Visual simulation system and method for igniting vegetation by breakdown arc of high-voltage transmission line

Abstract

The invention discloses a visual simulation system and method for igniting vegetation by a breakdown arc of a high-voltage power transmission line, and belongs to the field of simulation and characteristic test of a process of inducing a forest fire by the high-voltage power transmission line. The system comprises an altitude condition simulation box, a low-pressure regulation and control module, a temperature and humidity regulation and control module, a power-frequency high-voltage AC / DC power supply, a discharge breakdown arc ignition module, a discharge breakdown characteristic acquisition module and a combustion spread characteristic acquisition module. In the altitude condition simulation box, typical vegetation and a simulation wire are fixed in a proper configuration, and a power frequency high voltage AC / DC power supply, the simulation wire, the vegetation and a grounding line are connected to form a single phase-grounding circuit. Corresponding atmosphere is formed by adjusting altitude condition parameters in the altitude condition simulation box, output voltage and working conditions are regulated and controlled until multi-phase body discharge occurs, vegetation is punctured by an arc and burns, process phenomena are observed and recorded, and corresponding characteristic parameters are collected. Bidirectional safety prevention and control of the high-voltage power grid and the mountain fire in the high-altitude area can be realized.

Description

Technical Field

[0001] The present invention belongs to the field of high-voltage transmission line-induced forest fire process simulation and characteristic testing, and in particular relates to a visual simulation system and method for the combustion caused by the discharge breakdown arc when the local body or the fallen broken line of the high-voltage transmission line is close to and overlaps with the forest space and surface vegetation under environmental conditions in different altitude areas. Background Art

[0002] When constructing high-voltage power transmission and transformation projects, it is inevitable to cross terrain conditions such as mountains and forests in areas with different altitudes. Under such conditions, the corridor of high-voltage transmission lines is long, and the area covered by combustible and flammable vegetation is vast; at the same time, the increase in altitude leads to a gradual decrease in major meteorological parameters such as atmospheric pressure and air density, which in turn reduces the insulation air and air gap discharge voltage around electrical equipment. Therefore, when facing adverse meteorological conditions, geographical conditions and power grid failures, such as strong winds, heavy rainfall, heavy snowfall, aging / overcurrent / overheating of transmission lines, broken / fractured / drooping of transmission lines, crossing of transmission lines and trees, etc., the local body of the high-voltage transmission line or / and the drooping broken line are prone to overlap and approach the forest space and surface vegetation below, causing external insulation air discharge breakdown, generating high temperature (the center temperature of the arc column can reach 6000-7000℃ or even above 10000℃, and the surface temperature can reach 3000-4000℃) and high-energy (arc voltage is usually 10-100V, and arc current can reach more than thousands of amperes) arcs. When the arc further breaks down the vegetation and even the ground soil, it will induce vegetation combustion and even spread.

[0003] Specifically, when high-voltage transmission lines have design defects, age and fail during service, and forest vegetation overgrows under the lines, the lines and vegetation are prone to contact (such as overlapping) or proximity. In addition, under the influence of external forces such as strong winds, heavy rains, and heavy snowfalls, the lines are prone to severe dancing, sag, breakage, and falling off. At the same time, tree branches are also prone to shaking, breaking, and falling, resulting in long-term excessive contact (such as overlapping) or / and mutual proximity failures between trees and lines. These processes may generate high-temperature, high-energy arcs, which in turn cause discharge breakdown of multiphase bodies such as external insulating air and vegetation matrix, thereby causing vegetation to ignite (catch), burn, and spread, which may in turn induce wildfires. Therefore, it is particularly important to study the conditions, modes, characteristics, mechanisms, and effects and mechanisms of the interaction between transmission lines and wildfires, as well as the effects and mechanisms of various influencing factors. Such vegetation wildfire accidents induced by faults in high-voltage AC transmission lines occur from time to time, and are usually caused by strong winds, dangerous terrain, complex landforms, high altitudes, low temperatures, and low humidity. Compared with general wildfires, they spread faster and on a larger scale. Overall, they are accidents with a low probability, a high proportion, and serious consequences. They have become a serious hidden danger to the long-term safe operation of power grids, the long-term protection of forestry resources, and the friendly evolution of the environment and climate.

[0004] However, the existing technology has not yet conducted in-depth research on the related processes, characteristics and mechanisms of arc discharge breakdown and ignition, combustion and spread of vegetation when the local body of the high-voltage transmission line or / and the overlapping of the fallen broken line or / and the adjacent space or / and the surface vegetation occurs under different external conditions (such as altitude, atmospheric pressure, atmospheric temperature, atmospheric humidity, oxygen concentration, simulated conductors, etc.). Summary of the invention

[0005] The purpose of the present invention is to provide a visual simulation system and method for the arc breakdown and ignition of vegetation in high-voltage transmission lines under conditions of different altitudes, aiming to simulate the overall process of multi-phase discharge, breakdown, arcing and ignition of forest vegetation and inducing its combustion and spread caused by local body or / and line breakage faults of high-voltage transmission lines under environmental conditions in different altitudes, so as to realize the visual monitoring and analysis of the characteristic parameters of the overall process.

[0006] To achieve the above object, the present invention adopts the following technical solution: In a first aspect, the present invention provides a high-voltage transmission line breakdown arc ignition vegetation visualization simulation system, comprising an altitude condition simulation box, a low air pressure control module, a temperature and humidity control module, an industrial frequency high voltage AC and DC power supply, a discharge breakdown arc ignition module, a discharge breakdown characteristic acquisition module and a combustion spread characteristic acquisition module, wherein the altitude condition simulation box is provided with visualization glass; The altitude condition simulation box is used to provide environmental conditions for the discharge breakdown arc of high-voltage transmission lines at different altitudes to ignite vegetation; The low air pressure control module is used to adjust the air pressure inside the altitude condition simulation box according to different altitudes; The temperature and humidity control module is used to adjust the temperature and humidity inside the altitude condition simulation box; The industrial frequency high voltage AC and DC power supply is used to provide high voltage power for the discharge breakdown arc ignition module; The discharge breakdown arc ignition module is used to trigger the discharge breakdown arc of the high-voltage transmission line in the altitude condition simulation box to ignite the vegetation; The discharge breakdown characteristic acquisition module is used to collect data on characteristic parameters of the discharge breakdown arc occurrence and development process in the altitude condition simulation box under normal temperature and pressure and different altitude conditions; The combustion and spread characteristic acquisition module is used to collect data on characteristic parameters of vegetation combustion and spread processes in an altitude condition simulation box under normal temperature and pressure and different altitudes.

[0007] Optionally, the discharge breakdown arc ignition module includes a water resistor or a high-power metal resistor module, a simulated wire, a vegetation specimen and two high-voltage electrical insulation brackets. The water resistor or high-power metal resistor module is arranged outside the altitude condition simulation box, and the simulated wire, the vegetation specimen and the high-voltage electrical insulation bracket are arranged inside the altitude condition simulation box. One end of the water resistor or high-power metal resistor module is connected to the industrial frequency high-voltage AC and DC power supply, and the other end is connected to the non-discharge end of the simulated wire. The vegetation specimen is a space vegetation specimen. The simulated wire is horizontally fixed on one of the high-voltage electrical insulation brackets, and the other high-voltage electrical insulation bracket is used to fix the space vegetation specimen and make the space vegetation specimen vertically suspended, and the lower end of the space vegetation specimen is grounded.

[0008] Optionally, the discharge breakdown arc ignition module includes a water resistor or a high-power metal resistor module, a simulated wire, a vegetation test material, two high-voltage electrical insulation brackets and a steel plate fuel bed, an auxiliary horizontal metal support rod is connected between the two high-voltage electrical insulation brackets, the water resistor or high-power metal resistor module is arranged outside the altitude condition simulation box, the simulated wire, the vegetation test material, the high-voltage electrical insulation bracket and the steel plate fuel bed are arranged inside the altitude condition simulation box, one end of the water resistor or high-power metal resistor module is connected to the industrial frequency high-voltage AC and DC power supply, and the other end is connected to the auxiliary horizontal metal support rod, the vegetation test material is a surface vegetation test material, the discharge end of the simulated wire is suspended in the center, and the non-discharge end is fixed to the middle point of the auxiliary horizontal metal support rod, the surface vegetation test material is contained in the steel plate fuel bed and placed below the simulated wire, and the steel plate fuel bed is grounded.

[0009] Furthermore, the industrial frequency high-voltage AC / DC power supply includes a first AC power supply, a dedicated console for an experimental transformer, and an AC / DC high-voltage test transformer. The first AC power supply is connected to the dedicated console for the experimental transformer, the dedicated console for the experimental transformer is connected in series with the AC / DC high-voltage test transformer, the AC / DC high-voltage test transformer is connected to the discharge breakdown arc ignition module, the first AC power supply is used to power the experimental circuit, the dedicated console for the experimental transformer is used to control the AC / DC high-voltage test transformer to perform a step-up or step-down operation, and the AC / DC high-voltage test transformer is used to step up the experimental circuit.

[0010] Furthermore, the low air pressure control module includes a vacuum pump, a pump-trap isolation valve and a pressure gauge. The vacuum pump is connected to the interior of the altitude condition simulation box to adjust the air pressure inside the altitude condition simulation box; the pump-trap isolation valve and the pressure gauge are installed on the top of the altitude condition simulation box, the pump-trap isolation valve is used to control the flow of gas in and out of the altitude condition simulation box, and the pressure gauge is used to monitor the air pressure inside the altitude condition simulation box.

