Device and method for testing heat-conducting property of insulating material in cold region in low-voltage environment
By combining components such as a single-phase AC power supply, a thermal conductivity tester, and a low-temperature constant temperature circulator, combined with ceramic materials, the problem of thermal conductivity performance testing in cold, low-temperature, and low-voltage environments is solved, precise testing and data accuracy are achieved, and the safety and stability of the test are improved.
Patent Information
- Application Number
- CN202510936336.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-08
- Publication Date
- 2025-09-19
AI Technical Summary
Existing thermal conductivity testing devices are unable to simultaneously simulate the low temperature environment and low voltage operating conditions in cold regions, resulting in large deviations in test results and the inability to accurately obtain thermal conductivity data of insulating materials in actual usage scenarios.
Using single-phase AC power supply, thermal conductivity tester, low-temperature constant temperature circulator and other components, combined with ceramic materials to make hot and cold electrodes, a one-dimensional steady-state heat flow field is established through the heat flow method, and the temperature and sample fixation are precisely controlled to achieve accurate testing of insulating materials.
It realizes precise thermal conductivity testing in cold and low-voltage environments, provides accurate data basis, improves reliability for insulation material selection and design, and improves the safety and stability of testing.
Smart Images
Figure CN120668724A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of electrical insulation testing, and in particular relates to a device and a method for testing the thermal conductivity of insulation materials in cold regions under a low voltage environment. Background Art
[0002] Cold regions are characterized by low temperatures and large temperature differences. The performance of the insulation materials of electrical equipment operating in such environments will be significantly affected. For example, in power transformers, switchgear and other equipment in cold regions, changes in the thermal conductivity of the insulation materials under the action of low temperatures and voltages may lead to heat accumulation or uneven heat dissipation inside the equipment, thus affecting the normal operation and service life of the equipment.
[0003] However, existing thermal conductivity testing devices have many shortcomings. Most devices cannot simultaneously simulate the low temperature environment and low voltage conditions in cold regions, making it difficult to accurately obtain thermal conductivity data of insulating materials in actual usage scenarios. Some devices lack precision in sample fixation and temperature control, resulting in large deviations in test results. Moreover, during the test process, the voltage application and monitoring are not accurate enough to meet the testing requirements in low-voltage environments, making it impossible for test data to effectively guide the selection and design of insulating materials for electrical equipment in cold regions. Summary of the Invention
[0004] In view of this, the present invention aims to propose a device and method for testing the thermal conductivity of insulation materials in cold regions under a low-voltage environment, so as to solve the problem that most existing devices cannot simultaneously simulate the low-temperature environment and low-voltage working conditions in cold regions, and it is difficult to accurately obtain the thermal conductivity data of insulation materials in actual usage scenarios. Some devices have poor accuracy in sample fixation and temperature control, resulting in large deviations in test results.
[0005] To achieve the above object, the present invention adopts the following technical solutions: A device for testing the thermal conductivity of insulating materials in cold regions under a low-voltage environment comprises a computer, a single-phase AC power supply, a thermal conductivity tester, a temperature control console, and a low-temperature constant-temperature circulator. The single-phase AC power supply is equipped with a voltage adjustment knob for adjusting the output voltage and a current and voltage display for monitoring output parameters. The output end of the single-phase AC power supply is connected to two circular electrodes via a protection circuit, and a protection resistor is connected in series in the protection circuit. The thermal conductivity tester is equipped with a temperature control console. The computer is connected to the thermal conductivity tester. The thermal conductivity tester comprises a moving rod, a fixed rod, a hot electrode, and a cold electrode. The hot electrode is mounted on the fixed rod, and the cold electrode is mounted on the moving rod. A sample is placed between the cold electrode and the hot electrode. Two circular electrodes are symmetrically mounted on the upper end surface of the sample. The low-temperature constant-temperature circulator comprises a circulating water tank filled with circulating fluid and connected to the cold electrode via a water pipe. The hot electrode uses an electric heating element as a heat source.
[0006] Furthermore, both the cold electrode and the hot electrode are made of ceramic materials.
