Thermoplastic cable insulating material aging test device and aging test method

Abstract

The invention relates to a thermoplastic cable insulating material aging test device and an aging test method. The tested material is clamped and fixed through the filter screen assembly, and the filter screen assembly clamping the tested material is suspended in the drying oven through the chain and the bracket, so that the thermo-oxidative aging uniformity of the tested material in the drying oven can be effectively ensured, and the accuracy of a thermo-oxidative aging test result is further improved; according to the aging test method, the aging test device is adopted to perform the aging test on the tested material, the operation is simple, the service life prediction result of the tested material can be quickly obtained, and the applicability is high.

Description

Technical Field

[0001] The present invention relates to the technical field of aging testing, and particularly to an aging test device and an aging test method for a thermoplastic cable insulating material. Background Art

[0002] During the actual operation of a power system, electrical equipment in the primary system will be in an operating condition of high voltage and large current for a long time. The Joule heat continuously generated when the cable core passes through a large current will cause an obvious temperature rise phenomenon in the cable system, and the operating temperature of the cable will be maintained at 70 - 90°C for a long time. At this time, the polyolefin insulating material as the main insulation of the cable will undergo accelerated thermal-oxidative aging during long-term operation. Polyethylene material is a commonly used thermoplastic electrical insulating material. Existing research shows that for polyethylene materials, due to the presence of side chains on its molecular chain and a very small amount of C = C bonds formed during the polymerization process, it can undergo a thermal-oxidative reaction with oxygen at a certain temperature. The specific reaction process is as follows: When the molecular chain in the polyethylene molecular chain is heated, an active chain R· with free radicals is generated. R· can react with oxygen to form an active chain ROO·. The free radicals on ROO· react with H atoms on other chains to produce ROOH and a new active chain R·, and ROOH can continue to decompose into RO·, ROO·, and HOH. The peroxide ROO· will degrade under the action of heat into a molecular chain with an aldehyde group at one end, and at this time the molecular chain breaks. The thermal aging reaction continues, the molecular chain of polyethylene breaks, and aldehyde groups are formed at the chain ends, changing the chemical composition of the material and destroying the crystal structure inside the material. At the same time, due to the degradation of the molecular structure in the amorphous region of the material, the number of defects in the material increases, resulting in a decrease in the electrical insulation performance of the material, manifested as a decrease in the macroscopic breakdown field strength of the material, an increase in dielectric loss, and an increase in the amount of space charge accumulation, etc. That is, the occurrence of thermal-oxidative aging will lead to a decrease in the mechanical and insulation performance of the polyolefin insulating material, and it no longer meets the cable insulation performance requirements. Therefore, studying the thermal aging behavior of thermoplastic cable insulating materials is an important aspect for evaluating whether they can work stably for a long time.

[0003] During thermal aging, the higher the temperature, the more intense the thermal aging reaction of the material, the higher the reaction rate, and the faster the material ages. When evaluating the thermal-oxidative aging resistance and life of a material, in order to reduce the test time, a temperature higher than the actual operating temperature of the cable is generally selected as the temperature for constant-temperature thermal-oxidative aging for accelerated thermal-oxidative aging experiments. Currently, the main standard for accelerated thermal-oxidative aging experiments on cable insulating materials is GB / T 11026, and this standard has the following defects:

[0004] (1) This test standard mainly targets thermosetting materials represented by XLPE, and the material targeting is poor;

[0005] (2) In the current test standard, the accelerated aging temperature is higher than the melting point of the material itself (the melting point of PE is about 110 °C, and the thermal-oxidative aging temperature in the standard is 135 °C). The hanging placement method of the material specified in the standard is no longer suitable for the accelerated thermal-oxidative aging test of thermoplastic cable insulation materials;

[0006] (3) The end standard of the aging test of the material in the current test standard is single, and there are few characterization means.

