A simulation test device for the explosion and breakdown of a GIL three-pillar insulator

Abstract

The present invention discloses a GIL three-column insulator explosion and breakdown simulation test device, which includes a metal cavity, a mechanical stress loading device, a temperature loading device, and a power frequency high-voltage power supply system. The metal cavity is used to place the GIL three-column insulator and is filled with SF6 gas inside. The mechanical stress loading device loads mechanical stress on the GIL three-column insulator in the metal cavity through a hydraulic system. The temperature loading device heats the conductor temperature of the three-column insulator by controlling the temperature of the circulating oil. The power frequency high-voltage power supply system applies different voltages to the GIL three-column insulator through a high-voltage bushing. By the cooperation of the metal cavity, the mechanical stress loading device, the temperature loading device, and the power frequency high-voltage power supply system, the actual operating conditions of the GIL are simulated. While observing the explosion and breakdown process of the GIL three-column insulator under the combined action of electricity, heat, and force, by changing the mechanical stress, temperature, and voltage variables applied to the GIL three-column insulator, the influence of each variable on the explosion and breakdown of the GIL three-column insulator is studied.

Description

Technical Field

[0001] The present invention relates to the technical field of three-pillar insulator tests, and more specifically, to a simulation test device for explosion and breakdown of a GIL three-pillar insulator. Background Art

[0002] Gas-insulated transmission lines (abbreviated as GIL) have significant advantages such as large transmission capacity, low power loss, small floor area, and no electromagnetic environment effects, making them an ideal choice to replace traditional high-voltage plastic cables and overhead transmission lines. They can effectively solve the problem of power transmission channels in energy optimization and allocation, and are a key development direction for the large-scale utilization of clean energy and enhancing the power grid's resistance to natural disasters. At the same time, as a new type of transmission medium, they will also play an important role in future urban underground integrated energy pipe networks.

[0003] GIL is composed of a metal shell, insulators, and coaxial conductors. The core component, the three-pillar insulator, not only has to withstand a strong electric field but also strong mechanical stress. The mechanical stress of the three-pillar insulator may be caused by external loads during installation / operation or internal residual stress after curing. In the actual operation of ultra-high voltage transmission systems, the current can reach more than 4 kA. Due to the loss generated by the Joule heat of the central conductor and the eddy current generated by the induction of the outer shell, the GIL conductor and the outer shell will be in a heating state, causing the temperature of the GIL equipment to rise, and the three-pillar insulator is in a temperature gradient field. Therefore, the ultra-high voltage GIL three-pillar insulator is in an operating environment of high voltage, large current, and multi-field coupling for a long time, and bears the electro-thermal-mechanical coupling effect. Micro-defects in the insulator have no obvious impact on the insulator in the initial stage of operation, but during the operation process, they are under the long-term electro-thermal-mechanical multi-field coupling effect, and it is inevitable that they will expand and evolve, greatly increasing the risk of insulation breakdown and mechanical failure, and even leading to explosion and breakdown failures, threatening the safety of power transmission.

[0004] In summary, the three-pillar insulator faces the actual working conditions of strong electric fields, high air pressures, mechanical stress, and uneven temperature distribution in actual operation. The electro-thermal-mechanical coupling effect poses a great challenge to the insulation performance and mechanical reliability of GIL insulators. However, there is currently a gap in research that comprehensively considers and can quantitatively simulate the explosion and breakdown failures of GIL three-pillar insulators under the electro-thermal-mechanical coupling effect.

[0005] Therefore, it is urgent to develop a simulation test device for explosion and breakdown of a GIL three-pillar insulator based on the actual operating conditions of the GIL three-pillar insulator to study the breakdown and explosion evolution process of the three-pillar insulator in the GIL pipeline during actual operation. Summary of the Invention

[0006] The object of the present invention is to address the problem that the existing test platforms cannot quantitatively establish the correlation characteristics between the electro-thermal-mechanical coupling effect and the explosion and breakdown of the three-pillar insulators of GIL. A simulation test device for the explosion and breakdown of the three-pillar insulators of GIL is proposed, which can simulate the actual operating conditions of GIL. While observing the explosion and breakdown process of the three-pillar insulators of GIL under the electro-thermal-mechanical coupling effect, by changing variables such as the mechanical stress, temperature, and voltage applied to the insulators, the influence of each variable on the explosion and breakdown of the three-pillar insulators of GIL is studied.

