Device and method for measuring creeping discharge initial voltage and creeping flashover voltage

Abstract

The invention provides a device and method for measuring creeping discharge initial voltage and creeping flashover voltage, and relates to the technical field of high-voltage insulation. Discharge optical signals of surface initial voltage are converted into electric signals through the photomultiplier tube placed on the front window to achieve measurement of surface flashover initial voltage, the interior of the metal tank body is dark, the result is more accurate, the light shield is arranged in the metal tank body, the photomultiplier tube is protected against damage, and the accuracy is improved. The transverse displacement mechanical arm can complete movement of the potentiometer and the needle electrode, potential measurement and injection of charges at different positions are achieved, the actual situation is simulated, the camera placed on a rear window monitors whether the positions of the potentiometer and the needle electrode are correct or not, and the experiment reliability is improved. The SF6 inflation and deflation device realizes accurate measurement of air pressure, and observes the influence of different air pressure conditions on measurement of creeping discharge initial voltage and flashover voltage. The voltage divider is connected with the high-voltage side and the oscilloscope, the flashover voltage value is measured more accurately, and interference is avoided to a great extent.

Description

Technical Field

[0001] The invention belongs to the technical field of high-voltage insulation, and in particular relates to a device and a method for measuring a surface discharge starting voltage and a surface flashover voltage. Background Art

[0002] With the increasing demand for HVDC transmission, my country's power industry equipment will continue to strengthen innovation to ensure the green, low-carbon, safe and efficient development vision of power production and transportation. HVDC transmission system is a vital component of modern new power system. Since the operating conditions of HVDC transmission are much more complicated than traditional AC transmission, DC GIL, GIS and other equipment should have good insulation performance. Surface discharge is the most serious discharge phenomenon that damages insulation performance. Therefore, it is necessary to study the formation mechanism of surface discharge and the accumulation of charge at the interface, and analyze its influencing factors. In surface discharge, the gas-solid interface insulation problem is particularly prominent. Under the action of long-term DC voltage, a large amount of charge accumulates at the gas-solid interface, seriously distorting the interface electric field distribution, thereby reducing the surface tolerance characteristics of the solid medium. The accumulation of charge at the gas-solid interface creates conditions for the formation and development of streamers, which seriously restricts the development of DC power equipment and DC transmission. As a solid insulating material with good insulation properties, epoxy resin alumina mixture has been widely used in power system insulation equipment such as gas insulated switches and high-voltage bushings in recent years as solid insulation and mechanical support components. In view of this, a comprehensive experimental platform for surface charge quantitative injection and surface flashover was built to explore the SF 6 The influence of charge accumulation at the gas-solid interface on the surface discharge inception voltage and surface flashover voltage characteristics provides guidance and suggestions for the development and application of high-voltage DC equipment.

[0003] Existing flashover voltage measurement methods or devices focus on discussing or measuring the effects of a single or two factors on the surface discharge starting voltage and flashover voltage, ignoring the influence of multiple factors caused by complex environments in actual situations, and thus lack accuracy. Summary of the invention

[0004] In view of the above problems, the present invention proposes a device and method for measuring the surface discharge starting voltage and flashover voltage, which takes into account the influence of different surface charge injection amounts and injection positions under multiple gas pressures on the surface discharge starting voltage and flashover voltage, and realizes the accurate measurement of the surface discharge starting voltage and flashover voltage.

[0005] On the one hand, the present invention provides a device for measuring the surface discharge starting voltage and flashover voltage, comprising a metal tank, a high-voltage electrode, a high-voltage DC power supply access port, a pot-type insulator, a first lateral displacement mechanical arm, a SF 6Inflation and deflation device, vertical displacement mechanical arm, second lateral displacement mechanical arm, needle electrode, light shield, potentiometer, sample table, camera, photomultiplier tube, voltage divider and oscilloscope;

[0006] A basin insulator is fixed above the metal tank body, and a high-voltage DC power supply access port is arranged on the top of the basin insulator. A front window and a rear window are arranged at the front and rear of the metal tank body respectively. A photomultiplier tube is placed in front of the front window and connected to an oscilloscope. A camera is arranged outside the rear window. A vertical displacement mechanical arm equipped with a light shield is arranged below the metal tank body. The vertical displacement mechanical arm penetrates into the metal tank body. A lateral displacement mechanical arm is arranged on each side of the tank body, which are a first lateral displacement mechanical arm and a second lateral displacement mechanical arm. A potentiometer is arranged on the first lateral displacement mechanical arm, and a needle electrode is arranged on the second lateral displacement mechanical arm. At the same time, an SF is fixed on the tank body below one side of the lateral displacement mechanical arm. 6 The inflation and deflation device, a test bench and a high-voltage electrode are placed inside the metal tank body, and a voltage divider and an oscilloscope are placed outside the metal tank body, one end of the voltage divider is connected to the high-voltage DC voltage inlet, and the other end is connected to the oscilloscope;

[0007] The metal tank is used to provide a dark environment required for the experiment;

[0008] One end of the high-voltage electrode is connected to a high-voltage DC power supply through a high-voltage DC power supply inlet, and the other end is placed on the surface of the sample to provide a DC high voltage on the surface of the sample;

[0009] The pot-type insulator is used for insulation;

[0010] The front viewing window is used to provide a viewing angle for the photomultiplier tube;

[0011] The first lateral displacement mechanical arm is used to clamp and move the potentiometer;

[0012] The SF 6 The inflation and deflation device is used to control the SF 6 charging and releasing;

[0013] The vertical displacement mechanical arm is used to carry and move the sample table, and at the same time drive the light shield to move;

[0014] The second lateral displacement mechanical arm is used to move the needle electrode;

[0015] The rear view window is used to provide a viewing angle for the camera;

[0016] The needle electrode is used to inject electric charge into the metal tank;

[0017] The light shield is installed above the vertical displacement mechanical arm and is used to shield the light source of the front window when not in the experimental situation;

[0018] The potentiometer is used to measure the surface potential of the sample;

[0019] The test bench is used to carry the sample and provide insulation for it;

[0020] The camera is placed outside the rear window to observe the experimental process;

[0021] The photomultiplier tube is used to observe the light signal generated by the contact position between the high voltage electrode and the surface of the sample and convert it into an electrical signal;

[0022] The voltage divider is used to divide the voltage of the high voltage DC voltage access port and transmit it to the oscilloscope;

[0023] The oscilloscope is used to detect and record the real-time voltage value;

[0024] Furthermore, the metal tank body and the voltage divider are grounded via a common grounding wire;

[0025] On the other hand, the present invention also provides a method for measuring the surface discharge starting voltage and the flashover voltage, including a method for measuring the surface discharge starting voltage without charge injection, a method for measuring the surface flashover voltage without charge injection, a method for measuring the surface discharge starting voltage with charge injection, and a method for measuring the surface flashover voltage with charge injection;

[0026] The method for measuring the surface discharge starting voltage without charge injection specifically comprises the following steps:

[0027] A1: Place the dried sample in the center of the test bench, seal the metal can, and use a vacuum pump to put the metal can in a vacuum state. 6 The inflation and deflation device fills the metal tank with SF with a set initial air pressure. 6 gas;

[0028] A2: Turn on the photomultiplier tube installed in front of the front window, make sure that the camera placed outside the rear window is in the off state, and the cavity of the metal tank is in a dark environment. Connect a positive high-voltage DC power supply to the high-voltage DC power supply inlet, and provide high voltage on the surface of the sample through the high-voltage electrode. After the voltage of the high-voltage DC power supply is increased at a uniform speed to a certain voltage level, photons begin to be emitted at the contact position between the high-voltage electrode and the surface of the sample. Use the photomultiplier tube to observe the light signal and convert it into an electrical signal. The electrical signal is transmitted to the oscilloscope. When a waveform is observed on the oscilloscope with triggering set, stop pressurizing. When the recording conditions are met, record the surface discharge starting voltage and its waveform. Otherwise, continue pressurizing until the recording conditions are met;

[0029] A3: The voltage of the high-voltage DC power supply is uniformly reduced until the voltage drops to 0. The vertical displacement robot arm lowers the test table and the sample to the potential measurement position, and at the same time drives the light shield to fall and cover the front window to prevent the camera flash or other light sources from interfering and damaging the photomultiplier tube;

[0030] A4: The first lateral displacement mechanical arm starts to move, and the potentiometer is sent to the potential measurement position at a set distance from the sample. The camera in the rear view window starts to work, and observes whether the position measured by the potentiometer on the sample is the expected potential measurement position, and takes a photo to observe whether there is a discharge mark on the surface of the sample. If there is no mark, it indicates that the surface discharge starting voltage and its waveform are correct. The potentiometer is used to measure the potential to obtain the surface potential of the sample and execute A5. If there is a mark, the use of the surface discharge starting voltage and its waveform is abandoned, and return to A1;

[0031] A5: After completing the potential measurement, the potentiometer is returned to its original position by the first horizontal displacement robot arm, and the vertical displacement robot arm returns the test table and the sample to their original positions;

[0032] A6: Discharge the metal tank, discharge the waste gas after the experiment into a dedicated waste gas treatment channel, turn off the photomultiplier tube, then open the metal tank, switch the sample, seal the metal tank, use a vacuum pump to make the metal tank in a vacuum state, and increase the SF 6 The gas pressure value of the gas is set, and returns to A2 until the experiment is completed at the set final gas pressure value, and the measurement of the surface discharge starting voltage and the surface potential of the sample at each gas pressure under the positive voltage is completed;

[0033] A7: Change the connected high-voltage DC power supply to negative polarity, and complete the measurement of the surface discharge starting voltage and the surface potential of the sample at various gas pressures under negative voltage according to the methods of A1-A6;

[0034] The method for measuring the surface flashover voltage without charge injection specifically comprises the following steps:

[0035] B1: Place the dried sample in the center of the test bench, seal the metal can, and use a vacuum pump to put the metal can in a vacuum state. 6 The inflation and deflation device fills the metal tank with SF with a set initial air pressure. 6 gas;

[0036] B2: Connect a positive polarity high-voltage DC power supply to the high-voltage DC power supply inlet, provide high voltage on the surface of the sample through the high-voltage electrode, increase the voltage of the high-voltage DC power supply at a uniform speed, observe the waveform on the triggered oscilloscope connected to the voltage divider, and record the surface flashover voltage and its waveform;

[0037] B3: The voltage of the high-voltage DC power supply is uniformly reduced until the voltage drops to 0, and then the vertical displacement robot arm lowers the test platform and the sample to the potential measurement position;

[0038] B4: The first lateral displacement mechanical arm starts to move, and the potentiometer is sent to the potential measurement position at a set distance from the sample. The camera in the rear view window starts to work, and observes whether the position measured by the potentiometer on the sample is the expected potential measurement position, and takes a photo to observe whether there is a discharge mark on the surface of the sample. If there is no mark, it indicates that the surface flashover voltage and its waveform are correct. The potentiometer is used to measure the potential to obtain the surface potential of the sample and execute B5. If there is a mark, the use of the surface flashover voltage and its waveform is abandoned and the experiment is restarted in B1;

[0039] B5: After the potential measurement is completed, the potentiometer is sent back to its original position by the first horizontal displacement robot arm, and the vertical displacement robot arm sends the test table and the sample back to their original positions;

[0040] B6: Discharge the metal tube, discharge the waste gas after the experiment into a dedicated waste gas treatment channel, then open the metal tank, switch the sample, seal the metal tank, use a vacuum pump to make the metal tank in a vacuum state, and increase the SF 6 The gas pressure value of the gas is returned to B2 until the experiment under the set final pressure value is completed, and the surface flashover voltage and the surface potential of the sample under various pressures under positive voltage are measured;

[0041] B7: Change the connected high-voltage DC power supply to negative polarity, and complete the measurement of the surface flashover voltage and the surface potential of the sample under various air pressures under negative voltage according to the methods of B1-B6;

[0042] The method for measuring the surface discharge starting voltage under the condition of charge injection specifically comprises the following steps:

[0043] C1: Place the dried sample in the center of the test bench, seal the metal can, and use a vacuum pump to put the metal can in a vacuum state. 6 The inflation and deflation device fills the metal tank with gas of a set initial pressure value;

[0044] C2: The vertical displacement robot arm lowers the sample table to the charge injection position, and the second lateral displacement robot arm moves the needle electrode to the charge injection position at a set distance from the sample;

[0045] C3: Use a second power supply provided outside the needle electrode to power the needle electrode, set the charge injection amount and injection time, start injecting charge and wait for the charge injection to be completed;

[0046] C4: After the charge injection is completed, the second lateral displacement mechanical arm moves the needle electrode to the original position, and the potentiometer is moved by the first lateral displacement mechanical arm to the potential measurement position at a set distance from the sample. The camera in the rear view window starts to work to observe whether the position measured by the potentiometer on the sample is the expected potential measurement position, measure the potential and judge whether the charge injection amount reaches the set value according to the potential. If so, execute C5, otherwise return to C3;

[0047] C5: After completing the potential measurement, the potentiometer is sent back to its original position by the first lateral displacement mechanical arm;

[0048] C6: Use the vertical displacement mechanical arm to raise the test bench to the experimental position, turn on the photomultiplier tube installed in front of the front window, make sure that the camera placed behind the rear window is in the off state, the cavity of the metal tank is in a dark environment, connect a positive high-voltage DC power supply at the high-voltage DC power supply inlet, provide high voltage on the sample through the high-voltage electrode, and uniformly increase the voltage of the high-voltage DC power supply to a certain voltage level. Photons begin to be emitted from the contact position between the high-voltage electrode and the surface of the sample. Use the photomultiplier tube to observe the light signal and convert it into an electrical signal. The electrical signal is transmitted to the oscilloscope. When a waveform is observed on the oscilloscope with triggering set, stop pressurizing. When the recording conditions are met, record the surface discharge starting voltage and its waveform. Otherwise, continue pressurizing until the recording conditions are met;

