A medium voltage fireproof cable

Abstract

The present invention relates to the technical field of power cables and proposes a medium-voltage fire-resistant cable comprising a conductor and, in that order, an insulation layer, an armor layer, and a sheath layer. The insulation layer comprises the following components by weight: 70-80 parts polyethylene, 5-10 parts flame retardant, 3-5 parts cross-linking agent, 1-2 parts plasticizer, and 1-3 parts antioxidant. The sheath layer comprises the following components by weight: 100 parts polyvinyl chloride, 8-16 parts flame retardant, 1-2 parts plasticizer, 1-3 parts antioxidant, and 5-10 parts filler, which includes silica, inorganic fiber, and tetrapod-shaped zinc oxide whiskers. This technical solution addresses the poor strength and aging resistance of cables in related technologies.

Description

Technical Field

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

[0002] Medium-voltage power cables are widely used in the power industry. Since power cables are typically exposed to the air and continuously affected by various natural environmental factors during operation, such as solar radiation, humidity, chemical corrosion, and drastic changes in high and low temperatures, these factors inevitably accelerate cable aging, significantly reducing the cable's service life and increasing the frequency and cost of replacement and repair. Therefore, the development of an aging-resistant, fire-resistant medium-voltage cable is of great significance for improving the safety of power generation systems, meeting the needs of power transmission in special environments, and promoting the development of the power industry. Summary of the Invention

[0003] The present invention provides a medium-voltage fireproof cable, which solves the problem of poor strength and aging resistance of cables in the related art.

[0004] The technical solutions of the present invention are as follows:

[0005] The present invention provides a medium voltage fireproof cable, comprising a conductor and an insulation layer, an armor layer, and a sheath layer sequentially arranged outside the conductor;

[0006] The insulating layer comprises the following components in parts by weight: 70-80 parts of polyethylene, 5-10 parts of flame retardant, 3-5 parts of cross-linking agent, 1-2 parts of plasticizer, and 1-3 parts of antioxidant;

[0007] The sheath layer comprises the following components in parts by weight: 100 parts of polyvinyl chloride, 8 to 16 parts of flame retardant, 1 to 2 parts of plasticizer, 1 to 3 parts of antioxidant, and 5 to 10 parts of filler;

[0008] The filler comprises silicon dioxide, inorganic fiber and tetrapod-shaped zinc oxide whisker.

[0009] As a further technical solution, the mass ratio of the silica, inorganic fiber, and tetrapod-shaped zinc oxide whiskers is 1:3:1-2.

[0010] In the present invention, the mass ratio of silicon dioxide, inorganic fiber and tetrapod-shaped zinc oxide whisker is adjusted to 1:3:1-2, thereby further improving the strength and aging resistance of the cable.

[0011] As a further technical solution, the inorganic fibers include glass fibers and / or basalt fibers.

[0012] As a further technical solution, the preparation method of the filler includes the following steps: dispersing the inorganic fibers and tetrapod-shaped zinc oxide whiskers in a polyvinyl alcohol solution, drying, calcining, and mixing with silicon dioxide to obtain the filler.

[0013] In the present invention, the tetrapod-shaped zinc oxide whiskers are coated on the outside of the inorganic fibers, which reduces the agglomeration of the inorganic fibers and improves the bonding in the sheath matrix, thereby further improving the strength and aging resistance of the cable.

[0014] As a further technical solution, the mass volume ratio of polyvinyl alcohol to solvent in the polyvinyl alcohol solution is 1 g:10-15 mL; the mass ratio of the inorganic fiber to the polyvinyl alcohol is 3:1-2.

[0015] As a further technical solution, when the inorganic fibers are glass fibers and basalt fibers, the mass ratio of the glass fibers to the basalt fibers is 2:3 to 3:2.

[0016] In the present invention, especially when the inorganic fibers are glass fibers and basalt fibers, and the mass ratio of the glass fibers to the basalt fibers is 2:3 to 3:2, the strength and aging resistance of the cable are further improved.

[0017] As a further technical solution, the diameter of the inorganic fiber is 150-200 μm and the length is 2-4 mm; the diameter of the four-needle zinc oxide whisker is 0.5-5 μm and the length is 10-50 μm.

[0018] As a further technical solution, the calcination temperature is 1000-1050° C. and the calcination time is 50-70 minutes.

