A pilot discharge test system with decoupled adjustment of humidity and air pressure

Abstract

The present invention relates to a pilot discharge test system with decoupled adjustment of humidity and air pressure, belonging to the technical field of air gap pilot discharge equipment. It includes a tank body, a wall bushing embedded in the center of the top of the tank body, and an air drying device, an atomizer, a temperature and humidity and discharge electric field measuring instrument located outside the tank body; wherein, an observation window and a light-transmitting mirror, a reserved interface, a plurality of valves and a barometer are respectively installed on the outer wall of the tank body; a flat electrode is provided at the inner center of the bottom of the tank body through a length-adjustable support, and the lower end of the support is fixedly connected to the belt transmission device outside the bottom of the tank body; the lower end of the wall bushing vertically extending into the inside of the tank body is installed with a discharge electrode on the high-voltage side, and the upper end protrudes from the tank body and is connected to the high-voltage lead, and the distance between the lower end of the wall bushing and the flat electrode is adjusted to change between 10 cm and 70 cm through the belt transmission device. The present invention has the characteristics of decoupled adjustment of humidity and air pressure, high air pressure and voltage resistance, large gap size and convenient adjustment.

Description

Technical Field

[0001] The invention relates to a pilot discharge test system with decoupled and adjustable humidity and air pressure, belonging to the technical field of air gap pilot discharge equipment. Background Art

[0002] The study of air gap discharge is of great significance to the design of external insulation of power systems. In the process of studying the influence of atmospheric humidity and air pressure parameters on air gap discharge, it is often necessary to simulate different humidity and air pressure environments respectively, and conduct simulation tests on gaps of different distances. The air pressure span in the test is large, ranging from low pressure to high pressure (1kPa to 800kPa), so the test equipment needs to have a large pressure tolerance range. And the air humidity of the environment will increase or decrease sharply with the increase or decrease of air pressure. If the relative humidity of the air is about 50% under normal pressure, then when the air pressure increases to two atmospheres, the relative humidity will reach 100%. The simultaneous changes in air pressure and humidity make it impossible to control a single variable in the test. Therefore, humidity and air pressure must be decoupled in the simulation test.

[0003] The leader is a high conductivity plasma channel with a thermal ionization process. When the air gap (such as rod-plate gap, plate-plate gap, rod-rod gap, etc.) is long (greater than 1m), the discharge process of the air gap will produce a leader. Since high voltage is required to discharge the air gap, the equipment must be able to withstand high voltage. In addition, in order to achieve convenient adjustment of the air gap distance, the equipment should have a large size, and the gap distance should be adjustable from the outside during the test.

[0004] In the existing experimental equipment simulating different atmospheric conditions, the experiments on studying the influencing factors of long gap leader discharge have the following limitations: 1. The equipment size is limited. At present, the range of gap distance adjustment is generally less than 40cm, and the adjustment of longer gap distance cannot be achieved; 2. When the air pressure in the equipment is changed, the gas filled into the equipment is not absolutely dry, which will cause the humidity and air pressure to change at the same time, and cannot meet the needs of studying the influence of an atmospheric parameter on air gap discharge in the experiment; 3. When the voltage is increased, it is impossible to ensure that the equipment casing is at a low potential; 4. The thermometer and hygrometer for recording temperature and humidity cannot withstand the high air pressure to be added in the test; 5. The thermometer and hygrometer for recording temperature and humidity cannot meet the sensitivity and accuracy requirements of real-time recording of temperature and relative humidity in the test.

[0005] In summary, the existing experimental equipment for simulating different atmospheric conditions cannot meet the needs of air gap discharge influencing factors simulation test. In the field of long gap leader discharge, there is an urgent need for an atmospheric environment simulation device that can achieve humidity and air pressure decoupling, has a large gap distance, can withstand high pressure, and has an easily adjustable gap distance. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the existing technology and propose a leader discharge test system with decoupled adjustment of humidity and air pressure. This system is used in long-gap leader discharge simulation tests to study the effects of humidity and air pressure parameter changes on long-gap leader discharges. It can achieve decoupled adjustment of humidity and air pressure, can withstand a wide range of air pressure changes, and can conveniently and safely adjust the air gap distance from the outside.