[0011] Furthermore, the temperature and humidity control module includes a refrigeration system, a K-type armored thermocouple tree, a temperature acquisition module, a humidity transmitter, a humidity regulator and a data acquisition control and analysis system. The refrigeration system is connected to the interior of the altitude condition simulation box to adjust the temperature inside the altitude condition simulation box; the K-type armored thermocouple tree is connected to the two side walls of the altitude condition simulation box through a high vacuum aviation plug to measure the temperature of different dimensions inside the altitude condition simulation box, and transmits the measured temperature data to the data acquisition control and analysis system through the temperature acquisition module; the humidity regulator is arranged inside the altitude condition simulation box to adjust the humidity inside the altitude condition simulation box; the humidity transmitter is installed on the top of the altitude condition simulation box to measure the humidity inside the altitude condition simulation box.

[0012] Furthermore, the discharge breakdown characteristic acquisition module includes a current and voltage acquisition module, a high-definition camera, a high-speed camera, an infrared thermal imager and a schlieren instrument; the current and voltage acquisition module includes a first metal resistor, a digital oscilloscope, an isolation transformer, a resistor-capacitor voltage divider and a second AC power supply, one end of the first metal resistor is connected to the vegetation test material and the other end is grounded, the resistor-capacitor voltage divider is connected in parallel with the discharge breakdown arc ignition module, the resistor-capacitor voltage divider is grounded, the first metal resistor and the resistor-capacitor voltage divider are both connected in parallel with the digital oscilloscope, the digital oscilloscope is connected to the second AC power supply through an isolation transformer, and the digital oscilloscope is used to store and record the voltage and waveform of the first metal resistor and the resistor-capacitor voltage divider; the high-definition camera is used to collect visible light scene phenomena during the two-phase discharge breakdown process of gas and vegetation; the infrared thermal imager is used to collect infrared thermal imaging scene phenomena during the two-phase discharge breakdown process; the high-speed camera and schlieren instrument are used to collect schlieren scene phenomena during the two-phase discharge breakdown process.

[0013] Furthermore, the combustion spread characteristic acquisition module includes a K-type armored thermocouple tree, a temperature acquisition module, a data acquisition control and analysis system, a high-definition camera, a high-speed camera, an infrared thermal imager and a Schlieren instrument. The K-type armored thermocouple tree is connected to the two side walls of the altitude condition simulation box through a high-vacuum aviation plug, and is used to measure the temperature of vegetation specimens of different dimensions from breakdown to combustion, and transmit the measured temperature to the data acquisition control and analysis system through the temperature acquisition module; the high-definition camera is used to collect visible light scenes when vegetation burns and spreads; the infrared thermal imager is used to collect infrared thermal imaging scenes when vegetation burns and spreads; the high-speed camera and Schlieren instrument are used to collect Schlieren scenes when vegetation burns and spreads.

[0014] In a second aspect, the present invention provides a method for visually simulating vegetation ignition caused by arc breakdown of a high-voltage transmission line, comprising: Step 1, construction of a simulation configuration for the local body overlap / adjacent vegetation experiment of a high-voltage transmission line: vertically suspend and fix the space vegetation specimen on a high-voltage electrical insulation bracket, horizontally fix the simulated conductor on another high-voltage electrical insulation bracket, and the discharge end of the simulated conductor corresponds to the space vegetation specimen, and the gap between the discharge end of the simulated conductor and the space vegetation specimen is set to different gap distances, and the angle between the longitudinal central axis of the space vegetation and the vertical projection line of the middle point of the simulated conductor is adjusted to different angles, so that the air gap between the simulated conductor and the space vegetation specimen becomes an initial potential discharge channel; Step 2: Connect the water resistor or high-power metal resistor module to the non-discharge end of the simulated wire, and ground the lower end of the space vegetation test material to form a single-phase-ground circuit; in the altitude condition simulation box, which is a normal temperature and pressure atmospheric environment, use a power frequency high-voltage AC and DC power supply to provide power to the simulated wire, and perform voltage boost and voltage stabilization operations by gradually applying linear pressure until discharge breakdown occurs around the simulated wire; Step 3, observe the sub-link phenomena and characteristics from the appearance of air corona around the simulated conductor to the vegetation burning and spreading process; and after the occurrence of each sub-link phenomenon, collect and calculate the discharge breakdown scene phenomenon and characteristic parameters through the discharge breakdown characteristic acquisition module, and collect and calculate the vegetation burning and spreading scene phenomenon and characteristic parameters through the burning and spreading characteristic acquisition module; Step 4, rebuild the simulation experiment configuration according to step 1, adjust the air pressure in the altitude condition simulation box through the low pressure control module according to the set altitude simulation parameters, adjust the temperature and humidity in the altitude condition simulation box through the temperature and humidity control module, and repeat steps 2-3.

[0015] In a third aspect, the present invention provides a method for visually simulating vegetation ignition caused by arc breakdown of a high-voltage transmission line, comprising: Step 1: Construction of the simulated configuration of the experiment of high-voltage transmission line drooping and disconnection / adjacent vegetation: the discharge end of the simulated conductor is suspended in the middle, and the non-discharge end is fixed to the middle point of the auxiliary horizontal metal support rod; the surface vegetation test material is placed in the steel plate fuel bed and placed under the simulated conductor; the gap between the suspended end point of the simulated conductor and the top of the surface vegetation test material is set to different gap distances, and the angle between the longitudinal center axis of the simulated conductor and the vertical projection line of the middle point of the auxiliary horizontal metal support rod is adjusted to different angles, so that the air gap between the suspended end of the simulated conductor and the surface vegetation test material becomes the initial potential discharge channel; Step 2: Connect the water resistor or high-power metal resistor module to the auxiliary horizontal metal support rod, and ground the steel disc fuel bed to form a single-phase-ground circuit; in the altitude condition simulation box, under the normal temperature and pressure atmospheric environment, use the industrial frequency high-voltage AC and DC power supply to provide power to the simulation wire, and use a step-by-step linear pressure method to perform voltage boost and voltage stabilization operations until discharge breakdown occurs around the simulation wire; Step 3, observe the sub-link phenomena and characteristics from the appearance of air corona around the simulated conductor to the vegetation burning and spreading process; and after the occurrence of each sub-link phenomenon, collect and calculate the discharge breakdown scene phenomenon and characteristic parameters through the discharge breakdown characteristic acquisition module, and collect and calculate the vegetation burning and spreading scene phenomenon and characteristic parameters through the burning and spreading characteristic acquisition module; Step 4, rebuild the simulation experiment configuration according to step 1, adjust the air pressure in the altitude condition simulation box through the low pressure control module according to the set altitude simulation parameters, adjust the temperature and humidity in the altitude condition simulation box through the temperature and humidity control module, and repeat steps 2-3.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention can simulate the whole process characteristics and mechanism related experimental measurement and theoretical calculation method research of the arc ignition, vegetation combustion and spread caused by the partial body and down-break of high-voltage AC and DC transmission lines overlapping or / and being close to vegetation in space or on the ground under different altitude conditions; (2) The present invention uses an experimental box under simulated altitude conditions to dynamically monitor and collect the multi-physical field coupling process formed after vegetation combustion caused by high-voltage AC and DC transmission lines, covering multiple parameters such as pressure field, temperature field, humidity field, electric field, fire field (flame and smoke) and thermal field (heat flow). Through these data, the distribution state and interactive characteristics of multi-physical fields and composite media under complex environmental conditions, as well as the effects and influence mechanisms of typical micro-meteorological conditions on them can be more accurately and intuitively revealed; (3) The present invention pays special attention to the prediction accuracy of discharge characteristic parameters and the applicability of engineering applications in high-altitude areas (5000m and above). In specific implementations, the results of the discharge breakdown process phenomena, behavioral laws, and characteristic parameters under different altitude conditions obtained by the present invention can be referred to, and the influence of temperature, humidity, and complex conditions of vegetation and wildfires can be considered. By correcting the existing discharge characteristic curve, a discharge characteristic curve model that adapts to high-altitude conditions is established. Subsequently, the corrected curve model is verified and optimized to ensure its accuracy and reliability under complex environmental conditions, providing a scientific basis and technical support for practical engineering altitude correction methods; (4) Compared with traditional experimental devices with single working conditions, physical fields and functions, the visual simulation system of the present invention has a reasonable structure, convenient operation, stable performance and reliable testing. It has a forward-looking design concept, novel experimental scheme, flexible experimental content and good visual effect. The experimental process and theoretical calculation method are scientific and reasonable. The results obtained can be used to explore the corresponding evolution process conditions, phenomena, patterns, characteristics and mechanisms of the ignition, combustion and spread of forest vegetation caused by the failure of the local body or broken line of high-voltage transmission lines or / and adjacent vegetation under different altitudes, and to explore the influence and mechanism of external environmental conditions such as typical micrometeorological conditions on the ignition, combustion and fire spread of forest vegetation, so as to provide theoretical guidance and technical support for the line safety protection design and wildfire prevention and control under the complex environmental conditions of high-voltage transmission lines and wildfire coupling. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the composition of a visual simulation system for igniting vegetation due to arc breakdown of a high-voltage transmission line according to an embodiment of the present invention; Figure 2 Schematic diagram of the structure of a visual simulation system for igniting vegetation by arc breakdown of a high-voltage transmission line according to an embodiment of the present invention, (a) a front view, (b) a rear view; Figure 3 This is a schematic diagram of a configuration of a high-voltage transmission line tree-line overlap / nearby fault ignition space vegetation simulation experiment, taking a 35kV high-voltage transmission line as an example in an embodiment of the present invention; Figure 4 This is a schematic diagram of a simulation experiment configuration of a 35kV high-voltage transmission line as an example of a high-voltage transmission line disconnection and sagging fault igniting surface vegetation according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of a current and voltage acquisition module according to an embodiment of the present invention; Figure 6 The breakdown voltage curve of the poplar wood strips of the embodiment of the present invention when ignited by the simulated tree line overlap discharge breakdown arc under the conditions of different altitudes and an air gap of 5 cm; Figure 7 This is a diagram of a poplar wood strip according to an embodiment of the present invention being ignited by arc discharge and breakdown by steel rod electrodes lapped by simulated tree lines at an altitude of 1600m and an air gap of 1cm; Figure 8 Schematic diagram of the steel core aluminum stranded wire according to an embodiment of the present invention, (a) schematic diagram of the macroscopic morphology, (b) schematic diagram of the microscopic morphology; Fig. 9 It is a schematic diagram of the structure of a high-power metal resistor module according to an embodiment of the present invention.