[0019] As a further technical solution, the flame retardant is a hydroxide; the cross-linking agent is a peroxide; the antioxidant includes one or more of antioxidant 1010, antioxidant 168, and antioxidant 2246; and the plasticizer includes one or more of dibutyl phthalate, dioctyl phthalate, triphenyl phosphate, and dioctyl sebacate.

[0020] The present invention also provides a method for preparing a medium voltage fireproof cable, comprising the following steps:

[0021] After the components of the insulating layer and the sheath layer are mixed respectively, the insulating layer is extruded between the conductor and the armor layer, and the sheath layer is extruded outside the armor layer, and the resultant is formed to obtain a medium-voltage fireproof cable.

[0022] The working principle and beneficial effects of the present invention are:

[0023] In the present invention, the filler of the fireproof cable sheath layer is synergistically prepared using silicon dioxide, inorganic fiber, and tetrapod-shaped zinc oxide whiskers, thereby significantly improving the strength and aging resistance of the cable. DETAILED DESCRIPTION

[0024] 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 embodiments described 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 making any creative efforts are within the scope of protection of the present invention.

[0025] In the following examples and comparative examples, the model of polyethylene is T5070; the model of polyvinyl chloride is C-15; the model of maleic anhydride grafted polyethylene is M623XF; and the diameter of the tetrapod-shaped zinc oxide whiskers is 0.5-5 μm and the length is 10-50 μm.

[0026] Example 1

[0027] Medium voltage fireproof cable, including conductor and insulation layer, armor layer and sheath layer arranged on the outside of the conductor in sequence;

[0028] The insulating layer includes the following components in parts by weight: 70 parts of polyethylene, 5 parts of magnesium hydroxide, 3 parts of dicumyl peroxide, 1 part of dibutyl phthalate, and 1 part of antioxidant 2246;

[0029] The sheath layer comprises the following components in parts by weight: 100 parts of polyvinyl chloride, 8 parts of magnesium hydroxide, 1 part of dibutyl phthalate, 1 part of antioxidant 2246, and 5 parts of filler;

[0030] The filler is silica, basalt fiber, and tetrapod-shaped zinc oxide whiskers in a mass ratio of 1:3:3; the silica particle size is 100 nm; the basalt fiber has a diameter of 200 μm and a length of 4 mm;

[0031] A method for preparing a medium voltage fireproof cable comprises the following steps:

[0032] After the components of the insulation layer and the sheath layer are mixed respectively, the insulation layer is extruded between the conductor and the armor layer, and the sheath layer is extruded outside the armor layer, and formed to obtain a medium-voltage fireproof cable.

[0033] Example 2

[0034] Medium voltage fireproof cable, including conductor and insulation layer, armor layer and sheath layer arranged on the outside of the conductor in sequence;

[0035] The insulating layer includes the following components in parts by weight: 80 parts of polyethylene, 10 parts of magnesium hydroxide, 5 parts of dicumyl peroxide, 2 parts of dibutyl phthalate, and 3 parts of antioxidant 2246;

[0036] The sheath layer comprises the following components in parts by weight: 100 parts of polyvinyl chloride, 16 parts of magnesium hydroxide, 2 parts of dibutyl phthalate, 3 parts of antioxidant 2246, and 10 parts of filler;

[0037] The filler is silica, basalt fiber, and tetrapod-shaped zinc oxide whiskers in a mass ratio of 1:3:3; the silica particle size is 50 nm; the basalt fiber has a diameter of 150 μm and a length of 2 mm;

[0038] A method for preparing a medium voltage fireproof cable comprises the following steps:

[0039] After the components of the insulation layer and the sheath layer are mixed respectively, the insulation layer is extruded between the conductor and the armor layer, and the sheath layer is extruded outside the armor layer, and formed to obtain a medium-voltage fireproof cable.

[0040] Example 3

[0041] Medium voltage fireproof cable, including conductor and insulation layer, armor layer and sheath layer arranged on the outside of the conductor in sequence;

[0042] The insulating layer includes the following components in parts by weight: 75 parts of polyethylene, 8 parts of magnesium hydroxide, 4 parts of dicumyl peroxide, 2 parts of dibutyl phthalate, and 2 parts of antioxidant 2246;

[0043] The sheath layer comprises the following components in parts by weight: 100 parts of polyvinyl chloride, 12 parts of magnesium hydroxide, 1.5 parts of dibutyl phthalate, 2 parts of antioxidant 2246, and 10 parts of filler;

[0044] The filler is silica, basalt fiber, and tetrapod-shaped zinc oxide whiskers in a mass ratio of 1:3:3; the silica particle size is 80 nm; the basalt fiber has a diameter of 200 μm and a length of 2 mm;

[0045] A method for preparing a medium voltage fireproof cable comprises the following steps:

[0046] After the components of the insulation layer and the sheath layer are mixed respectively, the insulation layer is extruded between the conductor and the armor layer, and the sheath layer is extruded outside the armor layer, and formed to obtain a medium-voltage fireproof cable.