[0007] Furthermore, the test principle of the thermal conductivity tester is to establish a one-dimensional steady-state heat flow field by the heat flow method through a hot pole stable high temperature environment and a cold pole stable low temperature environment, directly measure the heat flux density q and temperature gradient dT / dx, and thus calculate the thermal conductivity coefficient of the thermal conductivity tester. The formula is as follows: .
[0008] Furthermore, the heating range of the hot pole is 25°C-100°C, and the cooling range of the cold pole is -35°C-25°C.
[0009] Furthermore, the single-phase AC power boost range is 0-200V.
[0010] Furthermore, the hot electrode is a cylindrical structure with an end face diameter of 30±0.1 mm, the geometric dimensions of the sample meet the following requirements: length 80-90 mm, width 45-55 mm, thickness 0.25-0.35 mm, and the fixing rod is a cylindrical guide mechanism with a diameter of 200±0.5 mm.
[0011] A method for testing a device for testing the thermal conductivity of insulation materials in cold regions under a low voltage environment comprises the following steps: Step 1: Apply thermal grease evenly to the contact areas between the sample surface and the cold and hot electrodes; Step 2: Heat the thermocouple through the temperature control console and turn on the cryostat. Use the computer to control the thermocouple heating temperature and set the cooling temperature through the cryostat panel. Step 3: After driving the moving rod and the fixing rod to fix the sample, the computer automatically measures the sample thickness, applies voltage to the sample using a single-phase AC power supply, and starts the test program when the temperatures of the cold and hot electrodes are stable; Step 4: After the test, disconnect the single-phase AC power supply to remove the voltage, remove the sample after the equipment is discharged, and finally clean the thermal grease on the contact surface of the hot electrode and the cold electrode with dust-free paper.
[0012] Furthermore, in step 3, it is necessary to ensure that the hot and cold electrode temperatures are stable at the set values for 120 seconds before starting the test.
[0013] Furthermore, after the test, the retraction displacement of the moving rod does not exceed 120 mm.
[0014] Furthermore, before the sample is measured, the surface needs to be wiped with non-woven fabric and dried in a vacuum environment at 25 °C for 2 h.
[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. By setting up components such as a single-phase AC power supply, a thermal conductivity tester, and a low-temperature constant temperature circulator, the present invention can effectively simulate the low-voltage environment in cold regions, accurately test the thermal conductivity of insulating materials under actual working conditions, and provide accurate data basis for the selection and design of insulating materials for electrical equipment in cold regions.
[0016] 2. The present invention uses ceramic materials to make the hot electrode and the cold electrode, which not only ensures good thermal conductivity but also has insulation performance, avoids voltage damage to the equipment, and improves the safety and stability of the test process.
[0017] 3. The present invention ensures the accuracy and reliability of test data, reduces test errors and improves test efficiency through precise temperature control and sample fixing system, as well as scientific test steps and parameter settings. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] 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: Figure 1 This is a schematic structural diagram of a device for testing the thermal conductivity of insulation materials in cold regions under a low voltage environment according to the present invention; Figure 2 It is a front view of the low-pressure thermal conductivity test structure; Figure 3 A top view of the low-voltage thermal conductivity test structure.
[0019] In the picture: 1- Computer, 2- Single-phase AC power supply, 3- Voltage adjustment knob, 4- Current and voltage display, 5- Protective resistor, 6- Thermal conductivity tester, 7- Temperature control console, 8- Moving rod, 9- Fixed rod, 10- Sample, 11- Circular electrode, 12- Hot electrode, 13- Cold electrode, 14- Water pipe, 15- Low temperature constant temperature circulator, 16- Circulating water tank, 17- Circulating fluid. DETAILED DESCRIPTION
[0020] 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.
