CN114791440A - Evaluation method of crosslinked inner shielding material - Google Patents
Evaluation method of crosslinked inner shielding material Download PDFInfo
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- 239000000463 material Substances 0.000 title claims abstract description 181
- 238000011156 evaluation Methods 0.000 title claims abstract description 18
- 238000012360 testing method Methods 0.000 claims abstract description 107
- 238000000034 method Methods 0.000 claims abstract description 18
- 238000004073 vulcanization Methods 0.000 claims description 55
- 238000002844 melting Methods 0.000 claims description 15
- 230000008018 melting Effects 0.000 claims description 15
- 238000001125 extrusion Methods 0.000 claims description 10
- 239000004033 plastic Substances 0.000 claims description 7
- 238000007670 refining Methods 0.000 claims description 7
- 238000004806 packaging method and process Methods 0.000 claims description 5
- 238000003825 pressing Methods 0.000 claims description 4
- 238000004132 cross linking Methods 0.000 abstract description 29
- 235000012431 wafers Nutrition 0.000 description 30
- 229920001971 elastomer Polymers 0.000 description 8
- 238000001816 cooling Methods 0.000 description 7
- 238000004519 manufacturing process Methods 0.000 description 7
- 238000010438 heat treatment Methods 0.000 description 6
- 238000009413 insulation Methods 0.000 description 6
- 229920006267 polyester film Polymers 0.000 description 4
- 238000005259 measurement Methods 0.000 description 3
- 230000035945 sensitivity Effects 0.000 description 3
- 238000010998 test method Methods 0.000 description 3
- 239000004020 conductor Substances 0.000 description 2
- 239000003431 cross linking reagent Substances 0.000 description 2
- 238000005034 decoration Methods 0.000 description 2
- 239000000806 elastomer Substances 0.000 description 2
- 230000002349 favourable effect Effects 0.000 description 2
- 238000012812 general test Methods 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- 239000002480 mineral oil Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 235000010446 mineral oil Nutrition 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
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- G—PHYSICS
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N25/00—Investigating or analyzing materials by the use of thermal means
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- H—ELECTRICITY
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- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B13/00—Apparatus or processes specially adapted for manufacturing conductors or cables
- H01B13/22—Sheathing; Armouring; Screening; Applying other protective layers
- H01B13/24—Sheathing; Armouring; Screening; Applying other protective layers by extrusion
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B7/00—Insulated conductors or cables characterised by their form
- H01B7/17—Protection against damage caused by external factors, e.g. sheaths or armouring
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Abstract
The invention relates to the technical field of crosslinked cables and provides an evaluation method of a crosslinked inner shielding material. The method provided by the invention can select the cross-linked inner shielding material which is difficult to generate the advanced cross-linking phenomenon from a plurality of inner shielding materials by measuring the thermal extension performance of the test sample prepared from the cross-linked inner shielding material and the temperature rise of the extruder body when the cross-linked inner shielding material is extruded, thereby providing necessary technical support for selecting the cross-linked inner shielding material with the optimal performance and improving the quality of a cross-linked cable product for preparing the cross-linked cable.
Description
Technical Field
The invention relates to the technical field of crosslinked cables, in particular to an evaluation method of a crosslinked inner shielding material.
Background
In the production of the crosslinked cable with the rated voltage of 3.6/6-26/35 kV, a crosslinked inner shielding material is required to be used, and the inner shielding material is required to be tightly extruded on the surface of a conductor, is in a concentric circle shape with the circular conductor and is tightly adhered to an insulating layer, so that the higher the surface roundness and smoothness of the inner shielding material are, the better the crosslinked cable with excellent quality is obtained. In the preparation process, the temperature of the cross-linked inner shielding material can be increased along with the increase of the temperature in the extruder, when the temperature exceeds the process temperature of the cross-linked inner shielding material, the cross-linked inner shielding material generates a cross-linking reaction in the extruder, and the product quality is ensured, and the cross-linked inner shielding material cannot generate the cross-linking reaction in the extruder during normal production.
However, in practical production, under the condition that the process conditions are stable, the extrusion effect of the inner shielding materials produced by different manufacturers meeting the current standard (JB/T10738-. Therefore, a method for evaluating whether the crosslinked inner shield material is pre-crosslinked is needed.
