A detection device and method for evaluating the effect of x-rays on gas-solid insulation systems

Abstract

The application discloses a detection device and method for evaluating the influence of X-rays on gas-solid insulation systems, and the detection device comprises a working platform, an X-ray instrument, a high-voltage sleeve, a transition cavity, a test cylinder, an isolation insulator, a test fixing frame, a surface charge measuring mechanism, a sample positioning testing mechanism and a control mechanism, the high-voltage sleeve, the transition cavity and the test cylinder are sequentially and sealingly connected from top to bottom to form a complete cavity, the isolation insulator divides the complete cavity into two independent air chambers, the test fixing frame is located in the test cylinder, the surface charge measuring mechanism and the sample positioning testing mechanism are arranged on the test fixing frame, and the driving assemblies of the surface charge measuring mechanism and the sample positioning testing mechanism are connected with the control mechanism. The application simulates the real operation environment of GIS equipment, evaluates the influence of X-rays on the insulation performance of insulating dielectric, and lays a foundation for visual positioning of insulation defects in GIS equipment by X-rays.

Description

Technical Field

[0001] This invention relates to the field of high voltage and insulation technology, specifically to a detection device and method for evaluating the effect of X-rays on gas-solid insulation systems. Background Technology

[0002] Gas-Insulated Switchgear (GIS) houses key components such as circuit breakers, disconnectors, grounding switches, busbars, instrument transformers, and surge arresters within a sealed metal enclosure filled with sulfur hexafluoride (SF6) gas, which offers superior insulation. This design effectively reduces equipment size and floor space. Furthermore, due to its enclosed structure, the conductive parts are completely surrounded by the metal casing, preventing contact with the outside environment and ensuring the GIS is unaffected by external influences. This results in high operational reliability, minimal maintenance, and long repair cycles. Simultaneously, proper grounding shields the enclosure from radiation and electric field interference generated by the internal conductors, and also blocks noise generated during circuit breaker operation. Therefore, the GIS will not interfere with communication or radio equipment.

[0003] Although GIS equipment is generally considered to be maintenance-free or even maintenance-free, some insulation defects inevitably occur during manufacturing, transportation, installation, maintenance, and operation. These defects include metal burrs on conductors, loose components or poor contact, air gaps formed by the separation of conductors from supporting insulators, residues after maintenance, and metal particles within the cavity. These insulation defects gradually deteriorate during long-term operation, and when they reach a certain level, they can lead to partial discharge (PD) inside the GIS equipment. PD accelerates further damage to the internal insulation of the GIS equipment, ultimately causing insulation failures and power outages, seriously threatening the safe and stable operation of the power grid.

[0004] Because GIS equipment employs a closed, modular structure with complex internal components, existing PD discharge detection methods struggle to accurately pinpoint the specific faulty component and the extent of the defect. Furthermore, power outages for GIS maintenance result in significant economic losses. Therefore, multi-directional X-ray imaging of power equipment, combined with specialized image processing and recognition technologies, can visualize its internal structure and rapidly diagnose its operational status, greatly improving the accuracy of fault location and identification. However, due to the high transmissibility and energy of X-rays, they significantly affect SF6 gas and polymer dielectrics. Therefore, studying the impact of X-rays on insulating dielectrics is crucial for the widespread adoption and application of X-ray detection technology in power transmission and distribution equipment.

[0005] Gas-Insulated Switchgear (GIS) houses key components such as circuit breakers, disconnectors, grounding switches, busbars, instrument transformers, and surge arresters within a sealed metal enclosure filled with sulfur hexafluoride (SF6) gas, which offers superior insulation. This design effectively reduces equipment size and floor space. Furthermore, due to its enclosed structure, the conductive parts are completely surrounded by the metal casing, preventing contact with the outside environment and ensuring the GIS is unaffected by external influences. This results in high operational reliability, minimal maintenance, and long repair cycles. Simultaneously, proper grounding shields the enclosure from radiation and electric field interference generated by the internal conductors, and also blocks noise generated during circuit breaker operation. GIS does not interfere with communication or radio equipment. Since its introduction in the 1970s, GIS has experienced rapid development and has been widely adopted in power grids worldwide.

[0006] Although GIS (Gas Insulation System) is generally considered to be low-maintenance or even maintenance-free, based on decades of operational experience, some insulation defects inevitably occur during manufacturing, transportation, installation, maintenance, and operation. These defects include metal burrs on conductors, loose components or poor contact, air gaps formed by the separation of conductors from supporting insulators, residues after maintenance, and metal particles within the cavity. These insulation defects gradually deteriorate during long-term operation, and when they reach a certain level, they can lead to partial discharge (PD) inside the equipment. PD accelerates further damage to the internal insulation, ultimately causing insulation failures and power outages, seriously threatening the safe and stable operation of the power grid.

[0007] Because GIS (Gas Insulation System) uses a closed, modular structure with complex internal components, existing PD (Power Distribution) discharge detection methods struggle to accurately pinpoint the specific faulty component and the extent of the defect. Furthermore, power outages for GIS maintenance result in significant economic losses. Therefore, multi-directional X-ray imaging of power equipment, combined with specialized image processing and recognition technologies, can visualize the internal structure and rapidly diagnose the operational status of GIS equipment, greatly improving the accuracy of fault location and identification. However, due to the high transmissibility and energy of X-rays, they significantly affect SF6 gas and polymer dielectrics (insulating dielectrics). Therefore, studying the impact of X-rays on the insulating dielectrics within GIS equipment is crucial for the widespread adoption and application of X-ray detection technology in power transmission and distribution equipment. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a detection device and method for evaluating the impact of X-rays on gas-solid insulation systems, simulating the real operating environment of GIS equipment, evaluating the impact of X-rays on the insulation performance of insulating dielectrics, and laying the foundation for X-ray visualization and location of insulation defects in GIS equipment.