[0049] C7: The voltage of the high-voltage DC power supply is uniformly reduced until the voltage drops to 0. The vertical displacement robot arm lowers the test table and the sample to the potential measurement position, and at the same time drives the light shield to fall and cover the front window to prevent the camera flash or other light sources from interfering and damaging the photomultiplier tube;

[0050] C8: The first lateral displacement mechanical arm starts to move, and the potentiometer is sent to the potential measurement position at a set distance from the sample. The camera in the rear view window starts to work, and observes whether the position measured by the potentiometer on the sample is the expected potential measurement position, and takes a photo to observe whether there is a discharge mark on the surface of the sample. If there is no mark, it indicates that the surface discharge starting voltage and its waveform are correct. The potentiometer is used to measure the potential to obtain the surface potential of the sample and execute C9. If there is a mark, the use of the surface discharge starting voltage and its waveform is abandoned, and the return is returned to C1;

[0051] C9: After completing the potential measurement, the potentiometer is sent back to its original position by the first lateral displacement robot arm, and the vertical displacement robot arm sends the test table and the sample back to their original positions;

[0052] C10: Discharge the metal tank, discharge the waste gas after the experiment into a dedicated waste gas treatment channel, turn off the photomultiplier tube, then open the metal tank, switch the sample, seal the metal tank, use a vacuum pump to make the metal tank in a vacuum state, and increase the SF 6The gas pressure value of the gas is set and returned to C2 until the experiment is completed at the set final gas pressure value, and the surface discharge starting voltage and sample surface potential measurement at each gas pressure under positive voltage are completed;

[0053] C11: Change the connected high-voltage DC power supply to negative polarity, and complete the measurement of the surface discharge starting voltage and the surface potential of the sample at various gas pressures under negative voltage according to the methods of C1-C10;

[0054] The method for measuring the surface flashover voltage under the condition of charge injection specifically comprises the following steps:

[0055] D1: Place the dried sample in the center of the test bench, seal the metal can, and use a vacuum pump to put the metal can in a vacuum state. 6 The inflation and deflation device fills the metal tank with SF with a set initial air pressure. 6 gas;

[0056] D2: The vertical displacement robot lowers the sample table to the charge injection position, and the second lateral displacement robot moves the needle electrode to a set distance from the sample;

[0057] D3: Use a second power supply provided outside the needle electrode to power the needle electrode, set the charge injection amount and injection time, start injecting charge and wait for the charge injection to be completed;

[0058] D4: After the charge injection is completed, the second lateral displacement mechanical arm moves the needle electrode to the original position, and the potentiometer is moved by the first lateral displacement mechanical arm to the set distance from the sample. The camera in the rear window starts to work to observe whether the position measured by the potentiometer on the sample is the expected potential measurement position, measure the potential and judge whether the charge injection amount reaches the set value according to the potential. If so, execute D5, otherwise return to D3;

[0059] D5: After completing the potential measurement, the potentiometer is sent back to its original position by the first lateral displacement mechanical arm;

[0060] D6: Use the vertical displacement mechanical arm to raise the test table to the experimental position, connect the positive polarity high-voltage DC power supply to the high-voltage DC power supply inlet, provide high voltage on the surface of the sample through the high-voltage electrode, increase the voltage of the high-voltage DC power supply at a uniform speed, observe the waveform on the triggered oscilloscope connected to the voltage divider, and record the surface flashover voltage and its waveform;

[0061] D7: The voltage of the high-voltage DC power supply is uniformly reduced until the voltage drops to 0, and then the vertical displacement robot arm lowers the test table and the sample to the potential measurement position;

[0062] D8: The first lateral displacement mechanical arm starts to move, and the potentiometer is sent to the potential measurement position at a set distance from the sample. The camera in the rear window starts to work, and observes whether the position measured by the potentiometer on the sample is the expected potential measurement position, and takes a photo to observe whether there is a discharge mark on the surface of the sample. If there is no mark, it indicates that the surface flashover voltage and its waveform are correct. The potentiometer is used to measure the potential to obtain the surface potential of the sample and execute D9. If there is a mark, the use of the surface flashover voltage and its waveform is abandoned and the experiment is restarted in D1.

[0063] D9: After completing the potential measurement, the potentiometer is sent back to its original position by the first lateral displacement robot arm, and the vertical displacement robot arm sends the test table and the sample back to their original positions;

[0064] D10: Discharge the metal tube, discharge the waste gas after the experiment into a dedicated waste gas treatment channel, then open the metal tank, switch the sample, seal the metal tank, use a vacuum pump to put the metal tank in a vacuum state, and increase the SF 6 The gas pressure value of the gas is returned to D2 until the experiment is completed at the set final pressure value, and the surface flashover voltage and sample surface potential measurement at each pressure under positive voltage are completed;

[0065] D11: Change the connected high-voltage DC power supply to negative polarity, and complete the measurement of the surface flashover voltage and the surface potential of the sample at various air pressures under negative voltage according to D1-D10.

[0066] Compared with the prior art, the beneficial effects of the present invention are:

[0067] The present invention uses a photomultiplier tube placed in the front window to convert the discharge light signal of the surface flashover starting voltage into an electrical signal to measure the surface flashover starting voltage. The experimental environment inside the metal tank is a dark environment, and the result is more accurate. A light shield is set inside the metal tank to protect the photomultiplier tube from damage and improve accuracy. Two lateral displacement mechanical arms can complete the movement of the potentiometer and the needle electrode, realize the measurement of the potential and the injection of charges at different positions, and better simulate the actual situation. The camera placed in the rear window can monitor in real time whether the position of the potentiometer and the needle electrode is correct, thereby increasing the reliability of the experiment. SF 6 The inflation and deflation device can realize accurate measurement of air pressure and observe the influence of different air pressure conditions on the measurement of surface discharge starting voltage and flashover voltage. The two sides of the voltage divider are connected to the high voltage side and the oscilloscope, which can measure the flashover voltage value more accurately and avoid interference to a great extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 A side view of a device for measuring the surface discharge inception voltage and the flashover voltage when measuring the surface discharge inception voltage and the flashover voltage of a test sample in an embodiment of the present invention;

[0069] Figure 2 It is a side view of a device for measuring the surface discharge starting voltage and the flashover voltage when the light shield covers the front window after the sample platform is lowered in the embodiment of the present invention;

[0070] Figure 3 A schematic diagram of a device for measuring surface discharge inception voltage and flashover voltage for potential measurement in an embodiment of the present invention;

[0071] Figure 4 A schematic diagram of a device for measuring surface discharge inception voltage and flashover voltage when injecting charge in an embodiment of the present invention;

