Crosslinked polyethylene insulating material detection method and system

Abstract

The invention discloses a cross-linked polyethylene insulating material detection method and system, and relates to the technical field of cross-linked polyethylene insulating material detection.The cross-linked polyethylene insulating material detection method comprises the steps that a cross-linked polyethylene sample piece is subjected to degassing treatment in a closed vacuum environment, and first treated gas is obtained; wherein the gas after the first treatment comprises a crosslinking by-product; performing gas chromatography experiment and infrared spectroscopic analysis on the gas after the first treatment to determine the content of a first cross-linking byproduct and the components of the first cross-linking byproduct; and carrying out space charge detection on the degassed crosslinked polyethylene sample piece by utilizing space charge test equipment in a closed vacuum environment. According to the invention, the accuracy of the detection result of the crosslinked polyethylene insulating material can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of cross-linked polyethylene insulation material detection, and particularly to a cross-linked polyethylene insulation material detection method and system. Background Art

[0002] Cross-linked polyethylene insulated cables will introduce cross-linking agents during the production process. However, the use of cross-linking agents will generate impurities such as cross-linking by-products, which will have a certain impact on the cable quality. Therefore, the detection and analysis of cross-linking by-products are of great significance for the control of cable quality.

[0003] In the related art, infrared spectroscopy, thermogravimetric analysis, gas chromatography, gas chromatography-mass spectrometry, and space charge testing are usually used to directly detect and analyze the degassed cable in the air environment. However, in the above methods, the cable samples to be tested are easily affected by oxidation and decomposition of air, etc., resulting in low accuracy of the cross-linking by-product detection results. Summary of the Invention

[0004] The main purpose of the present application is to provide a cross-linked polyethylene insulation material detection method and system, aiming to solve the technical problem of low accuracy of the cross-linked polyethylene insulation material detection results in the related art.

[0005] To achieve the above purpose, the present application proposes a cross-linked polyethylene insulation material detection method, which includes: Performing degassing treatment on the cross-linked polyethylene sample in a closed vacuum environment to obtain the first treated gas; wherein, the first treated gas includes cross-linking by-products; Performing gas chromatography experiment and infrared spectroscopy analysis on the first treated gas to determine the first cross-linking by-product content and the first cross-linking by-product components; In the closed vacuum environment, using a space charge testing device to perform space charge detection on the degassed cross-linked polyethylene sample.

[0006] In an embodiment, before the step of performing degassing treatment on the cross-linked polyethylene sample in a closed vacuum environment to obtain the first treated gas, the method further includes: Performing vacuum pumping on the closed environment where the cross-linked polyethylene sample is located until the vacuum degree of the closed environment reaches the first preset vacuum degree; Injecting inert gas into the closed environment until the vacuum degree of the closed environment reaches the second preset vacuum degree; wherein, the second preset vacuum degree is greater than the first preset vacuum degree; Repeating the vacuum pumping treatment and injecting inert gas for a preset number of times to obtain a closed vacuum environment filled with inert gas.

[0007] In one embodiment, before the step of degassing a cross-linked polyethylene sample in a sealed vacuum environment to obtain the first post-treatment gas, the method further includes: Cut the cross-linked polyethylene insulation layer of the cable according to a preset size to obtain a cross-linked polyethylene sample; wherein, the preset size is the test size of the space charge testing equipment.

[0008] In one embodiment, the steps of performing a gas chromatography experiment and an infrared spectroscopy analysis on the first post-treatment gas to determine the content and composition of the first cross-linked by-products include: When the temperature of the sealed vacuum environment returns to room temperature, perform a gas chromatography experiment and an infrared spectroscopy analysis on the first post-treatment gas to determine the content and composition of the first cross-linked by-products.

[0009] In one embodiment, the detection temperature range for space charge detection is from room temperature to 80 °C, and the detection voltage range for space charge detection is from 0 to 30 kV / mm.

[0010] In one embodiment, after the step of using a space charge testing equipment to perform space charge detection on the degassed cross-linked polyethylene sample in a sealed vacuum environment, the method further includes: Perform a gas chromatography experiment and an infrared spectroscopy analysis on the second post-treatment gas respectively to obtain the content and composition of the second cross-linked by-products; wherein, the second post-treatment gas is the gas in the sealed vacuum environment obtained after space charge detection. Based on the content and composition of the first cross-linked by-products, the content and composition of the second cross-linked by-products, determine the influence of space charge detection on the gas production components and gas production content of the cross-linked polyethylene sample.