Disclosure of Invention
The invention aims to provide an evaluation method of a cross-linked internal shielding material, which can accurately judge whether the cross-linked internal shielding material is subjected to early cross-linking.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides an evaluation method of a cross-linked inner shielding material, which comprises the steps of respectively carrying out a thermal extension test and a temperature rise test on the cross-linked inner shielding material to be evaluated; if the thermal extension test and the temperature rise test of the cross-linked inner shielding material to be evaluated are both qualified, judging that the cross-linked inner shielding material to be evaluated is a qualified product;
the thermal extension test comprises the following steps:
(1) plasticizing the cross-linked internal shielding material to be evaluated to obtain a film;
(2) vulcanizing the film obtained in the step (1) to obtain a sample wafer to be tested;
(3) testing the thermal extension performance of the sample wafer to be tested obtained in the step (2); if the thermal extension variation trend of the sample wafer to be tested meets the following conditions: the elongation rate of the cross-linked inner shielding material to be evaluated is more than or equal to 300% after 3min of vulcanization, the elongation rate of the cross-linked inner shielding material to be evaluated is 150-200% after 5min of vulcanization, the elongation rate of the cross-linked inner shielding material to be evaluated is 100-120% after 10min of vulcanization, and the elongation rate of the cross-linked inner shielding material to be evaluated is 50-80% after 15min of vulcanization; if the thermal extension variation trend of the sample wafer to be evaluated does not meet the requirement, determining that the thermal extension test of the cross-linked inner shielding material to be evaluated is unqualified;
the temperature rise test comprises: three-section extrusion is carried out on the cross-linked inner shielding material to be evaluated, and then the temperature rise of the extruder body is tested; if the temperature rise is satisfied: the temperature rise test of the cross-linked inner shielding material to be evaluated is qualified when the feeding section is less than 3 ℃, the melting section is less than 4 ℃ and the homogenizing section is less than 5 ℃; otherwise, judging that the temperature rise test of the cross-linked inner shielding material to be evaluated is unqualified.
Preferably, the temperature of plasticization in said step (1) is < 70 ℃.
Preferably, the equipment used for plasticizing in the step (1) is a double-roller plastic refining machine; the roller spacing of the double-roller plastic refining machine is 2.0-2.5 mm.
Preferably, the plasticizing process in the step (1) further comprises triangular packaging; the triangular packaging time is 3-4 min.
Preferably, the temperature of the vulcanization in the step (2) is 180-183 ℃.
Preferably, the sample to be tested obtained in the step (2) comprises a sample with the vulcanization time of 3min, 4min, 5min, 10min and 15 min.
Preferably, the pressurization mode before the vulcanization in the step (2) is as follows: pressurizing to 13-15 MPa, pre-pressing for 20-25 s, then reducing the pressure to 0MPa, keeping for 10-15 s, and finally pressurizing to 15-20 MPa.
Preferably, the size of the sample wafer to be measured in the step (2) is 200mm × 200mm, and the thickness is 1.0 ± 0.1 mm.
Preferably, the initial temperature of the feeding section body is 95-98 ℃, the initial temperature of the melting section body is 100-103 ℃, and the initial temperature of the homogenizing section body is 105-108 ℃.
Preferably, the temperature rise time of the extruder body is measured after three-stage extrusion for 5-6 min.
The invention provides an evaluation method of a cross-linked internal shielding material, which comprises the steps of respectively carrying out a thermal extension test and a temperature rise test on the cross-linked internal shielding material to be evaluated; if the thermal extension test and the temperature rise test of the cross-linked inner shielding material to be evaluated are both qualified, judging that the cross-linked inner shielding material to be evaluated is a qualified product; the thermal extension test comprises the following steps: (1) plasticizing the cross-linked inner shielding material to be evaluated to obtain a film; (2) vulcanizing the film obtained in the step (1) to obtain a sample wafer to be tested; (3) testing the thermal extension performance of the sample wafer to be tested obtained in the step (2); if the thermal extension variation trend of the sample wafer to be tested meets the following conditions: the elongation rate of the cross-linked inner shielding material to be evaluated is more than or equal to 300% after 3min of vulcanization, the elongation rate of the cross-linked inner shielding material to be evaluated is 150-200% after 5min of vulcanization, the elongation rate of the cross-linked inner shielding material to be evaluated is 100-120% after 10min of vulcanization, and the elongation rate of the cross-linked inner shielding material to be evaluated is 50-80% after 15min of vulcanization; if the thermal extension variation trend of the sample wafer to be evaluated does not meet the requirement, determining that the thermal extension test of the cross-linked inner shielding material to be evaluated is unqualified; the temperature rise test comprises: three-section extrusion is carried out on the cross-linked inner shielding material to be evaluated, and then the temperature rise of the extruder body is tested; if the temperature rise is satisfied: the temperature rise test of the cross-linked inner shielding material to be evaluated is qualified if the feeding section is less than 3 ℃, the melting section is less than 4 ℃, and the homogenizing section is less than 5 ℃; otherwise, judging that the temperature rise test of the cross-linked inner shielding material to be evaluated is unqualified. The method provided by the invention can select the cross-linked inner shielding material which is difficult to generate the advanced cross-linking phenomenon from a plurality of inner shielding materials by measuring the thermal extension performance of the test sample prepared from the cross-linked inner shielding material and the temperature rise of the extruder body when the cross-linked inner shielding material is extruded, thereby providing necessary technical support for selecting the cross-linked inner shielding material with the optimal performance and improving the quality of a cross-linked cable product for preparing the cross-linked cable.
