Solid insulation breakdown test device with adjustable temperature difference and test method thereof

Abstract

The invention provides a solid insulation breakdown test device with adjustable temperature difference and a test method thereof, and belongs to the technical field of high voltage and insulation. The problem in the prior art that the insulating material bears the temperature difference stress and the insulating property test is influenced because the external environment radiates heat and keeps low temperature is solved. The device comprises an intelligent console, a high-voltage discharge rod, a test transformer, a protective resistor, an upper electrode system, a lower electrode system and a low-temperature constant-temperature circulator, the intelligent console is connected with the test transformer through a circuit, and the high-voltage discharge rod is arranged between the intelligent console and the test transformer. Two ends of the protective resistor are respectively connected with the test transformer and the upper electrode system through circuits, the upper electrode system is connected with the lower electrode system, the lower electrode system is connected with the low-temperature constant-temperature circulator through a circuit, and a solid insulation sample to be tested is arranged between the upper electrode system and the lower electrode system. The device is mainly used for insulation sample breakdown test.

Description

Technical Field

[0001] The present invention belongs to the technical field of high voltage and insulation, and in particular relates to a solid insulation breakdown test device with adjustable temperature difference and a test method thereof. Background Art

[0002] With the all-round strengthening of high-quality development of new power systems, dry-type electrical equipment (such as dry-type transformers, dry-type reactors, etc.) has become the first choice to replace oil-immersed equipment due to its characteristics such as no need for insulating oil, no pollution, and recyclability. Therefore, higher requirements are placed on its power density, life, maintenance cost and environmental adaptability. Breakdown performance is the core indicator of insulating materials, and with the increase in extreme climates and the trend of high-density equipment, insulation performance under temperature difference will become one of the core directions of technological breakthroughs in dry-type equipment.

[0003] However, traditional breakdown tests are usually performed at a constant temperature and cannot simulate the temperature gradient formed by local heating and heat dissipation in actual equipment. For example, the high temperature generated inside the insulation material of the dry-type transformer winding due to the load, and the external temperature maintained at a lower level due to heat dissipation from the external environment (for example, the lowest temperature in cold areas in winter is -40°C), causing the insulation material to be subjected to temperature difference stress. In addition, during the test process, the impact of the synergistic effect of temperature difference gradient and electric field on insulation performance was not explored. Summary of the Invention

[0004] In view of this, the present invention aims to propose a solid insulation breakdown test device with adjustable temperature difference and a test method thereof, so as to solve the problem in the prior art that the insulation material is subjected to temperature difference stress due to the external environment dissipating heat and maintaining low temperature, thereby affecting its insulation performance test.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A solid insulation breakdown test device with an adjustable temperature difference comprises an intelligent control console, a high-voltage discharge rod, a test transformer, a protective resistor, an upper electrode system, a lower electrode system, and a low-temperature constant-temperature circulator. The intelligent control console is connected to the test transformer via a circuit, a high-voltage discharge rod is provided between the intelligent control console and the test transformer, two ends of the protective resistor are respectively connected to the test transformer and the upper electrode system via a circuit, the upper electrode system is connected to the lower electrode system, the lower electrode system is connected to the low-temperature constant-temperature circulator via a circuit, and a solid insulation sample to be tested is installed between the upper electrode system and the lower electrode system.

[0007] Furthermore, the upper electrode system includes an insulating load-bearing bracket, an insulating beam, a ceramic heating plate and an upper electrode. The insulating beam is connected to the insulating load-bearing bracket, the upper electrode is installed under the insulating beam, and a ceramic heating plate is installed on the upper end surface of the upper electrode.

[0008] Furthermore, the lower electrode system is placed on a load-bearing platform, and the lower electrode system includes a lower electrode, an aluminum nitride ceramic block and a cast iron plate. An oil tank is provided above the cast iron plate, and the aluminum nitride ceramic block is installed in the center of the oil tank. The lower electrode is installed on the aluminum nitride ceramic block, the upper electrode is in contact with the lower electrode, and the cast iron plate is connected to a low-temperature constant temperature circulator.

[0009] Furthermore, an isolation fence is provided on the outside of the intelligent control console, and the protective resistor is installed on a load-bearing bracket.