[0072] In the figure: 1-high voltage DC power supply inlet, 2-pot insulator, 3-front window, 4-first lateral displacement mechanical arm, 5-SF 6 Inflation and deflation device, 6-vertical displacement mechanical arm, 7-second lateral displacement mechanical arm, 8-rear view window, 9-needle electrode, 10-light shield, 11-potentiometer, 12-test bench. DETAILED DESCRIPTION

[0073] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0074] On the one hand, the present invention provides a device for measuring the surface discharge starting voltage and flashover voltage, comprising a metal tank, a high-voltage electrode, a high-voltage DC power supply access port 1, a pot-type insulator 2, a front window 3, a first lateral displacement mechanical arm 4, and a SF 6 Inflating and deflation device 5, vertical displacement mechanical arm 6, second lateral displacement mechanical arm 7, rear view window 8, needle electrode 9, light shield 10, potentiometer 11, sample table 12, camera, photomultiplier tube, voltage divider and oscilloscope;

[0075] A pot-type insulator 2 is fixed on the top of the metal tank body, a front window 3 and a rear window 8 are respectively provided on the front and rear of the metal tank body, a vertical displacement mechanical arm 6 is arranged under the tank body, and a lateral displacement mechanical arm is arranged on both sides of the tank body, which are respectively a first lateral displacement mechanical arm 4 and a second lateral displacement mechanical arm 7, and an SF6 inflation and deflation device 5 is fixed on the tank body under one side of the lateral displacement mechanical arm. The metal tank body is used to provide a dark environment required for the experiment;

[0076] The high-voltage DC power supply access port 1 is located on the top of the pot-type insulator 2 and is used to access the high-voltage DC power supply;

[0077] The pot-type insulator 2 is used for insulation;

[0078] The front viewing window 3 is used to provide a viewing angle for the photomultiplier tube;

[0079] The first lateral displacement mechanical arm 4 is provided with a potentiometer 11, which is used to clamp and move the potentiometer 11;

[0080] The vertical displacement mechanical arm 6 is disposed below the metal tank body and penetrates into the metal tank body, and is used to carry and move the sample table 12, and at the same time drive the light shield 10 to move;

[0081] The SF 6 The inflation and deflation device 5 is installed on the lower right side of the metal tank body to control the SF 6 charging and releasing;

[0082] The second lateral displacement mechanical arm 7 is provided with a needle electrode 9 for moving the needle electrode 9;

[0083] The light shield 10 is installed above the vertical displacement mechanical arm 6 to shield the light source of the front window 3 when not in the experimental state, protect the photomultiplier tube and improve the accuracy of the experiment;

[0084] The rear view window 8 is used to provide a viewing angle for the camera, so as to facilitate the shooting of the charge injection position and the potential measurement position, thereby ensuring the accuracy of the experimental data;

[0085] The needle electrode 9 is used to inject electric charge into the metal can body 1;

[0086] The potentiometer 11 is used to measure the surface potential of the sample;

[0087] The sample table 12 is located inside the metal tank and is used to carry the sample and provide insulation for it;

[0088] The photomultiplier tube is placed in front of the front viewing window 3 and connected to an oscilloscope, and is used to observe the light signal generated at the contact position between the high-voltage electrode and the surface of the sample and convert it into an electrical signal;

[0089] One end of the voltage divider is connected to the high-voltage DC voltage access port, and the other end is connected to the oscilloscope, and is used to divide the voltage of the high-voltage DC voltage access port and transmit it to the oscilloscope;

[0090] The oscilloscope is connected to the voltage divider to detect and record the real-time voltage value;

[0091] The high-voltage electrode is connected to a high-voltage DC power supply via a high-voltage DC power supply inlet 1, and is used to provide a DC high voltage on the surface of the sample;

[0092] The camera is placed outside the rear window 8 to observe the experimental process;

[0093] The metal tank body and the voltage divider are grounded via a common grounding wire;

[0094] On the other hand, the present invention also provides a method for measuring the surface discharge starting voltage and the flashover voltage, including a method for measuring the surface discharge starting voltage without charge injection, a method for measuring the surface flashover voltage without charge injection, a method for measuring the surface discharge starting voltage with charge injection, and a method for measuring the surface flashover voltage with charge injection;

[0095] The method for measuring the surface discharge starting voltage without charge injection specifically comprises the following steps:

[0096] A1: Place the dried sample in the center of the test table 12, seal the metal can, and use a vacuum pump to put the metal can 1 in a vacuum state. Figure 1 As shown, 0.1MPa SF6 is filled into the metal tank through the SF6 filling and degassing device 5. 6 gas;

[0097] In this embodiment, the epoxy resin aluminum oxide mixture sample is shown;

[0098] A2: Turn on the photomultiplier tube installed in front of the front window 3, make sure that the camera placed outside the rear window 8 is in the off state, the cavity of the metal tank is in a dark environment, connect a positive high-voltage DC power supply at the high-voltage DC power supply inlet 1, provide high voltage on the surface of the sample through the high-voltage electrode, and uniformly increase the voltage of the high-voltage DC power supply to a certain voltage level. Photons begin to be emitted at the contact position between the high-voltage electrode and the surface of the sample. Use the photomultiplier tube to observe the light signal and convert it into an electrical signal. The electrical signal is transmitted to the oscilloscope. When a waveform is observed on the oscilloscope with triggering set, stop pressurizing. When two sets of waveforms appear within 60 seconds, the surface discharge starting voltage and its waveform can be recorded. If two sets of waveforms do not appear within 60 seconds, continue pressurizing until two sets of waveforms appear within 60 seconds.

[0099] A3: The voltage of the high-voltage DC power supply is uniformly reduced until the voltage drops to 0. Then the vertical displacement robot arm 6 lowers the test table 12 and the sample to the position as shown in the figure. Figure 2 The potential measurement position shown, at the same time, drives the light shield 10 to fall and cover the front window 3, to prevent the camera flash or other light sources from interfering with or even damaging the photomultiplier tube;

[0100] A4: The first lateral displacement robot arm 4 starts to move, and the potentiometer 11 is sent to Figure 3The distance from the sample to the vertical height of 7mm is shown, and the camera of the rear view window 8 starts to work, and observes whether the position measured by the potentiometer 11 on the sample is the expected potential measurement position, and takes a photo to observe whether there is a discharge mark on the surface of the sample. If there is no mark, it indicates that the surface discharge starting voltage and its waveform are correct. The potentiometer 11 is used to measure the potential to obtain the surface potential of the sample and execute A5. If there is a mark, the surface discharge starting voltage and its waveform may be inaccurate, and the use of the surface discharge starting voltage and its waveform is abandoned, and the process returns to A1;

[0101] A5: After the potential measurement is completed, the potentiometer 11 is returned to its original position by the first lateral displacement robot arm 4, and the vertical displacement robot arm 6 returns the sample table 12 and the sample to their original positions;