[0011] In addition, to achieve the above object, the present application also proposes a cross-linked polyethylene insulation material detection system, which includes: A quartz vacuum chamber for providing a sealed vacuum environment; A heating device disposed in the quartz vacuum chamber for performing degassing treatment; A gas chromatograph connected to the quartz vacuum chamber through a sealing ring air inlet for performing a gas chromatography experiment on the gas in the sealed vacuum environment after degassing treatment to obtain the content of cross-linked by-products; An infrared spectrometer connected to the quartz vacuum chamber through a thermal infrared interface air inlet for performing an infrared spectroscopy analysis on the gas in the sealed vacuum environment after degassing treatment to obtain the composition of cross-linked by-products; A space charge testing equipment embedded in the quartz vacuum chamber for performing space charge detection on the degassed cross-linked polyethylene sample.

[0012] In one embodiment, the crosslinked polyethylene insulating material detection system further includes: A vacuum pump, connected to the quartz vacuum chamber through the vacuum pump air inlet, for evacuating the quartz vacuum chamber; An inert gas cylinder, connected to the quartz vacuum chamber through the gas cylinder air inlet, for injecting inert gas into the quartz vacuum chamber.

[0013] In one embodiment, the space charge testing device includes a test low-voltage electrode and a test high-voltage electrode; The test low-voltage electrode is disposed inside the quartz vacuum chamber; The test high-voltage electrode is embedded in the sealing cover part of the quartz vacuum chamber, and the test surface of the test high-voltage electrode is disposed opposite to the test surface of the test low-voltage electrode with a gap therebetween; the crosslinked polyethylene sample is placed in the gap for space charge detection.

[0014] In one embodiment, the quartz vacuum chamber is a cylindrical chamber; the diameter range of the cylindrical chamber is 25 to 40 cm, and the height range of the cylindrical chamber is 10 to 15 cm.

[0015] One or more technical solutions proposed by this application have at least the following technical effects: The crosslinked polyethylene insulating material detection method provided by this application can degas the crosslinked polyethylene sample in a closed vacuum environment, and perform gas chromatography experiments and infrared spectrum analysis on the processed gas to determine the content and components of the first crosslinked by-products; and can directly use the space charge testing device to detect the space charge of the crosslinked polyethylene sample after degassing treatment in the closed vacuum environment.

[0016] After degassing the crosslinked polyethylene sample in a closed vacuum environment, this application directly performs analysis of the content and components of the crosslinked by-products and space charge detection, integrating the degassing and detection processes of the crosslinked polyethylene sample in a closed environment, which can avoid the volatilization of crosslinked by-products after degassing treatment and affect subsequent detection; at the same time, the vacuum environment can also completely isolate the outside air, and can avoid the oxidation of the crosslinked polyethylene sample, thereby improving the accuracy of the crosslinked by-product detection results. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with this application, and are used together with the specification to explain the principles of this application.

[0018] To more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following will briefly introduce the drawings required for the description of the embodiments or related technologies. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 It is a schematic structural diagram of a cross-linked polyethylene insulating material detection system provided by an embodiment of the present application; Figure 2 It is a schematic flow diagram provided by the first embodiment of the cross-linked polyethylene insulating material detection method of the present application; Figure 3 It is a schematic brief flow diagram of the cross-linked polyethylene insulating material detection method provided by an embodiment of the present application.

[0020] The realization of the purpose, functional characteristics, and advantages of the present application will be further described with reference to the embodiments and the drawings. Detailed implementation manners

[0021] It should be understood that the specific embodiments described herein are only used to explain the technical solutions of the present application and are not used to limit the present application.

[0022] To better understand the technical solutions of the present application, the following will be described in detail in combination with the drawings in the specification and specific implementation manners.

[0023] The main solution of the embodiment of the present application is: degassing the cross-linked polyethylene sample in a sealed vacuum environment to obtain the first processed gas; wherein, the first processed gas includes cross-linking by-products; performing a gas chromatography experiment and infrared spectrum analysis on the first processed gas to determine the content and components of the first cross-linking by-products; and using a space charge test device to perform space charge detection on the degassed cross-linked polyethylene sample in a sealed vacuum environment.

