A GIS shell thermal stress temperature cycle loading test bench

Abstract

The present invention discloses a GIS shell thermal stress temperature cycle loading test bench. The present invention includes a mounting frame for placing the GIS shell and at least one temperature regulating device for tightly fitting on the surface of the GIS shell. The temperature regulating device is composed of a number of semiconductor refrigerators connected in series, and the tail of the first semiconductor refrigerator is connected to the head of the last semiconductor refrigerator to form a circle; each semiconductor refrigerator includes a fan, an upper aluminum heat conductive block, a semiconductor cooling sheet and a lower aluminum heat conductive block arranged in sequence from top to bottom, and the lower aluminum heat conductive block is used to tightly fit on the surface of the GIS shell; the mounting frame is equipped with a three-way force sensor for detecting the force magnitude of the GIS shell in the three directions of XYZ. The present invention can quickly and conveniently perform heating and cooling, and realizes rapid alternating loading of the temperature field of the GIS shell; the present invention adopts a modular design, and different numbers of temperature regulating modules can be installed according to different GIS shell diameters and lengths to adapt to different test scenarios.

Description

Technical Field

[0001] The invention belongs to the technical field of GIS shell test devices, in particular to a GIS shell thermal stress temperature cycle loading test bench. Background Art

[0002] Gas insulated fully enclosed switchgear (GIS) in the power grid is a complete set of devices composed of various high-voltage electrical appliances such as circuit breakers, disconnectors, grounding switches, busbars, etc. These devices or components are all enclosed in a metal shell and filled with SF 6 Gas is used as insulation and arc extinguishing medium; the shell used in GIS is a pressure-bearing component, requiring SF 6 The annual leakage rate is less than 1%. Once SF is generated due to damage to the GIS shell 6 Leakage not only affects the reliable operation of GIS and even the power system, but also pollutes the surrounding environment and endangers the health and life safety of workers.

[0003] GIS shells are available in two forms: integral casting and rolled plate welding. The overall dimensions are generally: cylinder diameter 400-1000mm, shell thickness 6-10mm, length 500-3000mm, and the material is generally aluminum alloy. During the production process, cast shells are prone to defects such as pores, shrinkage cavities, cold shuts, slag inclusions, and cracks; for welded shells, in addition to parent material defects, welds will also produce welding defects such as incomplete penetration, slag inclusions, pores, and cracks.

[0004] Before using the GIS shell, the manufacturer will generally conduct non-destructive testing, such as X-ray testing, ultrasonic testing, etc. If serious defects are found, they will generally not be shipped out. However, since the GIS shell is processed by casting or welding, there are always some defects to a greater or lesser extent. In the pressure vessel industry, the principle of "fitness for use" is proposed. For some minor defects, they are generally released for use. However, when these defects are subjected to alternating loads during use, the defects may gradually become larger. For example, the defects in the shell welds will gradually become larger or even crack, resulting in SF 6 leakage.

[0005] In Science, Technology and Engineering, Issue 1, 2017, Pages 213-217, Luo Hongjian et al. published an article entitled "Study on the Deformation Behavior of 1000kV UHV GIS Shell under Sunlight", which studied the deformation and stress of the GIS shell under the action of sunlight temperature difference. In the summer with a temperature difference of 10°C, the maximum temperature of the shell fluctuates by 21°C. The shell undergoes thermal expansion and contraction deformation due to temperature, and the axial deformation reaches 0.973mm. Due to the uneven temperature distribution and changes in various parts of the shell, the shell deforms non-uniformly, and the shell flange rotation angle reaches 0.01°. The shell temperature and deformation change in a 24h period. In the design, manufacturing and testing, special attention should be paid to the fatigue cumulative damage and failure that may be caused by this periodic environmental load.