[0009] The technical solution of this invention is as follows:

[0010] A testing device for evaluating the effect of X-rays on a gas-solid insulation system includes a working platform, an X-ray instrument, a high-voltage bushing, a transition cavity, a test cylinder, an isolation insulator, a test fixture, a surface charge measuring mechanism, a sample positioning and testing mechanism, and a control mechanism.

[0011] The high-pressure bushing has a closed top and an open bottom. The transition cavity is a tubular structure that runs vertically through the tube. The test cylinder is a vertically arranged cross tube structure. The bottom of the high-pressure bushing is sealed and connected to the top of the transition cavity. The bottom of the transition cavity is sealed and connected to the top of the test cylinder. The bottom of the test cylinder is sealed and connected to the working platform. The two ends of the horizontal part of the test cylinder are sealed structures.

[0012] The high-voltage bushing has a central conductor fixed inside, and the transition cavity has an isolation insulator fixed inside. The central part of the isolation insulator is provided with a connecting conductor. The bottom end of the central conductor is connected to the top of the connecting conductor. The isolation insulator divides the inner cavity composed of the high-voltage bushing, the transition cavity, and the test cylinder into two separate air chambers.

[0013] The test fixture is located in the vertical part of the test cylinder and its bottom end is fixed to the working platform. The support base plate at the top of the test fixture extends horizontally into the horizontal part of the test cylinder. A surface charge measuring mechanism is connected to the support base plate in the horizontal part of the test cylinder.

[0014] The sample positioning test mechanism includes a sample positioning stage, a lifting high-voltage guide rod, a grounding electrode, two finger electrodes, and a three-electrode system. The sample positioning stage is fixed to a support base plate at the cross intersection of the test cylinder. The X-ray instrument is positioned outside the test cylinder and angled downwards towards the sample positioning stage. The lifting high-voltage guide rod is connected to the support base plate and located directly above the sample positioning stage. The grounding electrode and the two finger electrodes are both positioned on the sample positioning stage. The two finger electrodes are both inverted L-shaped structures, with their bottom ends fixed to the sample positioning stage and their horizontal ends facing each other. The three-electrode system includes a first flat plate electrode, a second flat plate electrode, and a ring electrode. The first flat plate electrode is positioned on the sample positioning stage. The ring electrode is concentrically arranged around the second flat plate electrode and insulated from it. The second flat plate electrode is connected to the bottom end of the lifting high-voltage guide rod. When the grounding electrode and the finger electrodes are not connected to the sample positioning stage, the three-electrode system is connected to the corresponding lifting high-voltage guide rod and the sample positioning stage for testing.

[0015] The drive components of the surface charge measurement mechanism and the lifting high-voltage guide rod are both connected to an external control mechanism.

[0016] The detection device also includes a mobile trolley, and the working platform is fixed on the mobile trolley.

[0017] The high-voltage bushing is a high-voltage SF6 gas insulating bushing. An SF6 gas washing pipeline is connected to the end of the horizontal section of the test cylinder. The SF6 gas washing pipeline includes a vacuum pipeline and an SF6 gas filling pipeline. A vacuum valve is installed on the vacuum pipeline, and a gas filling valve is installed on the SF6 gas filling pipeline. The inlet of the vacuum pipeline and the outlet of the SF6 gas filling pipeline are both connected to the end of the horizontal section of the test cylinder. The outlet of the vacuum pipeline is connected to a vacuum pump, and the inlet of the SF6 gas filling pipeline is connected to an SF6 gas tank.

[0018] The isolation insulator is a basin-type insulator, with the convex surface of the basin-type insulator facing the high-voltage bushing and the concave surface of the basin-type insulator facing the test cylinder; the top of the connecting conductor is provided with a slot, and the bottom of the center conductor extends into the slot and engages with the connecting conductor.

[0019] The surface charge measurement mechanism includes an XY-axis linear module, a probe clamp, and an electrostatic probe. The XY-axis linear module is fixed to a support base plate inside the horizontal part of the test cylinder and connected to a control mechanism. The probe clamp is fixedly connected to the end of the XY-axis linear module. The electrostatic probe is clamped and fixed to the probe clamp with its probe facing downwards. The electrostatic probe is connected to an electrometer located outside the test cylinder. The XY-axis linear module moves the electrostatic probe to directly above the sample positioning stage to collect the surface charge of the sample to be tested positioned on the sample positioning stage.

[0020] The test cylinder is connected to a horizontally arranged side cavity, which intersects the horizontal part of the test cylinder perpendicularly. Both ends of the side cavity are provided with terminals, and the surface charge measuring mechanism and the grounding wire connected to the sample positioning test mechanism are both connected to the terminals.

[0021] The lifting high-pressure guide rod includes an electric lifting rod, a horizontal connecting seat, and a high-pressure guide rod. The electric lifting rod is connected to the control mechanism. The bottom end of the electric lifting rod is a fixed end, and the top end is a lifting end. The bottom end of the electric lifting rod is fixed to the support base plate. The high-pressure guide rod is located directly above the sample positioning stage. The two ends of the horizontal connecting seat are fixedly connected to the top end of the electric lifting rod and the top end of the high-pressure guide rod, respectively.

