the boundary conditions for calculation: when the circuit breaker is in the conducting state, the moving and stationary contacts in the arc-extinguishing chamber are connected and both are at high potential, and the actual operating voltage is applied; the support column and the ground are grounded at low potential, thereby realizing the simulation; 2.2: Apply working voltage, working current, and electromagnetic field values ​​to the current transformer conductors; calculate boundary conditions: apply the actual working voltage to the secondary winding, conductive rod, and high-potential housing; The simulation is achieved by applying zero potential to the shielding cover, the cement pillar, and the ground. 2.3: Apply working current and actual working voltage to the busbar, while applying zero potential to the support insulator, cement support and ground.

7. The method for confirming the safe distance for unmanned aerial vehicle (UAV) inspection operations in a 220kV substation according to claim 1, characterized in that: In step 4, the electric field, magnetic field, and radio field are simulated on the simulation models of key components in the substation and the UAV simulation model, and the magnitude and distribution of the electric field, magnetic field, and radio field experienced by the UAV are analyzed; specifically as follows: The magnitude of the electric field, magnetic field, and radio field experienced by the drone decreases rapidly with distance; and the attenuation is smaller with greater distance; the maximum electric field shown by the drone is mainly distributed on the surface of the drone's brushless motor; the maximum magnetic field and radio field experienced by the drone occur at the brushless motor; other parts, the closer to the key components of the substation, the greater the field strength. The spatial distribution characteristics of the electric field intensity and its attenuation with distance are analyzed; details are as follows: The electric field, magnetic field and radio field of the substation are non-uniformly distributed around the high-voltage equipment, and decay rapidly with distance, with the decay rate decreasing as the distance increases. Because the operating current of all key components in the substation is three-phase AC, the interference experienced by the UAV when inspecting the side phases and the middle phases is different. By placing the UAV around the middle phase and the side phases respectively, the difference in the field strength experienced by the UAV can be obtained. Based on the difference in the field strength experienced by the UAV, the electric field concentration phenomenon and magnetic convergence phenomenon of the brushless DC motor of the UAV can be further analyzed. Specifically: Electric field concentration phenomenon: the electric field distortion is concentrated on the surface of the brushless motor of the UAV; Magnetic convergence phenomenon: under the action of the magnetic field, the magnetic flux of the UAV naturally converges to the region with the least magnetic resistance. The path magnetic resistance of the magnetic material is much lower than that of the air gap and non-magnetic components, which directly leads to the concentration of magnetic flux in the key parts of the magnetic material.

8. The method for confirming the safe distance for unmanned aerial vehicle (UAV) inspection operations in a 220kV substation according to claim 1, characterized in that: In step 5, the spatial position and flight attitude of the UAV are changed to approach the key components of the substation from different angles, simulating the interference experienced by the UAV under actual working conditions. Further analysis and comparison are then conducted on the magnitude of the field strength experienced by the UAV during inspection operations, as well as the distribution patterns of electric, magnetic, and radio fields. Specifically, the following is a detailed analysis: Analysis of the magnitude of electric field strength experienced by UAVs during inspection operations: Changing the spatial position and flight attitude of the UAV will significantly affect the electric field, magnetic field and radio field interference it experiences during substation inspections; when the spatial position of the UAV remains unchanged, the electric field, magnetic field and radio field interference intensity experienced by attitude 4 is the greatest. At attitude 1, the electric field, magnetic field, and radio field interference are minimized; Distribution patterns of electric, magnetic, and radio fields: As distance increases, the attenuation of the magnetic field is the greatest, while that of the radio field is the smallest.

9. The method for confirming the safe distance for unmanned aerial vehicle (UAV) inspection operations in a 220kV substation according to claim 1, characterized in that: In step 7, the control delay distance and braking distance are determined based on the speed of the drone during operation and the delay time of its control signal; specifically as follows: Control delay distance: During the control signal delay, the drone typically maintains its current operating speed and flies at a constant speed; therefore, it can be directly calculated using the formula for constant speed flight distance, as shown below: d2=v×t d ; Where d2 is the control delay distance; v is the UAV operating speed; t d To control the signal delay time; Braking distance: The braking distance is the distance a drone travels from receiving a braking command to a complete stop at maximum deceleration; the specific formula is as follows: Where d3 is the braking distance; v is the drone's operating speed; a max This represents the maximum deceleration of the drone; The maximum wind speed that the drone can withstand during actual inspection operations was measured, and combined with the drone's own performance analysis, the impact of gusts on the drone's offset distance was confirmed; details are as follows: The impact of gusts on drone drift distance: The effect of gusts on drone drift is essentially the lateral drift caused by the lateral force of the wind. Short-duration gusts can be simplified to a uniform lateral wind interference model, as shown in the following formula: Where d4 is the offset distance affected by gusts; v w The lateral wind speed of the gust; t r The disturbance rejection response time of the flight control system; a w The lateral acceleration of the drone was caused by a gust of wind.

10. The method for confirming the safe distance for unmanned aerial vehicle (UAV) inspection operations in a 220kV substation according to claim 1, characterized in that: In step 8, the safe distance for drone inspection is accurately calculated. The calculation formula for the safe distance confirmation method for drone inspection operations is as follows: d y =max(d E ,d B ,d db )+(d1+d2+d3+d4)(9); In Equation (9): Hovering error distance d1: The stability of the UAV in maintaining a specified three-dimensional spatial position without deviation along the horizontal X, Y, and vertical Z axes without manual control intervention, and the deviation between the actual position and the preset target position; Control delay distance d2: The buffer distance caused by the delay of the remote control signal; Braking distance d3: The distance required for the drone to come to a complete stop from the start of braking; Gust-affected distance d4: The offset of the drone due to the influence of gusts; d E d represents the safe distance in an electric field. B d represents the safe distance for magnetic fields. db The safe distance for radio fields is represented by max(d). E ,d B ,d db () indicates taking the maximum of the three; After determining the safe distance for drone inspections based on the above formula, the space around the key equipment in the substation is divided into three parts: 1) Core No-Fly Zone: High-risk area adjacent to the main equipment, drones are strictly prohibited from entering; 2) Risk warning zone: A transitional area between no-fly zones and safe zones; 3) Normal safety zone: a low-risk area away from the main equipment.

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