[0102] A6: Use the grounding rod to discharge the metal tank, then open the venting valve on the SF6 gas filling and discharging device 5 to discharge the waste gas after the experiment into the dedicated waste gas treatment channel, turn off the photomultiplier tube, then open the metal tank, switch the sample, seal the metal tank, use a vacuum pump to make the metal tank 1 in a vacuum state, and increase the SF6 gas charged into the metal tank. 6 gas, and return to A2 until it is completed at 0.5MPaSF 6 The experiment was carried out under positive voltage to complete the measurement of the surface discharge starting voltage and the surface potential of the sample at various gas pressures;

[0103] A7: Change the connected high-voltage DC power supply to negative polarity, and complete the measurement of the surface discharge starting voltage and the surface potential of the sample at various gas pressures under negative voltage according to the methods of A1-A6;

[0104] The method for measuring the surface flashover voltage without charge injection specifically comprises the following steps:

[0105] B1: Place the dried sample in the center of the test table 12, seal the metal can, and use a vacuum pump to put the metal can 1 in a vacuum state. Figure 1 As shown, 0.1MPa SF6 is filled into the metal tank through the SF6 filling and degassing device 5. 6 gas;

[0106] B2: Connect a positive polarity high-voltage DC power supply to the high-voltage DC power supply inlet 1, provide high voltage on the surface of the sample through the high-voltage electrode, increase the voltage of the high-voltage DC power supply at a uniform speed, observe the waveform on the triggered oscilloscope connected to the voltage divider, and record the surface flashover voltage and its waveform;

[0107] B3: The voltage of the high-voltage DC power supply is uniformly reduced until the voltage drops to 0, and the vertical displacement robot arm 6 lowers the test table 12 and the sample to the position as shown in FIG. Figure 2 Potential measurement locations shown;

[0108] B4: The first lateral displacement robot arm 4 starts to move, and the potentiometer 11 is sent to Figure 3 The potential measurement position is 7mm away from the vertical height of the sample, and the camera of the rear view window 8 starts to work to observe whether the position measured by the potentiometer 11 on the sample is the expected potential measurement position, and take a photo to observe whether there is a discharge mark on the surface of the sample. If there is no mark, it indicates that the surface flashover voltage and its waveform are correct. The surface potential of the sample is obtained by measuring the potential with the potentiometer 11 and B5 is executed. If there is a mark, the surface flashover voltage and its waveform may be inaccurate. Abandon the use of this surface flashover voltage and its waveform and return to B1 to restart the experiment;

[0109] B5: After the potential measurement is completed, the potentiometer 11 is sent back to its original position by the first lateral displacement robot arm 4, and the vertical displacement robot arm 6 sends the test table 12 and the sample back to their original positions;

[0110] B6: Use the grounding rod to discharge the metal tube, then open the venting valve on the SF6 gas filling and discharging device 5 to discharge the waste gas after the experiment into the dedicated waste gas treatment channel, then open the metal tank, switch the sample, seal the metal tank, use the vacuum pump to make the metal tank 1 in a vacuum state, and increase the SF6 gas filled into the metal tank. 6 gas and return to B2 until it is completed at 0.5MPaSF 6 The experiment was carried out under positive voltage to complete the measurement of surface flashover voltage and sample surface potential at various gas pressures;

[0111] In this embodiment, the pressure is increased by 0.1 MPa at a time from 0.1 MPa to 0.5 MPa;

[0112] B7: Change the connected high-voltage DC power supply to negative polarity, and complete the measurement of the surface flashover voltage and the surface potential of the sample under various air pressures under negative voltage according to the methods of B1-B6;

[0113] The method for measuring the surface discharge starting voltage under the condition of charge injection specifically comprises the following steps:

[0114] C1: Place the dried sample in the center of the test table 12, seal the metal can, and use a vacuum pump to put the metal can 1 in a vacuum state. Figure 1 As shown, 0.1MPa SF6 is filled into the metal tank through the SF6 filling and degassing device 5. 6 gas;

[0115] C2: The vertical displacement robot arm 6 lowers the sample table 12 to the position as shown in FIG. Figure 4 Charge injection position: the second lateral displacement mechanical arm 7 moves the needle electrode 9 to the charge injection position at a vertical distance of 7 mm from the sample;

[0116] C3: using a second power supply provided outside the needle electrode 9 to power the needle electrode 9, setting the charge injection amount and injection time, starting to inject charge and waiting for the charge injection to be completed;

[0117] C4: After the charge injection is completed, the second lateral displacement mechanical arm 7 moves the needle electrode 9 to the original position, and the potentiometer 11 is moved by the first lateral displacement mechanical arm 4 to the potential measurement position at a vertical height of 7 mm from the sample. The camera of the rear view window 8 starts to work to observe whether the position measured by the potentiometer 11 on the sample is the expected potential measurement position, measure the potential and judge whether the charge injection amount reaches the set value according to the potential. If so, execute C5, otherwise return to C3;

[0118] C5: After completing the potential measurement, the potentiometer 11 is returned to its original position by the first lateral displacement mechanical arm 4;

[0119] C6: Use the vertical displacement mechanical arm 6 to raise the sample table 12 to the experimental position, turn on the photomultiplier tube installed in front of the front window 3, make sure that the camera placed behind the rear window 8 is in the off state, the cavity of the metal tank is in a dark environment, connect a positive high-voltage DC power supply at the high-voltage DC power supply inlet 1, provide high voltage on the sample through the high-voltage electrode, and uniformly increase the voltage of the high-voltage DC power supply to a certain voltage level. Photons begin to be emitted from the contact position between the high-voltage electrode and the surface of the sample. Use the photomultiplier tube to observe the light signal and convert it into an electrical signal. The electrical signal is transmitted to the oscilloscope. When a waveform is observed on the oscilloscope with triggering set, stop pressurizing. When two sets of waveforms appear within 60 seconds, the surface discharge starting voltage and its waveform can be recorded. If two sets of waveforms do not appear within 60 seconds, continue pressurizing until two sets of waveforms appear within 60 seconds.

[0120] C7: uniformly reduce the voltage of the high-voltage DC power supply until the voltage drops to 0, then the vertical displacement robot arm 6 lowers the test table 12 and the sample to the position as shown in the figure. Figure 2 The potential measurement position shown, at the same time, drives the light shield 10 to fall and cover the front window 3, to prevent the camera flash or other light sources from interfering with or even damaging the photomultiplier tube;

[0121] C8: The first lateral displacement robot arm 4 starts to move, and the potentiometer 11 is sent to Figure 3 The potential measurement position is 7mm away from the vertical height of the sample, and the camera of the rear view window 8 starts to work to observe whether the position measured by the potentiometer 11 on the sample is the expected potential measurement position, and take a photo to observe whether there is a discharge mark on the surface of the sample. If there is no mark, it indicates that the surface discharge starting voltage and its waveform are correct. The surface potential of the sample is obtained by using the potentiometer 11 to measure the potential and execute C9. If there is a mark, the surface discharge starting voltage and its waveform may be inaccurate, and the use of the surface discharge starting voltage and its waveform is abandoned, and the process returns to C1.