Detailed Description
The invention provides an evaluation method of a cross-linked internal shielding material, which comprises the steps of respectively carrying out a thermal extension test and a temperature rise test on the cross-linked internal shielding material to be evaluated; if the thermal extension test and the temperature rise test of the cross-linked inner shielding material to be evaluated are both qualified, judging that the cross-linked inner shielding material to be evaluated is a qualified product;
the thermal extension test comprises the following steps:
(1) plasticizing the cross-linked internal shielding material to be evaluated to obtain a film;
(2) vulcanizing the film obtained in the step (1) to obtain a sample wafer to be tested;
(3) testing the thermal extension performance of the sample wafer to be tested obtained in the step (2); if the thermal extension variation trend of the sample wafer to be tested meets the following conditions: the elongation rate of the cross-linked inner shielding material to be evaluated is more than or equal to 300% in 3min of vulcanization, the elongation rate of the cross-linked inner shielding material to be evaluated is 150-200% in 5min of vulcanization, the elongation rate of the cross-linked inner shielding material to be evaluated is 100-120% in 10min of vulcanization, and the elongation rate of the cross-linked inner shielding material to be evaluated is 50-80% in 15min of vulcanization; if the thermal extension variation trend of the sample wafer to be evaluated does not meet the requirement, determining that the thermal extension test of the cross-linked inner shielding material to be evaluated is unqualified;
the temperature rise test comprises: three-section extrusion is carried out on the cross-linked inner shielding material to be evaluated, and then the temperature rise of the extruder body is tested; if the temperature rise is satisfied: the temperature rise test of the cross-linked inner shielding material to be evaluated is qualified if the feeding section is less than 3 ℃, the melting section is less than 4 ℃, and the homogenizing section is less than 5 ℃; otherwise, judging that the temperature rise test of the cross-linked inner shielding material to be evaluated is unqualified.
The method comprises the steps of respectively carrying out thermal extension test and temperature rise test on a cross-linked inner shielding material to be evaluated; and if the thermal extension test and the temperature rise test of the cross-linked inner shielding material to be evaluated are qualified, judging that the cross-linked inner shielding material to be evaluated is a qualified product. According to the invention, the cross-linked inner shielding material which is not easy to generate the advanced cross-linking phenomenon can be selected from a plurality of inner shielding materials by respectively measuring the thermal extension performance of the cross-linked inner shielding material and the temperature rise of the extruder body when the cross-linked inner shielding material is extruded.
The evaluation method provided by the invention is suitable for various cross-linked internal shielding materials produced by various manufacturers. In the present invention, the crosslinked inner shield to be evaluated preferably includes: the 10kV cross-linked internal shielding material produced by Shanghai Wanyi has the batch number of 20509, the box number of 20, the 10kV cross-linked internal shielding material produced by Jiangsu Jiangyin, the batch number of 202003D14, the box number of 22, the 10kV cross-linked internal shielding material produced by Zhejiang Xin Fangde, the batch number of 210109, the box number of 18, the 10kV cross-linked internal shielding material produced by Nanjing Zhongsheng, the batch number of 210109 and the box number of 09.
In the present invention, the thermal extension test comprises the steps of:
(1) plasticizing the cross-linked internal shielding material to be evaluated to obtain a film;
(2) vulcanizing the film obtained in the step (1) to obtain a sample wafer to be tested;
(3) testing the thermal extension performance of the sample wafer to be tested obtained in the step (2); if the thermal extension variation trend of the sample wafer to be tested meets the following conditions: the elongation rate of the cross-linked inner shielding material to be evaluated is more than or equal to 300% after 3min of vulcanization, the elongation rate of the cross-linked inner shielding material to be evaluated is 150-200% after 5min of vulcanization, the elongation rate of the cross-linked inner shielding material to be evaluated is 100-120% after 10min of vulcanization, and the elongation rate of the cross-linked inner shielding material to be evaluated is 50-80% after 15min of vulcanization; and if the thermal extension variation trend of the sample wafer to be evaluated does not meet the requirement, judging that the thermal extension test of the cross-linked inner shielding material to be evaluated is unqualified.
The method plasticizes the cross-linked internal shielding material to be evaluated to obtain the film. The invention changes the cross-linking inner shielding material to be evaluated from smaller granular shape into larger thick sheet shape by plasticizing and produces the film with certain shape.
In the invention, the equipment used for plasticizing is preferably a double-roller plastic refining machine; the roller spacing of the double-roller plastic refining machine is preferably 2.0-2.5 mm. The source of the twin-roll plasticator is not particularly limited in the present invention, and commercially available products known to those skilled in the art may be used.
In the present invention, the temperature of the plasticization is preferably < 70 ℃. The invention preferably controls the plasticizing temperature within the range, which is favorable for ensuring the viscosity of the plasticized product.
In the present invention, the operation of controlling the plasticizing temperature is specifically preferably: in the plasticizing process, detecting the rubber material by using a temperature measuring gun; and when the temperature is close to 70 ℃, pulling down the rubber material from the roller, and when the temperature of the rubber material is reduced to 50-60 ℃, plasticizing the rubber material on a plasticator.
