A low temperature resistant medium voltage power cable

Abstract

The present invention relates to the field of cable technology, and proposes a low-temperature resistant medium-voltage power cable, comprising a cable core, a sheath, an isolation sleeve, an armor layer, and a protective layer arranged sequentially from the inside to the outside, wherein a filler is filled between the cable core and the sheath; the cable core is composed of a plurality of mutually twisted insulating cores, and the insulating core is composed of mutually twisted copper wires and an insulating layer sequentially coated outside the mutually twisted copper wires; the filler is an alkali-free glass fiber rope; the raw materials of the protective layer include the following components by weight: 100 parts of PVC resin, 40 to 50 parts of plasticizer, 30 to 40 parts of calcium carbonate, 6 to 8 parts of flame retardant, 3 to 6 parts of bis (4-aminocyclohexyl) ether, and 4 to 6 parts of auxiliary agent. Through the above technical scheme, the problems of low low-temperature resistance and short service life of medium-voltage power cables in the prior art are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of cables, and in particular to a low-temperature resistant medium-voltage power cable. Background Art

[0002] With the rapid development of modern life, the power grids in cities and towns are constantly being updated and upgraded, and the proportion of cables used in power distribution networks is increasing. The use of medium-voltage cables is also increasing, and the application range is becoming wider and wider. The types of medium-voltage cables are also increasing. Therefore, when selecting medium-voltage power cables, appropriate medium-voltage cables should be selected according to the diversity of the use environment. When used in harsh high-cold environments such as power generation, metallurgy, petroleum and ports, medium-voltage cables need to be able to maintain normal operation in low-temperature environments and have a long service life. Therefore, it is necessary to select low-temperature resistant medium-voltage power cables.

[0003] At present, medium-voltage power cables have problems with low-temperature resistance and poor mechanical properties. They cannot meet the special requirements of working in harsh environments. They are not widely used and have a short service life. Summary of the invention

[0004] The present invention provides a low-temperature resistant medium-voltage power cable, which solves the problem in the related art that the medium-voltage power cable has low low-temperature resistance and thus has a short service life.

[0005] The technical solution of the present invention is as follows:

[0006] The present invention provides a low-temperature resistant medium-voltage power cable, comprising a cable core, a sheath, an isolation sleeve, an armor layer, and a protective layer which are sequentially arranged from the inside to the outside, wherein a filler is filled between the cable core and the sheath; the cable core is composed of a plurality of mutually twisted insulating cores, and the insulating core is composed of mutually twisted copper wires and insulating layers sequentially coated on the mutually twisted copper wires; the filler is an alkali-free glass fiber rope; the raw materials of the protective layer include the following components in parts by weight: 100 parts of PVC resin, 40-50 parts of plasticizer, 30-40 parts of calcium carbonate, 6-8 parts of flame retardant, 3-6 parts of bis(4-aminocyclohexyl) ether, and 4-6 parts of additives.

[0007] As a further technical solution, the mass ratio of calcium carbonate to bis(4-aminocyclohexyl) ether is 7:1.

[0008] The present invention finds that by limiting the mass ratio of calcium carbonate to bis(4-aminocyclohexyl) ether to 7:1, the tensile strength, elongation at break, elongation at break at -40°C low temperature stretching and oxygen index of the protective layer can be further improved.

[0009] As a further technical solution, the PVC resin includes one or more of SY2500 PVC resin, S-1300 PVC resin, and S-1000 PVC resin.

[0010] As a further technical solution, the PVC resin consists of SY2500 PVC resin and S-1000 PVC resin.

[0011] The present invention finds that when the PVC resin is composed of SY2500 PVC resin and S-1000 PVC resin, the processing fluidity of preparing the protective layer can be better improved, and the tensile strength, elongation at break and elongation at break of the protective layer at -40°C low temperature stretching can be further improved.

[0012] As a further technical solution, the mass ratio of the SY2500 PVC resin to the S-1000 PVC resin is 1:1.5~5.

[0013] The present invention further limits the quality of SY2500 PVC resin and S-1000 PVC resin, and finds that when the mass ratio of SY2500 PVC resin to S-1000 PVC resin is 1:1.5-5, the tensile strength, elongation at break and elongation at break of the protective layer at -40°C low temperature stretching can be further improved.

[0014] As a further technical solution, the mass ratio of the SY2500 PVC resin to the S-1000 PVC resin is 3:7.

[0015] The present invention also found that when the mass ratio of SY2500 PVC resin to S-1000 PVC resin is limited to 3:7, the tensile strength, elongation at break and elongation at break at -40°C low temperature stretching of the obtained protective layer are the highest and the performance is the best.

[0016] As a further technical solution, the material used for the isolation sleeve layer is polyvinyl chloride resin.