[0010] Furthermore, a layer of thermal conductive silicone grease is coated between the ceramic heating plate and the upper electrode.

[0011] Furthermore, the upper electrode and the lower electrode are both made of brass.

[0012] A method for testing a solid insulation breakdown test device with an adjustable temperature difference comprises the following steps:

[0013] Step 1: Before testing, wipe the surface of the solid insulation sample to be tested with anhydrous ethanol to remove impurities on the surface, and then dry it in a vacuum environment at 35°C for 2 hours;

[0014] Step 2: Place the treated solid insulation sample to be tested on the lower electrode, and adjust the height of the upper electrode so that the upper electrode and the lower electrode fit tightly against the solid insulation sample to be tested;

[0015] Step 3: Set the heating temperature of the ceramic heater and the cooling temperature of the low-temperature constant temperature circulator, and keep running for 30 minutes to ensure that a stable temperature difference is formed between the upper and lower surfaces of the solid insulation sample to be tested. Then, operate the intelligent console to apply voltage to the solid insulation sample to test the breakdown performance of the solid insulation sample to be tested and record the voltage parameters at the time of breakdown.

[0016] Step 4: After discharging the residual charge of the test transformer using a high-voltage discharge rod, replace the solid insulation sample to be tested and repeat steps 1-3.

[0017] Furthermore, in step 1, the diameter of the solid insulation sample to be tested is 10 cm and the thickness is 1 mm.

[0018] Furthermore, in step 2, the upper electrode diameter is 25 mm and the lower electrode diameter is 75 mm.

[0019] Furthermore, in step 3, the voltage boosting method is uniform voltage boosting, and the voltage boosting rate is 10 kV / s.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The present invention utilizes a combination of a ceramic heater and a low-temperature constant-temperature circulator. The ceramic heater, with its rapid heating characteristics and excellent thermal conductivity and insulation properties, can efficiently heat the upper surface of the solid insulation sample to be tested. The low-temperature constant-temperature circulator provides a precisely controllable low-temperature environment for the lower surface of the sample by stably delivering a low-temperature circulating medium, thereby establishing a stable temperature gradient between the upper and lower surfaces of the sample. This device can simulate operating temperature differences in different environmental regions, different workloads, and other working conditions with high control accuracy, providing reliable and stable experimental conditions for breakdown testing.

[0022] 2. This invention takes into account the influence of temperature gradient on the material breakdown path, upgrading the insulation test from a single electric field assessment to a multi-physical field coupling analysis, filling a key gap in this field and significantly improving the engineering guidance value of the test results. For dry-type electrical equipment, its core significance lies in avoiding the risk of thermal-electrical combined failure from the design stage and promoting the development of equipment towards high reliability and high power density. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0024] Figure 1 This is a structural schematic diagram of a solid insulation breakdown test device with adjustable temperature difference according to the present invention;

[0025] Figure 2 Schematic diagram of the structure of the upper electrode system of the present invention;

[0026] Figure 3 Schematic diagram of the structure of the lower electrode system of the present invention.

[0027] In the picture:

[0028] 1-Intelligent control console, 2-Isolation fence, 3-High-voltage discharge rod, 4-Test transformer, 5-Protective resistor, 6-Load-bearing bracket, 7-Upper electrode system, 8-Insulation load-bearing bracket, 9-Insulation beam, 10-Ceramic heating plate, 11-Upper electrode, 12-Solid insulation sample to be tested, 13-Lower electrode system, 14-Lower electrode, 15-Aluminum nitride ceramic block, 16-Cast iron plate, 17-Load-bearing platform, 18-Low-temperature constant temperature circulator. DETAILED DESCRIPTION

[0029] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely explain the technical solutions in the embodiments of the present invention. It should be noted that the embodiments of the present invention and the features therein can be combined with each other in the absence of conflict, and the embodiments described are only part of the embodiments of the present invention, not all of the embodiments.