In the invention, the plasticizing process preferably further comprises triangular wrapping; the time for triangle packaging is preferably 3-4 min; the number of times of triangular packaging is preferably 6-8.
After the plasticization is finished, the invention preferably cools the plasticized product in air to room temperature to obtain the rubber sheet. In the invention, the thickness of the film is preferably 2-3 mm.
After a film is obtained, the film is vulcanized to obtain a sample wafer to be tested. The cross-linking inner shielding material is cross-linked through vulcanization, and the sample wafer to be tested is prepared.
In the invention, the upper surface and the lower surface of the rubber sheet are respectively covered with polyester films before vulcanization.
In the present invention, the melting point of the polyester film is preferably 200 ℃ or more. The invention is preferably advantageous to prepare better sample films by respectively covering the upper surface and the lower surface of the film with polyester films.
In the invention, the vulcanization temperature is preferably 180-183 ℃, and more preferably 180 ℃. The invention preferably controls the vulcanizing temperature within the range, which is favorable for ensuring the sufficient crosslinking of the crosslinked inner shielding material. In the invention, the vulcanization pressure is preferably 15 to 20MPa, and more preferably 15 MPa.
In the present invention, the pressurization before vulcanization is preferably performed by: pressurizing to 13-15 MPa, pre-pressing for 20-25 s, then reducing the pressure to 0MPa, keeping for 10-15 s, and finally pressurizing to 15-20 MPa; more preferably: pressurizing to 13MPa, pre-pressing for 20s, then reducing the pressure to 0MPa, keeping for 10s, and finally pressurizing to 15 MPa.
In the present invention, the time for the vulcanization is preferably 3min, 4min, 5min, 10min and 15 min. According to the invention, the sample wafers with the vulcanizing time of 3min, 4min, 5min, 10min and 15min are preferably prepared respectively, so that the subsequent thermal extension test of the cross-linked inner shielding material can be smoothly carried out.
In the invention, the size of the sample wafer to be detected is preferably 200mm multiplied by 200 mm; the thickness is preferably 1.0. + -. 0.1 mm.
After the sample wafer to be tested is obtained, the invention tests the thermal extension performance of the sample wafer to be tested according to the technical scheme. The invention judges whether the cross-linking inner shielding material to be evaluated is a qualified product or not by testing the thermal extension performance of the sample wafer to be evaluated.
In the invention, if the thermal extension variation trend of the sample wafer to be tested meets the following requirements: the elongation rate of the cross-linked inner shielding material to be evaluated is more than or equal to 300% after 3min of vulcanization, the elongation rate of the cross-linked inner shielding material to be evaluated is 150-200% after 5min of vulcanization, the elongation rate of the cross-linked inner shielding material to be evaluated is 100-120% after 10min of vulcanization, and the elongation rate of the cross-linked inner shielding material to be evaluated is 50-80% after 15min of vulcanization; and if the thermal extension variation trend of the sample wafer to be evaluated does not meet the requirement, judging that the thermal extension test of the cross-linked inner shielding material to be evaluated is unqualified.
In the present invention, the method of the thermal extension test preferably employs GB/T2951.21-2008 "general test methods for Cable and Cable insulation and sheath materials part 21: the special test method for the elastomer mixture comprises an ozone resistance test, a thermal extension test and a mineral oil immersion test.
In the present invention, the temperature rise test comprises: three-section extrusion is carried out on the cross-linked inner shielding material to be evaluated, and then the temperature rise of the extruder body is tested; if the temperature rise is satisfied: the temperature rise test of the cross-linked inner shielding material to be evaluated is qualified if the feeding section is less than 3 ℃, the melting section is less than 4 ℃, and the homogenizing section is less than 5 ℃; otherwise, judging that the temperature rise test of the cross-linked inner shielding material to be evaluated is unqualified.
In the invention, the initial temperature of the feeding section body is preferably 95-98 ℃, and more preferably 95-96 ℃; the initial temperature of the melting section body is preferably 100-103 ℃, and more preferably 100-102 ℃; the initial temperature of the homogenizing section body is preferably 105-108 ℃, and more preferably 105-106 ℃.
In the invention, the time for testing the temperature rise of the extruder body is preferably 5-6 min after three-stage extrusion.
In the invention, the die orifice temperature of the extruder is preferably 108-111 ℃; the rotating speed of the extruder is preferably 40-50 r/min; the flow rate of cooling compressed air in each section of the extruder body is preferably 10-11L/min.
The method provided by the invention can select the cross-linked inner shielding material which is difficult to generate the advanced cross-linking phenomenon from a plurality of inner shielding materials by measuring the thermal extension performance of the test sample prepared from the cross-linked inner shielding material and the temperature rise of the extruder body when the cross-linked inner shielding material is extruded, thereby providing necessary technical support for selecting the cross-linked inner shielding material with the optimal performance and improving the quality of a cross-linked cable product for preparing the cross-linked cable.