[0122] C9: After the potential measurement is completed, the potentiometer 11 is sent back to its original position by the first lateral displacement robot arm 4, and the vertical displacement robot arm 6 sends the test table 12 and the sample back to their original positions;

[0123] C10: Use the grounding rod to discharge the metal tank, then open the venting valve on the SF6 gas filling and discharging device 5 to discharge the waste gas after the experiment into the dedicated waste gas treatment channel, turn off the photomultiplier tube, then open the metal tank, switch the sample, seal the metal tank, use the vacuum pump to make the metal tank 1 in a vacuum state, and increase the SF6 gas charged into the metal tank. 6 gas and return to C2 until it is completed at 0.5MPaSF 6 The experiment was carried out under positive voltage to complete the measurement of the surface discharge starting voltage and the surface potential of the sample at various gas pressures;

[0124] C11: Change the connected high-voltage DC power supply to negative polarity, and complete the measurement of the surface discharge starting voltage and the surface potential of the sample at various gas pressures under negative voltage according to the methods of C1-C10;

[0125] Different results and data can be obtained by changing the electrode shape, electrode spacing, charge injection amount, injection time, and injection charge polarity.

[0126] The method for measuring the surface flashover voltage under the condition of charge injection specifically comprises the following steps:

[0127] D1: Place the dried sample in the center of the test table 12, seal the metal can, and use a vacuum pump to put the metal can 1 in a vacuum state. Figure 1 As shown, 0.1MPa SF6 is filled into the metal tank through the SF6 filling and degassing device 5. 6 gas;

[0128] D2: The vertical displacement robot arm 6 lowers the sample table 12 to the position as shown in FIG. Figure 4 At the charge injection position, the second lateral displacement mechanical arm 7 moves the needle electrode 9 to a position 7 mm vertically away from the sample;

[0129] D3: using a second power supply provided outside the needle electrode 9 to power the needle electrode 9, setting the charge injection amount and injection time, starting to inject charge and waiting for the charge injection to be completed;

[0130] D4: After the charge injection is completed, the second lateral displacement robot arm 7 moves the needle electrode 9 to the original position, and the potentiometer 11 is moved by the first lateral displacement robot arm 4 to the original position. Figure 3 At a vertical height of 7 mm from the sample, the camera of the rear view window 8 starts to work, observing whether the position measured by the potentiometer 11 on the sample is the expected potential measurement position, measuring the potential and judging whether the charge injection amount reaches the set value according to the potential, if so, executing D5, otherwise returning to D3;

[0131] D5: After completing the potential measurement, the potentiometer 11 is sent back to its original position by the first lateral displacement mechanical arm 4;

[0132] D6: Use the vertical displacement mechanical arm 6 to raise the test platform 12 to the experimental position, connect the high-voltage DC power supply with positive polarity at the high-voltage DC power supply inlet 1, provide high voltage on the surface of the sample through the high-voltage electrode, increase the voltage of the high-voltage DC power supply at a uniform speed, observe the waveform on the oscilloscope connected to the voltage divider and set to trigger, and record the surface flashover voltage and its waveform;

[0133] D7: uniformly reduce the voltage of the high-voltage DC power supply until the voltage drops to 0, and then the vertical displacement robot arm 6 lowers the test table 12 and the sample to the position as shown in FIG. Figure 2 Potential measurement locations shown;

[0134] D8: The first lateral displacement robot arm 4 starts to move, and the potentiometer 11 is sent to Figure 3 The potential measurement position is 7mm away from the vertical height of the sample, and the camera of the rear view window 8 starts to work to observe whether the position measured by the potentiometer 11 on the sample is the expected potential measurement position, and take a photo to observe whether there is a discharge mark on the surface of the sample. If there is no mark, it indicates that the surface flashover voltage and its waveform are correct. The surface potential of the sample is obtained by measuring the potential using the potentiometer 11 and D9 is executed. If there is a mark, the surface flashover voltage and its waveform may be inaccurate. The use of this surface flashover voltage and its waveform is abandoned and the experiment is restarted in D1;

[0135] D9: After the potential measurement is completed, the potentiometer 11 is sent back to its original position by the first lateral displacement robot arm 4, and the vertical displacement robot arm 6 sends the test table 12 and the sample back to their original positions;

[0136] D10: Use the grounding rod to discharge the metal tube, then open the venting valve on the SF6 gas filling and discharging device 5 to discharge the waste gas after the experiment into the dedicated waste gas treatment channel, then open the metal tank, switch the sample, seal the metal tank, use the vacuum pump to make the metal tank 1 in a vacuum state, and increase the SF6 gas filled into the metal tank. 6 gas and return to D2 until it is completed at 0.5MPaSF 6 The experiment was carried out under positive voltage to complete the measurement of surface flashover voltage and sample surface potential at various gas pressures;

[0137] D11: Change the connected high-voltage DC power supply to negative polarity, and complete the measurement of the surface flashover voltage and the surface potential of the sample at various air pressures under negative voltage according to the methods of D1-D10;

[0138] Different results and data can be obtained by changing the electrode shape, electrode spacing, charge injection amount, injection time, and injection charge polarity.

Claims

1. A device for measuring the surface discharge starting voltage and flashover voltage, characterized in that: It includes a metal tank, a high-voltage electrode, a high-voltage DC power supply access port, a pot-type insulator, a first lateral displacement mechanical arm, an SF6 gas-filling and deflation device, a vertical displacement mechanical arm, a second lateral displacement mechanical arm, a needle electrode, a light shield, a potentiometer, a test bench, a camera, a photomultiplier tube, a voltage divider and an oscilloscope; A basin insulator is fixed above the metal tank body, and a high-voltage DC power supply access port is arranged on the top of the basin insulator. A front window and a rear window are arranged at the front and rear of the metal tank body, respectively. A photomultiplier tube is placed in front of the front window, and the photomultiplier tube is connected to an oscilloscope. A camera is arranged outside the rear window. A vertical displacement mechanical arm equipped with a light shield is arranged below the metal tank body, and the vertical displacement mechanical arm penetrates into the metal tank body. A lateral displacement mechanical arm is arranged on each side of the tank body, which are a first lateral displacement mechanical arm and a second lateral displacement mechanical arm, respectively. A potentiometer is arranged on the first lateral displacement mechanical arm, and a needle electrode is arranged on the second lateral displacement mechanical arm. At the same time, an SF6 inflation and deflation device is fixed on the tank body below one side of the lateral displacement mechanical arm. A test bench and a high-voltage electrode are placed inside the metal tank body, and a voltage divider and an oscilloscope are placed outside the metal tank body. One end of the voltage divider is connected to the high-voltage DC voltage access port, and the other end is connected to the oscilloscope. The metal tank is used to provide a dark environment required for the experiment; One end of the high-voltage electrode is connected to a high-voltage DC power supply through a high-voltage DC power supply inlet, and the other end is placed on the surface of the sample to provide a DC high voltage on the surface of the sample; The high-voltage DC power supply inlet is used to access a high-voltage DC power supply; The pot-type insulator is used for insulation; The front viewing window is used to provide a viewing angle for the photomultiplier tube; The first lateral displacement mechanical arm is used to clamp and move the potentiometer; The SF6 gas charging and discharging device is used to control the charging and releasing of SF6 in the metal tank; The vertical displacement mechanical arm is used to carry and move the sample table, and at the same time drive the light shield to move; The second lateral displacement mechanical arm is used to move the needle electrode; The rear view window is used to provide a viewing angle for the camera; The needle electrode is used to inject electric charge into the metal tank; The light shield is installed above the vertical displacement mechanical arm and is used to shield the light source of the front window when not in the experimental situation; The potentiometer is used to measure the surface potential of the sample; The test bench is used to carry the sample and provide insulation for it; The camera is placed outside the rear window to observe the experimental process; The photomultiplier tube is used to observe the light signal generated by the contact position between the high voltage electrode and the surface of the sample and convert it into an electrical signal; The voltage divider is used to divide the voltage of the high voltage DC voltage access port and transmit it to the oscilloscope; The oscilloscope is used to detect and record the real-time voltage value.

