Clamp and device for testing flashover breakdown voltage along surface of sheet-shaped insulating material

Abstract

The utility model discloses a sheet insulating material surface flashover breakdown voltage test clamp and device, and belongs to the technical field of flashover breakdown voltage test clamps and devices thereof. On the basis of the lever balance principle, the thrust ball bearings are used at a plurality of joints, so that the electrodes can be adaptively adjusted according to the compression condition, the interface pressure of the two electrodes is always kept consistent, the single electrode can be ensured to be attached to the surface of a sample to the greatest extent, and the test efficiency is improved. And the two electrodes can share the same pressure at the same time, so that the consistency of condition control in the test process is improved, and the comparability of test results of different experimenters is ensured. Besides, the problems that gaps exist between the electrodes and the sample due to the problems that the thickness of the to-be-tested sample is not uniform or the surface roughness is large, and the stress conditions of the two electrodes are difficult to keep consistent are solved.

Description

Technical Field

[0001] The utility model relates to a test fixture and a device for surface flashover breakdown voltage of a sheet-shaped insulating material, belonging to the technical field of a test fixture and a device for surface flashover breakdown voltage. Background Art

[0002] High-voltage insulation materials refer to materials used for insulation protection in high-voltage power equipment and systems. With the rapid development of the high-voltage power transmission industry, higher requirements are placed on the voltage resistance of high-voltage insulation materials. In insulating equipment with complex structures, such as gas-insulated enclosed switchgear, composite insulators, pot-type insulators, etc., there are usually multiple gas-solid interfaces. The surface flashover breakdown voltage of the interface is usually much lower than the breakdown voltage of a pure air gap, so it is more likely to produce partial discharge, which in turn causes serious damage to power equipment. Therefore, the gas-solid interface is the weak link in this type of insulation structure, and increasing the surface flashover breakdown voltage is the key to improving the working reliability of high-voltage power equipment.

[0003] In the experimental study of flashover along the gas-solid interface, there are many types of electrodes to choose from, such as needle-needle electrode, needle-plate electrode, plate-plate electrode, finger electrode, etc. Among them, the finger electrode has the advantage of being easy to measure samples of different materials, thicknesses, and sizes, and is suitable for surface flashover experiments in a gas environment. However, the existing finger electrode device for measuring the breakdown voltage along the surface flashover still has many problems: ① It is difficult to monitor the contact pressure between the electrode and the material interface in real time; ② It is difficult to accurately control the contact pressure between the electrode and the material; ③ It is impossible to ensure the consistency of the pressure between the high-voltage electrode and the grounding electrode and the material interface.

[0004] For materials with different elastic moduli, it is necessary to properly adjust the contact pressure between the electrode and the material, and to accurately measure and control the pressure to ensure that the finger-shaped electrode is in close contact with the material. Only then can the measured surface discharge results be repeatable. Otherwise, if the pressure at the interface between the electrode and the material cannot be monitored, adjusted, or is asymmetric, it will inevitably affect the experimental results and data analysis. Summary of the invention

[0005] In order to further improve the controllability of a surface flashover experiment, the utility model provides a fixture and a device for testing the surface flashover breakdown voltage of a sheet-like insulating material.

[0006] The technical solution of this utility model:

[0007] One of the purposes of the utility model is to provide a surface flashover breakdown voltage test fixture for sheet-like insulating materials, which includes a base 1, a frame, a pressure sensing system, a balance system 4, a finger-shaped electrode 5 and a lifting platform 6; the frame is fixed on the base 1, and is composed of an upper beam 2-1, a lower beam 2-2 and a column 2-3 connected to both ends of the upper beam 2-1 and the lower beam 2-2; the pressure sensing system includes a pressure sensor 3-1 and a force block 3-2, the pressure sensor 3-1 is fixedly connected to the upper beam 2-1, the two sides of the force block 3-2 are hinged to the upper beam 2-1 through a connecting rod structure, and the lower part of the force block 3-2 is connected to the upper end of the balance system 4 through a universal joint 3-3; the lower end of the balance system 4 is connected to the finger-shaped electrode 5 through a metal block 9; the lifting platform 6 is connected to the lower beam 2-2 through a lead screw 7;

[0008] The sheet-like insulating material sample 8 to be tested is located on the lifting platform 6, and two finger-shaped electrodes 5 are located at two points on the surface of the sheet-like insulating material sample 8 with a certain insulation distance, and the two finger-shaped electrodes 5 are respectively connected to the high voltage end and the ground end of the AC and DC high voltage power supply.