[0022] A detection method for assessing the effect of X-rays on gas-solid insulation systems specifically includes the following steps:

[0023] (1) X-ray pretreatment: First, place the grounding electrode on the sample positioning stage and place the sample to be tested on the grounding electrode. Then, seal and connect the high-voltage bushing, the transition cavity, and the test cylinder in sequence and position them on the working platform. Fill the high-voltage bushing with SF6 gas and simultaneously perform SF6 gas washing on the test cylinder to fill it with SF6 gas. Finally, turn on the X-ray instrument and irradiate the sample to be tested with X-rays of a set intensity for a set time. Repeat the above steps to obtain multiple samples to be tested after X-ray irradiation treatment.

[0024] (2) Surface flashover and volume breakdown test: Before the test, the grounding electrode is placed on the sample positioning stage, and a sample to be tested after X-ray irradiation is placed on the grounding electrode. The center conductor inside the high-voltage bushing is connected to an external high-voltage DC power supply. The connecting conductor between the lifting high-voltage rod and the isolating insulator is connected by a wire. The control mechanism controls the lifting high-voltage rod to move down so that the bottom end of the lifting high-voltage rod contacts the sample to be tested. During the test, the test cylinder is kept in SF6 insulation. The sample to be tested is subjected to surface flashover or volume breakdown test by gradually increasing the voltage. The voltage of the high-voltage DC power supply is gradually increased from zero at a voltage increase rate of 0.5kV / s until the sample to be tested is broken down. At this time, the output of the high-voltage DC power supply is automatically cut off. During the test, the oscilloscope records the applied voltage of the high-voltage DC power supply and the discharge current on the grounding wire connected to the grounding electrode in real time. When the horizontal surface area of ​​the sample to be tested is large and the thickness is small, the volume breakdown test is performed. When the thickness of the sample to be tested is large and the horizontal surface area is small, the surface flashover test is performed.

[0025] (3) Surface charge accumulation detection test: Before the test, the grounding electrode is placed on the sample positioning stage, and a sample to be tested after being irradiated by X-ray is placed on the grounding electrode. The bottom ends of the vertical parts of the two finger electrodes are fixed to the sample positioning stage with insulating bolts and are located on the periphery of the sample to be tested. The horizontal parts of the two finger electrodes are in contact with the top surface of the sample to be tested. One finger electrode is connected to an external high-voltage DC power supply, and the other finger electrode is grounded. During the test, the test cylinder is kept in SF6 insulation. A DC voltage is applied to one of the finger electrodes. At the same time, the surface charge measurement mechanism is moved to the top of the sample to record the charge distribution on the surface of the sample at different times and obtain the surface charge evolution law of the sample at different times.

[0026] (4) SF6 gap breakdown test under different X-ray intensities: Before the test, the grounding electrode was placed on the sample positioning stage, and a test sample was placed on the grounding electrode. This test sample had not undergone X-ray pretreatment. The bottom ends of the vertical parts of the two finger electrodes were fixed to the sample positioning stage with insulating bolts and located on the periphery of the test sample. The horizontal parts of the two finger electrodes were in contact with the top surface of the test sample. One finger electrode was connected to an external high-voltage DC power supply, and the other finger electrode was grounded. During the test, the test cylinder was kept in SF6 insulation. The X-ray instrument was turned on and the test sample was irradiated with X-rays of a set intensity. At the same time, a DC voltage was applied to one of the finger electrodes, and the SF6 gap breakdown test was carried out on the test sample using the step-up voltage method. By replacing the test sample with a new one and irradiating different test samples with X-rays of different set intensities and carrying out SF6 gap breakdown test, the test results of the effect of different intensities of X-rays on gas gap breakdown were obtained.

[0027] (5) Volume conductivity and surface conductivity testing: Before the test, the first plate electrode is placed on the sample positioning stage, and a sample to be tested after X-ray irradiation is placed on the first plate electrode. The annular electrode is concentrically arranged around the second plate electrode and insulated from it. The second plate electrode is connected to the bottom end of the lifting high-voltage guide rod. The lifting high-voltage guide rod is moved down so that both the second plate electrode and the annular electrode are in contact with the top surface of the sample to be tested. During the test, the test cylinder is kept in an SF6 insulated state. When measuring the volume conductivity of the sample to be tested, the first plate electrode is placed on the sample positioning stage. The first plate electrode is connected to an external high-voltage DC power supply, the second plate electrode is grounded, and the third plate electrode is connected to an external electrometer. The leakage current of the sample is measured by the electrometer, and the volume conductivity of the sample is calculated based on the voltage of the high-voltage DC power supply and the leakage current. When measuring the surface conductivity of the sample, the second plate electrode is connected to an external high-voltage DC power supply, the third plate electrode is grounded, and the fourth plate electrode is connected to an external electrometer. The leakage current of the sample is measured by the electrometer, and the surface conductivity of the sample is calculated based on the voltage of the high-voltage DC power supply and the leakage current.