[0030] Specific implementation 1: See Figure 1-3 To describe this embodiment, a solid insulation breakdown test device with an adjustable temperature difference includes an intelligent control console 1, a high-voltage discharge rod 3, a test transformer 4, a protective resistor 5, an upper electrode system 7, a lower electrode system 13, and a low-temperature constant temperature circulator 18. The intelligent control console 1 is connected to the test transformer 4 through a circuit, a high-voltage discharge rod 3 is provided between the intelligent control console 1 and the test transformer 4, both ends of the protective resistor 5 are respectively connected to the test transformer 4 and the upper electrode system 7 through a circuit, and a solid insulation sample 12 to be tested is installed between the upper electrode system 7 and the lower electrode system 13.

[0031] In this embodiment, an isolation fence 2 is provided on the outside of the intelligent control console 1, and the protective resistor 5 is installed on the load-bearing bracket 6. The intelligent control console 1 is placed outside the isolation fence 2. Parameters can be set and data can be read through the LCD instrument. The signal processing unit inside the console analyzes and controls the boost mode and boost rate of the test transformer 4 and the heating temperature of the ceramic heating plate 10.

[0032] In this embodiment, the test transformer 4 is connected to the intelligent control console 1 through a circuit, and the internal voltage regulating device is accurately adjusted according to the signal to provide the high voltage output parameters required in the circuit, ensuring the accuracy and reliability of the test data.

[0033] In this embodiment, the protective resistor 5 is connected to the test transformer 4 and the upper electrode system 7 through a circuit and is placed on a load-bearing bracket 6 to limit the instantaneous overcurrent in the circuit caused by the breakdown of the solid insulation sample to be tested, thereby protecting the equipment in the circuit.

[0034] In this embodiment, the upper electrode system 7 includes an insulating load-bearing bracket 8, an insulating beam 9, a ceramic heating plate 10 and an upper electrode 11. The insulating beam 9 is connected to the insulating load-bearing bracket 8, and the upper electrode 11 is installed below the insulating beam 9. The ceramic heating plate 10 is installed on the upper end surface of the upper electrode 11. The height of the upper electrode 11 is adjusted by moving the position of the insulating beam 9 on the insulating load-bearing bracket 8, which facilitates the replacement of the solid insulation sample 12 to be tested and effective clamping with the lower electrode 14. The ceramic heating plate 10 is used to heat the upper electrode 11 to simulate the internal insulation temperature of dry-type electrical equipment under real working conditions.

[0035] In this embodiment, the lower electrode system 13 is connected to the low-temperature constant temperature circulator 18 through a circuit. The lower electrode system 13 is placed on a load-bearing platform 17. The lower electrode system 13 includes a lower electrode 14, an aluminum nitride ceramic block 15 and a cast iron plate 16. An oil tank is provided above the cast iron plate 16. The aluminum nitride ceramic block 15 is installed in the center of the oil tank. The lower electrode 14 is installed on the aluminum nitride ceramic block 15. The upper electrode 11 is in contact with the lower electrode 14. The cast iron plate 16 is connected to the low-temperature constant temperature circulator 18, wherein the cast iron plate 16 is welded with an oil tank for holding silicone oil to ensure that the lower electrode and the solid insulation sample to be tested are immersed in oil, thereby eliminating the influence of the air gap on the test results and improving the accuracy and stability of the test. The cast iron plate is cooled by being connected to the pipeline of the low-temperature constant temperature circulator 18, which is used to simulate the external environmental temperature of the insulation of dry-type electrical equipment under real working conditions.

[0036] During use, before testing the solid insulation sample 12 to be tested, it is necessary to wipe the surface with anhydrous ethanol to remove impurities, and continue drying for 2 hours in a vacuum environment at 35°C, place the pretreated solid insulation sample 12 to be tested on the lower electrode 14, adjust the height of the upper electrode 11, and make the upper and lower electrodes fit tightly against the insulation sample, set the heating temperature of the ceramic heating plate 10 and the cooling temperature of the low-temperature constant temperature circulator 18, and keep running for 30 minutes to ensure that a stable temperature difference condition is formed on the upper and lower surfaces of the solid insulation sample 12 to be tested, operate the intelligent control console 1 to apply voltage to the sample, test the breakdown performance of the sample and record the voltage parameters at the time of breakdown, use the high-voltage discharge rod 3 to discharge the residual charge of the test transformer 4, then replace the insulation sample and repeat the above operation.