[0017] As a further technical solution, the plasticizer includes one or more of dioctyl phthalate, butyl benzyl phthalate and diisobutyl phthalate.

[0018] As a further technical solution, the armor layer is an interlocking armor layer made of steel strips.

[0019] As a further technical solution, the steel strip is a four-sided galvanized steel strip.

[0020] As a further technical solution, the material of the wrapping layer is fire-resistant mica tape.

[0021] As a further technical solution, the insulating layer is a polyvinyl chloride insulating layer.

[0022] As a further technical solution, the thickness of the insulating layer is 0.7~1mm.

[0023] As a further technical solution, the thickness of the isolation sleeve layer is 0.3-0.5 mm.

[0024] As a further technical solution, the thickness of the protective layer is 0.8~1mm.

[0025] As a further technical solution, the auxiliary agent includes one or more of an antioxidant, a stabilizer, a dispersant, and a lubricant.

[0026] As a further technical solution, the antioxidant includes one or more of antioxidant 1010 , antioxidant 168 and antioxidant 1076 .

[0027] As a further technical solution, the stabilizer is a calcium zinc stabilizer.

[0028] As a further technical solution, the dispersant is one or both of tristearic acid glyceryl and polyvinyl alcohol.

[0029] As a further technical solution, the lubricant includes one or more of silicone oil, stearic acid and calcium stearate.

[0030] As a further technical solution, the flame retardant is a phosphorus-based flame retardant.

[0031] The present invention also provides a method for preparing a low-temperature resistant medium-voltage power cable, comprising the following steps:

[0032] S1. Filling the alkali-free glass fiber rope into the gaps between the twisted copper conductors to obtain a semi-finished cable core;

[0033] S2, extruding the insulating layer material onto the surface of the semi-finished cable core to obtain the cable core;

[0034] S3, winding the sheath material around the cable core to form a sheath;

[0035] S4, extruding the isolation sleeve material outside the wrapping layer to form an isolation sleeve layer;

[0036] S5. Wrap the armor layer material around the isolation sleeve to form an armor layer;

[0037] S6. After mixing the raw materials of the protective layer evenly, extrude and wrap them outside the armor layer to form a protective layer, thereby obtaining a low-temperature resistant medium-voltage power cable.

[0038] The working principle and beneficial effects of the present invention are:

[0039] In the present invention, the medium-voltage power cable comprises, from the inside to the outside, a cable core, a wrapping layer, an isolation sleeve layer, an armor layer and a protective layer, wherein the armor layer adopts an interlocking armor layer, which can make the cable have better flexibility, make the cable more solid and tough, and further improve the service life of the cable, and bis(4-aminocyclohexyl) ether is added to the outermost protective layer, and the addition of bis(4-aminocyclohexyl) ether can improve the tensile strength, elongation at break, elongation at break at -40°C low temperature stretching and oxygen index of the protective layer. DETAILED DESCRIPTION

[0040] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] In the following examples and comparative examples:

[0042] The working parameters of the twin-screw extruder are: zone 1 working temperature 175°C; zone 2 working temperature 180°C; zone 3 working temperature 185°C; zone 4 working temperature 195°C;

[0043] Fire-resistant mica tape, model 65, manufacturer Yangzhou Shengkai Electrical Insulation Co., Ltd.;

[0044] SY2500 PVC resin, degree of polymerization 2500, Tangshan Sanyou;

[0045] S-1300 PVC resin, degree of polymerization 1300, Qilu Petrochemical;

[0046] S-1000 PVC resin, degree of polymerization 1000, Qilu Petrochemical;

[0047] Calcium carbonate, heavy calcium carbonate, model 2500 mesh;

[0048] Stabilizer, calcium zinc stabilizer, model JL-D90, manufacturer Shijiazhuang Jinlei Chemical Technology Co., Ltd.

[0049] Example 1

[0050] A method for preparing a low-temperature resistant medium-voltage power cable comprises the following steps:

[0051] S1. Filling the alkali-free glass fiber rope into the gaps between the twisted copper conductors to obtain a semi-finished cable core;

[0052] S2, extruding S-1300 PVC resin on the surface of the semi-finished cable core to form an insulating layer with a thickness of 0.7 mm to obtain a cable core;

[0053] S3. Wrap the cable core with fire-resistant mica tape to form a wrapping layer;

[0054] S4, extruding S-1300 PVC resin outside the wrapping layer to form an isolation sleeve layer with a thickness of 0.3 mm;

[0055] S5. Wrap the armor layer material around the isolation sleeve to form an interlocking armor layer made of steel strips; wherein the steel strips are galvanized steel strips on four sides;

[0056] S6. After uniformly mixing 100 parts of S-1300 PVC resin, 40 parts of dioctyl phthalate, 30 parts of calcium carbonate, 6 parts of aluminum hypophosphite, 4 parts of bis(4-aminocyclohexyl) ether, 0.4 parts of antioxidant 1010, 3 parts of stabilizer, 0.3 parts of tristearin and 0.3 parts of calcium stearate, the mixture is extruded on the outside of the armor layer through a twin-screw extruder to form a protective layer with a thickness of 0.8 mm, thereby obtaining a low-temperature resistant medium-voltage power cable.