[0047] Example 4

[0048] The difference between this embodiment and embodiment 3 is that the fillers are silicon dioxide, basalt fiber, and tetrapod-shaped zinc oxide whiskers in a mass ratio of 1:3:0.5.

[0049] Example 5

[0050] The difference between this embodiment and embodiment 3 is that the fillers are silicon dioxide, basalt fiber, and tetrapod-shaped zinc oxide whiskers in a mass ratio of 1:3:1.

[0051] Example 6

[0052] The difference between this embodiment and embodiment 3 is that the fillers are silicon dioxide, basalt fiber, and tetrapod-shaped zinc oxide whiskers in a mass ratio of 1:3:2.

[0053] Example 7

[0054] The only difference between this embodiment and embodiment 6 is that the preparation method of the filler includes the following steps: dispersing basalt fibers and tetrapod-shaped zinc oxide whiskers in a polyvinyl alcohol solution, drying, calcining at 1000° C. for 70 min, and mixing with silicon dioxide to obtain the filler;

[0055] The mass volume ratio of polyvinyl alcohol to water in the polyvinyl alcohol solution is 1 g:10 mL; the mass ratio of basalt fiber to polyvinyl alcohol is 3:1.

[0056] Example 8

[0057] The only difference between this embodiment and embodiment 6 is that the preparation method of the filler includes the following steps: dispersing basalt fibers and tetrapod-shaped zinc oxide whiskers in a polyvinyl alcohol solution, drying, calcining at 1050° C. for 50 min, and mixing with silicon dioxide to obtain a filler;

[0058] The mass volume ratio of polyvinyl alcohol to water in the polyvinyl alcohol solution is 1 g:15 mL; the mass ratio of basalt fiber to polyvinyl alcohol is 3:2.

[0059] Example 9

[0060] The difference between this embodiment and embodiment 8 is that the basalt fiber is replaced by glass fiber, and the glass fiber has a diameter of 200 μm and a length of 4 mm.

[0061] Example 10

[0062] The difference between this embodiment and embodiment 8 is that two-fifths of the mass of the basalt fibers are replaced with glass fibers, and the glass fibers have a diameter of 200 μm and a length of 4 mm.

[0063] Example 11

[0064] The difference between this embodiment and embodiment 8 is that three-fifths of the mass of the basalt fibers are replaced with glass fibers, and the glass fibers have a diameter of 200 μm and a length of 4 mm.

[0065] Comparative Example 1

[0066] The only difference between this comparative example and Example 3 is that the fillers are silica and basalt fiber in a mass ratio of 1:3.

[0067] Comparative Example 2

[0068] The only difference between this comparative example and Example 3 is that the fillers are silicon dioxide and tetrapod-shaped zinc oxide whiskers in a mass ratio of 1:3.

[0069] Comparative Example 3

[0070] The only difference between this comparative example and Example 3 is that the fillers are basalt fiber and tetrapod-shaped zinc oxide whiskers in a mass ratio of 1:1.

[0071] According to the standards GB / T 12706.2-2020 “Extruded insulated power cables and accessories with rated voltages of 1 kV (Um=1.2 kV) to 35 kV (Um=40.5 kV) Part 2: Cables with rated voltages of 6 kV (Um=7.2 kV) to 30 kV (Um=36 kV)” and GB / T 2951.12-2008 “General test methods for insulation and sheathing materials of electric and optical cables Part 12: General test methods-Heat aging test method”, the medium voltage fire-resistant cables prepared in Examples 1 to 11 and Comparative Examples 1 to 3 were subjected to heat aging performance tests (158°C×168h). The tensile strength of the samples was recorded, and the change rate of the tensile strength of the samples before and after heat aging was calculated. The change rate of tensile strength=[(tensile strength after heat aging-tensile strength before heat aging) / tensile strength before heat aging]×100%.

[0072] The test results are shown in Table 1 below.