[0037] By combining the ceramic heating plate 10 and the low-temperature constant temperature circulator 18, the ceramic heating plate 10 can efficiently heat the upper surface of the solid insulation sample to be tested due to its rapid heating characteristics and excellent thermal conductivity and insulation properties; the low-temperature constant temperature circulator 18 provides a precisely controllable low-temperature environment for the lower surface of the sample by stably delivering the low-temperature circulating medium, thereby establishing a stable temperature gradient between the upper and lower surfaces of the sample. The device can simulate the operating temperature difference of different environmental regions, different workloads and other working conditions, and has high control accuracy, providing reliable and stable experimental conditions for breakdown testing. The device takes into account the influence of temperature gradient on the breakdown path of the material, upgrading the insulation test from a single electric field evaluation to a multi-physical field coupling analysis, filling the key gap in this field and significantly improving the engineering guidance value of the test results. For dry-type electrical equipment, its core significance lies in avoiding the risk of thermal-electrical combined failure from the design stage and promoting the development of equipment towards high reliability and high power density.

[0038] Specific embodiment 2: A layer of thermal conductive silicone grease is evenly coated between the bonding surface of the ceramic heating plate 10 and the upper electrode 11, which is used to efficiently transfer the heat generated by the heating plate to the upper electrode 11, so that the upper electrode 11 can quickly reach the predetermined operating temperature, and the temperature control system can collect data in real time to achieve precise control within the temperature range of 25°C-100°C.

[0039] Specific embodiment 3: The cooling liquid of the low-temperature constant temperature circulator 18 adopts a special antifreeze liquid to achieve precise control of the cooling temperature of the cast iron plate 16 within the temperature range of -30°C to 25°C.

[0040] Specific embodiment 4: The upper electrode 11 and the lower electrode 14 are both made of brass, which has good thermal conductivity, corrosion resistance and electrical conductivity. They are both cylindrical in shape, so that the electric field is evenly distributed.

[0041] Specific implementation 5: See Figure 1-3 This embodiment describes a method for testing a solid insulation breakdown test device with an adjustable temperature difference, comprising the following steps:

[0042] Step 1: Before testing, wipe the surface of the solid insulation sample 12 to be tested with anhydrous ethanol to remove impurities on the surface, and then dry it in a vacuum environment at 35°C for 2 hours;

[0043] Step 2: Place the processed solid insulation sample 12 to be tested on the lower electrode 14, and adjust the height of the upper electrode 11 so that the upper electrode 11 and the lower electrode 14 are tightly attached to the solid insulation sample 12 to be tested;

[0044] Step 3: Set the heating temperature of the ceramic heater 10 and the cooling temperature of the low-temperature constant temperature circulator 18, and keep them running for 30 minutes to ensure that a stable temperature difference condition is formed between the upper and lower surfaces of the solid insulation sample 12 to be tested. Then, operate the intelligent control console 1 to apply voltage to the solid insulation sample 12 to test the breakdown performance of the solid insulation sample 12 to be tested and record the voltage parameters at the time of breakdown;

[0045] Step 4: After discharging the residual charge of the test transformer 4 using the high-voltage discharge rod 3, replace the solid insulation sample 12 to be tested and repeat steps 1-3.

[0046] In this embodiment, the solid insulation sample 12 to be tested in step 1 has a diameter of 10 cm and a thickness of 1 mm.

[0047] In this embodiment, in step 2, the diameter of the upper electrode 11 is 25 mm, and the diameter of the lower electrode 14 is 75 mm.

[0048] In this embodiment, the voltage applied in step 3 is boosted at a constant speed, and the boost rate is 10 kV / s.

[0049] The specific embodiments of the present invention disclosed above are intended only to help illustrate the present invention. The specific embodiments do not describe all details in detail, nor do they limit the invention to the specific embodiments described. Numerous modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention.