[0007] The object of the present invention is achieved through the following technical solutions.

[0008] The simulation test device for the explosion and breakdown of the three-pillar insulators of GIL of the present invention includes a metal cavity capable of charging and discharging gas, a mechanical stress loading device, a temperature loading device, and a power frequency high-voltage power supply system; the metal cavity is used to place the three-pillar insulators of GIL and is filled with SF6 gas inside; the mechanical stress loading device loads mechanical stress on the three-pillar insulators of GIL inside the metal cavity through a hydraulic system; the temperature loading device heats the conductor temperature of the three-pillar insulators of GIL by controlling the temperature of the circulating oil; the power frequency high-voltage power supply system applies different voltages to the three-pillar insulators of GIL through a high-voltage bushing; by the cooperation of the metal cavity, the mechanical stress loading device, the temperature loading device, and the power frequency high-voltage power supply system, the actual operating conditions of GIL are simulated. While observing the explosion and breakdown process of the three-pillar insulators of GIL under the electro-thermal-mechanical coupling effect, by changing the mechanical stress, temperature, and voltage variables applied to the three-pillar insulators of GIL, the influence of each variable on the explosion and breakdown of the three-pillar insulators of GIL is studied.

[0009] An observation window for observing the explosion and breakdown process of the three-pillar insulators of GIL is provided on the side of the metal cavity; the metal cavity is provided with a gas charging and discharging port, and the gas charging and discharging port is connected to an SF6 gas cylinder through an exhaust pipe, and a pressure gauge and a gas charging and discharging valve are provided on this exhaust pipe; a scaled-down GIL model for installing the three-pillar insulators of GIL is provided inside the metal cavity, and a high-voltage bushing is provided on the top of the metal cavity. One end of the high-voltage bushing is connected to the conductor of the three-pillar insulators of GIL, and the other end is connected to the power frequency high-voltage power supply system.

[0010] An I-shaped support is provided at the bottom of the metal cavity, and the I-shaped support is fixedly connected to the flange below the metal cavity through a fastener. The middle of the flange is a wiring board to realize the line connection between the inside and the outside of the metal cavity.

[0011] The scaled GIL model consists of a base and a cylindrical metal shell. The GIL three-pillar insulator is installed inside the metal shell and fixed by screws. By rotating the metal shell, the GIL three-pillar insulator can be rotated 360 degrees, so as to adjust the angle between the legs of the GIL three-pillar insulator and the hydraulic rod, thereby applying mechanical stress in different directions to the legs of the GIL three-pillar insulator.

[0012] The mechanical stress loading device loads mechanical stress on the GIL three-pillar insulator through a hydraulic system. The hydraulic system consists of a hydraulic cylinder, a hydraulic pump, a hydraulic gauge, a hydraulic oil station, and a hydraulic rod. The hydraulic cylinder is fixed to the top of a metal cavity and is provided with two oil inlets and outlets. The two oil inlets and outlets are respectively connected to the hydraulic oil station through oil pipes. The hydraulic pump and the hydraulic gauge are arranged on one of the oil pipes. The hydraulic pump changes the direction of the hydraulic oil in the oil pipe entering and exiting the hydraulic cylinder, and then injects or extracts hydraulic oil into the hydraulic cylinder, so as to control the up and down movement direction of the hydraulic rod; one end of the hydraulic rod is located inside the hydraulic cylinder, and the movable space of the circular piece welded at the other end is in the metal cavity; a "convex"-shaped insulating bracket is set on the three-pillar insulator conductor of the GIL three-pillar insulator, and the hydraulic rod applies pressure to the "convex"-shaped insulating bracket by moving vertically downward, so that the three-pillar insulator conductor is subjected to vertical downward mechanical stress.