[0024] During the production process of cross-linked polyethylene insulated cables, the method of adding cross-linking agents is usually selected to make the polyethylene molecular chains combine with each other to form a three-dimensional network structure, so as to improve the mechanical properties, heat resistance and chemical stability of the material. However, the introduction of cross-linking agents will cause the breakage and recombination of some molecular chain chemical bonds, forming cross-linking by-products such as small molecule alkanes (methane, ethane, etc.), hydrogen, alcohols, acetophenone, etc. These substances will remain in the cross-linked polyethylene insulation in the form of impurities. Under the action of a high-voltage electric field, it is easy to form positive and negative ion pairs to trigger migration phenomena, and charge accumulation will occur inside the insulation layer, resulting in local electric field distortion, accelerating insulation aging, and even causing faults such as partial discharge and insulation breakdown, seriously threatening the safe operation of the cable; at the same time, conditions such as temperature, time and pressure during the production process also seriously affect the types and quantities of by-products. Therefore, studying the types and contents of cross-linking by-products and their distribution in the internal space charge of the insulation is of great significance for controlling the quality of the cable.

[0025] In related technologies, infrared spectroscopy, thermogravimetric analysis, gas chromatography, gas chromatography-mass spectrometry, and space charge testing are usually used to directly detect the degassed cable in an air environment to qualitatively analyze the influence of cross-linking by-products on the relevant physical properties of cross-linked polyethylene. However, in the above methods, the cable samples to be tested are easily affected by oxidation and decomposition of components such as air, resulting in low accuracy of the cross-linking by-product detection results, and it is impossible to accurately reflect the composition, content of cross-linking by-products in high-voltage cross-linked polyethylene insulated cables and their influence on space charge characteristics. Therefore, it is necessary to seek a detection method for cross-linked polyethylene insulation materials with higher detection accuracy.

[0026] This application provides a solution. After degassing treatment in a closed vacuum environment, the component content analysis of cross-linking by-products and the space charge detection of cross-linked polyethylene samples can be directly carried out. The degassing and detection processes are integrated in a closed environment, which can avoid the volatilization of cross-linking by-products after degassing treatment and affect subsequent detection; at the same time, the vacuum closed environment can completely isolate the external air and avoid the oxidation of cross-linked polyethylene samples, thereby improving the accuracy of cross-linking by-product detection results.

[0027] The following will be described and introduced through multiple embodiments.

[0028] Refer to Figure 1 , Figure 1 which is a schematic structural diagram of a cross-linked polyethylene insulation material detection system according to the embodiment solution of this application.

[0029] As Figure 1 shown, the cross-linked polyethylene insulation material detection system in this embodiment may include a quartz vacuum chamber 1, a heating device 2, a gas chromatograph 3, an infrared spectrometer 4, and a space charge testing device 5.

[0030] Among them, the quartz vacuum chamber 1 is mainly used to provide a sealed vacuum environment. The degassing and detection processes of the cross-linked polyethylene sample will be carried out in this sealed vacuum environment. The quartz vacuum chamber 1 can be filled with inert gases, etc., to avoid the reaction of the cross-linked polyethylene sample with oxygen or moisture in the air. At the same time, the quartz material has high temperature resistance and chemical resistance, which can ensure the stability of the degassing and detection processes to guarantee the accuracy of the test results. In a feasible implementation manner, the quartz vacuum chamber can be a cylindrical chamber. The internal space of the cylindrical chamber structure is evenly distributed, which is beneficial to the uniform heating of the cross-linked polyethylene sample by the heating device 2 during the subsequent degassing process. At the same time, it is also convenient for the installation and layout of other detection devices. The diameter range of the cylindrical chamber can be 25 to 40 cm, and the height range of the cylindrical chamber can be 10 to 15 cm. This size range can not only meet the placement and detection requirements of the cross-linked polyethylene sample but also prevent the chamber from being too large, increasing the volume and cost of the system.

[0031] The heating device 2 is arranged inside the quartz vacuum chamber 1 and can realize temperature control inside the chamber to perform degassing treatment. The degassing treatment mainly heats the cross-linked polyethylene sample so that the cross-linking by-products in the cross-linked polyethylene sample can be released for subsequent detection. The heating device 2 can be a resistance heater that generates heat by passing an electric current through a resistance wire to heat the quartz vacuum chamber and the cross-linked polyethylene sample; it can also be an infrared heating device that uses infrared radiation to heat the cross-linked polyethylene sample to release the cross-linking by-products.