[0018] In the figure, 1. First AC power supply; 2. Special control console for experimental transformer; 3. AC / DC high-voltage test transformer; 4. Water resistor or high-power metal resistor module; 5. Soft silicone high-voltage connecting wire; 6. Altitude condition simulation box; 7. Pressure gauge; 8. Humidity transmitter; 9. Pump well isolation valve; 10. Blind plate hole; 11. Visualization glass; 12. Simulation wire; 13. High-voltage electrical insulation bracket; 14. Vegetation test material; 15. Air compressor; 16. Vacuum pump; 17. Temperature acquisition module; 18. Data acquisition control and analysis system; 19-1, 19-2, passive voltage probe; 20. First metal resistor; 21. Digital oscilloscope; 22. Isolation transformer; 23. Second AC power supply; 24-1, 24-2, probe signal terminal; 25. Infrared thermal imager; 26. K-type armored thermocouple tree; 27. High-speed camera; 28. Resistor-capacitor voltage divider; 29-1, 29-2, 1x probe compensation box; 30. Polytetrafluoroethylene lining; 31. Rolling pulley; 32. Air filter; 33-1, 33-2, probe ground terminal; 34. Schlieren instrument; 35. Ground rod; 36. High vacuum aviation plug; 37. Air-cooled air cooler; 38. Humidifier; 39. High-definition camera; 40. Condenser; 41. Steel plate fuel bed; 42. Auxiliary horizontal metal support rod. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with specific examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention.

[0020] like Figure 1 As shown, a visual simulation system for high-voltage transmission line breakdown arc ignition of vegetation includes an altitude condition simulation box 6, a low pressure control module, a temperature and humidity control module, an industrial frequency high-voltage AC and DC power supply, a discharge breakdown arc ignition module, a discharge breakdown characteristic acquisition module and a combustion spread characteristic acquisition module.

[0021] The altitude condition simulation box 6 is used to provide environmental conditions for the discharge breakdown arc of high-voltage transmission lines to ignite vegetation at different altitudes (eg 0-5500m).

[0022] like Figure 1 As shown, the altitude condition simulation box 6 is a closed rectangular container made of stainless steel SUS304, with a thickness of 3mm, an external size of 1360mm×990mm×1700mm (length×width×height), and an internal size of 1100mm×800mm×800mm (length×width×height). Figure 2 As shown, the box door is sealed with a 8mm×10mm silicone rubber sealing strip. A polytetrafluoroethylene liner 30 is provided inside the box to prevent discharge from inside the box to the box. B1 grade thermal insulation cotton is provided between the box wall and the polytetrafluoroethylene liner 30.

[0023] The front of the box is embedded with a visualization glass 11 to clearly record the experimental process. The visualization glass 11 is made of fireproof glass.

[0024] A plurality of blind plate holes 10 are provided on the front and top of the box body, and the blind plate holes 10 are used for airtight connection of the wires.

[0025] High vacuum aviation plugs 36 are installed on both sides of the box to achieve airtight connection of electronic components.

[0026] A bracket is connected to the bottom of the box body, and a rolling pulley 31 is installed at the bottom of the bracket to achieve the mobility of the altitude condition simulation box 6.

[0027] The low pressure control module is used to adjust the internal air pressure of the altitude condition simulation box 6 according to different altitudes, for example, 55-101 kPa.

[0028] like Figure 1 As shown, the low air pressure control module includes a pressure gauge 7, a vacuum pump 16, a pump well isolation valve 9 and an air filter 32.

[0029] The vacuum pump 16 is arranged on the bracket, and the vacuum pump 16 is connected to the interior of the altitude condition simulation box 6 through a pipeline, and a manual valve is installed on the pipeline.

[0030] The pressure gauge 7 is embedded in the top of the altitude condition simulation box 6 through the blind plate hole 10, and is sealed by closing the valve on the blind plate hole 10. The pressure gauge 7 is used to monitor the atmospheric pressure in the altitude condition simulation box 6 in real time. The range of the pressure gauge 7 is 0-100 kPa, and the accuracy is 1 kPa.

[0031] The pump well isolation valve 9 is installed on the top of the altitude condition simulation box 6 to control the flow of gas in and out of the altitude condition simulation box 6 to ensure that the fluid flows according to the designed flow path.

[0032] The air filter 32 is used to filter pollutants such as burnt ash, dust, and tiny particles in the air to prevent them from entering the vacuum pump system.

[0033] By closing the pump well isolation valve 9 and starting the vacuum pump 16 to extract the air in the altitude condition simulation box 6, the air pressure in the altitude condition simulation box 6 can be reduced to a higher altitude air pressure level by adjusting the valve size of the vacuum pump 16. The air pressure in the box can be controlled to ensure the accuracy and stability of the experiment, thereby enabling the altitude condition simulation box 6 to operate in different air pressure environments.

[0034] The temperature and humidity control module is used to adjust the temperature (such as -5-25°C) and humidity (such as relative humidity 10-95%RH) inside the altitude condition simulation box 6.

[0035] like Figure 1 As shown, the temperature and humidity control module includes a refrigeration system, a K-type armored thermocouple tree 26, a temperature acquisition module 17, a data acquisition control and analysis system 18, a humidity transmitter 8 and a humidity regulator 38.

[0036] The refrigeration system is connected to the interior of the altitude condition simulation box 6 through a pipeline, and is used to adjust the temperature inside the altitude condition simulation box 6. The refrigeration system includes an air compressor 15, a condenser 40, and an air-cooled air cooler 37, and the air compressor 15, the condenser 40, and the air-cooled air cooler 37 are arranged on a bracket. The air compressor 15 is connected to the interior of the altitude condition simulation box through a pipeline, and the exhaust port of the air compressor 15 is connected to the inlet of the condenser 40 through a high-pressure copper pipe, and the air-cooled air cooler 37 is installed in the air flow channel outside the condenser 40.

[0037] The K-type armored thermocouple tree 26 is embedded in the two side walls of the altitude condition simulation box 6 to measure the temperature of different dimensions inside the altitude condition simulation box 6. The K-type armored thermocouple tree 26 is internally connected to the two side walls of the altitude condition simulation box 6 through a high vacuum aviation plug 36.

[0038] The K-type armored thermocouple tree 26 is connected to the temperature acquisition module 17 through a thermocouple compensation wire to realize the acquisition of the temperature of different dimensions in the box. The temperature acquisition module 17 is connected to the data acquisition control and analysis system 18, and the temperature measured by the K-type armored thermocouple tree 26 is transmitted to the data acquisition control and analysis system 18 through the temperature acquisition module 17.

[0039] The humidity regulator 38 is disposed inside the altitude condition simulation box 6, and is used to adjust the humidity inside the altitude condition simulation box 6. The relative humidity measurement range of the humidity regulator is 10-95%RH, and the accuracy is ±3%RH.

[0040] The humidity transmitter 8 is installed on the top of the altitude condition simulation box 6 through the blind plate hole 10 to measure the humidity in the altitude condition simulation box 6 .

[0041] By closing the door of the altitude condition simulation box 6, turning on the air compressor 15, the condenser 40, and the air-cooled air cooler 37, the temperature change operation inside the box is realized. The temperature inside the box is measured by the K-type armored thermocouple tree 26, and the collected temperature data is transmitted to the data acquisition control and analysis system 18 through the temperature acquisition module 17 to realize the monitoring and acquisition of the temperature inside the box. The humidity is measured by the humidity transmitter 8 and the humidity regulator 38 is used for humidification / drying to realize the regulation and control of the air humidity inside the box.

[0042] The industrial frequency high voltage AC and DC power supply is used to provide high voltage power for the discharge breakdown arc ignition module, such as 0-50kV, 0-150kV or 0-300kV.

[0043] The industrial frequency high-voltage AC / DC power supply is composed of a first AC power supply 1, a dedicated control console for experimental transformers 2, and an AC / DC high-voltage test transformer 3. The first AC power supply 1 is connected to the dedicated control console for experimental transformers 2, and the dedicated control console for experimental transformers 2 is connected to the AC / DC high-voltage test transformer 3 through a wire. The first AC power supply 1 is used to power the experimental circuit, and the dedicated control console for experimental transformers 2 is used to control the AC / DC high-voltage test transformer 3 to perform a step-up or step-down operation, and the AC / DC high-voltage test transformer 3 is used to achieve the step-up process. Among them, the first AC power supply adopts a 380V AC power supply, and the AC / DC high-voltage test transformer can adopt a 330kVA / 50kV, 100kVA / 150kV or 300kVA / 300kV AC / DC high-voltage test transformer.

[0044] The discharge breakdown arc ignition module is used to trigger the discharge breakdown arc of the high-voltage transmission line in the altitude condition simulation box 6 to ignite the vegetation.