[0007] Therefore, it is currently impossible to successfully complete the accelerated thermal-oxidative aging test of thermoplastic insulation materials according to the above standards. If the temperature lower than the melting temperature of thermoplastic polyethylene cable insulation material is used as the accelerated thermal-oxidative aging temperature point in IEC 62895, two problems will arise: (1) Based on the research experience of predecessors, whenever the temperature of polyethylene material increases by about 8 °C, its insulation life is reduced by half. Reducing the thermal-oxidative aging temperature can smoothly carry out the hanging aging placement method, but the entire aging cycle doubles, reducing the experimental efficiency; (2) When the material is in the molten state and the non-molten state, the difficulty of oxygen molecules entering the material interior is different, resulting in the inability to fully equivalent the thermal-oxidative aging rates in different phases, losing the comparison significance.

[0008] Therefore, it is very necessary to develop an aging test device and test method for thermoplastic cable insulation materials to comprehensively evaluate the life of thermoplastic cable insulation materials at normal working temperatures. Summary of the Invention

[0009] The purpose of the present invention is to provide an aging test device and test method for thermoplastic cable insulation materials by overcoming the deficiencies of the prior art.

[0010] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0011] In the first aspect, an aging test device for thermoplastic cable insulation materials provided by the present invention includes an oven, a bracket and a filter screen assembly. The filter screen assembly includes two layers of filter screens, metal wires and at least two chains. The two layers of filter screens in the filter screen assembly are used to clamp the samples of thermoplastic cable insulation materials. The metal wires are used to sew the edges of the two layers of filter screens. Hooks adapted to the chains are provided on the bracket. The filter screen assembly is connected to the hooks through the chains. The oven is provided with a door.

[0012] As a preferred embodiment of the present invention, the oven is provided with an air inlet and ventilation holes, and the air inlet is connected to a hot air blower.

[0013] As a preferred embodiment of the present invention, the oven includes a box body, and a heat insulation layer is provided on the inner wall of the box body.

[0014] Specifically, a temperature sensor is provided inside the oven, and a display screen and a controller are provided outside the oven. The hot air blower, the temperature sensor, and the display screen are electrically connected to the controller respectively.

[0015] A temperature adjustment knob and a switch are provided outside the oven, and the temperature adjustment knob and the switch are electrically connected to the controller respectively.

[0016] In a second aspect, a method for aging test of a thermoplastic cable insulation material provided by the present invention includes the following steps:

[0017] S1. Obtain samples of the material to be tested, divide the samples into n groups, each group containing m samples, where n is an integer not less than 3 and m is an integer not less than 3. The material to be tested is an unused thermoplastic cable insulation material of the same specification;

[0018] S2. Use the aging test device as described in the first aspect to conduct aging tests on each group of samples in a way that one group of samples corresponds to one aging temperature T;

[0019] Before conducting the aging test, clamp the sample in the middle between two layers of filter screens of the filter screen assembly, stitch and fix the edges of the two layers of filter screens with metal wires, leave at least a 1.5 cm gap between the sample and the metal wires, hang the filter screen assembly with the sample clamped on it on the bracket by using a chain and a hook, place the bracket inside the oven, and raise the temperature inside the oven to the aging temperature T.

[0020] As a preferred implementation manner of the present invention, step S2 further includes the following steps: During each group of aging tests, at preset intervals, take one sample for performance parameter testing, and calculate the obtained performance parameter retention rate Q;

[0021] When the obtained performance parameter retention rate Q ≤ the end retention rate Q of the performance parameter f terminate the aging test, and count the aging test time t f of each group to obtain the test data corresponding to the aging test time t f and the aging temperature T one by one;

[0022] After step S2, it further includes:

[0023] S3. According to the test data corresponding to the aging test time t f and the aging temperature T one by one, draw a relationship diagram of ln(t f ) and , and establish a linear fitting formula of ln(t f ) and ;

[0024] S4. Substitute T = T w into the linear fitting formula obtained in step S3, and calculate the working temperature T of the material to be testedw Under the service life.

[0025] In step S3, the ln(t f ) and The linear fitting formula of is: Where a and b are constants.

[0026] As a preferred embodiment of the present invention, among the n aging temperatures T, the temperature difference between two adjacent aging temperatures T is not less than 3K.

[0027] As a preferred embodiment of the present invention, the minimum temperature among the n aging temperatures T is not lower than the melting point T of the material to be tested m .