[0007] The present invention adopts the following technical solution:

[0008] A pilot discharge test system with decoupled adjustable humidity and air pressure, characterized in that it comprises a tank body, a wall bushing embedded in the center of the top of the tank body, and an air drying device, an atomizer, a temperature and humidity measuring instrument, and a discharge electric field measuring instrument located outside the tank body; wherein an observation window and a light-transmitting mirror are respectively installed on the outer side walls of the middle and lower parts of the tank body, and a reserved interface, a plurality of valves, and a plurality of barometers are also provided on the side walls of the tank body; the tank body is connected to the outlet of the air drying device and / or the atomizer through a water vapor inlet valve, and the tank body is connected to the temperature and humidity measuring instrument and / or the discharge electric field measuring instrument through a reserved interface An electric field measuring instrument is connected; a plurality of universal wheels are installed at the bottom of the tank body through evenly distributed pillars; a belt transmission device is also installed on the outer side of the bottom of the tank body, and a length-adjustable support is provided at the inner center of the bottom of the tank body, a flat electrode is fixed on the upper end of the support, and the lower end of the support is fixedly connected to the belt transmission device; the lower end of the wall bushing vertically extends into the interior of the tank body and a discharge electrode on the high-voltage side is installed at the end, the upper end of the wall bushing protrudes from the tank body and is connected to the external high-voltage lead, and the distance between the lower end of the wall bushing and the flat electrode is adjusted to vary between 10 cm and 70 cm through the belt transmission device.

[0009] The belt transmission device includes a guide rod fixed to one side of the support at the bottom of the tank body, a slider reciprocating on the guide rod, a fixed block fixed to one side of the guide rod, a transmission belt, a handle and a counter for reading the air gap distance, and the slider, the fixed slider and the center of the bottom of the tank body are all provided with bearings; wherein, the transmission belt passes around each bearing in turn, the bearing located at the center of the bottom of the tank body is fixedly connected to the lower end of the support inside the tank body, the bearing located on the fixed block is fixedly connected to the handle, and the bearing located on the slider is fixedly connected to the counter.

[0010] The air drying device is composed of a two-stage filter and a common air compressor connected together; or the air drying device uses a synthetic air compressor that provides a water molecule concentration of less than 3ppm, an oxygen content of 21% (volume), and a nitrogen content of 79% (volume).

[0011] The present invention proposes a leader discharge test system with decoupled adjustment of humidity and air pressure, which can simulate the influence of changes in atmospheric humidity and air pressure on leader discharge in a long gap leader discharge simulation test, and has the following characteristics and advantages:

[0012] 1. The present invention realizes the decoupling between humidity and air pressure when changing the air pressure, adopts a two-stage filter or an absolutely dry synthetic air compressor to adjust the air pressure in the tank, and adopts an atomizer to adjust the humidity in the tank, thereby realizing the control of a single variable to study the influence of humidity and air pressure on the air gap leader discharge.

[0013] 2. A belt transmission device with display count is designed at the bottom of the tank body of the present invention. The position of the flat electrode inside the tank body is adjusted by manually turning the handle, and the air gap distance can be directly read from the counter outside the tank body.

[0014] 3. The atomizer used in the present invention is based on the Venturi spray principle. In terms of increasing the humidity in the container, it ensures that the tank is isolated from the influence of the external environment. The atomizer uses compressed air to form a high-speed airflow through a small pipe orifice. The negative pressure generated drives the liquid water to be sprayed together, and the liquid water droplets are splashed around under high-speed impact inside the atomizer, turning the liquid water droplets into mist particles and spraying them out from the atomizing nozzle made of metal tantalum.

[0015] 4. The present invention adopts a high-precision and high-sensitivity temperature and humidity measuring instrument that can withstand high pressure (for example, 0.8 MPa) in the temperature and humidity measurement part, which can record temperature and relative humidity data in real time.