[0073] Table 1 Test results of sheath performance of medium voltage fireproof cable

[0074]

[0075] Compared with comparative examples 1 to 3, the sheath layer of the medium-voltage fire-resistant cables prepared in Examples 1 to 11 has higher tensile strength and lower tensile strength change rate, indicating that the filler of the fire-resistant cable sheath layer is synergistically made of silica, inorganic fiber, and tetrapod-shaped zinc oxide whiskers, which significantly improves the strength and aging resistance of the cable.

[0076] Compared with Examples 3 to 4, the tensile strength of the sheath layer of the medium-voltage fire-resistant cable prepared in Examples 5 to 6 is higher and the rate of change of tensile strength is lower, indicating that adjusting the mass ratio of silica, inorganic fiber, and tetrapod-shaped zinc oxide whiskers to 1:3:1 to 2 further improves the strength and aging resistance of the cable.

[0077] Compared with Examples 6 to 7, the sheath layer of the medium-voltage fire-resistant cables prepared in Examples 8 to 11 has higher tensile strength and lower tensile strength change rate, indicating that in the present invention, the four-needle zinc oxide whiskers are coated on the outside of the inorganic fibers, which reduces the agglomeration of the inorganic fibers and improves the bonding in the sheath matrix, further improving the strength and aging resistance of the cable.

[0078] Compared with Examples 8 to 9, the tensile strength of the sheath layer of the medium-voltage fire-resistant cable prepared in Examples 10 to 11 is higher and the rate of change of tensile strength is lower, indicating that especially when the inorganic fibers are glass fibers and basalt fibers, and the mass ratio of glass fibers to basalt fibers is 2:3 to 3:2, the strength and aging resistance of the cable are further improved.

[0079] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A medium voltage fireproof cable, characterized in that: It includes a conductor and an insulating layer, an armor layer, and a sheath layer sequentially arranged outside the conductor; The insulating layer comprises the following components in parts by weight: 70-80 parts of polyethylene, 5-10 parts of flame retardant, 3-5 parts of cross-linking agent, 1-2 parts of plasticizer, and 1-3 parts of antioxidant; The sheath layer comprises the following components in parts by weight: 100 parts of polyvinyl chloride, 8 to 16 parts of flame retardant, 1 to 2 parts of plasticizer, 1 to 3 parts of antioxidant, and 5 to 10 parts of filler; The filler includes silicon dioxide, inorganic fiber, and tetrapod-shaped zinc oxide whiskers; The mass ratio of the silicon dioxide, inorganic fiber and tetrapod-shaped zinc oxide whisker is 1:3:1-2; The preparation method of the filler comprises the following steps: dispersing the inorganic fibers and tetrapod-shaped zinc oxide whiskers in a polyvinyl alcohol solution, drying, calcining, and mixing with silicon dioxide to obtain the filler; The mass volume ratio of polyvinyl alcohol to solvent in the polyvinyl alcohol solution is 1 g:10-15 mL; the mass ratio of the inorganic fiber to the polyvinyl alcohol is 3:1-2; The calcination temperature is 1000-1050° C., and the calcination time is 50-70 minutes.

2. A medium voltage fireproof cable according to claim 1, characterized in that: The inorganic fibers include glass fibers and / or basalt fibers.

3. A medium voltage fireproof cable according to claim 2, characterized in that: When the inorganic fibers are glass fibers and basalt fibers, the mass ratio of the glass fibers to the basalt fibers is 2:3 to 3:

2.

4. A medium voltage fireproof cable according to claim 1, characterized in that: The inorganic fiber has a diameter of 150-200 μm and a length of 2-4 mm; the four-needle zinc oxide whisker has a diameter of 0.5-5 μm and a length of 10-50 μm.

5. A medium voltage fireproof cable according to claim 1, characterized in that: The flame retardant is hydroxide; the cross-linking agent is peroxide; the antioxidant includes one or more of antioxidant 1010, antioxidant 168, and antioxidant 2246; and the plasticizer includes one or more of dibutyl phthalate, dioctyl phthalate, triphenyl phosphate, and dioctyl sebacate.

6. The method for preparing a medium voltage fireproof cable according to any one of claims 1 to 5, characterized in that: The following steps are involved: After the components of the insulating layer and the sheath layer are mixed respectively, the insulating layer is extruded between the conductor and the armor layer, and the sheath layer is extruded outside the armor layer, and the resultant is formed to obtain a medium-voltage fireproof cable.

Images