Claims

1. A solid insulation breakdown test device with adjustable temperature difference, characterized in that: The invention comprises an intelligent control console (1), a high-voltage discharge rod (3), a test transformer (4), a protective resistor (5), an upper electrode system (7), a lower electrode system (13) and a low-temperature constant temperature circulator (18). The intelligent control console (1) is connected to the test transformer (4) via a circuit. A high-voltage discharge rod (3) is provided between the intelligent control console (1) and the test transformer (4). Two ends of the protective resistor (5) are respectively connected to the test transformer (4) and the upper electrode system (7) via a circuit. The upper electrode system (7) is connected to the lower electrode system (13). The lower electrode system (13) is connected to the low-temperature constant temperature circulator (18) via a circuit. A solid insulation sample (12) to be tested is provided between the upper electrode system (7) and the lower electrode system (13).

2. The solid insulation breakdown test device with adjustable temperature difference according to claim 1, characterized in that: The upper electrode system (7) comprises an insulating load-bearing support (8), an insulating crossbeam (9), a ceramic heating plate (10), and an upper electrode (11). The insulating crossbeam (9) is connected to the insulating load-bearing support (8). The upper electrode (11) is installed below the insulating crossbeam (9). The ceramic heating plate (10) is installed on the upper end surface of the upper electrode (11).

3. The solid insulation breakdown test device with adjustable temperature difference according to claim 2, characterized in that: The lower electrode system (13) is placed on a bearing platform (17). The lower electrode system (13) includes a lower electrode (14), an aluminum nitride ceramic block (15), and a cast iron plate (16). An oil tank is provided above the cast iron plate (16). The aluminum nitride ceramic block (15) is installed in the center of the oil tank. The lower electrode (14) is installed on the aluminum nitride ceramic block (15). The upper electrode (11) contacts the lower electrode (14). The cast iron plate (16) is connected to a low-temperature constant temperature circulator (18).

4. The solid insulation breakdown test device with adjustable temperature difference according to claim 1, characterized in that: An isolation fence (2) is provided outside the intelligent control console (1), and the protective resistor (5) is installed on a load-bearing bracket (6).

5. The solid insulation breakdown test device with adjustable temperature difference according to claim 2, characterized in that: A layer of thermally conductive silicone grease is coated between the ceramic heating plate (10) and the upper electrode (11).

6. The solid insulation breakdown test device with adjustable temperature difference according to claim 3, characterized in that: The upper electrode (11) and the lower electrode (14) are both made of brass.

7. A method for testing a solid insulation breakdown test device with an adjustable temperature difference according to any one of claims 1 to 6, characterized in that: It includes the following steps: Step 1: Before testing, wipe the surface of the solid insulation sample (12) to be tested with anhydrous ethanol to remove impurities on the surface, and then continue drying at 35°C in a vacuum environment for 2 hours; Step 2: placing the processed solid insulation sample (12) to be tested on the lower electrode (14), and adjusting the height of the upper electrode (11) so that the upper electrode (11) and the lower electrode (14) are closely attached to the solid insulation sample (12) to be tested; Step 3: Set the heating temperature of the ceramic heating plate (10) and the cooling temperature of the low-temperature constant temperature circulator (18), keep running for 30 minutes, ensure that a stable temperature difference condition is formed between the upper and lower surfaces of the solid insulation sample (12) to be tested, operate the intelligent control console (1) to apply voltage to the solid insulation sample (12) to test the breakdown performance of the solid insulation sample (12) to be tested and record the voltage parameters at the time of breakdown; Step 4: After discharging the residual charge of the test transformer (4) using a high-voltage discharge rod (3), replace the solid insulation sample (12) to be tested and repeat steps 1-3.

8. The testing method of a solid insulation breakdown testing device with adjustable temperature difference according to claim 7, characterized in that: In step 1, the solid insulation sample (12) to be tested has a diameter of 10 cm and a thickness of 1 mm.

9. The testing method of a solid insulation breakdown testing device with adjustable temperature difference according to claim 7, characterized in that: In step 2, the diameter of the upper electrode (11) is 25 mm, and the diameter of the lower electrode (14) is 75 mm.

10. The testing method of a solid insulation breakdown testing device with adjustable temperature difference according to claim 7, characterized in that: In step 3, the voltage is increased at a constant speed, and the voltage increase rate is 10 kV / s.

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