[0016] 5. The connection method between the wall bushing and the tank body of the present invention can increase the creepage distance, so that the tank body can be increased in voltage, ensuring that the tank body shell is located on the low-voltage side.

[0017] 6. The observation window of the tank body and the light-transmitting mirrors on both sides of the present invention are made of optical quartz glass, which has good light transmittance and can withstand the highest gas pressure intensity.

[0018] 7. In the present invention, the light-transmitting mirrors on both sides are coated with fully transparent green light films on both sides, and can be used in conjunction with the laser interferometer in the long-gap pilot discharge test. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a front view of the tank structure in the system of the present invention.

[0020] Figure 2 yes Figure 1 A view in the figure.

[0021] Figure 3 It is a left view of the tank structure in the system of the present invention.

[0022] Figure 4 It is a bottom view of the tank body in the system of the present invention.

[0023] Figure 5It is a comparison diagram of the relationship between the air pressure in the tank and the relative humidity after two solutions are adopted by the present invention to achieve the decoupling between the ambient humidity and the air pressure.

[0024] In the figure, 1. tank body, 2. wall sleeve, 3. observation window, 4. light mirror, 5. reserved interface, 6. pillar, 7. universal wheel, 8. lifting hole, 9. belt transmission device, 9-1. guide rod, 9-2. slider, 9-3. fixing block, 9-4. transmission belt, 9-5. bearing, 9-6. handle, 9-7. counter, 10. support, 11. flat electrode, 12. safety valve, 13. gas inlet and outlet valve, 14. outlet, 15. water vapor inlet valve, 16. high pressure gauge, 17. negative pressure gauge. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is described in detail below with reference to the accompanying drawings and embodiments:

[0026] The present invention provides a pilot discharge test system with decoupled adjustment of humidity and air pressure, comprising a tank body 1, a wall bushing 2 embedded at the top center of the tank body 1 (refer to Figure 1 ) and an air drying device, an atomizer, a temperature and humidity measuring instrument and a discharge electric field measuring instrument located outside the tank body 1 (the air drying device, the atomizer, the temperature and humidity measuring instrument and the discharge electric field measuring instrument are not shown in the figure); wherein, an observation window 3 and a light-transmitting mirror 4 are respectively installed on the outer side wall of the lower middle part of the tank body 1, and a reserved interface 5, a plurality of valves and a plurality of barometers (respectively as shown in Figure 2 , Figure 3 As shown), a lifting hole 8 is provided on the top of the tank body 1; wherein, the tank body 1 is connected to the outlet of the air drying device and / or the atomizer through a water vapor inlet valve 15, and the tank body 1 is connected to the temperature and humidity measuring instrument and / or the discharge electric field measuring instrument through a reserved interface 5; a plurality of universal wheels 7 are installed at the bottom of the tank body 1 through evenly distributed pillars 6, and the universal wheels facilitate the transportation and movement of the tank body; a belt transmission device 9 is installed on the outer side of the bottom of the tank body 1, such as Figure 4 As shown, a length-adjustable support 10 is provided at the inner center of the bottom of the tank body 1, a flat electrode 11 is fixed on the upper end of the support, and the lower end of the support is fixedly connected to the belt transmission device 9; the lower end of the wall bushing 2 vertically extends into the tank body 1 and the end is installed with a discharge electrode on the high-voltage side, the upper end of the wall bushing 2 protrudes from the tank body 1 and is connected to the external high-voltage lead, and the distance between the lower end of the wall bushing 2 and the flat electrode 11 (this distance is the rod-plate gap) is adjusted by the belt transmission device 9, and the adjustment range of the distance is between 10cm and 70cm.

[0027] The specific implementation and function of each component of the embodiment of the present invention are described as follows:

[0028] The total height of the tank body 1 including the wall sleeve 2 of this embodiment is 3.4 m, and the floor area is about 1.5 m2.