[0006] Obviously, in order to explore the influence and development law of the change of temperature field on the defects existing on the GIS shell, it is necessary to establish a set of test equipment suitable for the temperature field alternation of the GIS shell according to the use conditions of the GIS shell, study the relationship between defects, temperature field stress and non-destructive testing, and conduct a certain proportion of random inspections on some particularly important occasions or before the products leave the factory in the future. After a certain number of temperature alternating load tests are conducted on the GIS shell, non-destructive testing is conducted to ensure that the application of the GIS shell is safe. The size of the temperature alternating load can be determined according to the maximum temperature difference that may occur in the application site in a year, and the number of alternations can be determined according to an average of once a day and a design life of 40 years.

[0007] The conventional simulation method is to cover the GIS shell with a heating block and control the heating to reach the specified temperature. However, it is unable to simulate temperatures lower than the laboratory room temperature. To perform the next thermal stress cycle, the heating must be stopped and then slowly cooled down, or the covering heating block must be removed and air-cooled, which is time-consuming and laborious. Summary of the invention

[0008] The technical problem to be solved by the present invention is to overcome the defects of the above-mentioned prior art and provide a GIS shell thermal stress temperature cycle loading test bench, which is used to simulate the temperature field of the sun-exposed surface and the backlight surface of the GIS shell after installation under the action of sunlight, so as to detect the cyclic load of the temperature thermal stress of the GIS shell.

[0009] To this end, the present invention adopts the following technical solution: a GIS shell thermal stress temperature cycle loading test bench, comprising a mounting frame for placing the GIS shell and at least one temperature regulating device for tightly fitting on the surface of the GIS shell, wherein the temperature regulating device is composed of a plurality of semiconductor refrigerators connected in series, and the tail of the first semiconductor refrigerator is connected to the head of the last semiconductor refrigerator to form a circle;

[0010] Each semiconductor refrigerator comprises a fan, an upper aluminum heat-conducting block, a semiconductor cooling sheet and a lower aluminum heat-conducting block arranged in sequence from top to bottom, wherein the lower aluminum heat-conducting block is used to be in close contact with the surface of the GIS shell;

[0011] The mounting frame is provided with a three-way force sensor for detecting the force magnitude of the GIS shell in three directions of XYZ.

[0012] The force sensor of the present invention is used to detect the magnitude of forces in the three directions of XYZ, that is, it can detect the tension / compression caused by thermal expansion and contraction along the axis of the GIS shell, the force perpendicular to the horizontal plane, and the force parallel to the horizontal plane and the end face of the GIS shell. Therefore, by analyzing the forces in the three directions, the bending deformation force caused by the temperature difference between the upper and lower surfaces of the GIS shell can be obtained.

[0013] In order to accelerate the process of heating and cooling cycles of the GIS shell in the laboratory, the present invention proposes to use semiconductor refrigeration chips as heating sources and cooling sources. Semiconductor refrigeration chips, also called thermoelectric refrigeration chips, are, in principle, a heat transfer tool. When current passes through a thermocouple pair formed by a piece of N-type semiconductor material and a piece of P-type semiconductor material, heat transfer will occur between the two ends, and the heat will be transferred from one end to the other, thereby generating a temperature difference to form a hot and cold end. In other words, by installing heat-conducting aluminum blocks on both sides of the semiconductor refrigeration chip, it can be used as one side for heating and the other side for cooling, and by changing the direction of the current, the cold side can be turned into a hot side, and the hot side can be turned into a cold side. Theoretically speaking, when the heat dissipation is ideal enough, the temperature difference range of the semiconductor refrigeration chip can be achieved from a positive temperature of 90°C to a negative temperature of 130°C.

[0014] The semiconductor refrigerator has two electrode wires. When a 12V DC voltage is applied to the two electrode wires, one side of the semiconductor refrigerator heats up and the other side cools down. When the voltage polarity on the electrode wires is swapped, the heating side becomes the cooling side and the cooling side becomes the heating side.

[0015] Furthermore, a limiting groove is provided on the upper surface of the lower aluminum heat-conducting block, and the semiconductor cooling plate is placed in the limiting groove, and the semiconductor cooling plate is limited by the limiting groove.