The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It should be apparent that the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
Evaluating a 10kV cross-linked internal shielding material with a batch number of 20509 and a box number of 20 produced by Shanghai Wanyi, and marking as # 1;
thermal extension test:
(1) taking 400g of a # 1 crosslinked inner shielding material to be evaluated, plasticizing the material on a double-roller plastic refining machine with the temperature not exceeding 70 ℃ and the roller spacing of 2.0mm, monitoring the temperature of the material by using a temperature measuring gun, pulling all the material from a roller when the temperature of the material is close to 70 ℃, and putting the material on the plastic refining machine when the temperature of the material is reduced to 60 ℃; during plasticizing, a triangular bag is formed for eight times, the time is controlled to be 3min, and air cooling is carried out to room temperature after plasticizing is completed, so that a film with the thickness of 2mm is obtained;
(2) placing the film obtained in the step (1) in a mold, respectively covering polyester films with melting points of more than or equal to 200 ℃ on the upper surface and the lower surface of the film, then placing the mold in a flat vulcanizing machine with the temperature of 180 ℃, pressurizing to 13MPa for prepressing for 20s, then reducing the pressure to 0MPa for maintaining for 10s, finally pressurizing to 15MPa, vulcanizing under the pressure, starting timing when the temperature of the flat vulcanizing machine is raised back to 180 ℃, stopping heating after 3min, keeping the pressure unchanged, introducing cooling water for cooling, cooling to room temperature, taking out the mold, and taking out a sample wafer from the mold to obtain a sample wafer to be tested with the size of 200mm multiplied by 200mm and the thickness of 1.0 +/-0.1 mm;
(3) repeating the operations in the steps (1) and (2), and respectively preparing sample wafers to be tested with the vulcanization time of 4min, 5min, 10min and 15 min;
(4) according to GB/T2951.21-2008 "general test method for insulation and sheathing materials for electric and optical cables part 21: the test method of thermal extension in the test method special for elastomer mixture-ozone resistance test-thermal extension test-mineral oil immersion test-respectively tests the sample wafer to be tested prepared in the step (2) and the step (3), and the test results are shown in table 1; it can be seen that the elongation of the 1# inner shielding crosslinking material after vulcanization for 3min is 325%, the elongation after vulcanization for 5min is 175%, the elongation after vulcanization for 10min is 117%, and the elongation after vulcanization for 15min is 78%, which satisfies the trend of thermal extension change, and the 1# inner shielding crosslinking material to be evaluated is judged to be qualified in the thermal extension test;
and (3) temperature rise test:
carrying out three-section extrusion on the 1# cross-linked inner shielding material to be evaluated, wherein the temperature of the extruder body is set as follows: the initial temperature of the feeding section is 95 ℃, the initial temperature of the melting section is 100 ℃, the initial temperature of the homogenizing section is 105 ℃, and the temperature of the die orifice is 108 ℃; at the rotating speed of 40r/min, keeping the flow of the cooling compressed air in each section of the extruder body at 10L/min, trial extruding for 5min, and simultaneously testing the temperature rise of the extruder body, wherein the test results are shown in Table 2; it can be seen that the temperature rise of the feeding section is 0 ℃, the temperature rise of the melting section is 1 ℃, the temperature rise of the homogenizing section is 1 ℃, the temperature rise requirement is met, and the temperature rise test of the No. 1 crosslinked inner shielding material to be evaluated is qualified;
and (3) the thermal extension test and the temperature rise test of the 1# cross-linked inner shielding material to be evaluated are both qualified, and the 1# cross-linked inner shielding material is judged to be a qualified product.
Example 2
Evaluating the 10kV cross-linked inner shielding material with the batch number of 202003D14 and the box number of 22 produced by Jiangsu Jiangyin, and marking as 2 #;
the thermal extension test and the temperature rise test are performed in the same manner as in example 1, the results of the thermal extension test are shown in table 1, and the results of the temperature rise test are shown in table 2; as can be seen from Table 1, the elongation of the 2# inner shielding crosslinking material after vulcanization for 3min is 225%, the elongation after vulcanization for 5min is 102%, the elongation after vulcanization for 10min is 95%, and the elongation after vulcanization for 15min is 84%, which do not meet the thermal extension change trend, and the thermal extension test of the 2# inner shielding crosslinking material to be evaluated is determined to be unqualified; as can be seen from Table 2, the temperature rise of the feeding section No. 2 is 0 ℃, the temperature rise of the melting section is 6 ℃, the temperature rise of the homogenizing section is 7 ℃, the temperature rise requirement is not met, and the temperature rise test of the crosslinked inner shielding material No. 2 to be evaluated is unqualified;
and (3) the thermal extension test and the temperature rise test of the 2# cross-linked inner shielding material to be evaluated are not qualified, and the 2# cross-linked inner shielding material is judged to be a unqualified product.