[0013] The temperature loading device is arranged outside the metal cavity, and includes an oil bath pot, a temperature gauge, and a flow valve. The inlet and outlet of the oil bath pot are respectively connected to the two ports of the three-pillar insulator conductor of the GIL three-pillar insulator through an oil circulation pipeline, so as to form a circulation loop of insulating oil; the insulating oil heated to a preset temperature value enters the metal cavity through the oil circulation pipeline, flows through the three-pillar insulator conductor of the GIL three-pillar insulator, and then heats the three-pillar insulator conductor to a high temperature state, simulating the heating condition of the GIL current-carrying conductor.

[0014] The industrial frequency high-voltage power supply system is composed of a voltage regulator and a step-up transformer. The input end of the voltage regulator is connected to a 380V AC voltage source, and the output end is connected to the input end of the step-up transformer. A current-limiting resistor is connected between the output end of the step-up transformer and the high-voltage bushing.

[0015] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0016] The present invention applies mechanical stresses in different directions to the GIL three-pillar insulator through a mechanical stress loading device, loads different temperatures to the GIL three-pillar insulator through a temperature loading device to simulate the heating condition of the GIL current-carrying conductor, and loads different voltages to the GIL three-pillar insulator through an industrial frequency high-voltage power supply system to perform a bursting breakdown simulation test.

[0017] The explosion and breakdown simulation test device of the GIL three - pillar insulator of the present invention is reasonably designed. It can realize the explosion and breakdown test of the three - pillar insulator under the coupling action of electricity - heat - force, simulate the risks that the three - pillar insulator may face in the actual working conditions, and study the influence of electrical, thermal, and stress variables on the explosion and breakdown of the three - pillar insulator. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the inside of the metal cavity and the mechanical stress loading device in the present invention;

[0019] Figure 2 It is the front - view structural diagram of the scaled - down GIL model in the present invention;

[0020] Figure 3 It is the side - view structural diagram of the scaled - down GIL model in the present invention;

[0021] Figure 4 It is a schematic diagram of the temperature loading device in the present invention.

[0022] Reference numerals: 1 - I - shaped support; 2 - observation window; 3 - gas charging and discharging port; 4 - exhaust pipe; 5 - pressure gauge; 6 - SF6 gas cylinder; 7 - hydraulic pump; 8 - hydraulic pressure gauge; 9 - oil inlet and outlet; 10 - hydraulic cylinder; 11 - hydraulic rod; 12 - "convex" - shaped insulating support; 13 - scaled - down GIL model; 14 - high - voltage bushing; 15 - GIL three - pillar insulator; 16 - three - pillar insulator conductor; 17 - base; 18 - metal shell; 19 - oil bath; 20 - thermometer; 21 - flow valve; 22 - oil circulation pipeline; 23 - screw; 24 - gas charging and discharging valve; 25 - hydraulic oil station. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] The present invention will be further described below with reference to the drawings.

[0024] As Figures 1 to 4As shown in the figure, the GIL three-pillar insulator explosion and breakdown simulation test device of the present invention mainly includes a metal cavity capable of charging and discharging gas, a mechanical stress loading device, a temperature loading device, and a power frequency high-voltage power supply system. The metal cavity is used to place the GIL three-pillar insulator 15 and is filled with SF6 gas inside. The mechanical stress loading device loads mechanical stress on the GIL three-pillar insulator 15 inside the metal cavity through a hydraulic system. The temperature loading device heats the temperature of the three-pillar insulator conductor 16 of the GIL three-pillar insulator 15 by controlling the circulating oil temperature. The power frequency high-voltage power supply system applies different voltages to the GIL three-pillar insulator 15 through a high-voltage bushing. Through the cooperation of the metal cavity, the mechanical stress loading device, the temperature loading device, and the power frequency high-voltage power supply system, the actual operating conditions of the GIL can be simulated. While observing the explosion and breakdown process of the GIL three-pillar insulator 15 under the combined action of electricity, heat, and force, by changing variables such as the mechanical stress, temperature, and voltage applied to the GIL three-pillar insulator 15, the influence of each variable on the explosion and breakdown of the GIL three-pillar insulator 15 can be studied.