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] In the present invention, the material to be tested is clamped and fixed by the filter screen assembly, and the filter screen assembly clamping the material to be tested is suspended in the oven through the chain and the bracket, which can effectively ensure the uniformity of the thermal oxygen aging of the material to be tested in the oven, thereby improving the accuracy of the thermal oxygen aging test result.

[0030] The present invention provides a method for testing the aging of a thermoplastic cable insulation material. The aging test device is used to conduct an aging test on the material to be tested under different temperature conditions, and the retention rate of the performance parameters of the sample of the material to be tested is measured every preset time until the obtained retention rate Q of the performance parameters ≤ the end retention rate Q of the performance parameters f , and the aging test time t f The test data corresponding one-to-one with the aging temperature T are obtained. Furthermore, by establishing the linear fitting formula of ln(t f ) and , the service life of the material to be tested at the working temperature can be predicted. Therefore, the present invention provides a test method for the service life of a thermoplastic cable insulation material at the working temperature. The aging test operation is simpler, and the service life prediction result of the material to be tested can be obtained quickly and accurately, with strong applicability. Description of the Drawings

[0031] Figure 1 Is a longitudinal sectional view of the thermoplastic cable insulation material aging test device provided by the present invention;

[0032] Figure 2 Is a transverse sectional view of the oven provided by the present invention;

[0033] Figure 3 Is a schematic diagram of the filter screen clamp sticking and fixing provided by the present invention;

[0034] Figure 4 Is the ln(t f) and Linear fitting relationship diagram.

[0035] In the figure, 1 - oven, 11 - box body, 12 - insulation layer, 13 - air inlet, 14 - ventilation hole, 2 - filter screen assembly, 21 - filter screen, 22 - metal wire, 23 - chain, 3 - hot air blower, 4 - sample, 5 - bracket, 6 - hook. Specific implementation mode

[0036] To better illustrate the purpose, technical solution and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0037] Please refer to Figures 1 to 3 , the present invention provides a thermoplastic cable insulation material aging test device, including an oven 1, a bracket 5 and a filter screen assembly 2. The filter screen assembly 2 includes two layers of filter screens 21, metal wires 22 and at least two chains 23. The filter screen assembly 2 is used to clamp the thermoplastic cable insulation material sample 4. The metal wire 22 is used to sew the edges of the two layers of filter screens 21. Hooks 6 adapted to the chains 23 are arranged on the bracket 5. The filter screen assembly 2 is connected to the hooks 6 on the bracket 5 through the chains 23; the oven 1 is provided with an openable door.

[0038] The present invention clamps and fixes the sample through the filter screen assembly 2, and suspends the filter screen assembly 2 clamping the sample 4 on the bracket 5 through the chains 23 and the hooks 6, and places the bracket 5 in the oven 1, which can effectively ensure the uniformity of the thermal oxygen aging of the sample in the oven 1, thereby improving the accuracy of the thermal oxygen aging test results.

[0039] In one embodiment, the number of chains 23 in each filter screen assembly 2 is not less than four; the hooks 6 on the bracket 5 are divided into several groups, and several groups of hooks are equally spaced in the height direction of the bracket 5. The number of hooks 6 in each group is the same as the number of chains 23 in the filter screen assembly 2. For example, the number of chains 23 in the filter screen assembly 2 is four, the number of hooks in each group is four, and the four hooks in the same group are arranged on the bracket in a pairwise symmetric manner. One end of the four chains 23 is respectively wound around the metal wire 22 at the four corners of the filter screen 21, which helps the two filter screens 21 clamping the sample 4 to be suspended more stably in the oven 1.

[0040] In one embodiment, the number of filter screen assemblies 2 is not less than 3. It can be understood that the present invention does not particularly limit the number of filter screen assemblies 2, and those skilled in the art can set it according to actual needs.

[0041] In one embodiment, the mesh count of the filter screen 21 is not less than 100 meshes. The filter screen 21 with a mesh count not less than 100 meshes has a high resistance to thermal deformation, can limit the melt fluidity of the sample within an appropriate temperature range, can ensure that the sample maintains a sheet shape without obvious flow deformation, and at the same time ensures that the upper and lower surfaces of the sample can contact oxygen.