[0032] The gas chromatograph 3 can be connected to the quartz vacuum chamber 1 through the sealing ring air inlet 6 provided on the quartz vacuum chamber 1. The gas chromatograph 3 is a high-sensitivity and high-selectivity analytical instrument that can perform a gas chromatography experiment on the gas (including cross-linking by-products) in the sealed vacuum environment after degassing treatment to obtain the content of cross-linking by-products. In practical applications, the sampling needle of the gas chromatograph 3 can extract the gas in the sealed vacuum environment through the sealing ring air inlet 6 to carry out the gas chromatography experiment. The sealing ring air inlet can be a rubber sealing ring air inlet. The rubber sealing ring has good elasticity and sealing performance, which can maintain a good sealing effect at the connection during the sampling process of the sampling needle and maintain the sealed vacuum environment of the quartz vacuum chamber.

[0033] The infrared spectrometer 4 can be connected to the quartz vacuum chamber 1 through the thermal infrared interface air inlet 7. Infrared spectral analysis can determine the composition of the gas according to the absorption characteristics of gas molecules for infrared light. Therefore, through the connection between the infrared spectrometer 4 and the quartz vacuum chamber 1, the gas in the sealed vacuum environment after degassing treatment can be directly input into the infrared spectrometer 4 for infrared spectral analysis to obtain the composition of cross-linking by-products.

[0034] The space charge test device 5 is embedded in the quartz vacuum chamber 1 and is used to detect the space charge of the cross-linked polyethylene sample after degassing treatment. Space charge detection can understand the charge accumulation situation inside the cross-linked polyethylene sample, which is convenient for evaluating the insulation performance and reliability of the cable. Specifically, the space charge test device may include a test low-voltage electrode 5a and a test high-voltage electrode 5b; the test low-voltage electrode 5a is arranged inside the quartz vacuum chamber; the test high-voltage electrode 5b is embedded in the sealing cover part 1a of the quartz vacuum chamber 1, and the test surface of the test high-voltage electrode 5b is arranged opposite to the test surface of the test low-voltage electrode 5a with a gap; by applying different electric potentials to the test low-voltage electrode 5a and the test high-voltage electrode 5b respectively, an electric field can be formed in the gap, and thus the space charge of the cross-linked polyethylene sample placed in the gap can be detected.

[0035] In addition, in order to ensure the stability and purity of the inert gas in the quartz vacuum chamber 1, in a feasible implementation manner, the cross-linked polyethylene insulation material detection system may further include a vacuum pump 8 and an inert gas cylinder 9; wherein, the vacuum pump 8 is connected to the quartz vacuum chamber 1 through a vacuum pump air inlet 10 and is used to evacuate the quartz vacuum chamber 1 to remove air, moisture, etc. therein to form a vacuum environment; the vacuum pump 8 may also be configured with a vacuum gauge to detect the internal air pressure environment of the quartz vacuum chamber 1; the inert gas cylinder 9 is connected to the quartz vacuum chamber 1 through a gas cylinder air inlet 11 and is used to inject inert gas into the quartz vacuum chamber 1. Through the cooperation of the vacuum pump 8 and the inert gas cylinder 9, a sealed vacuum environment and an inert gas atmosphere in the quartz vacuum chamber 1 can be quickly established and maintained, providing a more stable and pure test environment, and further improving the accuracy and reliability of the detection results.

[0036] It can be understood that in the cross-linked polyethylene insulation material detection system provided in this embodiment, the heating device 2 is arranged inside the quartz vacuum chamber 1, and at the same time the quartz vacuum chamber 1 is connected to the gas chromatograph 3, the infrared spectrometer 4, and the space charge test device 5. Thus, after the cross-linked polyethylene sample is degassed in a vacuum closed environment filled with inert gas, the content analysis of the cross-linking by-products and the space charge detection of the cross-linked polyethylene sample can be directly carried out after the degassing treatment. The degassing and detection processes are integrated in a closed environment, which can avoid the volatilization of cross-linking by-products after degassing treatment and affect subsequent detection; at the same time, the vacuum environment containing inert gas can completely isolate the external air and can avoid the oxidation of the cross-linked polyethylene sample, thereby improving the accuracy of the cross-linking by-product detection results.