[0045] like Figure 1 and Figure 3 As shown, the discharge breakdown arc ignition module includes a water resistor or a high-power metal resistor module 4, a simulated wire 12, two high-voltage electrical insulation brackets 13 and a vegetation test material 14. The water resistor or the high-power metal resistor module 4 is arranged outside the altitude condition simulation box 6, and the simulated wire 12, the high-voltage electrical insulation bracket 13 and the vegetation test material 14 are arranged inside the altitude condition simulation box 6.

[0046] The water resistor or high-power metal resistor module 4 is installed above the AC / DC high-voltage test transformer 3 through a threaded connection and is connected in series with the AC / DC high-voltage test transformer 3 to achieve protection of the entire closed circuit and monitoring and early warning of the long-term operation of the AC / DC high-voltage test transformer 3.

[0047] The other end of the water resistor or high-power metal resistor module 4 is connected to the non-discharge end of the simulation wire 12 through the soft silicone high-voltage connecting wire 5 to achieve the transmission and protection of the high-voltage AC and DC power transformed by the AC and DC high-voltage test transformer 3.

[0048] The water resistor is composed of an acrylic shell, deionized water and parallel electrode plates, and has a resistance of 1.5MΩ. The lower electrode plate of the water resistor is connected to the AC / DC high-voltage test transformer 3 through a thread, and the upper electrode plate is connected to the simulation wire 12 through a soft silicone high-voltage connecting wire 5.

[0049] like Fig. 9 As shown, the high-power metal resistor module is composed of several metal resistors connected in series and parallel, with a resistance of 1.5MΩ and a power of 2kW. One end of the high-power metal resistor module is connected to the AC / DC high-voltage test transformer 3 through the high-voltage line connection port, and the other end is connected to the simulation wire 12 through the soft silicone high-voltage connection line 5.

[0050] The vegetation test materials 14 include space vegetation test materials and surface vegetation test materials.

[0051] The high-voltage electrical insulation support 13 is made of polytetrafluoroethylene and is used to fix the simulated conductor 12 and the vegetation test material 14 .

[0052] like Figure 3 As shown, in the simulation experiment of local body overlap / near fault ignition of space vegetation in high-voltage transmission line, the simulated wire 12 can be fixed to one of the high-voltage electrical insulation brackets 13 by an insulating clamp, and the other high-voltage electrical insulation bracket 13 is used to fix the space vegetation specimen. Specifically, the space vegetation specimen is vertically suspended and fixed on one of the high-voltage electrical insulation brackets 13, and the simulated wire 12 is horizontally fixed at 5.0 cm from the top of the space vegetation specimen, and the discharge end of the simulated wire 12 corresponds to the space vegetation specimen, so that the air gap between the discharge end of the simulated wire 12 and the space vegetation specimen becomes a potential discharge channel, and the ground wire is wound at 5.0 cm from the bottom of the space vegetation specimen to ground it. In the simulation experiment, the gap between the discharge end of the simulated conductor 12 and the space vegetation specimen can be set to different gap distances, such as 0.0, 2.0, 4.0, 5.0, 6.0, 8.0, 10.0 cm, etc., and the angle between the longitudinal center axis of the space vegetation specimen and the vertical projection line of the middle point of the simulated conductor (a straight line passing through the middle point of the simulated conductor and perpendicular to the simulated conductor) is adjusted to different angles, such as 0, 30, 45, 60, 90, 180°, etc., to simulate the experimental scenes of different overlap conditions of high-voltage transmission lines and forest vegetation.

[0053] In the local body lap joint / adjacent vegetation experiment of the high-voltage transmission line, the simulated conductor 12 selects a long section of simulated conductor (with a round or square vertical end face, equivalent to the wire end) as a local conductor of the simulated overhead high-voltage transmission line. A cylindrical metal electrode with a certain length can be used, such as a steel rod or copper rod with a length of 0.5-3.0m; or an actual steel-core aluminum stranded wire, such as a 35kV JKLGYJ / Q aluminum core light cross-linked polyethylene insulated steel core overhead cable with a length of 0.5-3.0m, a 110kV LGJ-120 / 20 steel-core aluminum stranded wire, a 220kV LGJ-400 / 35 steel-core aluminum stranded wire, a steel-core aluminum stranded wire such as Figure 8 shown.

[0054] like Figure 4As shown, in the experiment of overlapping conductors of fallen and broken high-voltage transmission lines / adjacent vegetation, an auxiliary horizontal metal support rod 42 is connected between two high-voltage electrical insulation supports 13. The auxiliary horizontal metal support rod 42 can be a steel rod or a steel bar, etc. One end (discharge end) of the simulated conductor 12 is suspended in the middle, and the other end is fixed to the middle point of the auxiliary horizontal metal support rod 42. The surface vegetation test material 14 is placed in an open square steel plate fuel bed 41 with a side height of 5.0 cm and a bottom side length of 30.0 cm. The height of the surface vegetation test material fragments is adjusted to 3.0 cm, and the simulated conductor 12 is fixed vertically above it. In the simulation experiment, the gap between the suspended end point of the simulated conductor 12 and the top of the surface vegetation specimen can be set to different gap distances, such as 0.0, 2.0, 4.0, 5.0, 6.0, 8.0, 10.0 cm, etc., and the included angle between the longitudinal center axis of the simulated conductor 12 and the vertical projection line of the middle point of the auxiliary horizontal metal support rod 42 is adjusted to different angles, such as 0, 30, 45, 60, 90, 180°, etc., so that the air gap between the suspended end of the simulated conductor 12 and the surface vegetation specimen becomes an initial potential discharge channel, thereby simulating the experimental scenario of different high-voltage transmission lines breaking and falling to ignite surface vegetation.

[0055] For the high-voltage transmission line drooping and broken line overlap / adjacent vegetation experiment, a disconnected simulated conductor (with a round or square vertical end face, equivalent to the wire end) is selected as a conductor to simulate the drooping and broken overhead high-voltage transmission line. The following can be used: a cylindrical metal electrode with a certain length (such as a steel rod or copper rod, with a length of 0.1-0.5m) or an actual steel-core aluminum stranded wire (same specifications as above, with a length of 0.1-0.5m); a metal electrode with a diameter of 1-20mm, a conical end face at one end, a cone angle of 10-60°, and a vertical or hemispherical section at the other end; an actual high-voltage transmission line section, with both ends having vertical sections obtained by grinding wheel cutting, and tied and fixed with aluminum wire hoops at a distance of 5-10mm from the two ends.

[0056] The discharge breakdown characteristic acquisition module is used to collect data on characteristic parameters of the discharge breakdown arc occurrence and development process in the altitude condition simulation box 6 under normal temperature and pressure and different altitude conditions.

[0057] like Figure 1 and Figure 5 As shown, the discharge breakdown characteristic acquisition module includes a current and voltage acquisition module, a high-definition camera 39 , a high-speed camera 27 , an infrared thermal imager 25 and a schlieren instrument 34 .

[0058] The current and voltage acquisition module includes a first metal resistor (200Ω) 20, a digital oscilloscope 21, an isolation transformer (220V to 220V) 22, a resistor-capacitor voltage divider (1000:1 voltage divider ratio) 28 and a second AC power supply 23. The second AC power supply 23 uses a 220V AC power supply.

[0059] The lower end of the space vegetation test material or the steel plate fuel bed 41 is connected to the first metal resistor 20, the other end of the first metal resistor 20 is grounded, the RC voltage divider 28 is connected in parallel with the discharge breakdown arc ignition module, the RC voltage divider 28 is grounded, the first metal resistor 20 and the RC voltage divider 28 are both connected in parallel with the digital oscilloscope 21, and the digital oscilloscope 21 is connected to the second AC power supply 23 through the isolation transformer 22. The digital oscilloscope 21 is used to store and record the voltage and waveform of the first metal resistor 20 and the RC voltage divider 28.

[0060] More specifically, the probe signal terminal 24-2 and the probe ground terminal 33-1 of the passive voltage probe 19-1 are respectively connected to the two ends of the RC voltage divider 28, and the 1x probe compensation box 29-2 of the passive voltage probe 19-1 is connected to the channel of the digital oscilloscope 21 to store and record the voltage and waveform on the RC voltage divider 28 connected in parallel with the discharge breakdown characteristic acquisition module, so as to further measure and draw the total voltage and its waveform (such as Figure 6 As shown). The probe signal terminal 24-1 and the probe ground terminal 33-2 of the passive voltage probe 19-2 are respectively connected to the two ends of the first metal resistor 20, and the 1x probe compensation box 29-1 of the passive voltage probe 19-2 is connected to the channel of the digital oscilloscope 21 to store and record the voltage and waveform of the first metal resistor 20 connected in series with the discharge breakdown characteristic acquisition module, thereby realizing the measurement of high-voltage power frequency AC and high-voltage DC electric field breakdown characteristics. The digital oscilloscope 21 is connected to the second AC power supply 23 through the isolation transformer 22 to protect the digital oscilloscope 21, electrically isolate it, and eliminate the ground loop. The arc voltage is as shown in formula (1): (1) Where: u arc and u ath are respectively the arc voltage and the median value of the voltage when the arc voltage changes from the power supply voltage of 0, in V; u s is the power supply voltage in V.

[0061] The high-definition camera 39 is used to collect visible light scene phenomena during the discharge breakdown process of major phase media such as gas (gaseous phase) and vegetation (solid phase), including corona and arc generation and development paths, corona and arc properties (shape, brightness, color, diameter, length, etc.), corona generation and arc propagation sounds and other related images, videos and audio.