[0029] The tank body 1 of this embodiment is cylindrical in shape, made of a stainless steel plate with an average thickness of 8 mm, with a diameter of 1.2 m, and a volume of about 3.2 m inside the tank body 1. 3 .

[0030] In this embodiment, an optical quartz glass with a diameter of 350 mm and a thickness of 30 mm is inlaid on the observation window 3 arranged on the side wall of the tank body 1, and the gap between the rod and the plate can be observed through the observation window; in addition, the observation window can be opened.

[0031] The light-transmitting mirror 4 of the present embodiment is symmetrically arranged on the side wall of the tank body 1 which is located at the same horizontal plane as the lower end of the wall-penetrating sleeve 2. The light-transmitting mirror of the present embodiment is made of optical quartz glass with a diameter of 120 mm and a thickness of 10 mm, and a fully transparent filter film with a thickness of 532 nm is coated on both sides of the light-transmitting mirror. The light-transmitting mirror is used to transmit the laser generated by an external laser interferometer. Further, the guide is measured by the laser interferometer and the existing optical interference principle (the specific measurement technology does not belong to the scope of the technical solution of the present invention).

[0032] The reserved interface 5 of this embodiment is a conventional detachable flange, through which the following functions can be achieved: 1) by fixing the photoelectric electric field sensor at the flange, it is used to measure the discharge electric field in the main tank; 2) by connecting the temperature and humidity sensor to the flange, it is used to measure the temperature and humidity in the tank; 3) in addition, other types of measuring instruments can be installed at the flange according to the test needs to achieve switching of various functions.

[0033] The multiple valves in this embodiment include a safety valve 12 arranged on the side wall of the tank body 1, a gas inlet and outlet valve 13 with an outlet 14, and a water vapor inlet valve 15; wherein, when the internal air pressure of the tank body 1 is greater than a set threshold value (the threshold value is set to 800 kPa in this embodiment), the safety valve 12 will automatically leak air to prevent the mirror body on the observation window 3 from breaking; oxygen, nitrogen, air, etc. required for the test can be introduced through the gas inlet and outlet valve 13, and the gas in the tank body can also be discharged; the water vapor inlet valve 15 is used to connect with an air drying device and / or an atomizer to change the air pressure and / or humidity in the tank body. The valves used in this embodiment are all conventional products.

[0034] The multiple pressure gauges in this embodiment include a high pressure gauge 16 and a negative pressure gauge 17, both of which are arranged on the side wall of the tank body 1 and have valves, and are used to measure the internal pressure of the tank body when the pressure is higher and lower than 1 atmosphere respectively; the pressure gauges used in this embodiment are all conventional products.

[0035] The belt transmission device 9 of this embodiment includes a guide rod 9-1 fixed to one side of the bottom support of the tank body 1, a slider 9-2 that can reciprocate on the guide rod, a fixed block 9-3 fixed to one side of the guide rod 9-1, a transmission belt 9-4, a handle 9-6 and a counter 9-7 for reading the air gap distance. The slider 9-2, the fixed slider 9-3 and the center of the bottom of the tank body 1 are all provided with bearings; wherein, the transmission belt 9-4 bypasses each bearing in turn, the bearing 9-5 located at the center of the bottom of the tank body 1 is fixedly connected to the lower end of the support 10 inside the tank body 1, the bearing located on the fixed block 9-3 is fixedly connected to the handle 9-6, and the bearing located on the slider 9-2 is fixedly connected to the counter 9-7; by manually turning the handle, each bearing is driven to rotate in turn, thereby changing the air gap distance (i.e., the rod-plate gap, during this process, the position of the wall sleeve 2 remains unchanged), and the air gap distance is read by the counter. The gap spacing adjustment accuracy of this embodiment is 1 mm, and the flat electrode rises 1 cm by manually turning the handle 10 times.