[0037] Based on this, the embodiments of the present application provide a method for detecting cross-linked polyethylene insulation materials, referring to Figure 2 , Figure 2 is a schematic flow chart of the first embodiment of the method for detecting cross-linked polyethylene insulation materials of the present application.

[0038] In this embodiment, the detection method of the cross-linked polyethylene insulating material may include steps S100 to S300: Step S100: Degas the cross-linked polyethylene sample in a closed vacuum environment to obtain the first processed gas; wherein, the first processed gas includes cross-linking by-products.

[0039] Step S200: Perform gas chromatography experiments and infrared spectroscopy analysis on the first processed gas to determine the content and components of the first cross-linking by-products.

[0040] Step S300: In a closed vacuum environment, use a space charge testing device to detect the space charge of the cross-linked polyethylene sample after degassing treatment.

[0041] Specifically, the cross-linked polyethylene sample can be placed in a closed vacuum environment (such as the quartz vacuum chamber 1 in the cross-linked polyethylene insulating material detection system) for degassing treatment: control the heating device 2 to make the temperature in the quartz vacuum chamber 1 reach the set temperature required for degassing treatment. Usually, the range of the set temperature is from room temperature to 600 °C, and the heating duration (i.e., the degassing duration) is from 0 to 9999 min. Through the heating operation, the cross-linking by-products in the cross-linked polyethylene sample can be released, facilitating subsequent detection; an inert gas can be filled in the above-mentioned closed vacuum environment. The closed vacuum environment filled with inert gas can prevent the cross-linked polyethylene sample from being affected by oxidation and decomposition of oxygen in the air, resulting in deviation of subsequent test data, and can better ensure the accuracy of the test results.

[0042] Meanwhile, in order to improve the authenticity and accuracy of test data, before step S100, the cross-linked polyethylene insulation layer of the cable can be intercepted according to a preset size to obtain a cross-linked polyethylene sample; wherein, the preset size is the test size of the space charge test equipment. That is to say, the size of the cross-linked polyethylene sample used in subsequent detection is the test size of the space charge test equipment, and this test size can be determined by the size of the test surface of the test electrode, etc.; for example, if the size of the test surface of the test electrode is 70mm×70mm, it can be determined that the size of the cross-linked polyethylene sample is 70mm×70mm×0.3mm; thus, the cross-linked polyethylene sample can correspond exactly to the test electrode, ensuring uniform distribution of the electric field strength on the cross-linked polyethylene sample during subsequent space charge detection, so as to obtain accurate space charge detection results; 0.3mm in the above size is the thickness of the cross-linked polyethylene sample, and the thickness of 0.3mm can balance the signal strength and resolution during space charge detection, improving the reliability of the detection results. In addition, using a cross-linked polyethylene sample with the same size as the test size of the space charge test equipment can also avoid secondary cutting of the cross-linked polyethylene sample to fit the test size, resulting in the volatilization of cross-linked by-product gases in the cross-linked polyethylene sample and affecting the subsequent detection results of gas components and contents.

[0043] After degassing treatment, the sealed vacuum environment will be filled with the first treated gas, and the first treated gas contains cross-linked by-products released from the cross-linked polyethylene sample; then, gas chromatography experiments and infrared spectroscopy analysis are carried out on the first treated gas to determine the content and components of the first cross-linked by-products in the cross-linked polyethylene sample; in practical applications, the sampling needle of the gas chromatograph 3 can be used to directly extract the gas in the sealed vacuum environment from the seal inlet 6 to carry out gas chromatography experiments to determine the content of the first cross-linked by-products; after the gas chromatograph 3 completes sampling, the thermal infrared interface inlet 7 connected to the infrared spectrometer 4 can be opened to allow the first treated gas to enter the infrared spectrometer 4 for infrared spectroscopy analysis to determine the components of the first cross-linked by-products. In related technologies, it may be necessary to prepare a solution to dissolve the cross-linked polyethylene sample to obtain a solution containing cross-linked by-products, and then carry out relevant analysis on the solution. However, the gas obtained after degassing treatment in this application can directly enter the analytical instrument for detection, avoiding the cumbersome operation of preparing the solution and simplifying the detection process.