[0062] The infrared thermal imager 25 is used to collect infrared thermal imaging scene phenomena during the two-phase discharge breakdown process, including the temperature distribution around the discharge breakdown channel and the arc area, and related images and videos of corona, arc and other process materials.

[0063] The high-speed camera 27 and the schlieren instrument 34 are used to collect schlieren scene phenomena during the two-phase discharge breakdown process, including the heat flow distribution and trajectory around the discharge breakdown channel and the arc area, as well as related images and videos of corona, arc and other process materials.

[0064] Through the digital oscilloscope 21 and the resistance value of the first metal resistor 20, typical discharge breakdown characteristic parameters can be collected and calculated, including breakdown / on-state voltage and breakdown / on-state current waveforms (shape, period, stage, gap breakdown point, etc.), breakdown / on-state voltage and breakdown / on-state current peak values, discharge breakdown / on-state duration, leakage current waveform (shape, number and distribution of burrs, etc.), leakage current peak value and polarity, discharge breakdown field strength, etc.

[0065] The combustion and spread characteristic acquisition module is used to collect data on characteristic parameters of vegetation combustion and spread process in the altitude condition simulation box 6 under normal temperature and pressure and different altitudes.

[0066] like Figure 1 As shown, the combustion spread characteristic acquisition module includes a K-type armored thermocouple tree 26, a temperature acquisition module 17, a data acquisition control and analysis system 18, a high-definition camera 39, a high-speed camera 27, an infrared thermal imager 25 and a schlieren 34.

[0067] The K-type armored thermocouple tree 26 is used to measure the temperature of vegetation specimens 14 of different dimensions from breakdown to combustion, and transmits the measured temperature to the data acquisition control and analysis system 18 through the temperature acquisition module 17.

[0068] Vegetation conductivity has a significant impact on vegetation temperature, as shown in formula (2): (2) In the formula: ln ρ T is the logarithm of vegetation conductivity; T is the absolute temperature of vegetation, in K; T 0 is the reference temperature, in K; ρ 0 is the conductivity of vegetation at the base temperature, in Ω·m; k a is a constant related to the vegetation itself; k b is the conductivity correction factor.

[0069] The high-definition camera 39 is used to collect visible light scenes when vegetation burns and spreads, including relevant images, videos and audios such as flames, smoke, water vapor and other process substances.

[0070] The infrared thermal imager 25 is used to collect infrared thermal imaging scenes when vegetation burns and spreads, including temperature distribution of vegetation surface, carbonized matrix and surrounding area (including smoke) and related images and videos of flames, smoke, water vapor and other process substances.

[0071] The high-speed camera 27 and the Schlieren instrument 34 are used to collect the Schlieren scenes when the vegetation is burning and spreading, including the heat flow distribution and trajectory of the flame and smoke, and the related images and videos of the flame, smoke, water vapor and other process substances.

[0072] The vegetation combustion and spread characteristic parameters include flame and smoke area temperature distribution, vegetation surface and carbonized matrix temperature, flame height, flame length, flame angle, flame conductivity, combustion rate and combustion intensity, etc. Among them, the flame and smoke area temperature distribution, vegetation surface and carbonized matrix temperature are collected by K-type armored thermocouple tree 26, the flame height, flame length and flame angle are collected by high-speed camera 27, the flame conductivity is calculated based on the flame resistance table, and the combustion rate and combustion intensity are collected by high-definition camera 39 and calculated based on the flame image.

[0073] During the entire process from the discharge arc to the vegetation burning and spreading, the high-definition camera 39 is used to collect images of the discharge arc generated in the visualization glass 11, such as Figure 7 As shown, the surface quality, structural characteristics or deformation of the vegetation are collected by high-speed camera 27 and Schlieren instrument 34. At the same time, the high-speed camera 27 and Schlieren instrument 34 are used to photograph and measure the trajectory and distribution of flame and smoke heat flow in the whole process of simulating the wire, arc contact point, arc body, vegetation ignition, arc development path, combustion and spread flow field.

[0074] The main acquisition parameters of the present invention include: (1) environmental parameters in the altitude condition simulation box: air pressure value, humidity distribution, temperature distribution; (2) space / surface vegetation parameters: mass loss rate, moisture content, conductivity, carbonization rate, etc. when vegetation is broken down, ignited, burned and spread, which can be obtained by analyzing the vegetation test materials after the experiment; (3) discharge breakdown characteristic parameters: corona and arc generation and development path, corona and arc shape, brightness, color, diameter, length, etc.; breakdown / conduction voltage and breakdown / conduction current waveform, breakdown / conduction voltage and breakdown / conduction current peak value, discharge breakdown / conduction duration, leakage current waveform, leakage current peak value and polarity, discharge breakdown field strength, etc. when vegetation is broken down and ignited. (4) vegetation combustion and spread characteristic parameters: flame height, flame length, flame angle, flame conductivity, flame and smoke temperature distribution, flame and temperature heat flow distribution and trajectory, combustion rate, spread rate and combustion intensity, etc.

[0075] The embodiment of the present invention further provides a method for visually simulating vegetation ignition caused by arc breakdown of a high-voltage transmission line, comprising the following steps: (1) Simulating the arc breakdown of high-voltage transmission lines under normal temperature and pressure conditions to ignite vegetation S11. Preparation of experimental materials Select typical space vegetation (such as spruce, poplar, alpine pine, birch, etc.) and / or typical surface vegetation of the same stack size (such as poplar branches, alpine pine needles, pine sawdust, pine needles, kidney fern, etc.). For space vegetation, natural branches with relatively uniform length, thickness and thickness are directly selected. To ensure the rigor and repeatability of the experiment, the selected space vegetation can also be processed into wooden strips of fixed size (such as 400.0mm (height) × 20.0mm (length) × 20.0mm (width)); for surface vegetation, natural branches with relatively uniform length, thickness and thickness are directly selected. To ensure the rigor and repeatability of the experiment, the selected surface vegetation can also be broken up to make its block size relatively uniform, and the selected surface vegetation can be placed in a self-made square steel pan fuel bed (for example, a height of 5.0-10.0cm and a bottom side length of 30.0-300.0cm). The thickness of the surface vegetation in the steel pan fuel bed can be adjusted to a uniform value, such as 1.0-10.0cm.

[0076] S12. Experimental simulation configuration construction 1) Construction of local body splicing / adjacent vegetation experimental simulation configuration of high-voltage transmission lines In the altitude condition simulation box 6, a high-voltage electrical insulation bracket 13 is used to horizontally fix the simulated wire 12 and isolate the power frequency high voltage at the same time, and another high-voltage electrical insulation bracket 13 is used to support the space vegetation specimen and make it vertically suspended and isolate the power frequency high voltage at the same time, and the gap between the discharge end of the simulated wire 12 and the space vegetation specimen is set to different gap distances (such as 0.0, 2.0, 4.0, 5.0, 6.0, 8.0, 10.0 cm, etc.), and the angle between the longitudinal center axis of the space vegetation specimen and the vertical projection line of the middle point of the simulated wire 12 is adjusted to different angles (such as 0, 30, 45, 60, 90, 180°, etc.), so that the air gap between the simulated wire 12 and the space vegetation specimen becomes an initial potential discharge channel.

[0077] In addition, a variety of working conditions can be achieved by adjusting different influencing factors, including but not limited to: (1) Influencing factors in the simulation box of altitude conditions: atmospheric pressure, ambient temperature, ambient humidity, etc.; (2) Influencing factors of vegetation: vegetation type, vegetation morphology, vegetation size, vegetation quality, vegetation humidity, vegetation conductivity, etc.; (3) Influencing factors of simulated high-voltage transmission lines: input power frequency AC and DC voltage, simulated conductor type, air gap distance between simulated conductor and vegetation, relative placement angle between simulated conductor and vegetation, etc.

[0078] 2) Construction of simulation configuration for high-voltage transmission line down-break connection / adjacent vegetation experiment In the altitude condition simulation box 6, a metal electrode with a sharp tip or a high-voltage transmission line section is used as a simulated conductor 12 to simulate a broken conductor, and one end (discharge end) of the simulated conductor 12 is suspended in the middle, and the other end is fixed to the middle point of the auxiliary horizontal metal support rod 42. Natural branches or fragmented branches and leaves and other surface vegetation are placed in the steel plate fuel bed 41 and placed under the simulated conductor 12. The gap between the suspended end point of the simulated conductor 12 and the top of the surface vegetation test material is set to different gap distances (such as 0.0, 2.0, 4.0, 5.0, 6.0, 8.0, 10.0 cm, etc.), and the angle between the longitudinal center axis of the simulated conductor 12 and the vertical projection line of the middle point of the auxiliary horizontal metal support rod is adjusted to different angles (such as 0, 30, 45, 60, 90, 180 degrees, etc.), so that the air gap between the suspended end of the simulated conductor 12 and the surface vegetation test material becomes an initial potential discharge channel.

[0079] Of course, various working conditions can also be achieved by adjusting the aforementioned different influencing factors.

[0080] S13, forming a single-phase-ground circuit High voltage AC and DC power is provided by using an AC and DC high voltage test transformer 3 such as 30kVA / 50kV (corresponding to 35kV high voltage transmission line), 100kVA / 150kV (corresponding to 110kV high voltage transmission line) or 300kVA / 300kV (corresponding to 220kV high voltage transmission line).

[0081] For the local body overlap / adjacent vegetation simulation experiment of the high-voltage transmission line, the power frequency voltage output end of the water resistor or high-power metal resistor module 4, that is, the high-voltage end is connected to one end (non-discharge end) of the simulation wire 12, and the lower end of the space vegetation specimen is grounded through the first metal resistor 20 to form a single-phase-grounding circuit.