[0028] During the tests in steps (2)-(5), the pressure of SF6 gas inside the test cylinder is controlled at 0.1MPa-0.5MPa. The specific operation of SF6 gas washing is as follows: the test cylinder is connected to a vacuum pumping line and an SF6 gas filling line. Before filling with SF6 gas, the filling valve on the SF6 gas filling line is closed, and the vacuum valve on the vacuum pumping line and the vacuum pump connected to the vacuum pumping line are opened. After the inside of the test cylinder is evacuated to a vacuum, the vacuum valve and the vacuum pump are closed, and the filling valve is opened. The SF6 gas cylinder connected to the SF6 filling pipeline is used to fill the test cylinder with SF6 gas at a pressure of 0.1 MPa. The above operation is repeated to evacuate the test cylinder to a vacuum and fill it with SF6 gas at a pressure of 0.1 MPa. After repeating this operation three times, the SF6 gas washing operation is completed. After evacuating the test cylinder to a vacuum again, the vacuum valve and vacuum pump are closed, the filling valve and SF6 gas cylinder are opened, and SF6 gas is filled in, ensuring that the pressure of SF6 gas in the test cylinder is controlled at 0.1 MPa-0.5 MPa.

[0029] Advantages of this invention:

[0030] The present invention provides a complete cavity composed of a high-voltage bushing, a transition cavity, and a test cylinder to simulate the internal operating environment of GIS equipment, ensuring that the test environment of the testing device is more in line with the actual application environment of GIS equipment engineering, and improving the accuracy of the test results for evaluating the insulating dielectric inside GIS equipment;

[0031] The sample positioning and testing mechanism of this invention is a selectable and detachable structure. Depending on different test requirements, different lifting high-voltage conductors, grounding electrodes, finger electrodes, and three-electrode systems can be connected to complete surface flashover and bulk breakdown tests, surface charge accumulation tests, SF6 gap breakdown tests under different X-ray intensities, and bulk conductivity and surface conductivity tests on the tested sample, i.e., the insulating dielectric. This allows for the evaluation of the impact of X-rays on the insulating performance of the insulating dielectric, laying the foundation for X-ray visualization and positioning of insulation defects within GIS equipment. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the detection device of the present invention for conducting surface flashover and bulk breakdown detection tests.

[0033] Figure 2 yes Figure 1 A schematic diagram of the structure of the lifting high-voltage guide rod and surface charge measurement mechanism.

[0034] Figure 3 This is a schematic diagram of the structure of the detection device of the present invention, which uses finger-shaped electrodes for detection tests.

[0035] Figure 4 yes Figure 3 A schematic diagram of the middle finger-shaped electrode connected to the sample positioning stage.

[0036] Figure 5 This is a schematic diagram of the structure of the detection device of the present invention for conducting volume conductivity and surface conductivity detection tests.

[0037] Figure 6 yes Figure 5 A schematic diagram of the three-electrode system connected to the sample positioning stage.

[0038] Figure 7 This is a circuit connection diagram for the three-electrode system of the present invention to perform a bulk conductivity detection test.

[0039] Figure 8 This is a circuit connection diagram for surface conductivity detection experiments using the three-electrode system of this invention.

[0040] Figure reference numerals: 1-Mobile trolley, 2-Working platform, 3-X-ray machine, 4-High voltage bushing, 41-Center conductor, 5-Transition cavity, 6-Test cylinder, 7-Pot insulator, 71-Connecting conductor, 8-Test fixture, 9-Surface charge measuring mechanism, 91-XY axis linear module, 92-Probe clamp, 93-Electrostatic probe, 10-Sample positioning and testing mechanism, 101-Sample positioning stage, 102-Electric lifting rod, 103-Horizontal connecting seat, 1 04-High voltage guide rod, 105-Grounding electrode, 106-Finger electrode, 107-First flat plate electrode, 108-Second flat plate electrode, 109-Ring electrode, 111-Vacuum pump line, 112-SF6 filling line, 113-Vacuum valve, 114-Filling valve, 115-Vacuum pump, 116-SF6 gas tank, 12-Side cavity, 13-Terminal, 14-Support base plate, 15-Sample under test, 16-High voltage DC power supply, 17-Electrometer. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] See Figures 1-6 A testing device for evaluating the effect of X-rays on a gas-solid insulation system includes a mobile trolley 1, a working platform 2, an X-ray instrument 3, a high-voltage bushing 4, a transition cavity 5, a test cylinder 6, a basin insulator 7, a test fixing frame 8, a surface charge measuring mechanism 9, a sample positioning and testing mechanism 10, and a control mechanism. The working platform 2 is fixed on the mobile trolley 1.

[0043] The high-voltage bushing 4 is a high-voltage SF6 gas insulating bushing. The top of the high-voltage bushing 4 is a closed structure, and the bottom is an open structure. The transition cavity 5 is a tubular structure running vertically through the interior. The test cylinder 6 is a vertically arranged cross-shaped tube structure. The bottom of the high-voltage bushing 4 is sealed and connected to the top of the transition cavity 5, and the bottom of the transition cavity 5 is sealed and connected to the top of the test cylinder 6. The bottom of the test cylinder 6 is sealed and connected to the working platform 2. The two ends of the horizontal section of the test cylinder 6 are sealed structures. One end of the horizontal section of the test cylinder 6 is connected to an SF6 gas washing pipeline. The SF6 gas washing pipeline includes a vacuum line 111 and an SF6 gas filling line 112. A vacuum valve 113 is provided on the test cylinder 6, and an inflation valve 114 is provided on the SF6 inflation pipeline 112. The air inlet of the vacuum pipeline 111 and the air outlet of the SF6 inflation pipeline 112 are both connected to one end of the horizontal part of the test cylinder 6. The air outlet of the vacuum pipeline 111 is connected to the vacuum pump 115, and the air inlet of the SF6 inflation pipeline 116 is connected to the SF6 gas tank 116. A horizontally arranged side cavity 12 is connected to the test cylinder 6. The side cavity 12 intersects the horizontal part of the test cylinder 6 perpendicularly. Both ends of the side cavity 12 are provided with terminals 13. The surface charge measuring mechanism 9 and the grounding wire connected to the sample positioning test mechanism 10 are both connected to the terminals 13.