[0057] Example 2

[0058] A method for preparing a low-temperature resistant medium-voltage power cable comprises the following steps:

[0059] S1. Filling the alkali-free glass fiber rope into the gaps between the twisted copper conductors to obtain a semi-finished cable core;

[0060] S2, extruding S-1300 PVC resin on the surface of the semi-finished cable core to form an insulation layer with a thickness of 0.8 mm to obtain a cable core;

[0061] S3. Wrap the cable core with fire-resistant mica tape to form a wrapping layer;

[0062] S4, extruding S-1300 PVC resin outside the wrapping layer to form an isolation sleeve layer with a thickness of 0.4 mm;

[0063] S5. Wrap the armor layer material around the isolation sleeve to form an interlocking armor layer made of steel strips; wherein the steel strips are galvanized steel strips on four sides;

[0064] S6. After uniformly mixing 100 parts of S-1300 PVC resin, 50 parts of dioctyl phthalate, 35 parts of calcium carbonate, 7 parts of aluminum hypophosphite, 5 parts of bis(4-aminocyclohexyl) ether, 0.4 parts of antioxidant 1010, 4 parts of stabilizer, 0.3 parts of tristearate glyceryl and 0.3 parts of calcium stearate additive, extrude them on the outside of the armor layer through a twin-screw extruder to form a protective layer with a thickness of 0.9 mm, and obtain a low-temperature resistant medium-voltage power cable.

[0065] Example 3

[0066] A method for preparing a low-temperature resistant medium-voltage power cable comprises the following steps:

[0067] S1. Filling the alkali-free glass fiber rope into the gaps between the twisted copper conductors to obtain a semi-finished cable core;

[0068] S2, extruding S-1300 PVC resin on the surface of the semi-finished cable core to form an insulating layer with a thickness of 1 mm to obtain a cable core;

[0069] S3. Wrap the cable core with fire-resistant mica tape to form a wrapping layer;

[0070] S4, extruding S-1300 PVC resin outside the wrapping layer to form an isolation sleeve layer with a thickness of 0.5 mm;

[0071] S5. Wrap the armor layer material around the isolation sleeve to form an interlocking armor layer made of steel strips; wherein the steel strips are galvanized steel strips on four sides;

[0072] S6. After uniformly mixing 100 parts of S-1300 PVC resin, 43 parts of dioctyl phthalate, 40 parts of calcium carbonate, 8 parts of aluminum hypophosphite, 6 parts of bis(4-aminocyclohexyl) ether, 0.4 parts of antioxidant 1010, 5 parts of stabilizer, 0.3 parts of polyvinyl alcohol and 0.3 parts of stearic acid, the mixture is extruded on the outside of the armor layer through a twin-screw extruder to form a protective layer with a thickness of 1 mm, thereby obtaining a low-temperature resistant medium-voltage power cable.

[0073] Example 4

[0074] The difference between this embodiment and embodiment 2 is that the amount of calcium carbonate is 37 parts and the amount of bis(4-aminocyclohexyl) ether is 3 parts.

[0075] Example 5

[0076] The difference between this embodiment and embodiment 2 is that the amount of calcium carbonate is 34 parts and the amount of bis(4-aminocyclohexyl) ether is 6 parts.

[0077] Example 6

[0078] The difference between this embodiment and embodiment 2 is that 100 parts of S-1300 PVC resin are replaced by 20 parts of SY2500 PVC resin and 80 parts of S-1000 PVC resin.

[0079] Example 7

[0080] The difference between this embodiment and embodiment 2 is that 100 parts of S-1300 PVC resin are replaced by 30 parts of SY2500 PVC resin and 70 parts of S-1000 PVC resin.

[0081] Example 8

[0082] The difference between this embodiment and embodiment 2 is that 100 parts of S-1300 PVC resin are replaced by 40 parts of SY2500 PVC resin and 60 parts of S-1000 PVC resin.

[0083] Example 9

[0084] The only difference between this embodiment and embodiment 2 is that 100 parts of S-1300 PVC resin are replaced by an equal amount of SY2500 PVC resin.

[0085] Example 10

[0086] The only difference between this embodiment and embodiment 2 is that 100 parts of S-1300 PVC resin are replaced by an equal amount of S-1000 PVC resin.

[0087] Comparative Example 1

[0088] The only difference between this comparative example and Example 2 is that no bis(4-aminocyclohexyl) ether is added.

