Test tool for gas insulation criterion research

Abstract

The utility model relates to a test tool for gas insulation criterion research, and belongs to the technical field of test tools, the test tool comprises a test box body and a capacitive high-voltage bushing communicated with the test box body, and the test box body comprises a shell, an upper electrode, a lower electrode and an insulation cushion block. According to the application, the test is relatively convenient, the surface breakdown voltage characteristic and the breakdown path of the solid insulation under the specified pressure can be obtained, and the air gap breakdown characteristic between the two electrodes (after the insulating cushion block between the electrodes is taken out) can be obtained. And design regulations are provided for turn-to-turn insulation design, main insulation design and lead-to-ground insulation design of the gas insulation transformer. The lower electrode of the test tool is designed to be a movable electrode, breakdown voltage values under different distances can be obtained by adjusting the distance between the lower electrode and the upper electrode, and a breakdown voltage curve can be drawn.

Description

Technical Field

[0001] This application relates to the technical field of test fixtures, and in particular to a test fixture for studying gas insulation criteria. Background Technology

[0002] As one of the most important pieces of equipment in a power system, the safety and stability of transformers are of paramount importance. To ensure the quality and performance of transformers, a series of tests are required, among which lightning impulse and switching impulse tests are essential components.

[0003] In order to study the discharge of different insulation structures under lightning strikes in a gas-insulating medium with a set electrode shape, our company has designed this test fixture structure for establishing gas insulation criteria. Utility Model Content

[0004] The purpose of this application is to provide a test fixture for studying gas insulation criteria, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, this application provides a test fixture for studying gas insulation criteria, employing the following technical solution:

[0006] A test fixture for studying gas insulation criteria includes a test chamber and a capacitive high-voltage bushing connected to the test chamber. The test chamber includes an outer shell, an upper electrode, a lower electrode, and an insulating pad. End caps are provided at both ends of the outer shell, and the end caps are detachably and sealed to the outer shell. An air inlet is provided on one end cap, and a valve is also installed at the air inlet. The upper electrode is fixed inside the upper wall of the outer shell and is electrically connected to the capacitive high-voltage bushing. The lower electrode is movably disposed through the bottom wall of the outer shell and is correspondingly disposed to the upper electrode. A bracket is also fixed at the bottom of the outer shell, and an adjusting screw is threaded onto the bracket. The top end of the adjusting screw is rotatably connected to the bottom end of the lower electrode. The insulating pad is disposed on the top surface of the lower electrode.

[0007] During testing, the lower electrode is connected to a grounding wire.

[0008] Preferably, an observation window is provided on one side of the outer casing in order to directly observe the electric shock situation inside the test chamber.

[0009] The test chamber is filled with environmentally friendly gas, and the gas pressure range is 0.2MPa-0.25MPa.

[0010] The electrode shapes at the ends of both the upper and lower electrodes are set to ring shapes.

[0011] Preferably, in order to provide better support for the testing work, a support base is also installed at the bottom of the housing.

[0012] The capacitive high-voltage bushing can be subjected to a lightning impulse voltage of 550KV.

[0013] In summary, this application includes at least one of the following beneficial technical effects: The test fixture for gas insulation criterion research has a simple structure and is relatively convenient for testing. It can obtain the surface breakdown voltage characteristics and breakdown path of solid insulation under a specified pressure, and can obtain the air gap breakdown characteristics between two electrodes (after removing the insulating pad between the electrodes). It provides design specifications for the inter-turn insulation design, main insulation design, and lead-to-ground insulation design of gas-insulated transformers. The lower electrode of the test fixture is designed as a movable electrode, and the breakdown voltage value at different distances can be obtained by adjusting the distance between the lower electrode and the upper electrode, thus enabling the plotting of the breakdown voltage curve. Attached Figure Description

[0014] Figure 1 This is a cross-sectional structural diagram of an embodiment of this application.

[0015] Figure 2 This is a schematic diagram illustrating the internal structure of the test chamber in an embodiment of this application.

[0016] Explanation of reference numerals in the attached drawings: 1. Test chamber; 11. Outer shell; 12. Upper electrode; 13. Lower electrode; 14. Insulating pad; 15. End cap; 16. Air inlet; 17. Valve; 18. Bracket; 2. Capacitive high-voltage bushing; 3. Adjusting screw; 4. Support base. Detailed Implementation

[0017] The following is in conjunction with the appendix Figure 1-2 This application will be described in further detail.