[0009] It is further defined that the pressure sensor 3-1 is a planar diaphragm box type force sensor, which is fixedly mounted on the upper beam 2-1, and the force-bearing surface is located below the upper beam 2-1; the force block 3-2 is a cylinder with an arc-shaped convex upper surface, and one end of the universal joint 3-3 is fixed to the lower surface of the force block 3-2; mounting supports are symmetrically arranged on both sides of the column of the force block 3-2, and the mounting supports are suspended on the upper beam 2-1 by being hinged to a connecting rod structure formed by a plurality of connecting rods, and are located directly below the force-bearing surface of the pressure sensor 3-1.

[0010] It is further defined that the balancing system 4 includes an upper base 4-1 and a lower base 4-2 made of insulating materials, and four support rods 4-3 connected to the upper base 4-1 and the lower base 4-2 at both ends of the same side through thrust ball bearings 4-4; a metal block 9 is installed between two support rods 4-3 located on different sides of the upper base 4-1 and the lower base 4-2 and in opposite positions.

[0011] It is further defined that the upper base 4-1 is a cuboid with a square through slot in the center, and the other end of the universal joint 3-3 is rotatably mounted at the center of the square through slot in the upper base 4-1.

[0012] It is further defined that the finger electrode 5 includes a finger electrode end 5-1 and a mounting end 5-2, and the metal block 9 is connected to the mounting end 5-2 through a thrust ball bearing 4-4.

[0013] It is further defined that the two finger electrodes 5 are placed opposite to each other with a spacing of 10 mm.

[0014] It is further defined that the lifting platform 6 includes, from top to bottom, a sample placement plate 7-1, a first connecting plate 7-2, a cross roller bearing 7-3 and a second connecting plate 7-4; the first connecting plate 7-2 is annular, the circular plate-shaped sample placement plate 7-1 is connected to the first connecting plate 7-2 by bolts, the first connecting plate 7-2 is connected to the outer ring of the cross roller bearing 7-3 by bolts, the second connecting plate 7-4 is connected to the inner ring of the cross roller bearing 7-3 by bolts, and the center of the second connecting plate 7-4 is fixedly connected to one end of the screw 7.

[0015] It is further defined that the other end of the lead screw 7 passes through the lower cross beam 2 - 2 and is connected to the handle 10 , and the movement and fixation of the lead screw 7 are achieved by means of a copper nut 11 and a locking screw 12 .

[0016] It is further defined that the lead screw 7 is fitted with the copper nut 11 through threaded cooperation, and the copper nut 11 is fixed on the lower cross beam 2 - 2 and is equipped with a locking screw 12 .

[0017] It is further defined that a horizontal plate and a pressure display screen of the pressure sensor 3-1 are installed above the upper crossbeam 2-1.

[0018] The second purpose of the utility model is to provide a device for testing the surface flashover breakdown voltage of a sheet-like insulating material, which comprises the above-mentioned fixture for testing the surface flashover breakdown voltage of a sheet-like insulating material, an AC / DC high-voltage power supply, an oscilloscope and a computer.

[0019] It is further defined that the computer and the oscilloscope use a network port output transmission, and the oscilloscope extracts and records the current flowing through the sheet-like insulating material sample 8 to be tested and the voltage at both ends.