[0044] In addition, before the gas chromatography experiment and infrared spectroscopy analysis of the gas after the first treatment, a degassing treatment is performed on the cross-linked polyethylene sample by heating. At this time, the temperature of the closed vacuum environment may be relatively high, and the gas temperature after the first treatment is also relatively high. The high gas temperature will affect the detection accuracy of the gas chromatograph and infrared spectrometer. At the same time, the high temperature will also affect the stability of the cross-linking by-products (such as testing in a high-temperature environment will cause the volatilization of cross-linking by-products such as methane), resulting in inaccurate detection results. Therefore, the gas chromatography experiment and infrared spectroscopy analysis of the gas after the first treatment can be carried out after the temperature of the closed vacuum environment returns to room temperature to determine the content and composition of the first cross-linking by-products. It can be understood that after the temperature of the closed vacuum environment returns to room temperature, a relatively stable and suitable temperature environment can be provided, avoiding the interference problem of the high-temperature environment on the detection instrument, and at the same time ensuring the stability of the gas composition and the standardization of the detection conditions, making the qualitative and quantitative analysis results of the cross-linking by-products closer to the true value.

[0045] Then, in the closed vacuum environment, a space charge test device is used to detect the space charge of the cross-linked polyethylene sample after degassing treatment to determine the charge accumulation in the cross-linked polyethylene sample. According to the test requirements, the heating device can be controlled to reach the specified temperature, and then the test voltage of the space charge test device can be set to carry out the space charge detection. The detection temperature range of the space charge detection can generally be set from room temperature to 80°C, and the detection voltage range of the space charge detection is 0 to 30 kV / mm.

[0046] At the same time, in order to analyze the influence of the space charge detection on the gas production components and content of the cross-linked polyethylene sample, after the space charge detection is completed, the gas chromatography experiment and infrared spectroscopy analysis can also be carried out on the gas after the second treatment respectively to obtain the content and composition of the second cross-linking by-products. Among them, the gas after the second treatment is the gas in the closed vacuum environment obtained after the space charge detection. Based on the content and composition of the first cross-linking by-products, the content and composition of the second cross-linking by-products, the influence of the space charge detection on the gas production components and content of the cross-linked polyethylene sample is determined. The gas chromatography experiment and infrared spectroscopy analysis of the gas after the second treatment can refer to the gas after the first treatment. By comparing the results of the content and composition of the first cross-linking by-products, the content and composition of the second cross-linking by-products, it can be determined whether the space charge detection will cause changes in the released content and composition of the cross-linking by-products of the cross-linked polyethylene sample, providing a more reliable basis for the cable performance evaluation.

[0047] It is worth mentioning that in order to ensure the stability and purity of the inert gas in the closed vacuum environment, steps A100 to A300 can be specifically included before step S100 to obtain a closed vacuum environment filled with inert gas.

[0048] Step A100: Evacuate the closed environment where the cross-linked polyethylene sample is located until the vacuum degree of the closed environment reaches the first preset vacuum degree.

[0049] Step A200: Inject inert gas into the closed environment until the vacuum degree of the closed environment reaches the second preset vacuum degree; wherein, the second preset vacuum degree is greater than the first preset vacuum degree.

[0050] Step A300: Repeat the evacuation process and the injection of inert gas for a preset number of times to obtain a closed vacuum environment filled with inert gas.

[0051] Specifically, equipment such as a vacuum pump can be used to evacuate the closed environment where the cross-linked polyethylene sample is located until the vacuum degree of the closed environment reaches the first preset vacuum degree; then, inert gas is injected into the evacuated closed environment until the vacuum degree of the closed environment reaches the second preset vacuum degree; the operations of evacuation and injection of inert gas are repeated multiple times to completely remove the gas and impurities inside the closed environment and obtain a closed vacuum environment filled with inert gas, ensuring the subsequent degassing and detection effects.

[0052] It can be understood that for the cross-linked polyethylene insulating material detection method provided in this embodiment, after degassing treatment in a closed vacuum environment filled with inert gas, the analysis of the content of cross-linking by-products and the space charge detection of the cross-linked polyethylene sample can be directly carried out. The degassing and detection processes are integrated in a closed environment, which can avoid the volatilization of cross-linking by-products after degassing treatment and affect subsequent detection; at the same time, the vacuum environment containing inert gas can completely isolate the external air and prevent the oxidation of the cross-linked polyethylene sample, thereby improving the accuracy of the cross-linking by-product detection results.