[0016] Furthermore, the upper aluminum heat conducting block and the lower aluminum heat conducting block are connected by screws, so that the semiconductor cooling sheet is clamped between the upper aluminum heat conducting block and the lower aluminum heat conducting block, thereby fixing the semiconductor cooling sheet. In order to further achieve better heat exchange, thermal grease can be applied on the surface of the upper aluminum heat conducting block and the lower aluminum heat conducting block.

[0017] Furthermore, the front and rear sides of the lower aluminum heat-conducting block are respectively formed with a groove and a boss. When two adjacent semiconductor refrigerators are connected in series, the boss of the lower aluminum heat-conducting block on one semiconductor refrigerator cooperates with the groove of the lower aluminum heat-conducting block on the other semiconductor refrigerator to achieve connection, and the boss is axially connected in the groove. By using this structure, multiple semiconductor refrigerators can be connected in series, and the two semiconductor refrigerators can rotate through the shaft.

[0018] Furthermore, the upper portion of the upper aluminum heat-conducting block is in a comb-tooth shape, which increases the heat dissipation surface area; the fan is installed on the comb-tooth surface of the upper aluminum heat-conducting block and fixed with screws.

[0019] Furthermore, the mounting frame includes a left mounting frame and a right mounting frame, the left mounting frame is connected to the left flange on the GIS shell through a first transition connection flange; one side of a connecting block is connected to the right flange on the GIS shell through a second transition connection flange, and the other side is installed with the three-way force sensor, and the three-way force sensor is installed on the right mounting frame. For the installation of GIS shells of different diameters, only the corresponding first and second transition connection flanges need to be customized.

[0020] Furthermore, a mounting base is provided below the left mounting frame and the right mounting frame, the left mounting frame is fixed on the mounting base, a T-shaped mounting groove for adjusting the position of the right mounting frame is provided on the mounting base below the right mounting frame, the bottom of the right mounting frame is placed in the T-shaped mounting groove and fixed to the mounting base by bolts. When the position of the right mounting frame needs to be adjusted, the bolts can be unscrewed.

[0021] Furthermore, in the same temperature regulating device, the tail shaft of the first semiconductor refrigerator is connected to the first terminal connecting block, and the head shaft of the last semiconductor refrigerator is connected to the second terminal connecting block. The two terminal connecting blocks are connected by bolts to facilitate the disassembly and assembly of the semiconductor refrigerator.

[0022] Furthermore, there are multiple temperature regulating devices, and the positions where the head and tail of all temperature regulating devices are connected are on the same side of the GIS shell and on the same horizontal plane. In the length direction of the GIS shell, according to the test needs, several temperature regulating devices can be placed at certain intervals to control the temperature of the entire GIS surface.

[0023] Furthermore, the lower surface of the lower aluminum heat conductive block is an arc surface, which is used to match the curvature of the GIS shell surface. The radius of the arc surface is consistent with the cylindrical radius of the GIS shell. For a certain GIS shell to be tested, the cylindrical radius is known, and the arc surface length of the lower aluminum heat conductive block can be an even number of blocks, each block is 2-4 times the length of the semiconductor refrigeration plate, and the two end connecting blocks cover the entire GIS shell circumference. There is still 10-30mm difference. If the cylindrical radius of the GIS shell changes, the lower aluminum heat conductive block needs to be reprocessed according to the above requirements. The width of the lower aluminum heat conductive block is consistent with the width of the upper aluminum heat conductive block, and is generally 2-4 times the width of the semiconductor refrigeration plate. There must be at least one flat surface as large as the surface of the semiconductor refrigeration plate in the center of the upper surface of the lower aluminum heat conductive block, which is in contact with the semiconductor refrigeration plate.

[0024] Furthermore, the test bench of the present invention also includes at least one strain gauge arranged on the GIS shell, which is used to measure the stress change on the surface of the GIS shell.