[0020] Beneficial effects:

[0021] (1) The surface flashover breakdown voltage test fixture for sheet-like insulating materials provided by the utility model is based on the lever balance principle and uses thrust ball bearings at multiple joints to ensure that the electrodes can be adaptively adjusted according to the pressure conditions, so that the interface pressure of the two electrodes is always consistent, which can not only ensure that a single electrode can fit the sample surface to the greatest extent, but also ensure that the two electrodes share the same amount of pressure at the same time, thereby improving the consistency of the control of the test process conditions and ensuring the comparability of the test results of different experimenters. In addition, it avoids the problem that there is a gap between the electrode and the sample due to uneven thickness or large surface roughness of the sample to be tested, and the pressure conditions of the two electrodes are difficult to keep consistent.

[0022] (2) The sheet-like insulating material surface flashover breakdown voltage test fixture provided by the utility model is equipped with a force sensor and a real-time display screen, which can make the surface flashover test be carried out under the specified electrode pressure conditions. For example, assuming that the test is carried out under a pressure of 0.1 MPa, the sum of the areas of the two electrodes on the drawing is known to be 678 mm 2 According to the pressure formula: P = F / S, the pressure required to maintain a pressure of 0.1MPa is calculated to be 67.8N. According to the gravity formula F = mg, g is taken as 9.8N / kg, and the applied force is calculated to be 6.92kg. By rotating the lifting platform handle to raise the platform and apply pressure, the platform is locked when the displayed value is 6.92kg, and the experiment can be carried out under the specified pressure (if the electrode is replaced or the experiment is carried out under other pressures, the same method is used for calculation). In addition, since the pressure sensor and the two electrodes are connected by an insulating structure, the pressure sensor will not be affected by high voltage or strong electric field during the entire experiment. Therefore, during the high voltage application process, the pressure sensor can still work normally and collect and display the interface pressure changes during the entire test process in real time. For some materials with good elasticity, such as plastics, rubber, fiberboard, etc., the mechanical relaxation behavior of the material during the test may cause the electrode and interface pressure to gradually decrease. This situation will inevitably affect the test results. If the existing technology is used in the past, this effect cannot be known, but the device of the present invention can be known in real time, and its possible impact can be avoided or evaluated.

[0023] (3) The placement platform of the fixture for testing the flashover breakdown voltage of sheet-shaped insulating materials provided by the utility model can flexibly place the sample, and can measure flat-plate samples of various thicknesses, shapes and sizes. In addition, the lifting platform is used to replace the sample, without the need to disassemble and install screws, and the single test cycle is short and the operation process is simple. It is not only convenient to replace the sample and adjust the experimental position, but also compatible with materials of different thicknesses for testing; a threaded screw is used to lift and lower the platform, which has the characteristics of simple operation and wide application range. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of a fixture for testing the surface flashover breakdown voltage of sheet-shaped insulating materials;

[0025] Figure 2 It is a schematic diagram of the structure after the balancing system is connected with the finger electrodes and the universal joint;

[0026] Figure 3 It is a schematic diagram of the structure before the universal joint and the upper base are connected;

[0027] Figure 4 It is a structural schematic diagram of the lifting platform;

[0028] Figure 5It is a schematic diagram of the connection structure between the lead screw and the lower crossbeam;

[0029] Figure 6 It is a schematic diagram of the structure of the sample placement plate;

[0030] Figure 7 is a structural schematic diagram of a first connecting plate;

[0031] Figure 8 is a structural schematic diagram of a second connecting plate;

[0032] In the figure, 1-base, 2-1-upper beam, 2-2-lower beam, 2-3-column, 3-1-pressure sensor, 3-2-force block, 4-balance system, 4-1-upper base, 4-2-lower base, 4-3-support rod, 4-4-thrust ball bearing, 5-finger-shaped electrode, 5-1-finger-shaped electrode end, 5-2-mounting end, 6-lifting platform, 7-screw, 7-1-sample placement plate, 7-2-first connecting plate, 7-3-cross roller bearing, 7-4-second connecting plate, 8-sheet insulating material sample to be tested, 9-metal block, 10-handle, 11-copper nut, 12-locking screw. DETAILED DESCRIPTION

[0033] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0034] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0035] Secondly, the experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, methods and instruments used are conventional materials, reagents, methods and instruments in the art unless otherwise specified, and can be obtained by those skilled in the art through commercial channels.