2. A device for measuring surface discharge inception voltage and flashover voltage according to claim 1, characterized in that: The metal tank and the voltage divider are grounded via a common grounding wire.

3. A method for measuring the surface discharge inception voltage and flashover voltage implemented by a device for measuring the surface discharge inception voltage and flashover voltage according to claim 1 or 2, characterized in that The invention comprises a method for measuring the surface discharge starting voltage without charge injection, a method for measuring the surface flashover voltage without charge injection, a method for measuring the surface discharge starting voltage with charge injection and a method for measuring the surface flashover voltage with charge injection.

4. A method for measuring surface discharge inception voltage and flashover voltage according to claim 3, characterized in that: The method for measuring the surface discharge starting voltage without charge injection specifically comprises the following steps: A1: Place the dried sample in the center of the test bench, seal the metal tank, use a vacuum pump to put the metal tank in a vacuum state, and fill the metal tank with SF6 gas of a set initial pressure value through the SF6 inflation and deflation device; A2: Turn on the photomultiplier tube installed in front of the front window, make sure that the camera placed outside the rear window is in the off state, the cavity of the metal tank is in a dark environment, connect a positive high-voltage DC power supply at the high-voltage DC power supply inlet, provide high voltage on the surface of the sample through the high-voltage electrode, and uniformly increase the voltage of the high-voltage DC power supply to a certain voltage level. Photons begin to be emitted at the contact position between the high-voltage electrode and the surface of the sample. Use the photomultiplier tube to observe the light signal and convert it into an electrical signal. The electrical signal is transmitted to the oscilloscope. When a waveform is observed on the oscilloscope with triggering set, stop pressurizing. When the recording conditions are met, record the surface discharge starting voltage and its waveform. Otherwise, continue pressurizing until the recording conditions are met; A3: The voltage of the high-voltage DC power supply is uniformly reduced until the voltage drops to 0. The vertical displacement robot arm lowers the test table and the sample to the potential measurement position, and at the same time drives the light shield to fall and cover the front window to prevent the camera flash or other light sources from interfering and damaging the photomultiplier tube; A4: The first lateral displacement mechanical arm starts to move, and the potentiometer is sent to the potential measurement position at a set distance from the sample. The camera in the rear view window starts to work, and observes whether the position measured by the potentiometer on the sample is the expected potential measurement position, and takes a photo to observe whether there is a discharge mark on the surface of the sample. If there is no mark, it indicates that the surface discharge starting voltage and its waveform are correct. The potentiometer is used to measure the potential to obtain the surface potential of the sample and execute A5. If there is a mark, the use of the surface discharge starting voltage and its waveform is abandoned, and return to A1; A5: After completing the potential measurement, the potentiometer is returned to its original position by the first horizontal displacement robot arm, and the vertical displacement robot arm returns the test table and the sample to their original positions; A6: discharge the metal tank, discharge the waste gas after the experiment into a dedicated waste gas treatment channel, close the photomultiplier tube, then open the metal tank, switch the sample, seal the metal tank, use a vacuum pump to make the metal tank in a vacuum state, increase the pressure of the SF6 gas filled into the metal tank, and return to A2 until the experiment is completed at the set final pressure value, and complete the measurement of the surface discharge starting voltage and the surface potential of the sample at various pressures under positive voltage; A7: Change the connected high-voltage DC power supply to negative polarity, and complete the measurement of the surface discharge starting voltage and the surface potential of the sample at various gas pressures under negative voltage according to the methods of A1-A6.

5. The method for measuring the surface discharge inception voltage and the flashover voltage according to claim 3, characterized in that: The method for measuring the surface flashover voltage without charge injection specifically comprises the following steps: B1: Place the dried sample in the center of the test bench, seal the metal tank, use a vacuum pump to put the metal tank in a vacuum state, and fill the metal tank with SF6 gas of a set initial pressure value through the SF6 inflation and deflation device; B2: Connect a positive polarity high-voltage DC power supply to the high-voltage DC power supply inlet, provide high voltage on the surface of the sample through the high-voltage electrode, increase the voltage of the high-voltage DC power supply at a uniform speed, observe the waveform on the triggered oscilloscope connected to the voltage divider, and record the surface flashover voltage and its waveform; B3: The voltage of the high-voltage DC power supply is uniformly reduced until the voltage drops to 0, and then the vertical displacement robot arm lowers the test platform and the sample to the potential measurement position; B4: The first lateral displacement mechanical arm starts to move, and the potentiometer is sent to the potential measurement position at a set distance from the sample. The camera in the rear window starts to work, and observes whether the position measured by the potentiometer on the sample is the expected potential measurement position, and takes a photo to observe whether there is a discharge mark on the surface of the sample. If there is no mark, it indicates that the surface flashover voltage and its waveform are correct. The potentiometer is used to measure the potential to obtain the surface potential of the sample and execute B5. If there is a mark, the use of the surface flashover voltage and its waveform is abandoned and the experiment is restarted in B1; B5: After the potential measurement is completed, the potentiometer is sent back to its original position by the first horizontal displacement robot arm, and the vertical displacement robot arm sends the test table and the sample back to their original positions; B6: discharge the metal tube, discharge the waste gas after the experiment into a dedicated waste gas treatment channel, then open the metal tank, switch the sample, seal the metal tank, use a vacuum pump to make the metal tank in a vacuum state, increase the pressure value of the SF6 gas filled into the metal tank and return to B2 until the experiment at the set final pressure value is completed, and the surface flashover voltage and sample surface potential at various pressures under positive voltage are measured; B7: Change the connected high-voltage DC power supply to negative polarity, and complete the measurement of the surface flashover voltage and the surface potential of the sample at various air pressures under negative voltage according to the methods of B1-B6.