Example 3
Evaluating 10kV cross-linked inner shielding material manufactured by Zhejiang Xin Fangde with the batch number of 210109 and the box number of 18, and marking as 3 #;
the thermal extension test and the temperature rise test are performed in the same manner as in example 1, the results of the thermal extension test are shown in table 1, and the results of the temperature rise test are shown in table 2; as can be seen from Table 1, the 3# internal shielding crosslinking material has 200% elongation after vulcanization for 3min, 90% elongation after vulcanization for 5min, 80% elongation after vulcanization for 10min and 70% elongation after vulcanization for 15min, and does not meet the thermal extension change trend, and the 3# internal shielding material to be evaluated is judged to be unqualified in the thermal extension test; as can be seen from Table 2, the temperature rise of the feeding section of No. 3 is 3 ℃, the temperature rise of the melting section is 8 ℃, the temperature rise of the homogenizing section is 10 ℃, the temperature rise requirement is not met, and the temperature rise test of the crosslinked inner shielding material to be evaluated of No. 3 is unqualified;
and (3) the thermal extension test and the temperature rise test of the crosslinked inner shielding material to be evaluated are both unqualified, and the crosslinked inner shielding material 3 is judged to be an unqualified product.
Example 4
Evaluating 10kV cross-linked inner shielding material with the batch number of 210109 and the box number of 09, which is overproduced in Nanjing, and marking as 4 #;
the thermal extension test and the temperature rise test are the same as those in example 1, the thermal extension test result is shown in table 1, and the temperature rise test result is shown in table 2; as can be seen from Table 1, the elongation of the 4# internal shielding crosslinking material after vulcanization for 3min is 80%, the elongation of the material after vulcanization for 5min is 65%, the elongation of the material after vulcanization for 10min is 60%, and the elongation of the material after vulcanization for 15min is 60%, so that the thermal extension change trend is not met, and the 4# internal shielding crosslinking material to be evaluated is judged to be unqualified in the thermal extension test; as can be seen from Table 2, the temperature rise of the feeding section No. 4 is 7 ℃, the temperature rise of the melting section is 12 ℃, the temperature rise of the homogenizing section is 15 ℃, the temperature rise requirement is not met, and the temperature rise test of the crosslinked inner shielding material No. 4 to be evaluated is unqualified;
and (4) judging that the cross-linked inner shielding material No. 4 is a defective product if the thermal extension test and the temperature rise test of the cross-linked inner shielding material No. 4 to be evaluated are both unqualified.
TABLE 1 results of the thermal elongation test of examples 1-4
As can be seen from Table 1, the thermal elongation performance of the crosslinked inner shielding material produced by four manufacturers after vulcanization for 15min all meets the requirements of JB/T10738 and 2007 semiconductive shielding material for extruded insulation cables with rated voltage of 35kV and below. Moreover, the difference of the thermal extension indexes of the cross-linking inner shielding materials produced by four manufacturers is smaller and smaller along with the prolonging of the vulcanization time, and the difference is very small at 15 min.
The crosslinked inner shielding material produced by the manufacturer # 4 has a large amount of obvious crosslinking agents (or the crosslinking agents are not uniformly dispersed, or the material is pre-crosslinked by the manufacturer), and the elongation under the load is only 80% at 3min, which indicates that the crosslinking is completed in a short time, and the product is unqualified and cannot be used for preparing crosslinked cables.
The thermal extension index of the cross-linking internal shielding material produced by the manufacturer No. 1 has a slow change trend, and is not easy to generate early cross-linking in production, and the thermal extension index of the cross-linking internal shielding material produced by the manufacturer No. 2 and the manufacturer No. 3 has a steep change trend, and is easy to generate early cross-linking in production.
TABLE 2 temperature rise test results of examples 1 to 4
As can be seen from Table 2, the crosslinked inner shield material produced by the manufacturer # 1 has small frictional heating, and the frictional heating is almost the same as the cooling capacity of an extruder, so the temperature rise is low. In addition, in actual use, no pre-crosslinking phenomenon occurs.
The cross-linking inner shielding materials produced by manufacturers 2# and 3# have large frictional heating, and the frictional heating is larger than the cooling capacity of an extruder, so the temperature rise is higher. In addition, in practical use, a plurality of tests show that the pre-crosslinking phenomenon occurs after a plurality of hours of production, and only goods can be returned.
The crosslinked inner shielding material produced by the No. 4 manufacturer is pre-crosslinked, so that the friction heating is large, the temperature rise is highest, and the crosslinked inner shielding material cannot be used basically. In addition, in the actual use, in the production preparation stage, the surface of the head material extruded by the extruder is rough, and cannot be improved after being adjusted for several times, so that the advanced crosslinking phenomenon obviously occurs, and the head material cannot be used for producing crosslinked cables and can only be returned.
The insulated wire core of the crosslinked cable is made of 10kV crosslinked inner shielding materials produced by No. 1, No. 2 and No. 3 manufacturers, the electrical property of the insulated wire core is tested, and the test result is shown in Table 3.