[0044] A center conductor 41 is fixed inside the high-voltage bushing 4, and a basin-type insulator 7 is fixed inside the transition cavity 5. The convex surface of the basin-type insulator 7 faces the high-voltage bushing 4, and the concave surface of the basin-type insulator 7 faces the test cylinder 6. The basin-type insulator 7 divides the inner cavity composed of the high-voltage bushing 4, the transition cavity 5, and the test cylinder 6 into two separate air chambers. A connecting conductor 71 is provided in the center part of the basin-type insulator 7. A slot is provided at the top of the connecting conductor 71, and the bottom of the center conductor 41 extends into the slot and engages with the connecting conductor 71.

[0045] The test fixture 8 is located in the vertical part of the test cylinder 6 and its bottom end is fixed on the working platform 2. The support base plate 14 at the top of the test fixture 8 extends horizontally into the horizontal part of the test cylinder 6. A surface charge measuring mechanism 9 is connected to the support base plate 14 located in the horizontal part of the test cylinder 6.

[0046] The surface charge measurement mechanism 9 includes an XY-axis linear module 91, a probe clamp 92, and an electrostatic probe 93. The XY-axis linear module 91 is fixed on the support base plate 14 inside the horizontal part of the test cylinder and connected to an external control mechanism. The probe clamp 92 is fixedly connected to the end of the XY-axis linear module 91. The electrostatic probe 93 is clamped and fixed on the probe clamp 92 with its probe facing downward. The electrostatic probe 93 is connected to an electrometer located outside the test cylinder 6. The XY-axis linear module 91 moves the electrostatic probe 93 to directly above the sample positioning test mechanism 10 to collect the surface charge of the sample 15 positioned on the sample positioning test mechanism 10.

[0047] The sample positioning test mechanism 10 includes a sample positioning stage 101, a lifting high-voltage guide rod, a grounding electrode 105, two finger electrodes 106, and a three-electrode system 106. The sample positioning stage 101 is fixed on the support base plate 14 at the cross intersection of the test cylinder 6. The X-ray instrument 3 is located outside the test cylinder 6 and faces downwards towards the sample positioning stage 101. The lifting high-voltage guide rod includes an electric lifting rod 102, a horizontal connecting seat 103, and a high-voltage guide rod 104. The electric lifting rod 102 is connected to an external control mechanism. The bottom end of the electric lifting rod 102 is a fixed end, and the top end is a lifting end. The bottom end of the electric lifting rod 102 is fixed on the support base plate 14. The high-voltage guide rod 104 is located directly above the sample positioning stage 101. The two ends of the horizontal connecting seat 103 are respectively fixed to the top end of the electric lifting rod 102 and the top end of the high-voltage guide rod 104. The three-electrode system consists of a ground electrode 105 and two finger electrodes 106, both of which are mounted on the sample positioning stage 101. The two finger electrodes 106 are inverted L-shaped structures, with their bottom ends fixed to the sample positioning stage 101 and their horizontal ends facing each other. The three-electrode system includes a first flat plate electrode 107, a second flat plate electrode 108, and a ring electrode 109. The first flat plate electrode 107 is mounted on the sample positioning stage 101, and the ring electrode 109 is concentrically arranged around the second flat plate electrode 108 and insulated from it. The second flat plate electrode 108 is connected to the bottom end of the high-voltage guide rod 104. When the ground electrode 105 and finger electrodes 106 are not connected to the sample positioning stage 101, the three-electrode system is connected to the corresponding high-voltage guide rod 104 and the sample positioning stage 101 for testing.

[0048] A detection method for assessing the effect of X-rays on gas-solid insulation systems specifically includes the following steps:

[0049] (1) See Figure 1X-ray pretreatment: First, place the grounding electrode 105 on the sample positioning stage 101, and place the sample to be tested 15 on the grounding electrode 105. Then, seal and connect the high-voltage bushing 4, the transition cavity 5, and the test cylinder 6 in sequence and position them on the working platform 2. Inject SF6 gas into the high-voltage bushing 4, and simultaneously perform SF6 gas washing on the test cylinder 6 to fill it with SF6 gas. Finally, turn on the X-ray instrument 3 and irradiate the sample to be tested 15 with X-rays of a set intensity for a set time. Repeat the above steps to obtain multiple samples after X-ray irradiation treatment. The specific operation of SF6 gas washing is as follows: before injecting SF6 gas, close the gas filling valve 114 and turn on the vacuum pump. After the test cylinder 6 is evacuated to a vacuum using valve 113 and vacuum pump 115, the vacuum valve 113 and vacuum pump 115 are closed, and the gas filling valve 114 and the outlet valve of the SF6 gas tank 116 are opened to fill it with SF6 gas at a pressure of 0.1 MPa. The above operation is repeated to evacuate the test cylinder 6 to a vacuum and fill it with SF6 gas at a pressure of 0.1 MPa. After repeating this operation three times, the SF6 gas washing operation is completed. After evacuating the test cylinder 6 to a vacuum again, the vacuum valve 113 and vacuum pump 115 are closed, and the gas filling valve 114 and the outlet valve of the SF6 gas tank 116 are opened to fill it with SF6 gas according to the test conditions, ensuring that the pressure of the SF6 gas in the test cylinder 6 is controlled at 0.1 MPa-0.5 MPa.