[0089] Test example

[0090] The low temperature resistant medium voltage power cables prepared in Examples 1 to 10 and Comparative Example 1 were tested for elongation at break and tensile strength of the protective layer according to the test method in GB / T 2951.11-2008; the elongation at break of the protective layer at -40°C low temperature stretching was tested according to the test method in GB / T 2951.14; the oxygen index of the protective layer was tested according to the test method in GB / T 2406.2-2009, and the test results are shown in Table 1;

[0091] Performance determination of low temperature resistant medium voltage power cable protective layer in Examples 1 to 10 and Comparative Example 1

[0092]

[0093] Compared with Example 2, Comparative Example 1 does not add bis(4-aminocyclohexyl) ether. As a result, the tensile strength, elongation at break, elongation at break after low-temperature stretching at -40°C and oxygen index of the protective layer in Comparative Example 1 are all lower than those in Example 1, indicating that the addition of bis(4-aminocyclohexyl) ether can improve the tensile strength, elongation at break, elongation at break after low-temperature stretching at -40°C and oxygen index of the protective layer.

[0094] Compared with Example 2, Examples 4 to 5 change the mass ratio of calcium carbonate to bis(4-aminocyclohexyl) ether. As a result, the tensile strength, elongation at break, elongation at break at -40°C low-temperature stretching, and oxygen index of the protective layer in Example 2 are all higher than those in Examples 4 and 5, indicating that when the mass ratio of calcium carbonate to bis(4-aminocyclohexyl) ether is 7:1, the tensile strength, elongation at break, elongation at break at -40°C low-temperature stretching, and oxygen index of the protective layer can be further improved.

[0095] Compared with Example 2, Example 9 replaces 100 parts of S-1300 PVC resin with an equal amount of S-2500 PVC resin, Example 10 replaces 100 parts of S-1300 PVC resin with an equal amount of S-1000 PVC resin, and Examples 6 to 8 replace 100 parts of S-1300 PVC resin with SY2500 PVC resin and 80 parts of S-1000 PVC resin in different mass ratios. As a result, the tensile strength, elongation at break, elongation at break at -40°C low temperature stretching, and oxygen index of the protective layer in Examples 2 and 9 to 10 are all lower than those in Examples 6 to 8, indicating that when the PVC resin in the present invention is composed of SY2500 PVC resin and S-1000 PVC resin, the tensile strength, elongation at break, elongation at break at -40°C low temperature stretching, and oxygen index of the protective layer can be further improved.

[0096] And by comparison, it is found that the tensile strength, elongation at break, elongation at break at -40°C low temperature stretching and oxygen index of the protective layer in Example 7 are higher than those in Example 6 and Example 8, indicating that when the mass ratio of SY2500 PVC resin to S-1000 PVC resin is 3:7, the tensile strength, elongation at break, elongation at break at -40°C low temperature stretching and oxygen index of the protective layer can be further improved.

[0097] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A low temperature resistant medium voltage power cable, characterized in that: The invention comprises a cable core, a wrapping layer, an isolation sleeve layer, an armor layer and a protective layer which are arranged in sequence from the inside to the outside, wherein a filler is filled between the cable core and the wrapping layer; the cable core is composed of a plurality of mutually twisted insulating cores, and the insulating core is composed of mutually twisted copper wires and insulating layers sequentially coated on the mutually twisted copper wires; the filler is an alkali-free glass fiber rope; the raw materials of the protective layer include the following components in parts by weight: 100 parts of PVC resin, 40-50 parts of plasticizer, 30-40 parts of calcium carbonate, 6-8 parts of flame retardant, 3-6 parts of bis(4-aminocyclohexyl) ether and 4-6 parts of auxiliary agent.

2. A low temperature resistant medium voltage power cable according to claim 1, characterized in that: The armor layer is an interlocking armor layer made of steel strips.

3. A low temperature resistant medium voltage power cable according to claim 2, characterized in that: The steel strip is a four-sided galvanized steel strip.

4. A low temperature resistant medium voltage power cable according to claim 1, characterized in that: The material of the wrapping layer is fire-resistant mica tape.

5. The low temperature resistant medium voltage power cable according to claim 1, characterized in that: The insulating layer is a polyvinyl chloride insulating layer.

6. A low temperature resistant medium voltage power cable according to claim 1, characterized in that: The thickness of the insulating layer is 0.7-1 mm.

7. A low temperature resistant medium voltage power cable according to claim 1, characterized in that: The thickness of the isolation sleeve layer is 0.3-0.5 mm.

8. The low temperature resistant medium voltage power cable according to claim 1, characterized in that: The thickness of the protective layer is 0.8-1 mm.

9. The low temperature resistant medium voltage power cable according to claim 1, characterized in that: The auxiliary agent includes one or more of an antioxidant, a stabilizer, a dispersant, and a lubricant.

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