[0042] In one embodiment, the oven 1 includes a box body 11, the inner wall of the box body 11 is provided with a heat insulation layer 12, the oven 1 is provided with an air inlet 13 and a ventilation hole 14, and the air inlet 13 is connected to a hot air blower 3.

[0043] Specifically, a temperature sensor is provided inside the oven 1, a display screen and a controller are provided outside the oven 1, and the hot air blower 3, the temperature sensor, and the display screen are electrically connected to the controller respectively.

[0044] A temperature adjustment knob and a switch are provided outside the oven 1, and the temperature adjustment knob and the switch are electrically connected to the controller respectively.

[0045] In the present invention, by providing the switch, it is convenient to turn on and off the hot air blower 3; by providing the temperature adjustment knob, it is convenient to set the heating temperature; by providing the display screen, parameters such as the set temperature, the heating temperature inside the oven 1, and the heating time can be displayed in real time.

[0046] In a second aspect, a method for aging test of a thermoplastic cable insulation material provided by the present invention includes the following steps:

[0047] S1. Obtain samples of the material to be tested, divide the samples into n groups, each group contains m samples, n is an integer not less than 3, m is an integer not less than 3, and the material to be tested is an unused thermoplastic cable insulation material of the same specification;

[0048] S2. Use the aging test device as described in the first aspect to conduct an aging test on each group of samples in a manner that one group of samples corresponds to one aging temperature T.

[0049] Before conducting the aging test, center the sample between two filter screens of the filter screen assembly, stitch and fix the edges of the two filter screens with a metal wire, leave at least a 1.5 cm gap between the sample and the metal wire, hang the filter screen assembly with the sample clamped thereon on the bracket by using a chain and a hook, place the bracket in the oven, and raise the temperature in the oven to the aging temperature T.

[0050] In step S2, the sample is clamped between two filter meshes 21, and the edges of the two filter meshes 21 are stitched and fixed with a metal wire 22, and a distance of at least 1.5 cm is left between the sample and the metal wire 22, which can effectively avoid affecting the thermal oxygen aging test result due to the deformation of the edge area of the filter mesh assembly 2 in a high-temperature environment. Specifically, the distance between the sample and the metal wire 22 can be 1.5 cm, 2 cm, 2.5 cm, 3 cm, 3.5 cm, 4 cm, 4.5 cm, 5 cm or a range composed of any two sets of these values.

[0051] In one embodiment, step S2 further includes the following steps: during each aging test process, at preset time intervals, take a sample for performance parameter testing, and calculate the obtained performance parameter retention rate Q;

[0052] When the obtained performance parameter retention rate Q ≤ the end retention rate Q of the performance parameter f terminate the aging test, and count the aging test time t f to obtain the test data corresponding to the aging test time t f and the aging temperature T one by one;

[0053] After step S2, it further includes:

[0054] S3. According to the test data corresponding to the aging test time t f and the aging temperature T one by one, draw a relationship diagram of ln(t f ) and , establish a linear fitting formula of ln(t f ) and ;

[0055] S4. Substitute T = T w into the linear fitting formula obtained in step S3, and calculate the service life of the material under test at the working temperature T w .

[0056] Specifically, in step S3, the linear fitting formula of ln(t f ) and is: where a and b are constants.

[0057] In one embodiment, among the n aging temperatures T, the temperature difference between two adjacent aging temperatures T is not less than 3K. Specifically, the temperature difference can be 3K, 5K, 8K, 10K or a range composed of any two sets of these values.

[0058] In one embodiment, the minimum temperature among the n aging temperatures T is not lower than the melting point T m of the material under test. Specifically, the minimum temperature among the n aging temperatures T is not less than Tm +3K and not greater than T m +10K.

[0059] In the present invention, T and T m are Kelvin temperatures.

[0060] In one embodiment, the performance parameter is the elongation at break or the mass of the sample.