[0021] Specific implementation 1: See Figure 1-3This embodiment describes a device for testing the thermal conductivity of insulating materials in cold regions under a low-voltage environment, comprising a computer 1, a single-phase AC power supply 2, a thermal conductivity tester 6, a temperature control console 7, and a low-temperature constant-temperature circulator 15. The single-phase AC power supply 2 is equipped with a voltage adjustment knob 3 for adjusting the output voltage and a current and voltage display 4 for monitoring output parameters. The output end of the single-phase AC power supply 2 is connected to two circular electrodes 11 through a protection circuit, and a protection resistor 5 is connected in series in the protection circuit. The thermal conductivity tester 6 is equipped with a temperature control console 7. The computer 1 It is connected to a thermal conductivity tester 6, which includes a moving rod 8, a fixed rod 9, a hot electrode 12 and a cold electrode 13. The hot electrode 12 is mounted on the fixed rod 9, and the cold electrode 13 is mounted on the moving rod 8. A sample 10 is placed between the cold electrode 13 and the hot electrode 12. Two circular electrodes 11 are symmetrically mounted on the upper end surface of the sample 10. The low-temperature constant temperature circulator 15 includes a circulating water tank 16. The circulating water tank 16 is filled with circulating liquid 17 and is connected to the cold electrode 13 through a water pipe 14. The hot electrode 12 uses an electric heating element as a heat source.
[0022] The single-phase AC power supply 2 adjusts the output voltage through the voltage regulating knob 3, and its output end is connected to two circular electrodes 11 through a protection circuit. A protection resistor 5 is connected in series in the protection circuit. The power supply output parameters are monitored in real time through the current and voltage display 4. The thermal conductivity tester 6 is intelligently controlled by the computer 1. Its hot pole 12 uses an electric heating element as a heat source. The system accurately adjusts the input current through the computer 1 so that the hot pole 12 maintains a stable temperature field and provides a constant heat flow output. In terms of sample fixation, the sample is accurately positioned by the fixed rod 9, and the clamping action is performed by the moving rod 8 to form a reliable three-dimensional constraint system to ensure that the sample 9 maintains a stable contact state during the test. The circulating water tank 16 is connected to the cold pole 13 through a water pipe 14, and is filled with a special circulating fluid 17. The circulating fluid 17 is a special antifreeze fluid. The low-temperature constant temperature circulator 15 achieves precise control of the temperature of the cold pole 13 by setting the control panel buttons, thereby improving the accuracy and reliability of the experiment.
[0023] During use, evenly apply thermal grease to the contact area between the surface of the sample 10 and the cold electrode 13 and the hot electrode 12, heat the hot electrode 12 through the temperature control console 7 and turn on the low-temperature constant temperature circulator 15, adjust the heating temperature of the hot electrode 12 through the computer 1, set the cooling temperature through the low-temperature constant temperature circulator 15 panel, drive the moving rod 8 and the fixed rod 9 to fix the sample 10, and then the computer 1 automatically measures the thickness of the sample 10. A single-phase AC power supply 2 is used to apply voltage to the sample 10, and the test program is started when the temperature of the cold electrode 13 and the hot electrode 12 is stable. After the test is completed, the single-phase AC power supply 2 is first disconnected to remove the voltage, and the sample 10 is taken out after the equipment is placed. Finally, the thermal grease on the contact surface of the hot electrode 12 and the cold electrode 13 is cleaned with dust-free paper.
[0024] By setting up components such as a single-phase AC power supply 2, a thermal conductivity tester 6, and a low-temperature constant temperature circulator 15, the low-voltage environment in cold regions can be effectively simulated, and the thermal conductivity of insulating materials under actual working conditions can be accurately tested, providing accurate data basis for the selection and design of insulating materials for electrical equipment in cold regions. Through precise temperature control and sample fixing systems, as well as scientific test steps and parameter settings, the accuracy and reliability of test data are ensured, test errors are reduced, and test efficiency is improved.
[0025] Specific implementation method 2: See Figure 1-3 In this embodiment, the cold electrode 13 and the hot electrode 12 are both made of ceramic material. Using ceramic material to make the hot electrode and the cold electrode not only ensures good thermal conductivity but also has insulation performance, avoids voltage damage to the equipment, and improves the safety and stability of the test process.