[0018] This application discloses a test fixture for studying gas insulation criteria, referring to... Figure 1-2The test chamber includes a test housing 1 and a capacitive high-voltage bushing 2 connected to the test housing 1. The capacitive high-voltage bushing 2 can apply a lightning impulse voltage of 550KV. The test housing 1 includes a shell 11, an upper electrode 12, a lower electrode 13, and an insulating pad 14. End caps 15 are provided at both ends of the shell 11. The end caps 15 are detachably and sealed to the shell 11. An air inlet 16 is provided on one end cap 15, and a valve 17 is also installed at the air inlet 16. The upper electrode 12 is fixed inside the upper wall of the shell 11 and is electrically connected to the capacitive high-voltage bushing 2. The lower electrode 13 movably penetrates the shell 11. The bottom wall is set with the lower electrode 13 corresponding to the upper electrode 12. The bottom of the outer shell 11 is also fixed with a bracket 18. The bracket 18 is threaded with an adjusting screw 3. The top of the adjusting screw 3 is rotatably connected to the bottom of the lower electrode 13. The electrode shapes at the ends of the upper electrode 12 and the lower electrode 13 are both set as ring shapes. An insulating pad 14 is set on the top surface of the lower electrode 13. During the test, the lower electrode 13 is connected to a grounding wire. The test chamber 1 is filled with environmentally friendly gas, and the pressure value of the gas is in the range of 0.2MPa-0.25MPa. The environmentally friendly gas can be CO2, CO2 / C4d, etc.

[0019] In order to directly observe the electric shock situation inside the test chamber 1, an observation window is provided on one side of the outer casing 11. At the same time, in order to improve the test accuracy, an oscilloscope can be installed in the external circuit of the capacitive high voltage bushing 2.

[0020] Reference Figure 1 In order to ensure that the test fixture is placed stably, a support base 4 is also installed at the bottom of the outer shell 11.

[0021] The implementation principle of a test fixture for studying gas insulation criteria in this application embodiment is as follows:

[0022] During testing, the model structure is first simulated and calculated. Based on the calculation results, the structure under the most stringent operating conditions is found, and the theoretical breakdown voltage can be calculated through simulation.

[0023] During the actual test, based on the structure calculated by simulation, the shim was placed on the lower electrode 13, and the adjusting screw 3 was rotated to adjust the distance between the shim and the upper electrode 12 to maintain consistency with the structure calculated by simulation. After the overall structure was assembled, the pre-set environmentally friendly gas was filled in at a pressure of 0.2 MPa.

[0024] When applying a lightning impulse voltage, the voltage is initially applied at U50 (50% of the simulated voltage), increasing by 10% increments until the surface of the insulating pad 14 inside the test chamber 1 breaks down, thus obtaining the measured breakdown voltage value. By comparing the breakdown voltage with the simulation calculation, the calculation coefficients are corrected, improving the accuracy of the simulation calculation and providing a reliable basis for simulation calculations of different structures.

[0025] This test fixture allows for the acquisition of surface breakdown voltage characteristics and breakdown paths of solid insulation under specified pressure, as well as the air gap breakdown characteristics between two electrodes (after removing the insulating pad 14 between the electrodes). It provides design specifications for inter-turn insulation design, main insulation design, and lead-to-ground insulation design of gas-insulated transformers. The lower electrode 13 of the test fixture is designed as a movable electrode; by adjusting the distance between the lower electrode 13 and the upper electrode 12, breakdown voltage values ​​at different distances can be obtained, allowing for the plotting of breakdown voltage curves.

[0026] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A test fixture for studying gas insulation criteria, characterized in that: The test chamber includes a test housing (1) and a capacitor-type high-voltage bushing (2) connected to the test housing (1). The test housing (1) includes a shell (11), an upper electrode (12), a lower electrode (13), and an insulating pad (14). The shell (11) has end caps (15) at both ends, which are detachably and sealed to the shell (11). An air inlet (16) is provided on one side of the end cap (15), and a valve (17) is installed at the air inlet (16). The upper electrode (12) is fixed to the test housing. The lower electrode (13) is located inside the upper wall of the outer shell (11) and is electrically connected to the capacitor high voltage bushing (2). The lower electrode (13) is movably installed through the bottom wall of the outer shell (11). The lower electrode (13) is correspondingly installed with the upper electrode (12). A bracket (18) is also fixed at the bottom of the outer shell (11). An adjusting screw (3) is threaded onto the bracket (18). The top end of the adjusting screw (3) is rotatably connected to the bottom end of the lower electrode (13). An insulating pad (14) is installed on the top surface of the lower electrode (13).

2. The test fixture for studying gas insulation criteria according to claim 1, characterized in that: During testing, the lower electrode (13) is connected to a grounding wire.

3. The test fixture for studying gas insulation criteria according to claim 1, characterized in that: An observation window is provided on one side of the outer casing (11).

4. The test fixture for studying gas insulation criteria according to claim 1, characterized in that: The test chamber (1) is filled with environmentally friendly gas, and the gas pressure range is 0.2MPA-0.25MPA.

5. The test fixture for studying gas insulation criteria according to claim 1, characterized in that: The electrode shapes at the ends of the upper electrode (12) and the lower electrode (13) are both set to ring shapes.

6. The test fixture for studying gas insulation criteria according to claim 1, characterized in that: The bottom of the outer casing (11) is also equipped with a support base (4).

7. The test fixture for studying gas insulation criteria according to claim 1, characterized in that: The capacitive high-voltage bushing (2) is capable of applying a lightning impulse voltage of 550KV.

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