[0050] (2) See Figure 1 and Figure 2 Surface flashover and bulk breakdown tests: Before the test, the grounding electrode 105 is placed on the sample positioning stage 101, and a test sample 15, which has been treated with X-ray irradiation, is placed on the grounding electrode 105. The center conductor 41 inside the high-voltage bushing 4 is connected to an external high-voltage DC power supply. The high-voltage guide rod 104 is connected to the connecting conductor 71 of the basin insulator 7 through a wire. The electric lifting rod 102 drives the high-voltage guide rod 104 to move down, so that the bottom end of the high-voltage guide rod 104 contacts the test sample 15. During the test, the pressure of SF6 gas in the test cylinder 6 is controlled at 0.1MPa-0.5MPa. The surface flashover test of the test sample 15 is carried out by the step-up method. The voltage of the high-voltage DC power supply is gradually increased from zero at a step-up rate of 0.5kV / s until the test sample 15 is broken down. At this time, the output of the high-voltage DC power supply is automatically cut off. During the test, the oscilloscope records the applied voltage of the high-voltage DC power supply and the discharge current on the grounding wire connected to the grounding electrode in real time.

[0051] (3) See Figure 3 and Figure 4Surface charge accumulation detection test: Before the test, the grounding electrode 105 is placed on the sample positioning stage 101, and a test sample 15, which has been treated with X-ray irradiation, is placed on the grounding electrode 105. The bottom ends of the vertical parts of the two finger electrodes 106 are fixed to the sample positioning stage 101 with insulating bolts and are symmetrically arranged around the test sample 15. The horizontal parts of the two finger electrodes 106 are in contact with the top surface of the test sample 15. One finger electrode 106 is connected to an external high-voltage DC power supply, and the other finger electrode 106 is grounded. During the test, the pressure of SF6 gas in the test cylinder 6 is controlled at 0.1MPa-0.5MPa. A DC voltage is applied to one of the finger electrodes 106. At the same time, the electrostatic probe 93 of the surface charge measurement mechanism is moved to the top of the test sample 15 to record the charge distribution on the surface of the test sample 15 at different times, and to obtain the surface charge evolution law of the test sample 15 at different times.

[0052] (4) See Figure 3 and Figure 4 SF6 gap breakdown test under different X-ray intensities: Before the test, the grounding electrode 105 is placed on the sample positioning stage 101, and a test sample is placed on the grounding electrode 16. This test sample 15 has not undergone X-ray pretreatment. The bottom ends of the vertical parts of the two finger electrodes 106 are fixed to the sample positioning stage 101 with insulating bolts and are symmetrically arranged around the test sample 15. The horizontal parts of the two finger electrodes 106 are in contact with the top surface of the test sample 15. One finger electrode 106 is connected to an external high-voltage DC power supply, and the other finger electrode 106 is grounded. During the experiment, the pressure of SF6 gas inside the test cylinder 6 was controlled at 0.1MPa-0.5MPa. The X-ray instrument 3 was turned on and the sample 15 was irradiated with X-rays of a set intensity. At the same time, a DC voltage was applied to one of the finger electrodes 106, and the SF6 gap breakdown test was carried out on the sample 15 using a step-up voltage method. By replacing the sample 15 with a new one and irradiating different samples 15 with X-rays of different set intensities and carrying out SF6 gap breakdown tests, the experimental results of the effect of X-rays of different intensities on gas gap breakdown were obtained.

[0053] (5) See Figure 5 and Figure 6Volume conductivity and surface conductivity testing: Before the test, the first plate electrode 107 is placed on the sample positioning stage 101. A test sample 15, after being treated with X-rays, is placed on the first plate electrode 107. The annular electrode 109 is concentrically arranged around the second plate electrode 108 and insulated from it. The second plate electrode 108 is connected to the bottom end of the high-voltage guide rod 104. The high-voltage guide rod 104 is moved down so that both the second plate electrode 108 and the annular electrode 109 are in contact with the top surface of the test sample 15. During the test, the pressure of SF6 gas inside the test cylinder 6 is controlled at 0.1MPa-0.5MPa. See Figure 7 When measuring the bulk conductivity of the sample 15, the first plate electrode 107 is connected to an external high-voltage DC power supply 16, the ring electrode 109 is grounded, and the second plate electrode 108 is connected to an external electrometer 17. The leakage current of the sample 15 is measured by the electrometer 17, and the bulk conductivity of the sample 15 is calculated based on the voltage of the high-voltage DC power supply and the leakage current. See [link to relevant documentation]. Figure 8 When measuring the surface conductivity of the sample 15, the ring electrode 109 is connected to an external high-voltage DC power supply 16, the second plate electrode 108 is grounded, and the first plate electrode 107 is connected to an external electrometer 17. The leakage current of the sample 15 is measured by the electrometer 17, and the surface conductivity of the sample 15 is calculated based on the voltage of the high-voltage DC power supply and the leakage current.