Electrical Properties of insulated core of crosslinked Cable made of 10kV crosslinked inner Shielding materials manufactured by manufacturers of Table 31 #, 2#, and 3#, respectively
As can be seen from table 3, the voltage test: the cable insulation wire cores prepared by 10kV cross-linked internal shielding materials produced by manufacturers 1#, 2# and 3# meet the standard requirements and are not broken down; partial discharge test: the cable insulated wire core prepared by the 10kV cross-linked inner shielding material produced by the No. 1 manufacturer meets the standard requirement, the discharge capacity is small (when the test sensitivity is 5pC, the actual measurement value is 3pC), the cable insulated wire core prepared by the 10kV cross-linked inner shielding material produced by the No. 2 manufacturer does not meet the standard requirement, the discharge capacity is high (when the test sensitivity is 7.8pC, the actual measurement value is 82pC), the cable insulated wire core prepared by the 10kV cross-linked inner shielding material produced by the No. 3 manufacturer does not meet the standard requirement, and the discharge capacity is high (when the test sensitivity is 9.5pC, the actual measurement value is 104 pC); 4h pressure resistance test: the cable insulation core prepared by the 10kV cross-linked inner shielding material produced by the No. 1 manufacturer meets the standard requirement and is not broken down, and the cable insulation core prepared by the 10kV cross-linked inner shielding material produced by the No. 2 manufacturer and the No. 3 manufacturer does not meet the standard requirement and is broken down. Therefore, the cable prepared by the 10kV cross-linked inner shielding material produced by the No. 1 manufacturer has higher quality, and the cables produced by the materials of the No. 2 and No. 3 manufacturers have potential quality hazards, so that the evaluation method provided by the invention is proved to be accurate and reliable.
The embodiment shows that the evaluation method provided by the invention can select the cross-linked inner shielding material which is not easy to generate the advanced cross-linking phenomenon from a plurality of inner shielding materials, and provides necessary technical support for selecting the cross-linked inner shielding material with the optimal performance and improving the quality of the cross-linked cable product.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (10)
1. The method for evaluating the cross-linked inner shielding material comprises the following steps of respectively carrying out a thermal extension test and a temperature rise test on the cross-linked inner shielding material to be evaluated; if the thermal extension test and the temperature rise test of the cross-linked inner shielding material to be evaluated are both qualified, judging that the cross-linked inner shielding material to be evaluated is a qualified product;
the thermal extension test comprises the following steps:
(1) plasticizing the cross-linked internal shielding material to be evaluated to obtain a film;
(2) vulcanizing the film obtained in the step (1) to obtain a sample wafer to be tested;
(3) testing the thermal extension performance of the sample wafer to be tested obtained in the step (2); if the thermal extension variation trend of the sample wafer to be tested meets the following conditions: the elongation rate of the cross-linked inner shielding material to be evaluated is more than or equal to 300% in 3min of vulcanization, the elongation rate of the cross-linked inner shielding material to be evaluated is 150-200% in 5min of vulcanization, the elongation rate of the cross-linked inner shielding material to be evaluated is 100-120% in 10min of vulcanization, and the elongation rate of the cross-linked inner shielding material to be evaluated is 50-80% in 15min of vulcanization; if the thermal extension variation trend of the sample wafer to be evaluated does not meet the requirement, determining that the thermal extension test of the cross-linked inner shielding material to be evaluated is unqualified;
the temperature rise test comprises: three-section extrusion is carried out on the cross-linked inner shielding material to be evaluated, and then the temperature rise of the extruder body is tested; if the temperature rise meets the following conditions: the temperature rise test of the cross-linked inner shielding material to be evaluated is qualified if the feeding section is less than 3 ℃, the melting section is less than 4 ℃, and the homogenizing section is less than 5 ℃; otherwise, judging that the temperature rise test of the cross-linked inner shielding material to be evaluated is unqualified.
2. The evaluation method according to claim 1, wherein the temperature of plasticization in the step (1) is < 70 ℃.
3. The evaluation method according to claim 1 or 2, wherein the apparatus used for the plasticization in the step (1) is a twin-roll plasticator; the roller spacing of the double-roller plastic refining machine is 2.0-2.5 mm.
4. The method according to claim 1, wherein the plasticizing process in the step (1) further comprises triangulating; and the triangular packaging time is 3-4 min.
5. The method according to claim 1, wherein the vulcanization temperature in the step (2) is 180 to 183 ℃.
6. The evaluation method according to claim 1, wherein the sample to be tested obtained in the step (2) includes sample pieces having a vulcanization time of 3min, 4min, 5min, 10min and 15 min.
7. The evaluation method according to claim 1, wherein the pressurization before the vulcanization in the step (2) is performed by: pressurizing to 13-15 MPa, pre-pressing for 20-25 s, then reducing the pressure to 0MPa, keeping for 10-15 s, and finally pressurizing to 15-20 MPa.