[0036] The wall bushing 2 of this embodiment is a solid columnar structure. The connection between the wall bushing and the tank body 1 is connected by a sealing flange, and the rest of the wall bushing is an umbrella skirt. The total length of the wall bushing 2 of this embodiment is 2.64 meters, 1.28 meters of the length extending into the inner side of the tank body 1, 1.36 meters of the length located on the outer side of the tank body 1, and the length of the connection part is 0.4 meters; the wall bushing 2 can withstand a maximum lightning impulse voltage of 550kV and an operating impulse voltage of about 500kV. During the test, since the discharge electrodes and high-voltage leads on the high-voltage side are installed at both ends of the wall bushing 2, both ends of the wall bushing are high-voltage sides; and the flat electrode 11 inside the tank body 1 is the low-voltage side. To ensure that the tank body 1 is also on the low-voltage side, a metal connection is used between the tank body 1 and the flat electrode 11.

[0037] The air drying device of the present invention is composed of a two-stage filter connected to a common air compressor, and the outlet of the two-stage filter is connected to the water vapor inlet valve as the outlet of the air dryer. The two-stage filter of this embodiment adopts a high-precision two-stage filter of model XT-107F produced by Xinteks Company of the United States, and the two-stage filter includes a first-stage filter component mainly composed of a coarse filter screen, a honeycomb water collector, a drainer connected to the bottom of the water collector, and an automatic drain valve connected to the drainer, and a second-stage fiber filter screen made of stainless steel wire and special cotton; the second-stage fiber filter screen is connected to the water vapor inlet valve 15 on the side wall of the tank body 1 through a pipeline.

[0038] The specific working process of the air drying device of this embodiment is as follows: in the initial stage of adjusting the air pressure inside the tank body 1, ordinary compressed air containing water or various impurities (high voltage has an adsorption effect on some impurities in the air, so the air quality of high-voltage laboratories is relatively poor) enters the first-stage filter component to produce a coalescence effect, and more than 95% of the water droplets, oil droplets and large particles in the compressed air will be adsorbed on the coarse filter, and the water will condense into larger water droplets; then enters the air and water separation stage, the compressed air speed slows down, so that the impurity particles and water droplets gather on the honeycomb water collector, and the water droplets carrying the impurity particles flow along the bottom of the water collector to the drainage device and are discharged through the automatic drain valve. At this time, more than 95% of the water droplets and large particle impurities in the compressed air have been filtered out by the first-stage filter component and then enter the second-stage fiber filter. After the air enters the second-stage fiber filter, the fiber structure of the filter generates thousands of small vortices. At the same time, the air is accelerated dozens of times, forming a vacuum zone in the center of the vortex. The water droplets that are not filtered out by the first-stage filter component are vaporized, converted, and filtered out again, and impurity particles as small as 5μm are also completely filtered out by the second-stage filter. The air source used in this solution is compressed air, which can be obtained locally.

[0039] In addition, for the case where the air pressure required for the in-tank test is lower than 3 atmospheres, the air drying device of the present invention can also be implemented by a high-purity synthetic air compressor that can provide a water molecule concentration of less than 3ppm, an oxygen content of 21% (volume), and a nitrogen content of 79% (volume). This solution has a better effect on the decoupling regulation of humidity and air pressure than the above solution. Considering the volume and number of the high-purity gas mixed gas cylinders used, this solution can be used when the air pressure required for the in-tank test is lower than 3 atmospheres.

[0040] Figure 5 The following is a comparison chart of the relationship between the air pressure and relative humidity in the tank using two-stage filters + ordinary air source, high-purity synthetic air source, and untreated air (respectively shown as dots, triangles, and squares in the figure). Figure 5 As shown in the figure, after adding the two solutions, the air pressure and humidity in the tank 1 have been basically decoupled. Since synthetic dry air is used at the air source, the water content in this synthetic air is very small. 3 The synthetic air contains no more than 5 mL of water, so the decoupling effect is optimal.