[0025] An I-shaped bracket 1 is provided at the bottom of the metal cavity. The I-shaped bracket 1 is fixedly connected to the flange below the metal cavity through fasteners such as nuts and washers. The middle part of the flange is a wiring board, which can realize the connection of the internal and external circuits of the metal cavity. Two I-shaped brackets 1 can be provided and are made of I-shaped steel. The midpoint between the two I-shaped brackets 1 and the center of gravity of the entire metal cavity are on the same vertical line, which can ensure the stability of the metal cavity and prevent it from tilting due to the installation of devices such as the hydraulic cylinder 10 and the high-voltage bushing 14.

[0026] A scaled-down GIL model 13 for installing the GIL three-pillar insulator 15 is arranged inside the metal cavity. The scaled-down GIL model 14 is composed of a base 17 and a cylindrical metal shell 18. The metal shell 18 is horizontally placed on the base 17. The GIL three-pillar insulator 15 is installed inside the metal shell 18 and fixed by screws 23. The three-pillar insulator conductor 16 is coaxially arranged with the metal shell 18, and both ends of the three-pillar insulator conductor 16 extend to both sides of the metal shell 18. An observation window 2 for observing the explosion and breakdown process of the GIL three-pillar insulator 15 is arranged on the side of the metal cavity. The metal cavity is provided with a gas charging and discharging port 3. The gas charging and discharging port 3 is connected to an SF6 gas cylinder 6 through an exhaust pipe 4. A pressure gauge 5 and a gas charging and discharging valve 24 are arranged on the exhaust pipe 4 for charging and discharging SF6 gas into the metal cavity. The pressure gauge 5 is used to display the air pressure value inside the metal cavity. The exhaust pipe 4 adopts a rubber exhaust pipe, and the SF6 gas cylinder 6 is used to store and recycle SF6 gas. Among them, the observation window 2 can be arranged on both side surfaces of the metal cavity. The observation window 2 can adopt tempered glass with a thickness of 3 cm. The tempered glass layer is clamped between flanges. After the flanges of the glass observation window are fixed to the metal cavity through fastening screws, the metal cavity is closed into a sealed space, and 0.4 MPa of SF6 gas can be filled into the closed cavity through the gas charging and discharging port to increase the breakdown field strength of the air gap. To ensure the airtightness of the metal cavity, the metal cavity and other components such as the hydraulic system or the high-voltage bushing 14 are fixed by flanges. An annular groove is arranged between each pair of flanges, and a rubber sealing ring is placed in the groove to ensure the airtightness between the observation window 2 and the metal cavity.

[0027] The mechanical stress loading device loads mechanical stress on the GIL three-pillar insulator 15 through a hydraulic system. The hydraulic system is composed of a hydraulic cylinder 10, a hydraulic pump 7, a hydraulic pressure gauge 8, a hydraulic oil station 25, and a hydraulic rod 11. The hydraulic cylinder 10 is fixed to the outer top of the metal cavity through a flange and is provided with two oil inlet and outlet ports 9. The two oil inlet and outlet ports 9 are respectively connected to the hydraulic oil station 25 through oil pipes. The hydraulic pump 7 and the hydraulic pressure gauge 8 are arranged on one of the oil pipes. Through the hydraulic pump 7, any one of the two oil pipes can be selected as the oil outlet pipe, and the other is the return pipe. By changing the direction of the hydraulic oil flowing in and out of the hydraulic cylinder 10 through the hydraulic pump 7, hydraulic oil is pumped into or out of the hydraulic cylinder 10, thereby controlling the up and down movement direction of the hydraulic rod 11 inside the hydraulic cylinder 10. The hydraulic oil station 25 can select the direction of the hydraulic oil in the two oil pipes according to the hydraulic rod 11, and then pump hydraulic oil into or out of the hydraulic cylinder 10 to control the movement direction of the hydraulic rod 11 inside the hydraulic cylinder 10.