[0054] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A detection device for evaluating the effect of X-rays on a gas-solid insulation system, characterized in that: It includes a working platform, X-ray instrument, high-voltage bushing, transition cavity, test cylinder, isolation insulator, test fixture, surface charge measurement mechanism, sample positioning and testing mechanism, and control mechanism; The high-pressure bushing has a closed top and an open bottom. The transition cavity is a tubular structure that runs vertically through the tube. The test cylinder is a vertically arranged cross tube structure. The bottom of the high-pressure bushing is sealed and connected to the top of the transition cavity. The bottom of the transition cavity is sealed and connected to the top of the test cylinder. The bottom of the test cylinder is sealed and connected to the working platform. The two ends of the horizontal part of the test cylinder are sealed structures. The high-voltage bushing has a central conductor fixed inside, and the transition cavity has an isolation insulator fixed inside. The central part of the isolation insulator is provided with a connecting conductor. The bottom end of the central conductor is connected to the top of the connecting conductor. The isolation insulator divides the inner cavity composed of the high-voltage bushing, the transition cavity, and the test cylinder into two separate air chambers. The test fixture is located in the vertical part of the test cylinder and its bottom end is fixed to the working platform. The support base plate at the top of the test fixture extends horizontally into the horizontal part of the test cylinder. A surface charge measuring mechanism is connected to the support base plate in the horizontal part of the test cylinder. The sample positioning test mechanism includes a sample positioning stage, a lifting high-voltage guide rod, a grounding electrode, two finger electrodes, and a three-electrode system. The sample positioning stage is fixed to a support base plate at the cross intersection of the test cylinder. The X-ray instrument is positioned outside the test cylinder and angled downwards towards the sample positioning stage. The lifting high-voltage guide rod is connected to the support base plate and located directly above the sample positioning stage. The grounding electrode and the two finger electrodes are both positioned on the sample positioning stage. The two finger electrodes are both inverted L-shaped structures, with their bottom ends fixed to the sample positioning stage and their horizontal ends facing each other. The three-electrode system includes a first flat plate electrode, a second flat plate electrode, and a ring electrode. The first flat plate electrode is positioned on the sample positioning stage. The ring electrode is concentrically arranged around the second flat plate electrode and insulated from it. The second flat plate electrode is connected to the bottom end of the lifting high-voltage guide rod. When the grounding electrode and the finger electrodes are not connected to the sample positioning stage, the three-electrode system is connected to the corresponding lifting high-voltage guide rod and the sample positioning stage for testing. The drive components of the surface charge measurement mechanism and the lifting high-voltage guide rod are both connected to an external control mechanism.

2. The detection device for evaluating the effect of X-rays on a gas-solid insulation system according to claim 1, characterized in that: The detection device also includes a mobile trolley, and the working platform is fixed on the mobile trolley.

3. The detection device for evaluating the effect of X-rays on a gas-solid insulation system according to claim 2, characterized in that: The high-voltage bushing is a high-voltage SF6 gas insulating bushing. An SF6 gas washing pipeline is connected to the end of the horizontal section of the test cylinder. The SF6 gas washing pipeline includes a vacuum pipeline and an SF6 gas filling pipeline. A vacuum valve is installed on the vacuum pipeline, and a gas filling valve is installed on the SF6 gas filling pipeline. The inlet of the vacuum pipeline and the outlet of the SF6 gas filling pipeline are both connected to the end of the horizontal section of the test cylinder. The outlet of the vacuum pipeline is connected to a vacuum pump, and the inlet of the SF6 gas filling pipeline is connected to an SF6 gas tank.

4. The detection device for evaluating the effect of X-rays on a gas-solid insulation system according to claim 3, characterized in that: The isolation insulator is a basin-type insulator, with the convex surface of the basin-type insulator facing the high-voltage bushing and the concave surface of the basin-type insulator facing the test cylinder; the top of the connecting conductor is provided with a slot, and the bottom of the center conductor extends into the slot and engages with the connecting conductor.

5. The detection device for evaluating the effect of X-rays on a gas-solid insulation system according to claim 4, characterized in that: The surface charge measurement mechanism includes an XY-axis linear module, a probe clamp, and an electrostatic probe. The XY-axis linear module is fixed to a support base plate inside the horizontal part of the test cylinder and connected to a control mechanism. The probe clamp is fixedly connected to the end of the XY-axis linear module. The electrostatic probe is clamped and fixed to the probe clamp with its probe facing downwards. The electrostatic probe is connected to an electrometer located outside the test cylinder. The XY-axis linear module moves the electrostatic probe to directly above the sample positioning stage to collect the surface charge of the sample to be tested positioned on the sample positioning stage.

6. The detection device for evaluating the effect of X-rays on a gas-solid insulation system according to claim 5, characterized in that: The test cylinder is connected to a horizontally arranged side cavity, which intersects the horizontal part of the test cylinder perpendicularly. Both ends of the side cavity are provided with terminals, and the surface charge measuring mechanism and the grounding wire connected to the sample positioning test mechanism are both connected to the terminals.

7. A detection device for evaluating the effect of X-rays on a gas-solid insulation system according to claim 6, characterized in that: The lifting high-pressure guide rod includes an electric lifting rod, a horizontal connecting seat, and a high-pressure guide rod. The electric lifting rod is connected to the control mechanism. The bottom end of the electric lifting rod is a fixed end, and the top end is a lifting end. The bottom end of the electric lifting rod is fixed to the support base plate. The high-pressure guide rod is located directly above the sample positioning stage. The two ends of the horizontal connecting seat are fixedly connected to the top end of the electric lifting rod and the top end of the high-pressure guide rod, respectively.