[0053] Exemplarily, to facilitate understanding of the implementation process of the cross-linked polyethylene insulating material detection method in the above embodiment, please refer to Figure 3 , Figure 3 A schematic diagram of the brief process of a cross-linked polyethylene insulating material detection method is provided, and the specific steps are as follows: (1) Prepare the sample: Cut a cross-linked polyethylene insulating thin sheet to obtain a cross-linked polyethylene sample with a size of 70mm×70mm×0.3mm, which is matched with the test size of the space charge testing equipment.

[0054] (2) Place the sample: Place the cross-linked polyethylene sample between the high-voltage test electrode and the low-voltage test electrode of the space charge testing equipment to ensure that the cross-linked polyethylene sample can be in close contact with the high- and low-voltage electrodes without air gaps.

[0055] (3) Air extraction and replacement treatment: The quartz vacuum chamber is evacuated. When the vacuum degree of the quartz vacuum chamber reaches the first preset vacuum degree of 10 -2 Pa or below, stop air extraction and introduce inert gas into the quartz vacuum chamber. When the vacuum degree of the quartz vacuum chamber reaches the second preset vacuum degree of 1 Pa, stop gas introduction; subsequently, continue the air extraction and gas introduction operations. After cycling the "air extraction - gas introduction" process 3 - 6 times, the quartz vacuum chamber can be filled with inert gas protection gas to ensure that there is no interference from impurity gases in the quartz vacuum chamber.

[0056] (4) Degassing treatment: Adjust the quartz vacuum chamber to the preset temperature required for degassing. The temperature range is generally from room temperature to 600 °C, and start timing. The degassing time for timing is 0 to 9999 min.

[0057] (5) Gas content detection: After the degassing treatment is completed and the temperature in the quartz vacuum chamber returns to room temperature, use the sampling needle of the gas chromatograph to extract gas at the inlet of the rubber seal of the quartz vacuum chamber to conduct a gas chromatography experiment to test the content of the volatile gas (i.e., the content of the first cross - linked by - product) obtained from the degassing treatment.

[0058] (6) Gas component detection: After the sampling of the gas chromatography experiment is completed, open the inlet connected to the thermal infrared interface of the side of the quartz vacuum chamber connected to the infrared spectrometer, and use the infrared spectrometer to test the components of the volatile gas (i.e., the components of the first cross - linked by - product) obtained from the degassing treatment.

[0059] (7) Space charge detection: Set the test temperature required for space charge detection. The temperature range is generally from room temperature to 80 °C, and set the test voltage required. The voltage range is 0 to 30 kV / mm, and then conduct a space charge test to study the internal charge accumulation of the cross - linked polyethylene sample.

[0060] (8) Steps (5) and (6) can be repeated to determine the influence of space charge detection on the gas production components and content of the cross - linked polyethylene sample; (9) Based on the foregoing steps, the analysis results of the cross - linked by - product components, cross - linked by - product content, and space charge characteristics of the cross - linked polyethylene sample can be obtained.

[0061] It should be noted that the above examples are only for understanding this application and do not constitute a limitation to the detection method of the cross - linked polyethylene insulating material of this application. Based on this technical concept, more simple transformations in various forms are within the protection scope of this application.

[0062] The above - mentioned are only some embodiments of this application. Therefore, the protection scope is not limited. All equivalent structural transformations made under the technical concept of this application by using the content of the specification and drawings of this application, or directly / indirectly applied in other related technical fields are included in the protection scope.

Claims

1. A method for detecting a cross-linked polyethylene insulating material, characterized in that, The detection method for the cross-linked polyethylene insulating material includes: Performing degassing treatment on the cross-linked polyethylene sample in a sealed vacuum environment to obtain the first post-treatment gas; wherein, the first post-treatment gas includes cross-linking by-products; Performing gas chromatography experiments and infrared spectroscopy analysis on the first post-treatment gas to determine the content and composition of the first cross-linking by-products; In the sealed vacuum environment, using a space charge testing device to perform space charge detection on the cross-linked polyethylene sample after degassing treatment.