[0028] One end of the hydraulic rod 11 is located inside the hydraulic cylinder 10, and the circular piece welded to the other end has an activity space inside the metal cavity. The stroke range of the hydraulic rod 11 is inside the cavity, and the direction is controlled by the hydraulic cylinder 10 and can move up and down. On the three-pillar insulator conductor 16 of the GIL three-pillar insulator 15, a "convex"-shaped insulating bracket 12 is erected. The "convex"-shaped insulating bracket 12 is erected between the hydraulic rod 11 and the three-pillar insulator conductor 16. The hydraulic rod 11 applies pressure to the "convex"-shaped insulating bracket 12 by moving vertically downward, so that the three-pillar insulator conductor 16 bears the mechanical stress vertically downward, realizing the loading of mechanical stress on the GIL three-pillar insulator 15. Remove the observation window 2, install the GIL three-pillar insulator 15 into the reduced-scale GIL model 13 in the metal cavity. By rotating the metal shell 18, the GIL three-pillar insulator 15 can be rotated 360 degrees, so as to adjust the angle between the legs of the GIL three-pillar insulator 15 and the hydraulic rod 11, and then apply mechanical stress in different directions to the legs of the GIL three-pillar insulator 15. Among them, the "convex"-shaped insulating bracket 12 can adopt an acrylic insulating bracket. The hydraulic pump 7 can control the pressure value pumped into the hydraulic cylinder 10. The pressure applied by the hydraulic system on the hydraulic rod 11, that is, the mechanical stress value applied by the hydraulic system on the three-pillar insulator conductor 16, can be read through the pressure gauge 8. The present invention can apply a mechanical stress of 0-2000N to the GIL three-pillar insulator 15.

[0029] The temperature loading device is arranged outside the metal cavity and loads different temperatures on the GIL three-pillar insulator 15 through oil circulation. The temperature loading device mainly includes an oil bath 19, a thermometer 20, and a flow valve 21. The inlet and outlet of the oil bath 19 are respectively connected to the two ports of the three-pillar insulator conductor 16 of the GIL three-pillar insulator 15 through an oil circulation pipeline 22 to form a circulation loop of insulating oil. The insulating oil is heated in the oil bath 19, and the circulating oil temperature can be read through the thermometer 20. The insulating oil that has been heated to the preset temperature enters the metal cavity through the oil circulation pipeline 22 (the metal cavity is provided with a reserved interface for accessing the oil circulation pipeline 22), flows through the inside of the three-pillar insulator conductor 16 of the GIL three-pillar insulator 15, and then heats the three-pillar insulator conductor 16 to a high temperature state to simulate the heating condition of the GIL current-carrying conductor. Since the SF6 gas with a pressure of 0.4-0.5MPa needs to be filled in the metal cavity during the experiment, the pressure in the metal cavity is higher than the atmospheric pressure of the air. A booster pump is needed to drive the insulating oil in the oil bath 19 into the cavity and flow into the inside of the three-pillar insulator conductor 16. The flow valve 21 is used to control the flow rate of the insulating oil in the oil circulation pipeline 22. The capacity of the oil bath 19 is 10L, the power is 2kW, the temperature control range is from room temperature to 200°C, and the flow rate is 40L / min. The temperature control device supporting the oil bath 19 adopts a PID controller to control the constant temperature and variable temperature rate.