[0036] like Figures 1 to 8As shown, a fixture for testing the surface flashover breakdown voltage of a sheet-like insulating material comprises a base 1, a frame, a pressure sensing system, a balancing system 4, a finger-shaped electrode 5 and a lifting platform 6; the frame is fixed on the base 1, and is composed of an upper beam 2-1, a lower beam 2-2 and a column 2-3 connected to both ends of the upper beam 2-1 and the lower beam 2-2; the pressure sensing system comprises a pressure sensor 3-1 and a force block 3-2, the pressure sensor 3-1 is fixedly connected to the upper beam 2-1, the two sides of the force block 3-2 are hinged to the upper beam 2-1 through a connecting rod structure, and the lower part of the force block 3-2 is connected to the upper end of the balancing system 4 through a universal joint 3-3; the lower end of the balancing system 4 is connected to the finger-shaped electrode 5 through a metal block 9; the lifting platform 6 is connected to the lower beam 2-2 through a lead screw 7;

[0037] The sheet-like insulating material sample 8 to be tested is located on the lifting platform 6, and two finger-shaped electrodes 5 are located at two points on the surface of the sheet-like insulating material sample 8 with a certain insulation distance, and the two finger-shaped electrodes 5 are respectively connected to the high voltage end and the ground end of the AC and DC high voltage power supply.

[0038] The pressure sensor 3-1 is a plane diaphragm-type force sensor, which is fixedly mounted on the upper crossbeam 2-1, and the force-bearing surface is located below the upper crossbeam 2-1; the force block 3-2 is a cylinder with an arc-shaped convex upper surface, and one end of the universal joint 3-3 is fixed to the lower surface of the force block 3-2; mounting brackets are symmetrically arranged on both sides of the column of the force block 3-2, and the mounting brackets are hingedly suspended on the upper crossbeam 2-1 through a connecting rod structure hinged by multiple connecting rods, and are located directly below the force-bearing surface of the pressure sensor 3-1. A horizontal plate and a pressure display screen of the pressure sensor 3-1 are installed above the upper crossbeam 2-1. With such a configuration, the pressure sensor 3-1 is a plane diaphragm-type force sensor, one side of which is a force-bearing surface, which can bear force in the center of the circle, bear force evenly, and cannot be subjected to twisting force; the other side has a threaded mounting hole, and the pressure sensor 3-1 is connected and fixed to the middle position of the upper crossbeam 2-1 by screws, and the value measured by the pressure sensor 3-1 will be transmitted to the display screen installed at the top of the entire device. The upper surface of the force block 3-2 is set to an arc convex shape in order to better fit with the pressure sensor 3-1 to make the measurement more accurate. In addition, the force block 3-2 is suspended on the upper crossbeam 2-1 through a connecting rod structure, so that the force block 3-2 is stably suspended directly below the pressure sensor 3-1, so that the balance system 4 can accurately fit the center position of the force surface during measurement, and the force measurement is more accurate.

[0039] When not conducting the experiment, the force block 3-2 is not in contact with the pressure sensor 3-1, and there is a certain gap between them. To ensure the accuracy of the pressure sensor 3-1 during the experiment, the center of the cylindrical contact surface of the force block 3-2 must coincide with the center of the force surface of the pressure sensor 3-1.