[0026] Specific implementation 3: See Figure 1-3 In this embodiment, the test principle of the thermal conductivity tester 6 is to establish a one-dimensional steady-state heat flow field by using the hot electrode 12 to stabilize the high temperature environment and the cold electrode 13 to stabilize the low temperature environment, and directly measure the heat flux density q and the temperature gradient dT / dx, thereby calculating the thermal conductivity coefficient of the thermal conductivity tester 6. The formula is as follows: .
[0027] Specific implementation 4: See Figure 1-3 In this embodiment, the heating range of the hot electrode 12 is 25°C-100°C, and the cooling range of the cold electrode 13 is -35°C-25°C.
[0028] Specific implementation 5: See Figure 1-3 To illustrate this embodiment, the single-phase AC power supply 2 has a boost range of 0-200V, and its maximum operating voltage is set to be lower than 50% of the material breakdown voltage to ensure the safety and reliability of the test process.
[0029] Specific implementation 6: See Figure 1-3 To illustrate this embodiment, the hot electrode 12 is a cylindrical structure with an end face diameter of 30±0.1 mm. The geometric dimensions of the sample 10 meet the following requirements: length 80-90 mm, width 45-55 mm, thickness 0.25-0.35 mm, and the length and width tolerances are controlled within ±0.5 mm, and the thickness tolerances are controlled within ±0.02 mm. The fixing rod 9 is a cylindrical guide mechanism with a diameter of 200±0.5 mm. The circular electrode 11 is a symmetrically arranged circular electrode with a contact surface diameter of 10±0.05 mm.
[0030] Specific implementation 7: See Figure 1-3This embodiment describes a method for testing a device for testing the thermal conductivity of insulation materials in cold regions under a low voltage environment, comprising the following steps: Step 1: Apply thermal grease evenly to the contact areas between the surface of the sample 10 and the cold electrode 13 and the hot electrode 12; Step 2: Heat the hot electrode 12 through the temperature control console 7 and turn on the low-temperature constant temperature circulator 15, control the heating temperature of the hot electrode 12 through the computer 1, and set the cooling temperature through the low-temperature constant temperature circulator 15 panel; Step 3: After driving the movable rod 8 and the fixed rod 9 to fix the sample 10, the computer 1 automatically measures the thickness of the sample 10, applies voltage to the sample 10 using the single-phase AC power supply 2, and starts the test program when the temperature of the cold electrode 13 and the hot electrode 12 are stable; Step 4: After the test is completed, disconnect the single-phase AC power supply 2 to remove the voltage. After the equipment is discharged, remove the sample 10. Finally, clean the thermal grease on the contact surface of the hot electrode 12 and the cold electrode 13 with dust-free paper.
[0031] Specific implementation 8: See Figure 1-3 To illustrate this embodiment, in step 3, it is necessary to ensure that the temperatures of the hot electrode 12 and the cold electrode 13 are stable at the set values for at least 120 seconds before starting the test.
[0032] Specific implementation method 9: See Figure 1-3 To illustrate this embodiment, the moving rod 8 needs to be closed by the computer 1 before the test, and the formal test can be carried out only after the measured thickness returns to zero. After the test is completed, the retraction displacement of the moving rod 8 does not exceed 120 mm.
[0033] Specific implementation 10: See Figure 1-3 To illustrate this embodiment, before measuring the sample 10, the surface needs to be wiped with a non-woven fabric and dried in a vacuum environment at 25° C. for 2 h.
[0034] 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 device for testing the thermal conductivity of insulation materials in cold regions under a low voltage environment, characterized by: The invention comprises a computer (1), a single-phase AC power supply (2), a thermal conductivity tester (6), a temperature control console (7) and a low-temperature constant temperature circulator (15), wherein the single-phase AC power supply (2) is provided with a voltage adjustment knob (3) for adjusting the output voltage and a current and voltage display (4) for monitoring the output parameters, the output end of the single-phase AC power supply (2) is connected to two circular electrodes (11) via a protection circuit, a protection resistor (5) is connected in series in the protection circuit, the thermal conductivity tester (6) is provided with a temperature control console (7), the computer (1) is connected to the thermal conductivity tester (6), and the thermal conductivity tester (6) includes The invention comprises a moving rod (8), a fixed rod (9), a hot electrode (12) and a cold electrode (13), wherein the hot electrode (12) is mounted on the fixed rod (9), and the cold electrode (13) is mounted on the moving rod (8). A sample (10) is placed between the cold electrode (13) and the hot electrode (12), and two circular electrodes (11) are symmetrically mounted on the upper end surface of the sample (10). The low-temperature constant temperature circulator (15) comprises a circulating water tank (16), the circulating water tank (16) is filled with circulating liquid (17) and is connected to the cold electrode (13) through a water pipe (14), and the hot electrode (12) uses an electric heating element as a heat source.