[0082] For the high-voltage transmission line broken line overlap / adjacent vegetation simulation experiment, the power frequency voltage output end, i.e., the high voltage end, of the water resistor or high-power metal resistor module 4 is connected to the auxiliary horizontal metal support rod 42, and the steel plate fuel bed 41 where the surface vegetation test material is located is grounded through the first metal resistor 20 to form a single-phase-ground circuit.

[0083] S14, industrial frequency AC and DC voltage boost and voltage stabilization operation.

[0084] Under normal temperature and pressure atmospheric environment, use industrial frequency high voltage AC and DC power supply to provide power to the simulated conductor 12, load vegetation, and gradually apply linearly, that is, raise the voltage to 80% of the expected flashover voltage, and then raise the expected voltage by 5% each time, maintain the voltage at the expected value for a period of time, and slow down the voltage increase speed after the "sizzling" corona discharge sound appears, until the discharge breakdown occurs around the simulated conductor. At this time, if the discharge breakdown forms a yellow or bright white continuous arc, the industrial frequency voltage at this moment is stably maintained, so that a nonlinear, non-uniform, transient stable electric field similar to a rod-rod (space vegetation) or rod-plate (surface vegetation) electrode is constructed between the discharge end of the simulated conductor and the vegetation, and crosses the simulated conductor, air gap, vegetation surface, vegetation matrix (containing certain pores and moisture) or crosses the simulated conductor, air gap, vegetation surface, vegetation matrix, steel plate fuel bed matrix and other solid, gas and liquid media along the way, and some of the phases may be crossed multiple times.

[0085] S15. Observation and statistics of arc occurrence and development characteristics and vegetation burning conditions.

[0086] According to step S14, after the power frequency voltage is increased and stabilized at a certain level, for the high-voltage transmission line local body overlap / adjacent vegetation experimental simulation configuration or the high-voltage transmission line drooping and broken line overlap / adjacent vegetation experimental simulation configuration, through the visualization glass 11, the observer can use vision, hearing and high-definition camera 39 to observe the formation and maintenance of the simulated single-phase-to-ground line, including the appearance of air corona around the simulated conductor, the generation of the initial arc, the forward development of the arc, the arc breaking through (conducting) the air gap and discharging, the arc front reaching the vegetation surface, the arc front igniting the vegetation, the arc breaking through (conducting) the vegetation (and soil) matrix and discharging, vegetation ignition and combustion (bright flames, pyrolysis and carbonization, release of water vapor and combustion products (including smoke), special sounds, etc.), vegetation flame maintenance and development, vegetation combustion spread and other important sub-link phenomena and characteristics, and the frequency of flame occurrence can be counted and the corresponding probability can be calculated through multiple experiments.

[0087] S16. Collection of discharge breakdown scene phenomena and process characteristic parameters.

[0088] After the occurrence of the series of important sub-link phenomena described in step S15, the high-definition camera 39, high-speed camera 27, infrared thermal imager 25, schlieren instrument 34, and digital oscilloscope 21 are used to collect and calculate the following discharge breakdown scene phenomena and characteristic parameters: visible light scene phenomena in the discharge breakdown process of main phase media such as gas (gas phase) and vegetation (solid phase) (corona and arc generation and development path, corona and arc shape, brightness, color, diameter, length, etc.); infrared thermal imaging scene phenomena in the two-phase discharge breakdown process (including temperature distribution around the discharge breakdown channel and arc area, etc.); schlieren scene phenomena in the two-phase discharge breakdown process (including heat flow distribution and trajectory around the discharge breakdown channel and arc area, etc.); breakdown / on-state voltage and breakdown / on-state current waveforms, breakdown / on-state voltage and breakdown / on-state current peaks, discharge breakdown / on-state duration, leakage current waveform, leakage current peak and polarity, discharge breakdown field strength, etc. when vegetation is broken down and ignited by the arc.

[0089] S17. Collection of phenomena and process characteristics of vegetation burning and spread scenarios.

[0090] After the occurrence of the series of important sub-link phenomena described in step S15, the following vegetation burning and spreading scene phenomena and characteristic parameters are collected and calculated through the K-type armored thermocouple tree 26, the temperature acquisition module 17, the data acquisition control and analysis system 18, the high-definition camera 39, the high-speed camera 27, the infrared thermal imager 25 and the schlieren instrument 34: visible light scene during vegetation burning and spreading; infrared thermal imaging scene during vegetation burning and spreading (including the temperature distribution of the vegetation surface, carbonized matrix and surrounding area <including flue gas>, etc.); schlieren scene during vegetation burning and spreading (including the flame and flue gas heat flow distribution and trajectory, etc.); flame and smoke area temperature distribution, vegetation surface and carbonized matrix temperature, flame height, flame length, flame angle, flame conductivity, combustion rate, spread rate and combustion intensity, etc.

[0091] S18, safe discharge and end of experiment When the vegetation burning and spreading process in the above-mentioned high-voltage discharge breakdown arc igniting vegetation experiment is completely completed, the burned area is completely carbonized after the vegetation flame is extinguished and there is no open flame and subsequent continuous smoldering phenomenon, the industrial frequency high-voltage AC and DC power supply is stopped, and a period of time is allowed for the internal area of ​​the altitude condition simulation box 6 to cool and the smoke to dissipate. The box is opened, and the simulated wire 12, the vegetation test material 14, the connecting ground wire, etc. are contacted through the grounding rod 35 for safe discharge, and the overall experimental process is completed. Among them, the grounding rod 35 is as follows Figure 1 shown.

[0092] (2) Simulating the arc breakdown of high-voltage transmission lines and igniting vegetation under different altitude conditions S21. According to the above-mentioned method for igniting vegetation by arc breakdown of high-voltage transmission lines at normal temperature and pressure, repeat steps S11-S13, and after completing the construction of the experimental simulation configuration in the altitude condition simulation box 6, close the box door and seal the box body.

[0093] S22. Adjustment of atmospheric pressure inside the box at different altitudes Before the experiment, the vacuum pump system is used to simulate the air pressure under different altitude conditions in the altitude condition simulation box 6. During the adjustment process, the pressure changes in the box are monitored in real time and adjusted according to the set altitude simulation parameters. For example, when the simulated altitude is 5000m, the corresponding air pressure is about 50kPa.

[0094] S23. Adjustment of the internal ambient temperature of the box at different altitudes The ambient temperature inside the box is adjusted by the temperature and humidity control module. Set the required temperature range and change rate to ensure stable control and recording of temperature parameters during the experiment. The temperature inside the box is stabilized within the range of -5℃ to 25℃ by the temperature and humidity control module, and the change rate is controlled at 1℃ / min.

[0095] S24. Adjustment of humidity inside the box at different altitudes The humidity transmitter 8 and the humidity regulator 38 are used to adjust the ambient humidity in the box to keep the humidity in the box stable within a set range, for example, to keep the relative humidity in the box fluctuating between 30% and 70%.

[0096] S25. Repeat step S14 according to the above method of igniting vegetation by arc breakdown of high-voltage transmission line at normal temperature and pressure.

[0097] S26. Repeat step S15 according to the above method of igniting vegetation by arc breakdown of high-voltage transmission line at normal temperature and pressure.

[0098] S27. Repeat step S16 according to the above method for igniting vegetation by arc breakdown of high-voltage transmission line at normal temperature and pressure.

[0099] S28. Repeat step S17 according to the above method of igniting vegetation by arc breakdown of high-voltage transmission line at normal temperature and pressure.

[0100] S29, safe discharge and end of experiment Referring to the above-mentioned method of igniting vegetation by arc discharge breakdown of high-voltage transmission lines under normal temperature and pressure, when the vegetation combustion and spread process in the experiment of igniting vegetation by arc discharge breakdown under different altitude conditions is completely completed, the burned area is completely carbonized after the vegetation flame is extinguished and there is no open flame and subsequent continuous smoldering phenomenon, the industrial frequency high-voltage AC and DC power supply is stopped, and a period of time is allowed to cool the internal area of ​​the altitude condition simulation box and the smoke dissipate, and the vacuum pump system and the temperature and humidity control module are adjusted respectively, and a period of time is allowed to wait until the environment inside the box returns to normal temperature and pressure. Open the box, and use the grounding rod 35 to contact the simulated wire, the vegetation test material, the ground wire, etc. for safe discharge, and an overall experimental process is completed.

[0101] The present invention can simulate the following differences in the discharge breakdown characteristics of multiphase bodies (external insulating air and vegetation, etc.) and the burning and spreading characteristics of vegetation under different altitude conditions, normal temperature and pressure conditions, and the two conditions: (1) As the simulated altitude increases, the volume density and breakdown voltage of the insulating air dielectric outside the high-voltage transmission line in the natural environment will decrease. Therefore, in order to achieve the same AC and DC input voltage level of the industrial frequency power supply, it usually takes a longer time to step up the voltage.

[0102] (2) As atmospheric pressure decreases, the discharge breakdown characteristics of the external insulating air and vegetation change significantly. Under low pressure conditions, the air density decreases, resulting in more localized formation of corona and arc, reduced arc brightness, lighter color, and reduced diameter and length. In addition, low pressure makes the sound produced by the arc weaker or higher frequency, and the sound propagation characteristics change. In infrared thermal imaging scenes, low pressure causes the gas density to decrease, making the temperature distribution of the arc and the discharge breakdown channel more uneven and the temperature difference more obvious. Due to the thin air, heat dissipation is accelerated, the thermal effect of the arc is limited, and the accumulation and propagation of heat is reduced. In the schlieren scene, the heat flow distribution and trajectory of the arc path also become more uneven. In typical discharge breakdown characteristics, low pressure causes the breakdown voltage to increase, requiring a stronger electric field strength to induce breakdown, the breakdown current peak decreases, and the arc duration is prolonged. The waveform and peak of the leakage current also become more unstable.