[0040] The balancing system 4 includes an upper base 4-1 and a lower base 4-2 made of insulating materials, and four support rods 4-3 connected to the upper base 4-1 and the lower base 4-2 at the same ends of the same side through thrust ball bearings 4-4; a metal block 9 is installed between two support rods 4-3 located on different sides of the upper base 4-1 and the lower base 4-2 and opposite to each other. The upper base 4-1 is a rectangular parallelepiped with a square through slot in the center, and the other end of the universal joint 3-3 is rotatably installed at the center of the square through slot of the upper base 4-1. In this way, the upper base 4-1 and the lower base 4-2 and the support rods 4-3 form a parallelogram structure frame with a changeable angle through the thrust ball bearings 4-4, so that the balancing system 4 can adapt to the angle tilt caused by the unevenness of the sheet insulating material sample 8 to be tested, and even if there is a large angle tilt in the lateral direction, the finger electrode 5 can be balanced and subjected to force, and then the finger electrode 5 can fit the sample tightly. At the same time, the universal joint 3-3 is installed at the center position of the upper base 4-1, so the upper base 4-1 is a lever arm, and the connection point between the upper base 4-1 and the universal joint 3-3 is a fulcrum to form a lever. Since the two force arms of the lever are equal in length, no matter how the angle of the parallelogram changes, it will not affect the balanced force of the two metal blocks 9 and the two finger electrodes 5, so that the pressure on the two finger electrodes 5 is the same.

[0041] The finger-shaped electrode 5 includes a finger-shaped electrode end 5-1 and a mounting end 5-2, and the metal block 9 is connected to the mounting end 5-2 through a thrust ball bearing 4-4. In this arrangement, the front end of the finger-shaped electrode 5 is a hemispherical finger-shaped electrode end 5-1 similar to a finger, and the rear end is a square mounting end 5-2, which is convenient for installation with the metal block 9, and the two are connected through the thrust ball bearing 4-4, so that the finger-shaped electrode 5 can rotate flexibly and perform adaptive adjustment according to the force. In addition, the rear end of the finger-shaped electrode 5 is used to connect the high-voltage line and the grounding line. In order to reduce the tip discharge as much as possible, the sharp corners and edges of all non-experimental parts of the finger-shaped electrode 5 are smoothed. Since the surface is very smooth, it is difficult to clamp the wiring clamp of the external lead wire. For this reason, a straight groove is opened at the place where the conductive clamp clamps the electrode to facilitate wiring. During the experiment, the two finger electrodes 5 are placed opposite to each other. If the distance between the two finger electrodes 5 needs to be changed during the experiment, the two finger electrodes 5 need to be replaced with electrodes with the same parameters except for the length. To ensure the same gravity on both sides, the structures and materials of the two finger electrodes 5 are completely consistent after replacement. In addition, during the experiment, the only charged parts are the metal block 9 and the finger electrodes 5, so the thrust ball bearing 4-4 ​​and the metal block 9 are fixed to the balance system 4 with nylon screws.

[0042] The lifting platform 6 includes a sample placement plate 7-1, a first connecting plate 7-2, a cross roller bearing 7-3 and a second connecting plate 7-4 from top to bottom; the first connecting plate 7-2 is annular, the circular plate-shaped sample placement plate 7-1 is connected to the first connecting plate 7-2 by bolts, the first connecting plate 7-2 is connected to the outer ring of the cross roller bearing 7-3 by bolts, the second connecting plate 7-4 is connected to the inner ring of the cross roller bearing 7-3 by bolts, and the center of the second connecting plate 7-4 is fixedly connected to one end of the lead screw 7. In this arrangement, the sample placement plate 7-1, the first connecting plate 7-2, the cross roller bearing 7-3 and the second connecting plate 7-4 are connected together in sequence by screws. This connection method transfers the screw fixing position to the edge of the placement platform, ensuring that the placement platform 7-1 is smooth and flat, and the cross roller bearing 7-3 will offset the rotation force, so that the platform goes straight up and down.