[0030] A high-voltage bushing 14 is provided at the top of the metal cavity, and the metal cavity and the high-voltage bushing 14 are connected by a flange. One end of the high-voltage bushing 14 is connected to the three-pillar insulator conductor 16 of the GIL three-pillar insulator 15 inside the metal cavity, and the other end is connected to the power frequency high-voltage power supply system outside the metal cavity. Different voltages are applied to the GIL three-pillar insulator 15 through the power frequency high-voltage power supply system to conduct a simulation test of explosion and breakdown. The power frequency high-voltage power supply system is mainly composed of a voltage regulator and a step-up transformer. The input end of the voltage regulator is connected to a 380V AC voltage source, and the output end is connected to the input end of the step-up transformer. A current-limiting resistor is connected between the output end of the step-up transformer and the high-voltage bushing.

[0031] Among them, the voltage regulator is rated to input a power frequency 380V AC voltage, and the output voltage can be continuously changed in the range of 0 - 430V. And when the current exceeds the set value, the overcurrent relay inside the device starts to cut off the power automatically to protect the experimental circuit. The rated input voltage of the step-up transformer is 400V, the rated output voltage is 200kV, and the no-load operation time is 1min. After the 380V power frequency voltage is boosted by the voltage regulator and the transformer, the output end of the step-up transformer is connected to the upper end of the high-voltage bushing 14 through a current-limiting resistor, and the three-pillar insulator conductor 16 inside the metal cavity is connected to the lower end of the high-voltage bushing 14. The voltage value applied to the GIL three-pillar insulator 15 can be read by using an AC-DC voltage divider. A relatively high short-circuit current may occur during the breakdown test of the GIL three-pillar insulator 15. In order to limit the short-circuit current during the breakdown of the GIL three-pillar insulator 15 and avoid damage to the high-voltage power supply, a 1MΩ current-limiting resistor is connected between the output end of the step-up transformer and the high-voltage bushing 14. A capacitor voltage divider and a voltmeter are used in cooperation to monitor and measure the output voltage of the step-up transformer. The voltage division ratio of the capacitor voltage divider is 1000:1, and the capacitor voltage divider and the voltmeter are calibrated, and the measurement error is less than 1%. More specifically, in this embodiment, a voltage of 200kV can be applied to the GIL three-pillar insulator 15. More specifically, during the test process, the explosion and breakdown process of the GIL three-pillar insulator can be observed and recorded through the observation windows 2 at both ends of the cavity.

[0032] Although the functions and working processes of the present invention are described above in conjunction with the accompanying drawings, the present invention is not limited to the above specific functions and working processes. The above specific embodiments are merely illustrative and not restrictive. Under the inspiration of the present invention, those of ordinary skill in the art can also make many forms without departing from the purpose of the present invention and the scope protected by the claims, and these all belong to the protection scope of the present invention.