2. The device for testing thermal conductivity of insulation materials in cold regions under low voltage conditions according to claim 1, characterized in that: The cold electrode (13) and the hot electrode (12) are both made of ceramic materials.
3. The device for testing thermal conductivity of insulation materials in cold regions under low voltage conditions according to claim 1, characterized in that: The test principle of the thermal conductivity tester (6) is to establish a one-dimensional steady-state heat flow field by using a hot electrode (12) to stabilize a high temperature environment and a cold electrode (13) to stabilize a low temperature environment, and directly measure the heat flux density q and the temperature gradient dT / dx, thereby calculating the thermal conductivity coefficient of the thermal conductivity tester (6). The formula is as follows: 。 4. The device for testing thermal conductivity of insulation materials in cold regions under low voltage conditions according to claim 2, characterized in that: The heating range of the hot pole (12) is 25°C-100°C, and the cooling range of the cold pole (13) is -35°C-25°C.
5. The device for testing thermal conductivity of insulation materials in cold regions under low voltage conditions according to claim 1, characterized in that: The single-phase AC power supply (2) has a voltage boost range of 0-200V.
6. The device for testing thermal conductivity of insulation materials in cold regions under low voltage conditions according to claim 1, characterized in that: The hot electrode (12) is a cylindrical structure with an end diameter of 30±0.1 mm. The geometric dimensions of the sample (10) meet the following requirements: length 80-90 mm, width 45-55 mm, and thickness 0.25-0.35 mm. The fixing rod (9) is a cylindrical guide mechanism with a diameter of 200±0.5 mm.
7. A method for testing the thermal conductivity of insulation materials in cold regions under a low voltage environment according to any one of claims 1 to 6, characterized in that: It includes the following steps: Step 1: Apply thermal grease evenly to the contact area between the surface of the sample (10) and the cold electrode (13) and the hot electrode (12); Step 2: Heat the hot electrode (12) through the temperature control console (7) and turn on the low-temperature constant temperature circulator (15), control the heating temperature of the hot electrode (12) through the computer (1), and set the cooling temperature through the low-temperature constant temperature circulator (15) panel; Step 3: After driving the movable rod (8) and the fixed rod (9) to fix the sample (10), the computer (1) automatically measures the thickness of the sample (10), applies voltage to the sample (10) using a single-phase AC power supply (2), and starts the test program when the temperature of the cold electrode (13) and the hot electrode (12) are stable; Step 4: After the test is completed, disconnect the single-phase AC power supply (2) to remove the voltage, and then remove the sample (10) after the equipment is discharged. Finally, use dust-free paper to clean the thermal grease on the contact surface of the hot electrode (12) and the cold electrode (13).
8. The device for testing thermal conductivity of insulation materials in cold regions under low voltage conditions according to claim 7, characterized in that: In step 3, it is necessary to ensure that the temperature of the hot electrode (12) and the cold electrode (13) is stable at the set value for 120 seconds before starting the test.
9. The device for testing thermal conductivity of insulation materials in cold regions under low voltage conditions according to claim 7, characterized in that: After the test, the retraction displacement of the moving rod (8) does not exceed 120 mm.
10. The device for testing thermal conductivity of insulation materials in cold regions under low voltage conditions according to claim 7, characterized in that: Before measuring the sample (10), the surface needs to be wiped with non-woven cloth and dried in a vacuum environment at 25°C for 2 h.