[0103] (3) As the ambient temperature decreases, the discharge breakdown characteristics of the external insulating air and vegetation will change significantly. In the visible light scene, the brightness of the flame decreases, the shape becomes smaller and the color becomes darker, while the smoke becomes denser and the diffusion speed slows down. In addition, low temperature also makes the sound produced by the arc weaker, the sound frequency lower, and the pitch higher, which affects the sound propagation effect. In the infrared thermal imaging scene, the low temperature environment reduces the heat conduction efficiency of the vegetation surface and the carbonized matrix, making the temperature distribution in the arc area more localized, and the heat exchange effect of the arc is weakened, resulting in uneven temperature distribution. The cooling effect accelerates the heat loss, affecting the stability of the arc and the heat accumulation. In the schlieren scene, low temperature makes the heat flow distribution and trajectory of the arc show more obvious local characteristics, the heat flow distribution of the arc becomes uneven, and the heat flow trajectory of the arc is more random, causing the discharge process to become slower and more irregular. In the typical discharge breakdown characteristics, low temperature leads to an increase in the breakdown voltage because a higher electric field strength is required to induce breakdown. At the same time, the breakdown current peak decreases, and the formation and stability of the arc are also affected. In addition, the arc duration is prolonged in a low temperature environment, and the waveform and peak value of the leakage current become more irregular due to the influence of low temperature.

[0104] (4) As the ambient humidity increases, the discharge breakdown characteristics of the external insulating air and vegetation will change significantly. The sound produced by the arc is clearer because water vapor affects the propagation of sound. In infrared thermal imaging scenes, high humidity increases the water vapor content in the air, making the temperature distribution of the arc more uniform. Water vapor has certain heat absorption and heat storage properties. Its presence can enhance the thermal effect of the arc, but it also causes a local cooling effect, affecting the uniform distribution of heat. In the schlieren scene, high humidity makes the heat flow distribution of the arc more uniform. High humidity helps to improve the stability of the arc, but it also affects the flow path and distribution of the arc. In typical discharge breakdown characteristics, high humidity leads to a decrease in breakdown voltage because water vapor increases the conductivity of the air, while the breakdown current peak increases, making the arc current more stable and intense. The leakage current will also increase because water vapor makes it easier for charges to move in the electric field.

[0105] (5) As atmospheric pressure decreases, air density decreases, which affects the combustion and spread characteristics of vegetation. In visible light scenes, the brightness of the flame and the concentration of smoke decrease, the flame shape and smoke flow become more irregular, the volume of the flame and smoke increases, and the diffusion rate of combustion and smoke becomes slower and more localized. In infrared thermal imaging scenes, due to the thin air, the temperature distribution of the vegetation surface and the carbonized matrix shows greater unevenness, the heat distribution area of ​​the flame becomes smaller, and the temperature rise of the carbonized matrix and the surrounding area becomes slower. In addition, in the schlieren scene, the heat flow distribution and trajectory of the flame and smoke in the low-pressure environment become more localized, and the heat flow path of the flame is not as uniform as under low-altitude conditions, resulting in changes in the trajectory and pattern of flame spread.

[0106] (6) As the ambient temperature decreases, the visible light characteristics of the flame and smoke become weaker, the flame appears smaller and darker, and the smoke becomes denser and diffuses more slowly. In infrared thermal imaging scenes, low temperatures will reduce the heat conduction efficiency of the vegetation surface and the carbonized matrix, making the temperature distribution of the flame and carbonized area more localized, reducing the thermal effect of the flame and making the temperature distribution uneven. In the schlieren scene, the heat flux distribution and trajectory of the flame in a low temperature environment show more obvious local characteristics, and the combustion process is slower and more irregular.

[0107] (7) As the ambient humidity increases, the burning and spread of vegetation show obvious changes. In visible light scenes, high humidity will enhance the light scattering effect, make the characteristics of flames and smoke more obvious, increase the concentration of smoke, enhance the brightness of the flame, and make the shape and diffusion characteristics of the flame more significant. In infrared thermal imaging scenes, high humidity increases the water vapor content in the air, which makes the temperature distribution of the flame and carbonization area more uniform. Although the thermal effect of the flame is enhanced, the cooling effect of water vapor is also affected. In the schlieren scene, the heat flow distribution of flames and smoke in a high humidity environment becomes more uniform. High humidity helps to improve the stability of the flame, but it also affects the spread path of the flame.

[0108] The present invention simulates the phenomenon of discharge breakdown arc and vegetation ignition caused by local body or broken line overlap or / and nearby space and / or surface vegetation faults in high-voltage transmission lines under typical meteorological conditions such as atmospheric pressure, oxygen content, temperature and humidity at different altitudes. The present invention can observe and record in real time the generation, development and propagation process of discharge breakdown arc and the dynamic situation of vegetation ignition, combustion and spread caused by arc when the high-voltage transmission line is overlapped and / or near vegetation as the power frequency voltage increases, explore the effects of various influencing factors such as altitude meteorological conditions, forest vegetation and high-voltage transmission lines, use special combustion flow field diagnostic technology to capture the details and special phenomena of the overall evolution process of vegetation combustion and spread induced by discharge breakdown arc under various working conditions, obtain regional temperature distribution, arc and flame front trajectory (position) and heat flow distribution and trajectory, collect parameters such as multiple discharge breakdown arc characteristics of two phases of main gas and vegetation, vegetation combustion and spread characteristics, and assist in deducing critical conditions, evolution characteristics and mechanisms of vegetation ignition by discharge breakdown arc and the action conditions and mechanisms of typical influencing factors.

[0109] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are included in the scope of the claims of the present invention to be approved.

Claims

1. A visual simulation system for high-voltage transmission line arc breakdown and vegetation ignition, characterized in that: It comprises an altitude condition simulation box (6), a low air pressure control module, a temperature and humidity control module, an industrial frequency high voltage AC and DC power supply, a discharge breakdown arc ignition module, a discharge breakdown characteristic acquisition module and a combustion spread characteristic acquisition module, wherein the altitude condition simulation box (6) is provided with a visualization glass (11); The altitude condition simulation box (6) is used to provide environmental conditions for the discharge breakdown arc of high-voltage transmission lines at different altitudes to ignite vegetation; The low air pressure control module is used to adjust the internal air pressure of the altitude condition simulation box (6) according to different altitudes; The temperature and humidity control module is used to adjust the internal temperature and humidity of the altitude condition simulation box (6); The industrial frequency high voltage AC and DC power supply is used to provide high voltage power for the discharge breakdown arc ignition module; The discharge breakdown arc ignition module is used to trigger a discharge breakdown arc of a high-voltage transmission line in an altitude condition simulation box (6) to ignite vegetation; The discharge breakdown characteristic acquisition module is used to collect data on characteristic parameters of the discharge breakdown arc occurrence and development process in the altitude condition simulation box (6) under normal temperature and pressure and different altitude conditions; The combustion and spread characteristic acquisition module is used to collect data on characteristic parameters of vegetation combustion and spread processes in an altitude condition simulation box (6) under normal temperature and pressure conditions and at different altitudes.

2. The high-voltage transmission line arc breakdown vegetation ignition visualization simulation system according to claim 1 is characterized in that: The discharge breakdown arc ignition module comprises a water resistor or a high-power metal resistor module (4), a simulated wire (12), a vegetation test material (14) and two high-voltage electrical insulation brackets (13); the water resistor or the high-power metal resistor module (4) is arranged outside the altitude condition simulation box (6); the simulated wire (12), the vegetation test material (14) and the high-voltage electrical insulation bracket (13) are arranged inside the altitude condition simulation box (6); one end of the water resistor or the high-power metal resistor module (4) is connected to an industrial frequency high-voltage AC and DC power supply, and the other end is connected to a non-discharge end of the simulated wire (12); the vegetation test material (14) is a space vegetation test material; the simulated wire (12) is horizontally fixed to one of the high-voltage electrical insulation brackets (13); the other high-voltage electrical insulation bracket (13) is used to fix the space vegetation test material and make the space vegetation test material vertically suspended in the air; the lower end of the space vegetation test material is grounded.

3. The high-voltage transmission line arc breakdown vegetation ignition visualization simulation system according to claim 1 is characterized in that: The discharge breakdown arc ignition module comprises a water resistor or a high-power metal resistor module (4), a simulated conductor (12), a vegetation test material (14), two high-voltage electrical insulation brackets (13) and a steel plate fuel bed (41), wherein an auxiliary horizontal metal support rod (42) is connected between the two high-voltage electrical insulation brackets (13), the water resistor or the high-power metal resistor module (4) is arranged outside the altitude condition simulation box (6), and the simulated conductor (12), the vegetation test material (14), the high-voltage electrical insulation bracket (13) and the steel plate fuel bed (41) are connected to each other. The water resistor or high-power metal resistor module (4) is arranged in an altitude condition simulation box (6), one end of the water resistor or high-power metal resistor module (4) is connected to a power frequency high-voltage AC and DC power source, and the other end is connected to an auxiliary horizontal metal support rod (42), the vegetation test material (14) is a ground vegetation test material, the discharge end of the simulation wire (12) is suspended in the middle, and the non-discharge end is fixed to the middle point of the auxiliary horizontal metal support rod (42), the ground vegetation test material is contained in a steel plate fuel bed (41) and placed below the simulation wire (12), and the steel plate fuel bed (41) is grounded.