Claims

1. A simulation test device for explosion and breakdown of a GIL three-pillar insulator, characterized in that, It includes a metal cavity capable of storing and releasing gas, a mechanical stress loading device, a temperature loading device, and a power frequency high-voltage power supply system. The metal cavity is used to place the GIL three-pillar insulator (15) and is filled with SF6 gas inside. The mechanical stress loading device loads mechanical stress on the GIL three-pillar insulator (15) inside the metal cavity through a hydraulic system. The temperature loading device heats the temperature of the three-pillar insulator conductor (16) of the GIL three-pillar insulator (15) by controlling the circulating oil temperature. The power frequency high-voltage power supply system applies different voltages to the GIL three-pillar insulator (15) through a high-voltage bushing (14). By the cooperation of the metal cavity, the mechanical stress loading device, the temperature loading device, and the power frequency high-voltage power supply system, the actual operating conditions of the GIL are simulated. While observing the explosion and breakdown process of the GIL three-pillar insulator (15) under the combined action of electricity, heat, and force, by changing the mechanical stress, temperature, and voltage variables applied to the GIL three-pillar insulator (15), the influence of each variable on the explosion and breakdown of the GIL three-pillar insulator (15) is studied; Among them, an observation window (2) for observing the explosion and breakdown process of the GIL three-pillar insulator (15) is provided on the side of the metal cavity. The metal cavity is provided with a gas charging and discharging port (3), and the gas charging and discharging port (3) is connected to an SF6 gas cylinder (6) through an exhaust pipe (4). A pressure gauge (5) and a gas charging and discharging valve (24) are provided on the exhaust pipe (4). A scaled-down GIL model (13) for installing the GIL three-pillar insulator (15) is provided inside the metal cavity. A high-voltage bushing (14) is provided on the top of the metal cavity. One end of the high-voltage bushing (14) is connected to the three-pillar insulator conductor (16) of the GIL three-pillar insulator (15), and the other end is connected to the power frequency high-voltage power supply system. The scaled-down GIL model (13) consists of a base (17) and a cylindrical metal shell (18). The GIL three-pillar insulator (15) is installed inside the metal shell (18) and fixed by screws (23). By rotating the metal shell (18), the GIL three-pillar insulator (15) can be rotated 360 degrees, so as to adjust the angle between the legs of the GIL three-pillar insulator (15) and the hydraulic rod (11), and then apply mechanical stress in different directions to the legs of the GIL three-pillar insulator (15); The mechanical stress loading device applies mechanical stress to the three-pillar insulator (15) of the GIL through a hydraulic system. The hydraulic system consists of a hydraulic cylinder (10), a hydraulic pump (7), a hydraulic pressure gauge (8), a hydraulic oil station (25), and a hydraulic rod (11). The hydraulic cylinder (10) is fixed to the top of the metal cavity and is provided with two oil inlet and outlet ports (9). The two oil inlet and outlet ports (9) are respectively connected to the hydraulic oil station (25) through oil pipes. The hydraulic pump (7) and the hydraulic pressure gauge (8) are arranged on one of the oil pipes. By changing the direction of the hydraulic oil flowing in and out of the hydraulic cylinder (10) through the hydraulic pump (7), hydraulic oil is injected into or withdrawn from the hydraulic cylinder (10), thereby controlling the up and down movement direction of the hydraulic rod (11). One end of the hydraulic rod (11) is located inside the hydraulic cylinder (10), and the circular piece welded to the other end has an activity space inside the metal cavity. A "convex"-shaped insulating support (12) is erected on the three-pillar insulator conductors (16) of the three-pillar insulator (15) of the GIL. The hydraulic rod (11) applies pressure to the "convex"-shaped insulating support (12) by moving vertically downward, thereby causing the three-pillar insulator conductors (16) to bear mechanical stress vertically downward.

2. The GIL three-pillar insulator explosion and breakdown simulation test device according to claim 1, wherein, An I-shaped support (1) is provided at the bottom of the metal cavity. The I-shaped support (1) is fixedly connected to the flange below the metal cavity through fasteners. The middle part of the flange is a wiring board, which realizes the connection of the internal and external circuits of the metal cavity.

3. The GIL three-pillar insulator explosion and breakdown simulation test device according to claim 1, characterized in that, The temperature loading device is arranged outside the metal cavity and includes an oil bath (19), a thermometer (20), and a flow valve (21). The inlet and outlet of the oil bath (19) are respectively connected to the two ends of the three-pillar insulator conductor (16) of the three-pillar insulator (15) of the GIL through an oil circulation pipeline (22) to form a circulation loop of insulating oil. The insulating oil heated to a preset temperature value enters the metal cavity through the oil circulation pipeline (22), flows through the three-pillar insulator conductor (16) of the three-pillar insulator (15) of the GIL, and then heats the three-pillar insulator conductor (16) to a high-temperature state to simulate the heating condition of the GIL current-carrying conductor.

4. The GIL three-pillar insulator explosion and breakdown simulation test device according to claim 1, characterized in that The power frequency high-voltage power supply system consists of a voltage regulator and a step-up transformer. The input end of the voltage regulator is connected to a 380V AC voltage source, and the output end is connected to the input end of the step-up transformer. A current-limiting resistor is connected between the output end of the step-up transformer and the high-voltage bushing.

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