8. The detection method for evaluating the influence of X-rays on a gas-solid insulation system using the detection device according to claim 7, characterized in that: Specifically, it includes the following steps: (1) X-ray pretreatment: First, place the grounding electrode on the sample positioning stage, place the sample to be tested on the grounding electrode, then seal and connect the high-voltage bushing, the transition cavity and the test cylinder in sequence and position them on the working platform, fill the high-voltage bushing with SF6 gas, and at the same time perform SF6 gas washing operation on the test cylinder so that the test cylinder is filled with SF6 gas, and finally turn on the X-ray instrument and use X-rays of set intensity to irradiate the sample to be tested for a set time. Repeat the above steps to obtain multiple test samples after X-ray irradiation. (2) Surface flashover and volume breakdown test: Before the test, the grounding electrode is placed on the sample positioning stage, and a test sample that has been treated with X-ray is placed on the grounding electrode. The center conductor inside the high voltage bushing is connected to an external high voltage DC power supply. The connecting conductor between the lifting high voltage rod and the isolation insulator is connected by a wire. The control mechanism controls the lifting high voltage rod to move down so that the bottom end of the lifting high voltage rod contacts the test sample. During the test, the test cylinder is kept in SF6 insulation. The test sample is subjected to surface flashover or volume breakdown test by gradually increasing the voltage. The voltage of the high voltage DC power supply is gradually increased from zero at a voltage increase rate of 0.5 kV / s until the test sample is broken down. At this time, the output of the high voltage DC power supply is automatically cut off. During the test, the oscilloscope records the applied voltage of the high voltage DC power supply and the discharge current on the grounding wire connected to the grounding electrode in real time. (3) Surface charge accumulation detection test: Before the test, the grounding electrode is placed on the sample positioning stage, and a sample to be tested after being irradiated by X-ray is placed on the grounding electrode. The bottom ends of the vertical parts of the two finger electrodes are fixed to the sample positioning stage with insulating bolts and are located on the periphery of the sample to be tested. The horizontal parts of the two finger electrodes are in contact with the top surface of the sample to be tested. One finger electrode is connected to an external high voltage DC power supply, and the other finger electrode is grounded. During the test, the test cylinder is kept in SF6 insulation. A DC voltage is applied to one of the finger electrodes. At the same time, the surface charge measuring mechanism is moved to the top of the sample to record the charge distribution on the surface of the sample at different times and obtain the surface charge evolution law of the sample at different times. (4) SF6 gap breakdown test under different X-ray intensities: Before the test, the grounding electrode was placed on the sample positioning stage, and a test sample was placed on the grounding electrode. This test sample had not been pretreated by X-ray. The bottom ends of the vertical parts of the two finger electrodes were fixed to the sample positioning stage with insulating bolts and located on the periphery of the test sample. The horizontal parts of the two finger electrodes were in contact with the top surface of the test sample. One finger electrode was connected to an external high-voltage DC power supply, and the other finger electrode was grounded. During the test, the test cylinder was kept in SF6 insulation. The X-ray instrument was turned on and the test sample was irradiated with X-rays of a set intensity. At the same time, a DC voltage was applied to one of the finger electrodes, and the SF6 gap breakdown test was carried out on the test sample using the step-up voltage method. By replacing the test sample with a new one and irradiating different test samples with X-rays of different set intensities and carrying out SF6 gap breakdown test, the test results of the effect of different intensities of X-rays on gas gap breakdown were obtained. (5) Volume conductivity and surface conductivity testing: Before the test, the first plate electrode is placed on the sample positioning stage, and a sample to be tested after X-ray irradiation is placed on the first plate electrode. The annular electrode is concentrically arranged around the second plate electrode and insulated from it. The second plate electrode is connected to the bottom end of the lifting high-voltage guide rod. The lifting high-voltage guide rod is moved down so that both the second plate electrode and the annular electrode are in contact with the top surface of the sample to be tested. During the test, the test cylinder is kept in an SF6 insulated state. When measuring the volume conductivity of the sample to be tested, the first plate electrode is placed on the sample positioning stage. The first plate electrode is connected to an external high-voltage DC power supply, the second plate electrode is grounded, and the third plate electrode is connected to an external electrometer. The leakage current of the sample is measured by the electrometer, and the volume conductivity of the sample is calculated based on the voltage of the high-voltage DC power supply and the leakage current. When measuring the surface conductivity of the sample, the second plate electrode is connected to an external high-voltage DC power supply, the third plate electrode is grounded, and the fourth plate electrode is connected to an external electrometer. The leakage current of the sample is measured by the electrometer, and the surface conductivity of the sample is calculated based on the voltage of the high-voltage DC power supply and the leakage current.

9. The detection method according to claim 8, characterized in that: During the tests in steps (2)-(5), the pressure of SF6 gas inside the test cylinder is controlled at 0.1MPa-0.5MPa. The specific operation of SF6 gas washing is as follows: the test cylinder is connected to a vacuum pumping line and an SF6 gas filling line. Before filling with SF6 gas, the filling valve on the SF6 gas filling line is closed, and the vacuum valve on the vacuum pumping line and the vacuum pump connected to the vacuum pumping line are opened. After the inside of the test cylinder is evacuated to a vacuum, the vacuum valve and the vacuum pump are closed, and the filling valve is opened. The SF6 gas cylinder connected to the SF6 filling pipeline is used to fill the test cylinder with SF6 gas at a pressure of 0.1 MPa. The above operation is repeated to evacuate the test cylinder to a vacuum and fill it with SF6 gas at a pressure of 0.1 MPa. After repeating this operation three times, the SF6 gas washing operation is completed. After evacuating the test cylinder to a vacuum again, the vacuum valve and vacuum pump are closed, the filling valve and SF6 gas cylinder are opened, and SF6 gas is filled in, ensuring that the pressure of SF6 gas in the test cylinder is controlled at 0.1 MPa-0.5 MPa.

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