[0061] In one embodiment, the performance parameter is the elongation at break. The test method for the retention rate of the elongation at break is as follows: Take out a filter screen assembly 2 clamping a sample from the oven 1. After removing the filter screen assembly 2, press the sample at the corresponding aging temperature by using a hot press to eliminate the grid lines on the sample and make the surface of the sample flat. Then cut off the edges of the pressed sample to the size required for testing. The minimum width of the cut-off edge part is not less than 1 cm. Test the elongation at break according to the standard GB / T 1040.1-2006. The tensile rate during the test is 100 mm / min; Calculate the retention rate of the elongation at break (denoted as Q) according to the following formula: Retention rate of elongation at break = (elongation at break after aging - initial elongation at break) / initial elongation at break * 100%.

[0062] It can be understood that cutting off the edge part of the pressed sample and the minimum width of the cut-off edge is not less than 1 cm can avoid the edge effect from affecting the test results.

[0063] The present invention provides the following to facilitate the understanding of the present invention. These embodiments are provided by the present invention not to limit the scope of the claims.

[0064] Please refer to Figures 1 to 3 , the aging test device adopted in each embodiment includes an oven 1, a bracket 5 and a plurality of filter screen assemblies 2. The filter screen assembly 2 includes two layers of filter screens 21, metal wires 22 and at least two chains 23. The filter screen assembly 2 is used for clamping a sample of thermoplastic cable insulation material 4. Hooks 6 adapted to the chains 23 are arranged on the bracket 5; The oven 1 is provided with an openable and closable door. The number of chains 23 included in the filter screen assembly 2 is four, the number of each group of hooks is four, and the four hooks in the same group are arranged on the bracket in a pairwise symmetric manner.

[0065] The mesh number of the filter screen 21 is 200 meshes.

[0066] The oven 1 includes a box body 11, the inner wall of the box body 11 is provided with a heat insulation layer 12, the oven 1 is provided with an air inlet 13 and air vent holes 14, and the air inlet 13 is connected to a hot air blower 3; a temperature sensor is arranged inside the oven 1, a display screen and a controller are arranged outside the oven 1, and the hot air blower 3, the temperature sensor and the display screen are respectively electrically connected to the controller; a temperature adjustment knob and a switch are arranged outside the oven 1, and the temperature adjustment knob and the switch are respectively electrically connected to the controller.

[0067] Embodiment 1

[0068] A method for aging test of a thermoplastic cable insulating material provided in this embodiment includes the following steps:

[0069] (1) Cut the commercially available thermoplastic cable insulating material and use a tablet press to make sheet samples of the same specification, and the size of the samples is 10mm×10mm×1mm;

[0070] Take a sample and test its elongation at break to obtain the initial elongation at break of the sample;

[0071] Take a sample and use a differential scanning calorimeter to test the melting point of the sample to be 403K (i.e., 130°C);

[0072] Divide the samples into 3 groups, with each group containing 25 samples;

[0073] Use the aging test device to conduct aging tests on each group of samples in such a way that one group of samples corresponds to one aging temperature T; the aging temperatures T corresponding to each group of samples are 408K, 418K, and 428K respectively;

[0074] Before conducting the aging test, load each group of samples into the oven 1 of the corresponding aging test device by the following method: Center the sample and clamp it between two layers of filter meshes 21 of the filter mesh assembly 2, use a metal wire 22 to stitch and fix the edges of the two layers of filter meshes 21, leaving a 5 cm gap between the sample and the metal wire 22, the number of chains 23 equipped for each filter mesh assembly 2 is four, respectively entangle one end of the four chains 23 with the metal wire 22 at the four corners of the filter mesh 21, connect the other end of the chain 23 to the hook 6, so that the two layers of filter meshes 21 clamping the sample 4 are stably suspended on the bracket 5, place the bracket 5 in the oven 1, and heat the temperature in the oven 1 to the aging temperature T and then keep it warm;

[0075] During each group of aging tests, heat the temperature in the oven 1 to the aging temperature T and then start timing and keep it warm. Every 5 days, take one sample from each group of samples and test the retention rate Q of its elongation at break;