2. The cross-linked polyethylene insulation material detection method according to claim 1, characterized in that, Before the step of performing degassing treatment on the cross-linked polyethylene sample in a sealed vacuum environment to obtain the first post-treatment gas, the method further includes: Performing vacuum pumping on the sealed environment where the cross-linked polyethylene sample is located until the vacuum degree of the sealed environment reaches a first preset vacuum degree; Injecting an inert gas into the sealed environment until the vacuum degree of the sealed environment reaches a second preset vacuum degree; wherein, the second preset vacuum degree is greater than the first preset vacuum degree; Repeating the vacuum pumping treatment and the injection of the inert gas for a preset number of times to obtain a sealed vacuum environment filled with the inert gas.

3. The detection method of the crosslinked polyethylene insulating material according to claim 1, wherein, Before the step of performing degassing treatment on the cross-linked polyethylene sample in a sealed vacuum environment to obtain the first post-treatment gas, the method further includes: Cutting the cross-linked polyethylene insulating layer of the cable according to a preset size to obtain the cross-linked polyethylene sample; wherein, the preset size is the test size of the space charge testing device.

4. The detection method of the cross-linked polyethylene insulating material according to claim 1, characterized in that The step of performing gas chromatography experiments and infrared spectroscopy analysis on the first post-treatment gas to determine the content and composition of the first cross-linking by-products includes: Under the condition that the temperature of the sealed vacuum environment returns to room temperature, performing gas chromatography experiments and infrared spectroscopy analysis on the first post-treatment gas to determine the content of the first cross-linking by-products and the composition of the first cross-linking by-products.

5. The detection method of the cross-linked polyethylene insulating material according to claim 1, wherein, The detection temperature range of the space charge detection is from room temperature to 80 °C, and the detection voltage range of the space charge detection is from 0 to 30 kV / mm.

6. The detection method of the cross-linked polyethylene insulating material according to any one of claims 1 to 5, characterized in that, After the step of using a space charge testing device to perform space charge detection on the cross-linked polyethylene sample after degassing treatment in the sealed vacuum environment, the method further includes: Performing gas chromatography experiments and infrared spectroscopy analysis on the second post-treatment gas respectively to obtain the content of the second cross-linking by-products and the composition of the second cross-linking by-products; wherein, the second post-treatment gas is the gas in the sealed vacuum environment obtained after space charge detection; Based on the content of the first cross-linking by-products, the composition of the first cross-linking by-products, the content of the second cross-linking by-products, and the composition of the second cross-linking by-products, determining the influence of the space charge detection on the gas production components and gas production content of the cross-linked polyethylene sample.

7. A cross-linked polyethylene insulation material detection system, characterized in that, The cross-linked polyethylene insulating material detection system includes: A quartz vacuum chamber for providing a sealed vacuum environment; A heating device disposed in the quartz vacuum chamber for performing degassing treatment; A gas chromatograph connected to the quartz vacuum chamber through a sealing ring air inlet for performing gas chromatography experiments on the gas in the sealed vacuum environment after degassing treatment to obtain the content of cross-linking by-products; An infrared spectrometer is connected to the quartz vacuum chamber through a thermal infrared interface air inlet, and is used to perform infrared spectral analysis on the gas in the sealed vacuum environment after degassing treatment to obtain the composition of cross-linking by-products; A space charge testing device is embedded in the quartz vacuum chamber and is used to detect the space charge of the cross-linked polyethylene sample after degassing treatment.

8. The cross-linked polyethylene insulation material detection system according to claim 7, wherein, The cross-linked polyethylene insulating material detection system further includes: A vacuum pump is connected to the quartz vacuum chamber through a vacuum pump air inlet and is used to evacuate the quartz vacuum chamber; An inert gas cylinder is connected to the quartz vacuum chamber through a cylinder air inlet and is used to inject inert gas into the quartz vacuum chamber.

9. The cross-linked polyethylene insulation material detection system according to claim 7, characterized in that, The space charge testing device includes a test low-voltage electrode and a test high-voltage electrode; The test low-voltage electrode is arranged in the quartz vacuum chamber; The test high-voltage electrode is embedded in the sealing cover part of the quartz vacuum chamber, and the test surface of the test high-voltage electrode is arranged opposite to the test surface of the test low-voltage electrode with a gap therebetween; the cross-linked polyethylene sample is placed in the gap for space charge detection.

10. The cross-linked polyethylene insulation material detection system according to claim 7, characterized in that, The quartz vacuum chamber is a cylindrical chamber; the diameter range of the cylindrical chamber is 25 to 40 cm, and the height range of the cylindrical chamber is 10 to 15 cm.

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