[0025] Furthermore, the test bench of the present invention also includes at least one temperature sensor disposed on the GIS shell, and the temperature sensor is used to measure the surface temperature of the GIS shell. The temperature sensor can be arranged at multiple locations on the surface of the GIS shell according to the need for measuring temperature.

[0026] The beneficial effects of the present invention are as follows:

[0027] 1. The present invention can quickly and conveniently perform heating and cooling, and realizes rapid alternating loading of the temperature field of the GIS shell.

[0028] 2. The modular design allows different numbers of temperature control modules to be installed according to different GIS shell diameters and lengths to adapt to different test scenarios.

[0029] 3. Compared with the traditional temperature field strain detection, the present invention can perform low temperature tests in addition to heating tests. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the structure of the present invention installed on a GIS housing;

[0031] Figure 2 yes Figure 1 Left side view;

[0032] Figure 3 yes Figure 1 Right side view;

[0033] Figure 4 yes Figure 1 A top view of

[0034] Figure 5 It is a structural schematic diagram of the temperature regulating device of the present invention;

[0035] Figure 6 It is a structural schematic diagram of the semiconductor refrigerator of the present invention;

[0036] Figure 7 It is a schematic diagram of the connection of two adjacent semiconductor refrigerators of the present invention.

[0037] In the figure, 1-GIS shell, 2-temperature regulating device, 3-second transition connecting flange, 4-connecting block, 5-three-way force sensor, 6-right mounting frame, 7-mounting base, 8-left mounting frame, 9-first transition connecting flange, 10-T-shaped mounting groove, 11-strain gauge, 12-temperature sensor, 20-semiconductor refrigerator, 21-lower aluminum heat conducting block, 22-semiconductor refrigerator, 23-upper aluminum heat conducting block, 24-fan, 25-first end connecting block, 27-second end connecting block, 28-limiting groove, 211-groove, 212-boss. DETAILED DESCRIPTION

[0038] The present invention will be further described below in conjunction with the accompanying drawings and specific implementation methods.

[0039] like Figure 1-7 A GIS shell thermal stress temperature cycle loading test bench is shown, which is composed of a mounting frame for placing a GIS shell 1 and a plurality of temperature regulating devices 2 for tightly fitting on the surface of the GIS shell. The temperature regulating device 2 is composed of a plurality of semiconductor refrigerators 20 connected in series, and the tail of the first semiconductor refrigerator is connected to the head of the last semiconductor refrigerator to form a circle.

[0040] In each temperature regulating device 2, the number of semiconductor coolers is determined by the radius of the GIS shell. For example, if the radius of the GIS shell is 300mm, the gap is 20mm, the arc length of each block is initially set to 150mm, and the length of the end connection block is 30mm, then the number of blocks required is: (2*300*3.14159-20-60) / 150=12.03 blocks, which is rounded to an even number of blocks 12, then the actual length of each block is: (2*300*3.14159-80) / 12=150.41mm.

[0041] Each semiconductor refrigerator 20 is composed of a fan 24, an upper aluminum heat-conducting block 23, a semiconductor cooling sheet 22 and a lower aluminum heat-conducting block 21 which are arranged in sequence from top to bottom. The lower aluminum heat-conducting block 21 is used to be in close contact with the surface of the GIS shell 1.

[0042] The upper surface of the lower aluminum heat conducting block 21 is provided with a limiting groove 28, and the semiconductor cooling plate 22 is placed in the limiting groove 28. The lower surface of the lower aluminum heat conducting block 21 is a curved surface, which is used to match the curvature of the surface of the GIS shell 1.

[0043] The upper aluminum heat-conducting block 23 and the lower aluminum heat-conducting block 21 are connected by screws, so that the semiconductor cooling sheet 22 is clamped between the upper aluminum heat-conducting block 23 and the lower aluminum heat-conducting block 21 .