[0043] The other end of the lead screw 7 passes through the lower cross beam 2-2 and is connected to the handle 10, and the movement and fixation of the lead screw 7 are achieved through the copper nut 11 and the locking screw 12. The lead screw 7 is fitted with the copper nut 11 through threaded cooperation, and the copper nut 11 is fixed on the lower cross beam 2-2 and equipped with a locking screw 12. In this way, the copper nut 11 is fixed on the lower cross beam 2-2 and equipped with a locking screw 12. The copper nut 11 and the lead screw 7 are threadedly matched, so when the handle 10 is rotated, the copper nut 11 does not move but the lead screw 7 moves, and the lead screw 7 drives the lifting platform 6 connected to its top to rise or fall. It avoids the problem of using an epoxy board as a placement platform plate and the lead screw directly connected with screws to produce a countersunk hole at the center of the platform, which makes the experimental platform uneven, and then affects the experimental data. In addition, a single epoxy board is used as a placement platform plate, which will rotate and rise when the platform is raised and lowered, and it is difficult to ensure that the surface breakdown occurs in a predetermined area.

[0044] The lead screw 7 is 100 mm long, 10 mm in diameter, and has a lead of 1 mm. The smaller the lead (or thread angle) of the lead screw 7 is, the more accurate the pressure control is. When the lifting platform 6 is lowered, it is sufficient to leave space for changing the sample. It does not need to be lowered too much, so the length of the lead screw 7 does not need to be too long. When the lifting platform 6 is raised to a suitable position, the locking knob 12 on the copper nut 11 is rotated to fix the lead screw 7.

[0045] Use the above-mentioned sheet insulation material surface flashover breakdown voltage test fixture to test:

[0046] 1. Preparation before testing

[0047] 1. Fix the experimental device and enhance its stability to ensure that it will not shake when the handle is rotated.

[0048] 2. Calibrate the experimental device to ensure that the pressure sensor 3-1, the balance system 4, and the lifting platform 6 are parallel to the ground in a static state. The force block 3-2 does not contact the pressure sensor 3-1, and there is a certain gap between the two.

[0049] 3. Measure the bottom area of ​​the finger-shaped electrode and calculate how much pressure is needed to maintain the pressure required for the experiment.

[0050] 2. Experimental steps

[0051] 1. Clean the sample surface and the bottom surface of the finger-shaped electrode 5, loosen the locking knob 12 on the lead screw 7, rotate the handle 10 to lower the lifting platform 6, adjust the position of the sample and place it on the lifting platform 6 (make sure that the two finger-shaped electrodes 5 are completely attached to the sample during the experiment).

[0052] 2. Rotate the handle 10 to raise the lifting platform 6. As the platform rises, the bottoms of the two finger electrodes 5 will be close to the sample, and the lever constructed by the balance system 4 will balance the force on the two finger electrodes 5. The lowering platform 6 continues to rise, and the force block 3-2 on the top of the lever contacts the pressure sensor 3-1. The pressure sensor 3-1 transmits the received pressure to the display screen for display. When the pressure rises to the required value, rotate the locking knob 12 to fix the lifting platform 6.

[0053] 3. Connect the high voltage lead wire and the ground wire to the two finger-shaped electrodes 5 respectively. After the operator moves away from the low voltage safety area, the high voltage power supply can be connected to carry out the surface flashover experiment.

[0054] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A fixture for testing the surface flashover breakdown voltage of sheet-like insulating materials, characterized in that: The invention comprises a base (1), a frame, a pressure sensing system, a balancing system (4), a finger-shaped electrode (5) and a lifting platform (6); the frame is fixed on the base (1), and is composed of an upper crossbeam (2-1), a lower crossbeam (2-2) and a column (2-3) connected to both ends of the upper crossbeam (2-1) and the lower crossbeam (2-2); the pressure sensing system comprises a pressure sensor (3-1) and a force block (3-2); the pressure sensor (3-1) is fixedly connected to the upper crossbeam (2-1); both sides of the force block (3-2) are hinged to the upper crossbeam (2-1) through a connecting rod structure; the lower end of the force block (3-2) is connected to the upper end of the balancing system (4) through a universal joint (3-3); the lower end of the balancing system (4) is connected to the finger-shaped electrode (5) through a metal block (9); the lifting platform (6) is connected to the lower crossbeam (2-2) through a lead screw (7); The sheet-shaped insulating material sample (8) to be tested is located on a lifting platform (6), two finger-shaped electrodes (5) are located at two points on the surface of the sheet-shaped insulating material sample (8) to be tested with a certain insulation distance, and the two finger-shaped electrodes (5) are respectively connected to the high voltage end and the ground end of an AC / DC high voltage power supply.