4. The high-voltage transmission line arc breakdown vegetation ignition visualization simulation system according to claim 1 is characterized in that: The industrial frequency high-voltage AC / DC power supply comprises a first AC power supply (1), a dedicated control console for an experimental transformer (2), and an AC / DC high-voltage test transformer (3); the first AC power supply (1) is connected to the dedicated control console for the experimental transformer (2); the dedicated control console for the experimental transformer (2) is connected in series to the AC / DC high-voltage test transformer (3); the AC / DC high-voltage test transformer (3) is connected to the discharge breakdown arc ignition module; the first AC power supply (1) is used to supply power to the experimental circuit; the dedicated control console for the experimental transformer (2) is used to control the AC / DC high-voltage test transformer (3) to perform a step-up or step-down operation; and the AC / DC high-voltage test transformer (3) is used to step up the voltage of the experimental circuit.

5. The high-voltage transmission line arc breakdown vegetation ignition visualization simulation system according to claim 1 is characterized in that: The low air pressure control module comprises a vacuum pump (16), a pump trap isolation valve (9) and a pressure gauge (7); the vacuum pump (16) is connected to the interior of the altitude condition simulation box (6) and is used to adjust the air pressure in the altitude condition simulation box (6); the pump trap isolation valve (9) and the pressure gauge (7) are installed on the top of the altitude condition simulation box (6); the pump trap isolation valve (9) is used to control the flow of gas in and out of the altitude condition simulation box (6); and the pressure gauge (7) is used to monitor the air pressure inside the altitude condition simulation box (6).

6. The high-voltage transmission line arc breakdown vegetation ignition visualization simulation system according to claim 1 is characterized in that: The temperature and humidity control module comprises a refrigeration system, a K-type armored thermocouple tree (26), a temperature acquisition module (17), a humidity transmitter (8), a humidity regulator (38) and a data acquisition control and analysis system (18). The refrigeration system is connected to the interior of the altitude condition simulation box (6) and is used to adjust the temperature inside the altitude condition simulation box (6); the K-type armored thermocouple tree (26) is connected to the two side walls of the altitude condition simulation box (6) through a high vacuum aviation plug (36) and is used to measure the temperature of different dimensions inside the altitude condition simulation box (6), and transmits the measured temperature data to the data acquisition control and analysis system (18) through the temperature acquisition module (17); the humidity regulator (38) is arranged inside the altitude condition simulation box (6) and is used to adjust the humidity inside the altitude condition simulation box (6); the humidity transmitter (8) is installed on the top of the altitude condition simulation box (6) and is used to measure the humidity inside the altitude condition simulation box (6).

7. The high-voltage transmission line arc breakdown vegetation ignition visualization simulation system according to claim 2 or 3, characterized in that: The discharge breakdown characteristic acquisition module comprises a current and voltage acquisition module, a high-definition camera (39), a high-speed camera (27), an infrared thermal imager (25) and a schlieren instrument (34); the current and voltage acquisition module comprises a first metal resistor (20), a digital oscilloscope (21), an isolation transformer (22), a resistor-capacitor voltage divider (28) and a second AC power supply (23); one end of the first metal resistor (20) is connected to the vegetation test material (14) and the other end is grounded; the resistor-capacitor voltage divider (28) is connected in parallel to the discharge breakdown arc ignition module; the resistor-capacitor voltage divider (28) is grounded; the first metal resistor (20) and the resistor-capacitor voltage divider (28) are connected to the vegetation test material (14) and the other end is grounded; The voltage dividers (28) are connected in parallel to the digital oscilloscope (21), the digital oscilloscope (21) is connected to the second AC power supply (23) via the isolation transformer (22), the digital oscilloscope (21) is used to store and record the voltage and waveform of the first metal resistor (20) and the resistor-capacitor voltage divider (28); the high-definition camera (39) is used to collect visible light scene phenomena during the two-phase discharge breakdown process of gas and vegetation; the infrared thermal imager (25) is used to collect infrared thermal imaging scene phenomena during the two-phase discharge breakdown process; the high-speed camera (27) and the schlieren instrument (34) are used to collect schlieren scene phenomena during the two-phase discharge breakdown process.

8. The high-voltage transmission line arc breakdown vegetation ignition visualization simulation system according to claim 2 or 3, characterized in that: The combustion propagation characteristic acquisition module comprises a K-type armored thermocouple tree (26), a temperature acquisition module (17), a data acquisition control and analysis system (18), a high-definition camera (39), a high-speed camera (27), an infrared thermal imager (25) and a schlieren instrument (34). The K-type armored thermocouple tree (26) is connected to the two side walls of the altitude condition simulation box (6) through a high vacuum aviation plug (36) and is used to measure the temperature of vegetation test materials (14) of different dimensions from breakdown to combustion, and transmits the measured temperature to the data acquisition control and analysis system (18) through the temperature acquisition module (17); the high-definition camera (39) is used to acquire visible light scenes when vegetation burns and spreads; the infrared thermal imager (25) is used to acquire infrared thermal imaging scenes when vegetation burns and spreads; and the high-speed camera (27) and the schlieren instrument (34) are used to acquire schlieren scenes when vegetation burns and spreads.

9. A visual simulation method for igniting vegetation due to arc breakdown of high-voltage transmission lines, characterized in that: Based on the high-voltage transmission line arc breakdown ignition vegetation visualization simulation system of claim 2, the method comprises: Step 1, construction of a simulation configuration for a local body overlap / adjacent vegetation experiment of a high-voltage transmission line: vertically suspending and fixing a space vegetation specimen on a high-voltage electrical insulation support (13), horizontally fixing a simulated conductor (12) on another high-voltage electrical insulation support (13), and setting a discharge end of the simulated conductor (12) to correspond to the space vegetation specimen, setting a gap between the discharge end of the simulated conductor (12) and the space vegetation specimen to different gap distances, and adjusting the angle between the longitudinal center axis of the space vegetation and the vertical projection line of the middle point of the simulated conductor (12) to different angles, so that the air gap between the simulated conductor (12) and the space vegetation specimen becomes an initial potential discharge channel; Step 2, connecting the water resistor or high-power metal resistor module (4) to the non-discharge end of the simulated wire (12), and grounding the lower end of the space vegetation test material to form a single-phase-ground circuit; in the altitude condition simulation box (6) under a normal temperature and pressure atmospheric environment, using an industrial frequency high-voltage AC and DC power supply to provide power to the simulated wire (12), and performing a step-by-step linear pressure step-up and voltage stabilization operation until a discharge breakdown occurs around the simulated wire (12); Step 3, observing the sub-link phenomena and characteristics from the appearance of air corona around the simulated conductor (12) to the vegetation burning and spreading process; and after the occurrence of each sub-link phenomenon, collecting and calculating the discharge breakdown scene phenomenon and characteristic parameters through the discharge breakdown characteristic acquisition module, and collecting and calculating the vegetation burning and spreading scene phenomenon and characteristic parameters through the burning and spreading characteristic acquisition module; Step 4, rebuild the simulation experiment configuration according to step 1, adjust the air pressure in the altitude condition simulation box (6) through the low pressure control module according to the set altitude simulation parameters, adjust the temperature and humidity in the altitude condition simulation box (6) through the temperature and humidity control module, and repeat steps 2-3.

10. A visual simulation method for igniting vegetation due to arc breakdown of a high-voltage transmission line, characterized in that: Based on the high-voltage transmission line arc breakdown ignition vegetation visualization simulation system of claim 3, the method comprises: Step 1, constructing a simulated configuration for a high-voltage transmission line falling and disconnection overlap / adjacent vegetation experiment: suspending the discharge end of the simulated conductor (12) in the middle, fixing the non-discharge end at a point in the middle of the auxiliary horizontal metal support rod (42), placing the surface vegetation test material in a steel plate fuel bed (41) and placing it below the simulated conductor (12); setting the gap between the suspended end point of the simulated conductor (12) and the top of the surface vegetation test material to different gap distances, and adjusting the included angle between the longitudinal center axis of the simulated conductor (12) and the vertical projection line of the middle point of the auxiliary horizontal metal support rod (42) to different angles, so that the air gap between the suspended end of the simulated conductor (12) and the surface vegetation test material becomes an initial potential discharge channel; Step 2, connecting the water resistor or high-power metal resistor module (4) to the auxiliary horizontal metal support rod (42), grounding the steel plate fuel bed (41), and forming a single-phase-ground circuit; in the altitude condition simulation box (6) under normal temperature and pressure atmospheric environment, using a power frequency high-voltage AC and DC power supply to provide power to the simulation wire (12), using a step-by-step linear pressure method to perform voltage boost and voltage stabilization operations until discharge breakdown occurs around the simulation wire (12); Step 3, observing the sub-link phenomena and characteristics from the appearance of air corona around the simulated conductor (12) to the vegetation burning and spreading process; and after the occurrence of each sub-link phenomenon, collecting and calculating the discharge breakdown scene phenomenon and characteristic parameters through the discharge breakdown characteristic acquisition module, and collecting and calculating the vegetation burning and spreading scene phenomenon and characteristic parameters through the burning and spreading characteristic acquisition module; Step 4, rebuild the simulation experiment configuration according to step 1, adjust the air pressure in the altitude condition simulation box (6) through the low pressure control module according to the set altitude simulation parameters, adjust the temperature and humidity in the altitude condition simulation box (6) through the temperature and humidity control module, and repeat steps 2-3.

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