[0044] The front and rear sides of the lower aluminum heat-conducting block 21 are respectively formed with a groove 211 and a boss 212. When two adjacent semiconductor refrigerators are connected in series, the boss of the lower aluminum heat-conducting block on one semiconductor refrigerator and the groove of the lower aluminum heat-conducting block on the other semiconductor refrigerator are used to achieve connection, and the boss axis is connected in the groove.

[0045] The upper portion of the upper aluminum heat-conducting block 23 is in a comb-tooth shape, and the fan 24 is installed on the comb-tooth-shaped surface of the upper aluminum heat-conducting block 23 and fixed by screws.

[0046] The mounting frame includes a left mounting frame 8 and a right mounting frame 6. The left mounting frame 8 is connected to the left flange on the GIS shell through a first transition connection flange 9. One side of the connecting block 4 is connected to the right flange on the GIS shell through a second transition connection flange 3, and a three-way force sensor 5 is installed on the other side. The three-way force sensor 5 is installed on the right mounting frame 6.

[0047] A mounting base 7 is provided below the left mounting frame 8 and the right mounting frame 6, and the left mounting frame 8 is fixed on the mounting base 7. A T-shaped mounting groove 10 for adjusting the position of the right mounting frame is provided on the mounting base below the right mounting frame, and the bottom of the right mounting frame 6 is placed in the T-shaped mounting groove 10 and fixed to the mounting base 7 by bolts.

[0048] In the same temperature regulating device, the tail end of the first semiconductor refrigerator is axially connected to the first terminal connecting block 25 , and the head end of the last semiconductor refrigerator is axially connected to the second terminal connecting block 27 , and the two terminal connecting blocks are connected by bolts 26 .

[0049] There are multiple temperature regulating devices, and the positions where the head and tail of all the temperature regulating devices are connected are on the same side of the GIS shell and on the same horizontal plane.

[0050] The GIS shell is provided with a strain gauge 11 for measuring stress changes on the surface of the GIS shell.

[0051] The GIS shell is provided with a temperature sensor 12, which is used to measure the surface temperature of the GIS shell. The temperature sensor can be arranged at multiple locations on the surface of the GIS shell according to the need for measuring temperature.

[0052] The working principle of heating of the present invention is as follows:

[0053] Cover the GIS shell with N temperature adjustment devices 2, ensure that the bolt tightening position at each notch is at the same GIS shell angle (i.e., on the same side of the GIS shell and on the same horizontal plane), so that N corresponding semiconductor refrigerators 20 along the axial direction cover the GIS shell at the same angle. The corresponding semiconductor refrigerators 20 at the same angle are connected in parallel and controlled by the same DC power supply. In this way, since there are an even number of M semiconductor refrigerators 20 on the circumference of the shell, a total of M groups of DC power supplies are required for control.

[0054] During the simulation test, according to the angle of sunlight shining on the shell surface, the corresponding semiconductor refrigerator 20 can be selected to be controlled for heating. In the shaded area, if the set temperature is lower than the laboratory room temperature, the corresponding semiconductor refrigerator 20 and the GIS shell surface can also be used for cooling. If the temperature adjustment device 2 is composed of 12 semiconductor refrigerators 20, if the sun shines directly on the GIS shell at noon, the 6 on the upper surface of the GIS shell are in a high-temperature heating state, and the temperature of the top few can be made higher, while the 6 on the lower surface are in a low-temperature state, and the temperature on each arc surface can be independently controlled.

[0055] When the GIS shell temperature is heated to the set temperature and kept warm for a specified time, after completing one test, the GIS shell needs to be restored to room temperature for a second heating test. At this time, the semiconductor refrigerator 20 will be stopped from being heated or cooled, and the power supply will be turned off. To avoid damage to the semiconductor refrigeration sheet, the power can be turned off for 3-5 minutes, and then the DC power supply is reversed to cool or heat. With room temperature as the control target temperature, the semiconductor refrigerator is cooled or heated to achieve rapid cooling back to room temperature, preparing for the next heating test. In this way, there is no need to remove the covered temperature adjustment device, and the number of tests can be greatly accelerated, improving efficiency.