6. A method for measuring surface discharge inception voltage and flashover voltage according to claim 3, characterized in that: The method for measuring the surface discharge starting voltage under the condition of charge injection specifically comprises the following steps: C1: Place the dried sample in the center of the test bench, seal the metal tank, use a vacuum pump to put the metal tank in a vacuum state, and fill the metal tank with gas of the set initial pressure value through the SF6 inflation and deflation device; C2: The vertical displacement robot arm lowers the sample table to the charge injection position, and the second lateral displacement robot arm moves the needle electrode to the charge injection position at a set distance from the sample; C3: Use a second power supply provided outside the needle electrode to power the needle electrode, set the charge injection amount and injection time, start injecting charge and wait for the charge injection to be completed; C4: After the charge injection is completed, the second lateral displacement mechanical arm moves the needle electrode to the original position, and the potentiometer is moved by the first lateral displacement mechanical arm to the potential measurement position at a set distance from the sample. The camera in the rear view window starts to work to observe whether the position measured by the potentiometer on the sample is the expected potential measurement position, measure the potential and judge whether the charge injection amount reaches the set value according to the potential. If so, execute C5, otherwise return to C3; C5: After completing the potential measurement, the potentiometer is sent back to its original position by the first lateral displacement mechanical arm; C6: Use the vertical displacement mechanical arm to raise the test bench to the experimental position, turn on the photomultiplier tube installed in front of the front window, make sure that the camera placed behind the rear window is in the off state, the cavity of the metal tank is in a dark environment, connect a positive high-voltage DC power supply at the high-voltage DC power supply inlet, provide high voltage on the sample through the high-voltage electrode, and uniformly increase the voltage of the high-voltage DC power supply to a certain voltage level. Photons begin to be emitted from the contact position between the high-voltage electrode and the surface of the sample. Use the photomultiplier tube to observe the light signal and convert it into an electrical signal. The electrical signal is transmitted to the oscilloscope. When a waveform is observed on the oscilloscope with triggering set, stop pressurizing. When the recording conditions are met, record the surface discharge starting voltage and its waveform. Otherwise, continue pressurizing until the recording conditions are met; C7: The voltage of the high-voltage DC power supply is uniformly reduced until the voltage drops to 0. The vertical displacement robot arm lowers the test table and the sample to the potential measurement position, and at the same time drives the light shield to fall and cover the front window to prevent the camera flash or other light sources from interfering and damaging the photomultiplier tube; C8: The first lateral displacement mechanical arm starts to move, and the potentiometer is sent to the potential measurement position at a set distance from the sample. The camera in the rear view window starts to work, and observes whether the position measured by the potentiometer on the sample is the expected potential measurement position, and takes a photo to observe whether there is a discharge mark on the surface of the sample. If there is no mark, it indicates that the surface discharge starting voltage and its waveform are correct. The potentiometer is used to measure the potential to obtain the surface potential of the sample and execute C9. If there is a mark, the use of the surface discharge starting voltage and its waveform is abandoned, and the return is returned to C1; C9: After completing the potential measurement, the potentiometer is sent back to its original position by the first lateral displacement robot arm, and the vertical displacement robot arm sends the test table and the sample back to their original positions; C10: discharge the metal tank, discharge the waste gas after the experiment into a dedicated waste gas treatment channel, close the photomultiplier tube, then open the metal tank, switch the sample, seal the metal tank, use a vacuum pump to put the metal tank in a vacuum state, increase the pressure value of the SF6 gas filled into the metal tank, and return to C2 until the experiment is completed at the set final pressure value, and complete the measurement of the surface discharge starting voltage and the surface potential of the sample at various pressures under positive voltage; C11: Change the connected high-voltage DC power supply to negative polarity, and complete the measurement of the surface discharge starting voltage and the surface potential of the sample at various gas pressures under negative voltage according to the methods of C1-C10.

7. A method for measuring surface discharge inception voltage and flashover voltage according to claim 3, characterized in that: The method for measuring the surface flashover voltage under the condition of charge injection specifically comprises the following steps: D1: Place the dried sample in the center of the test bench, seal the metal tank, use a vacuum pump to put the metal tank in a vacuum state, and fill the metal tank with SF6 gas of a set initial pressure value through the SF6 inflation and deflation device; D2: The vertical displacement robot lowers the sample table to the charge injection position, and the second lateral displacement robot moves the needle electrode to a set distance from the sample; D3: Use a second power supply provided outside the needle electrode to power the needle electrode, set the charge injection amount and injection time, start injecting charge and wait for the charge injection to be completed; D4: After the charge injection is completed, the second lateral displacement mechanical arm moves the needle electrode to the original position, and the potentiometer is moved by the first lateral displacement mechanical arm to the set distance from the sample. The camera in the rear window starts to work to observe whether the position measured by the potentiometer on the sample is the expected potential measurement position, measure the potential and judge whether the charge injection amount reaches the set value according to the potential. If so, execute D5, otherwise return to D3; D5: After completing the potential measurement, the potentiometer is sent back to its original position by the first lateral displacement mechanical arm; D6: Use the vertical displacement mechanical arm to raise the test table to the experimental position, connect a positive high-voltage DC power supply at the high-voltage DC power supply inlet, and the high-voltage electrode provides high voltage on the surface of the sample. The voltage of the high-voltage DC power supply is increased at a uniform speed. A waveform is observed on the triggered oscilloscope connected to the voltage divider, and the surface flashover voltage and its waveform can be recorded. D7: The voltage of the high-voltage DC power supply is uniformly reduced until the voltage drops to 0, and then the vertical displacement robot arm lowers the test table and the sample to the potential measurement position; D8: The first lateral displacement mechanical arm starts to move, and the potentiometer is sent to the potential measurement position at a set distance from the sample. The camera in the rear window starts to work, and observes whether the position measured by the potentiometer on the sample is the expected potential measurement position, and takes a photo to observe whether there is a discharge mark on the surface of the sample. If there is no mark, it indicates that the surface flashover voltage and its waveform are correct. The potentiometer is used to measure the potential to obtain the surface potential of the sample and execute D9. If there is a mark, the use of the surface flashover voltage and its waveform is abandoned and the experiment is restarted in D1. D9: After completing the potential measurement, the potentiometer is sent back to its original position by the first lateral displacement robot arm, and the vertical displacement robot arm sends the test table and the sample back to their original positions; D10: discharge the metal tube, discharge the waste gas after the experiment into a dedicated waste gas treatment channel, then open the metal tank, switch the sample, seal the metal tank, use a vacuum pump to make the metal tank in a vacuum state, and increase the pressure value of the SF6 gas filled into the metal tank and return to D2 until the experiment is completed at the set final pressure value, and complete the measurement of the surface flashover voltage and the surface potential of the sample at various pressures under positive voltage; D11: Change the connected high-voltage DC power supply to negative polarity, and complete the measurement of the surface flashover voltage and the surface potential of the sample at various air pressures under negative voltage according to the methods of D1-D10.

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