[0041] The atomizer of this embodiment adopts the tantalum metal atomizer of Beijing Puxi General Instrument Co., Ltd., model B305002-01-01-00. The atomizer mainly includes a liquid water tank, a rubber dropper, an atomizing nozzle, a narrow-mouthed air pipe, a wide-mouthed air pipe, and a compressed air cylinder connected in sequence. The atomizing nozzle and the narrow-mouthed air pipe are respectively provided with a switch valve, and the atomizing nozzle is made of metal tantalum using a conventional process, and the wide-mouthed air pipe is provided with a conversion valve; the atomizer is located outside the main tank body 1, and the atomizing nozzle of the atomizer is connected to the water vapor inlet valve 15 of the tank body 1. The atomizer is based on the Venturi injection principle, using compressed air to form a high-speed airflow through the narrow-mouthed air pipe, and the negative pressure generated drives the liquid water to be sprayed together, and splashes around under high-speed impact inside the atomizer to turn the liquid water droplets into mist particles and spray out from the atomizing nozzle.

[0042] The temperature and humidity measuring instrument of this embodiment is composed of a display host located outside the tank body 1 and a temperature and humidity sensor installed at a reserved interface on the side wall of the tank body, and the probe of the sensor is located inside the tank body 1; wherein the temperature and relative humidity at the sensor are respectively displayed on the screen of the display host; the measurement accuracy of the temperature sensor is ±0.5°C, and the measurement accuracy of the humidity sensor is ±3%RH; the sealed housing of the sensor probe can withstand a maximum gas pressure of 0.8MPa.

[0043] When reducing the humidity in the tank 1 under normal pressure, due to the large volume of the tank itself, and when changing the pressure test, the absolute humidity in the tank should be reduced to 3g / m 3 Or below, the present invention adopts a combination of multiple dehumidification methods. When the humidity of the tank body is much greater than the external ambient humidity, a continuous ventilation method is adopted, and compressed air after two-stage filtration is introduced into the water vapor inlet valve 15, and the outlet 14 of the gas inlet and outlet valve 13 is opened (when the gas inlet and outlet valve is opened, if the gas pressure in the tank is higher than the atmospheric pressure and the tank body is not ventilated, the gas will be discharged from this outlet). In this way, the high-humidity air in the tank body can be gradually discharged, and the humidity in the tank body can be quickly reduced to near the ambient humidity. After that, the rate of humidity reduction begins to slow down. At this time, the observation window can be opened to put a desiccant on the flat electrode in the tank body, and then the ventilation is continued. After a period of time, the humidity will drop to a minimum value, which is generally 3g / m 3Another way is to evacuate first and then fill. When evacuating, a maximum of one atmosphere is allowed. Therefore, it takes a short time to evacuate to near vacuum using a negative pressure pump, about 10 minutes. Then, dry compressed air or synthetic air is filled into the main tank until the high-pressure barometer shows 1.2 atmospheres. Then, the air outlet is opened and the main tank is left to discharge the excess gas inside and return to normal pressure. Since the main tank is large in size, when judging whether the air pressure inside the main tank is normal pressure, one cannot simply rely on the indication on the barometer. One must also listen carefully to see if there is any obvious sound of air in and out.