[0056] The above description is only an example of a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A GIS shell thermal stress temperature cycle loading test bench, comprising a mounting frame for placing a GIS shell (1) and at least one temperature regulating device (2) for tightly fitting on the surface of the GIS shell, characterized in that: The temperature regulating device (2) is composed of a plurality of semiconductor refrigerators (20) connected in series, wherein the tail of the first semiconductor refrigerator is connected to the head of the last semiconductor refrigerator to form a circle; Each semiconductor refrigerator (20) comprises a fan (24), an upper aluminum heat-conducting block (23), a semiconductor cooling sheet (22) and a lower aluminum heat-conducting block (21) which are arranged in sequence from top to bottom, wherein the lower aluminum heat-conducting block (21) is used to be in close contact with the surface of the GIS housing (1); The mounting frame is provided with a three-way force sensor (5) for detecting the magnitude of the force of the GIS housing (1) in three directions of X, Y and Z; The front and rear sides of the lower aluminum heat-conducting block (21) are respectively formed with a groove (211) and a boss (212); when two adjacent semiconductor refrigerators are connected in series, the boss of the lower aluminum heat-conducting block on one semiconductor refrigerator cooperates with the groove of the lower aluminum heat-conducting block on the other semiconductor refrigerator to achieve connection, and the boss is axially connected in the groove; The upper portion of the upper aluminum heat-conducting block (23) is in a comb-tooth shape, and the fan (24) is mounted on the comb-tooth-shaped surface of the upper aluminum heat-conducting block (23) and fixed by screws.

2. A GIS shell thermal stress temperature cycle loading test bench according to claim 1, characterized in that: The upper surface of the lower aluminum heat-conducting block (21) is provided with a limiting groove (28), and the semiconductor cooling plate (22) is placed in the limiting groove (28).

3. A GIS shell thermal stress temperature cycle loading test bench according to claim 2, characterized in that: The upper aluminum heat conducting block (23) and the lower aluminum heat conducting block (21) are connected by screws, so that the semiconductor cooling plate (22) is clamped between the upper aluminum heat conducting block (23) and the lower aluminum heat conducting block (21).

4. A GIS shell thermal stress temperature cycle loading test bench according to claim 1, 2 or 3, characterized in that: The mounting frame comprises a left mounting frame (8) and a right mounting frame (6), wherein the left mounting frame (8) is connected to the left flange on the GIS shell via a first transition connection flange (9); one side of a connecting block (4) is connected to the right flange on the GIS shell via a second transition connection flange (3), and the other side is installed with the three-way force sensor (5), wherein the three-way force sensor (5) is installed on the right mounting frame (6).

5. A GIS shell thermal stress temperature cycle loading test bench according to claim 4, characterized in that: A mounting base (7) is provided below the left mounting frame (8) and the right mounting frame (6); the left mounting frame (8) is fixed on the mounting base (7); a T-shaped mounting groove (10) for adjusting the position of the right mounting frame is provided on the mounting base below the right mounting frame; the bottom of the right mounting frame (6) is placed in the T-shaped mounting groove (10) and is fixed to the mounting base (7) by bolts.

6. A GIS shell thermal stress temperature cycle loading test bench according to claim 1, 2 or 3, characterized in that: In the same temperature regulating device, the tail of the first semiconductor refrigerator is axially connected to the first terminal connection block (25), the head of the last semiconductor refrigerator is axially connected to the second terminal connection block (27), and the two terminal connection blocks are connected by bolts.

7. A GIS shell thermal stress temperature cycle loading test bench according to claim 6, characterized in that: There are multiple temperature regulating devices, and the positions where the head and tail of all the temperature regulating devices are connected are on the same side of the GIS shell and on the same horizontal plane.

8. A GIS shell thermal stress temperature cycle loading test bench according to claim 1, 2 or 3, characterized in that: The lower surface of the lower aluminum heat-conducting block (21) is a curved surface, which is used to match the curvature of the surface of the GIS shell (1).

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