[0076] The test method for the retention rate of elongation at break is as follows: After removing the filter component 2, use a hot press to press the sample at a corresponding temperature of 180°C under a pressure of 10 MPa for 5 minutes to eliminate the grid pattern on the sample and make the surface of the sample flat. Since the pressing time is very short, the influence of the pressing process on the aging degree of the sample can be ignored. Then cut off the edges of the pressed sample to the size required for testing, and the minimum width of the cut-off edge is not less than 1.5 cm. Test the elongation at break according to GB / T 1040.1-2006, and the tensile rate during testing is 100 mm / min. Calculate the retention rate of elongation at break (denoted as Q) according to the following formula: Retention rate of elongation at break = (Elongation at break after aging - Initial elongation at break) / Initial elongation at break * 100%;

[0077] When the obtained retention rate of elongation at break Q ≤ 50%, terminate the aging test and count the aging test time t of each group f , and obtain the aging test time t f The test data corresponding to the aging temperature T one by one are as follows:

[0078] The service life of the sample at 408K is 105 days, the service life of the sample at 418K°C is 40 days, and the service life of the sample at 428K°C is 15 days;

[0079] (2) According to the test data corresponding to the aging test time t f and the aging temperature T one by one, draw a relationship diagram of ln(t f ) and (as shown in Figure 4 ), establish a linear fitting formula of ln(t f ) and , where a is 16985.8 and b is -36.97;

[0080] (3) Substitute T = 363K into the obtained linear fitting formula to calculate the service life of the tested material at 363K (i.e., 90°C). The calculation result shows that the service life exceeds 49 years.

[0081] Example 2

[0082] A thermoplastic cable insulation material aging test method provided in this example includes the following steps:

[0083] (1) Cut the commercially available thermoplastic cable insulation material and use a tablet press to make it into sheet samples of the same specification. The size of the sample is 10mm × 10mm × 1mm; Divide the samples into n groups, with each group containing m samples. The tested material is the un-serviced thermoplastic cable insulation material of the same specification;

[0084] Take a sample and use a differential scanning calorimeter to measure the melting point of the sample as 403 K (i.e., 130 °C);

[0085] Divide the sample into 3 groups, with each group containing 25 samples;

[0086] Use the described aging test device to conduct aging tests on each group of samples in a way that one group of samples corresponds to one aging temperature T; the aging temperatures T corresponding to each group of samples are 408 K, 418 K, and 428 K respectively;

[0087] Before conducting the aging test, load each group of samples into the oven 1 of the corresponding aging test device using the following method: Center the weighed sample between the two layers of filter screens 21 of the filter screen assembly 2, and use a metal wire 22 to stitch and fix the edges of the two layers of filter screens 21, leaving a 5 cm gap between the sample and the metal wire 22. Each filter screen assembly 2 is equipped with four chains 23. Connect one end of each of the four chains 23 to the metal wire 22 at the four corners of the filter screen 21, and connect the other end of the chain 23 to the hook 6, so that the two filter screens 21 sandwiching the sample 4 are stably suspended on the bracket 5, and place the bracket 5 in the oven 1;

[0088] During each group of aging tests, after raising the temperature in the oven 1 to the aging temperature T, start timing and keep it at a constant temperature. Every 5 days, take a sample from the oven 1, cool it to room temperature (25 °C), and then weigh it to obtain the mass of the aged sample. Calculate the mass retention rate (denoted as Q) according to the following formula: Mass retention rate = (mass after aging - initial mass) / initial mass * 100%;

[0089] When the mass retention rate Q ≤ 95%, terminate the aging test and count the aging test time t f , and obtain the aging test time t f The test data corresponding one-to-one with the aging temperature T are as follows:

[0090] The service life of the sample at 408 K is 110 days, the service life of the sample at 418 K is 40 days, and the service life of the sample at 428 K is 15 days;

[0091] (2) According to the test data corresponding one-to-one with the aging test time t f and the aging temperature T, plot a relationship graph of ln(t f ) and , establish a linear fitting formula of ln(t f ) and , where a is 17395 and b is -37.93;

[0092] (3) Substitute T = 363K into the linear fitting formula obtained in step S4 to calculate the service life of the material under test at 90°C. The calculation result shows that the service life exceeds 59 years.