Claims

1. A pilot discharge test system with decoupled adjustment of humidity and air pressure, characterized in that: The invention comprises a tank body, a wall-penetrating sleeve embedded at the center of the top of the tank body, and an air drying device, an atomizer, a temperature and humidity measuring instrument, and a discharge electric field measuring instrument located outside the tank body; wherein the air drying device is composed of a two-stage filter connected to an ordinary air compressor, ordinary compressed air enters the first-stage filter component to produce a coalescence effect, more than 95% of water droplets and large particle impurities in the ordinary compressed air are filtered out by the first-stage filter component, and then enters the second-stage fiber filter net, after entering the second-stage fiber filter net, the fiber structure of the filter net causes the air to generate thousands of small vortices, and at the same time the air is accelerated by dozens of times, forming a vacuum zone in the center of the vortex, and the water droplets not filtered out by the first-stage filter component are vaporized, converted, and filtered out again, and impurity particles as small as 5 μm are also completely filtered out by the second-stage fiber filter net; the outlet of the two-stage filter is connected to the water vapor inlet valve as the outlet of the air dryer, and an observation window and a light-transmitting mirror are respectively installed on the outer side walls of the middle and lower parts of the tank body, and a reserved interface, a plurality of valves and a plurality of barometer; the tank body is connected to the outlet of the air drying device and / or the atomizer through a water vapor inlet valve, and the tank body is connected to a temperature and humidity measuring instrument and / or a discharge electric field measuring instrument through a reserved interface; when the humidity of the tank body is much greater than the external ambient humidity, a continuous filling and ventilation method is adopted, compressed air after two-stage filtration is introduced into the water vapor inlet valve, the outlet of the gas inlet and outlet valve is opened, and the high-humidity air in the tank body is gradually discharged; a plurality of universal wheels are installed at the bottom of the tank body through evenly distributed pillars; the outer side of the bottom of the tank body is also equipped with A belt transmission device is installed, and a length-adjustable support is provided at the inner center of the bottom of the tank body. A flat electrode is fixed on the upper end of the support. The tank body and the flat electrode are connected by metal. The lower end of the support is fixedly connected to the belt transmission device; the lower end of the wall bushing vertically extends into the interior of the tank body and a discharge electrode on the high-voltage side is installed at this end. The upper end of the wall bushing protrudes from the tank body and is connected to the external high-voltage lead. The distance between the lower end of the wall bushing and the flat electrode is adjusted to vary between 10 cm and 70 cm through the belt transmission device.

2. The pilot discharge test system according to claim 1, characterized in that: The multiple valves include a safety valve, a gas inlet and outlet valve with an outlet, and a water vapor inlet valve; among them, when the air pressure inside the tank is greater than a set threshold, the safety valve will automatically leak to prevent the mirror body of the observation window from breaking.

3. The pilot discharge test system according to claim 1, characterized in that: The belt transmission device includes a guide rod fixed to one side of the support at the bottom of the tank body, a slider reciprocating on the guide rod, a fixed block fixed to one side of the guide rod, a transmission belt, a handle and a counter for reading the air gap distance, and the slider, the fixed slider and the center of the bottom of the tank body are all provided with bearings; wherein, the transmission belt passes around each bearing in turn, the bearing located at the center of the bottom of the tank body is fixedly connected to the lower end of the support inside the tank body, the bearing located on the fixed block is fixedly connected to the handle, and the bearing located on the slider is fixedly connected to the counter.

4. The pilot discharge test system according to claim 1, characterized in that: The two ends of the wall bushing are high-voltage sides, and the connection between the wall bushing and the tank body is connected by a sealing flange; the tank body and the flat electrode are low-voltage sides, and the tank body and the flat electrode are connected by metal.

5. The pilot discharge test system according to claim 1, characterized in that: The air drying device is composed of a two-stage filter and a common air compressor connected together; or the air drying device uses a synthetic air compressor that provides a water molecule concentration of less than 3ppm, an oxygen volume content of 21%, and a nitrogen volume content of 79%.

6. The pilot discharge test system according to claim 1, characterized in that: The atomizer has an atomizing nozzle made of metal tantalum, and the nozzle is connected to the water vapor inlet valve of the tank body.

7. The pilot discharge test system according to claim 1, characterized in that: The temperature and humidity measuring instrument is composed of a display host located outside the tank body and a temperature and humidity sensor installed at a reserved interface on the side wall of the tank body, and the probe of the temperature and humidity sensor is located inside the tank body; wherein the temperature and relative humidity at the sensor are respectively displayed on the screen of the display host; the measurement accuracy of the temperature sensor is ±0.5°C, and the measurement accuracy of the humidity sensor is ±3%RH; the sealed housing of the sensor probe can withstand a maximum gas pressure of 0.8MPa.

8. The pilot discharge test system according to claim 1, characterized in that: The light-transmitting mirror is symmetrically arranged on the side wall of the tank body at the same horizontal plane as the lower end of the wall-penetrating sleeve. The light-transmitting mirror adopts optical quartz glass and has full-transmittance filter film on both sides. The light-transmitting mirror is used to transmit the laser generated by the laser interferometer outside the tank body.

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