2. The sheet-like insulating material surface flashover breakdown voltage test fixture according to claim 1, characterized in that: The pressure sensor (3-1) is a plane diaphragm box type force sensor, which is fixedly mounted on the upper crossbeam (2-1), and the force-bearing surface is located below the upper crossbeam (2-1); the force-bearing block (3-2) is a cylinder with an arc-shaped convex upper surface, and one end of the universal joint (3-3) is fixed to the lower surface of the force-bearing block (3-2); mounting supports are symmetrically arranged on both sides of the column of the force-bearing block (3-2), and the mounting supports are suspended on the upper crossbeam (2-1) by being hinged to a connecting rod structure formed by hinged connection of a plurality of connecting rods, and are located directly below the force-bearing surface of the pressure sensor (3-1).

3. The sheet-like insulating material surface flashover breakdown voltage test fixture according to claim 1, characterized in that: The balancing system (4) comprises an upper base (4-1) and a lower base (4-2) made of insulating materials, and four support rods (4-3) connected to the upper base (4-1) and the lower base (4-2) at both ends of the same side through thrust ball bearings (4-4); a metal block (9) is installed between two support rods (4-3) located on different sides of the upper base (4-1) and the lower base (4-2) and in opposite positions.

4. The sheet-like insulating material surface flashover breakdown voltage test fixture according to claim 1 or 3, characterized in that: The upper base (4-1) is a cuboid with a square through slot at the center, and the other end of the universal joint (3-3) is rotatably mounted at the center of the square through slot of the upper base (4-1).

5. The sheet-like insulating material surface flashover breakdown voltage test fixture according to claim 1 or 3, characterized in that: The finger-shaped electrode (5) comprises a finger-shaped electrode end (5-1) and a mounting end (5-2), and the metal block (9) is connected to the mounting end (5-2) via a thrust ball bearing (4-4).

6. The sheet-like insulating material surface flashover breakdown voltage test fixture according to claim 1, characterized in that: The lifting platform (6) comprises, from top to bottom, a sample placement plate (7-1), a first connecting plate (7-2), a cross roller bearing (7-3) and a second connecting plate (7-4); the first connecting plate (7-2) is annular, the circular plate-shaped sample placement plate (7-1) is connected to the first connecting plate (7-2) by bolts, the first connecting plate (7-2) is connected to the outer ring of the cross roller bearing (7-3) by bolts, the second connecting plate (7-4) is connected to the inner ring of the cross roller bearing (7-3) by bolts, and the center of the second connecting plate (7-4) is fixedly connected to one end of the lead screw (7).

7. The fixture for testing the surface flashover breakdown voltage of sheet-like insulating materials according to claim 6, characterized in that: The other end of the lead screw (7) passes through the lower cross beam (2-2) and is connected to the handle (10), and the movement and fixation of the lead screw (7) are achieved through the copper nut (11) and the locking screw (12).

8. The sheet-like insulating material surface flashover breakdown voltage test fixture according to claim 7, characterized in that: The lead screw (7) is fitted with the copper nut (11) through threaded engagement, and the copper nut (11) is fixed on the lower cross beam (2-2) and is provided with a locking screw (12).

9. The sheet-like insulating material surface flashover breakdown voltage test fixture according to claim 1, characterized in that: A horizontal plate and a pressure display screen of a pressure sensor (3-1) are installed above the upper horizontal beam (2-1).

10. A device for testing the surface flashover breakdown voltage of sheet-like insulating materials, characterized in that: The invention comprises the sheet-shaped insulating material surface flashover breakdown voltage test fixture as claimed in any one of claims 1 to 9, an AC / DC high voltage power supply, an oscilloscope and a computer.

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