8. The evaluation method according to claim 1, wherein the sample wafer to be measured in the step (2) has a size of 200mm x 200mm and a thickness of 1.0 ± 0.1 mm.
9. The evaluation method according to claim 1, wherein the initial temperature of the feeding section body is 95 to 98 ℃, the initial temperature of the melting section body is 100 to 103 ℃, and the initial temperature of the homogenizing section body is 105 to 108 ℃.
10. The evaluation method according to claim 1, wherein the time for testing the temperature rise of the extruder body is 5-6 min after three-stage extrusion.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024099001A1 (en) * | 2022-11-07 | 2024-05-16 | 南方电网科学研究院有限责任公司 | Method and apparatus for identifying scorching phenomenon of semi-conductive shielding material of high-voltage cable |
| WO2024114377A1 (en) * | 2022-11-30 | 2024-06-06 | 广东电网有限责任公司东莞供电局 | Method and apparatus for evaluating performance of insulation-to-shielding matches for high-voltage alternating-current cables |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003185606A (en) * | 2001-12-19 | 2003-07-03 | Fujikura Ltd | Evaluation method for sheath material used in fire- retardant cable |
| JP2007238958A (en) * | 2000-10-18 | 2007-09-20 | Mitsui Chemicals Inc | Foam of urethane-based thermoplastic elastomer composition and process for producing the foam |
| CN101817950A (en) * | 2010-04-29 | 2010-09-01 | 上海科悦高分子材料有限公司 | Screen material for 35kV grade high/medium voltage crosslinked cable conductor layer and preparation method thereof |
| JP2011086786A (en) * | 2009-10-16 | 2011-04-28 | Bridgestone Corp | Method of manufacturing light permeable electromagnetic shield material, and light permeable electromagnetic shield material |
| CN113782275A (en) * | 2020-06-10 | 2021-12-10 | 昆明电缆集团昆电工电缆有限公司 | Water-blocking method for rubber sleeve cable during vulcanization |
| CN114216926A (en) * | 2021-11-18 | 2022-03-22 | 深圳供电局有限公司 | Rheological property evaluation method of crosslinked semiconductive shielding material |
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007238958A (en) * | 2000-10-18 | 2007-09-20 | Mitsui Chemicals Inc | Foam of urethane-based thermoplastic elastomer composition and process for producing the foam |
| JP2003185606A (en) * | 2001-12-19 | 2003-07-03 | Fujikura Ltd | Evaluation method for sheath material used in fire- retardant cable |
| JP2011086786A (en) * | 2009-10-16 | 2011-04-28 | Bridgestone Corp | Method of manufacturing light permeable electromagnetic shield material, and light permeable electromagnetic shield material |
| CN101817950A (en) * | 2010-04-29 | 2010-09-01 | 上海科悦高分子材料有限公司 | Screen material for 35kV grade high/medium voltage crosslinked cable conductor layer and preparation method thereof |
| CN113782275A (en) * | 2020-06-10 | 2021-12-10 | 昆明电缆集团昆电工电缆有限公司 | Water-blocking method for rubber sleeve cable during vulcanization |
| CN114216926A (en) * | 2021-11-18 | 2022-03-22 | 深圳供电局有限公司 | Rheological property evaluation method of crosslinked semiconductive shielding material |
Non-Patent Citations (4)
| Title |
|---|
| GANG YE; CHANGXIN CAI; BICHANG ZHOU; MINGZHU YE: "Simulation of electrical trees in XLPE cable insulation and electric field analysis", 《 THE JOURNAL OF ENGINEERING》, vol. 2019, no. 16, 6 April 2019 (2019-04-06), pages 1882 - 1885, XP006085129, DOI: 10.1049/joe.2018.8704 * |
| 张书华，刘伟军: "《高性能电缆材料及其应用技术》", 30 November 2015, 上海交通大学出版社, pages: 154 - 161 * |
| 房跃斌, 蒋陆肆: "预制分支电缆浸水电压试验及制造工艺探讨", 电线电缆, no. 05, 25 October 2005 (2005-10-25), pages 21 - 23 * |
| 龚国祥;解向前;倪勇等: "《GB/T 19216.1-2021在火焰条件下电缆或光缆的线路完整性试验 第1部分：火焰温度不低于830 ℃的供火并施加冲击振动，额定电压0.6/1 kV及以下外径超过20 mm电缆的试验方法》", 21 May 2021, 国家市场监督管理总局;国家标准化管理委员会, pages: 1 - 17 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024099001A1 (en) * | 2022-11-07 | 2024-05-16 | 南方电网科学研究院有限责任公司 | Method and apparatus for identifying scorching phenomenon of semi-conductive shielding material of high-voltage cable |
| WO2024114377A1 (en) * | 2022-11-30 | 2024-06-06 | 广东电网有限责任公司东莞供电局 | Method and apparatus for evaluating performance of insulation-to-shielding matches for high-voltage alternating-current cables |
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