[0093] All directional indicators (such as up and down) in the present invention are only used to explain the relative positional relationship, movement conditions, etc. between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indicator also changes accordingly.

[0094] In the description of the present invention, it should also be noted that the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion.

[0095] For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A thermoplastic cable insulation material aging test device, characterized in that: The invention comprises an oven, a support and a filter assembly, wherein the filter assembly comprises two layers of filter mesh, a metal wire and at least two chains, the two layers of filter mesh in the filter assembly are used to clamp the thermoplastic cable insulation material sample, the metal wire is used to sew the edges of the two layers of filter mesh, the support is provided with a hook adapted to the chain, the filter assembly is connected to the hook through the chain, and the oven is provided with a door.

2. The thermoplastic cable insulation material aging test device according to claim 1, characterized in that: The oven is provided with an air inlet and an air vent, and the air inlet is connected to a hot air blower.

3. The thermoplastic cable insulation material aging test device according to claim 1, characterized in that: The oven comprises a box body, and a heat-insulating layer is arranged on the inner wall of the box body.

4. The thermoplastic cable insulation material aging test device as claimed in claim 3, characterized in that: A temperature sensor is arranged inside the oven, a display screen and a controller are arranged outside the oven, and the hot air blower, the temperature sensor and the display screen are electrically connected to the controller respectively; A temperature regulating knob and a switch are arranged outside the oven, and the temperature regulating knob and the switch are electrically connected to the controller respectively.

5. A method for testing aging of thermoplastic cable insulation materials, characterized in that: The steps include: S1. Obtain samples of the material to be tested, divide the samples into n groups, each group contains m samples, n is an integer not less than 3, m is an integer not less than 3, and the material to be tested is an unserved thermoplastic cable insulation material of the same specification; S2. Performing an aging test on each group of samples in a manner that one group of samples corresponds to one aging temperature T using the aging test device as described in any one of claims 1 to 4; Before the aging test, the sample is sandwiched between the two layers of filter screens of the filter screen assembly, and the edges of the two layers of filter screens are fixed by sewing with metal wires, so that there is a distance of at least 1.5 cm between the sample and the metal wires. The filter screen assembly with the sample is hung on a bracket with a chain and a hook, and the bracket is placed in an oven, and the temperature in the oven is raised to the aging temperature T.

6. The thermoplastic cable insulation material aging test method according to claim 5, characterized in that: Step S2 also includes the following steps: during each set of aging test, a sample is taken out from the oven at a preset time interval to perform a performance parameter test, and the performance parameter retention rate Q is calculated, thereby obtaining a series of test data, wherein the test data includes the aging time and the performance parameter retention rate Q corresponding to the aging time; When the obtained performance parameter retention rate Q ≤ the end point retention rate Q of the performance parameter f When t is reached, the aging test is terminated and the aging test time t of each group is counted. f , get the aging test time t f Test data corresponding to the aging temperature T; After step S2, the following steps are also included: S3, according to the aging test time t f The test data corresponding to the aging temperature T are plotted as ln(t f )and The relationship diagram of ln(t f )and The linear fitting formula of S4. Set T = T w Substitute into the linear fitting formula obtained in step S4 to calculate the measured material at the working temperature T w The following service life.

7. The thermoplastic cable insulation material aging test method according to claim 5, characterized in that: Among the n aging temperatures T, the temperature difference between two adjacent aging temperatures T is not less than 3K.

8. The thermoplastic cable insulation material aging test method according to claim 5, characterized in that: The minimum temperature among the n aging temperatures T is not lower than the melting point T of the material being tested. m .

9. The thermoplastic cable insulation material aging test method according to claim 5, characterized in that: The material to be tested is a thermoplastic cable insulation material, and the performance parameter is the mass of the sample or the elongation at break of the sample.

10. The thermoplastic cable insulation material aging test method according to claim 6, characterized in that: In step S3, the ln(t f )and The linear fitting formula is: Where a and b are constants.

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