CN212434277U - 110kV power cable with A-type flame-retardant structure - Google Patents
110kV power cable with A-type flame-retardant structure Download PDFInfo
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- CN212434277U CN212434277U CN202020803889.8U CN202020803889U CN212434277U CN 212434277 U CN212434277 U CN 212434277U CN 202020803889 U CN202020803889 U CN 202020803889U CN 212434277 U CN212434277 U CN 212434277U
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Abstract
A110 kV power cable with an A-type flame-retardant structure is structurally characterized in that: an inner shielding layer, a middle insulating layer and an outer shielding layer are wrapped outside the copper conductor from inside to outside to form an insulating wire core; wrapping a semi-conductive shielding layer around the periphery of the insulated wire core; wrapping an aluminum sheath outside the semiconductive shielding layer, coating a flame-retardant asphalt anti-corrosion protective layer outside the aluminum sheath, and sequentially wrapping a comprehensive sheath consisting of a high-electric flame-retardant polyethylene sheath and a flame-retardant conductive polyolefin sheath material outside the flame-retardant asphalt anti-corrosion protective layer; the semi-conductive shielding layer is formed by sequentially overlapping and wrapping two layers of semi-conductive polyester bulk tapes; the thickness of the flame-retardant asphalt anti-corrosion protective layer is 0.2mm-0.4 mm; the thickness of the high-electric flame-retardant polyethylene sheath is 4.8 mm-5.2 mm; the thickness of the flame-retardant conductive polyolefin sheath is 0.2 mm-0.3 mm. The cable is an A-type flame-retardant power cable with excellent performance.
Description
Technical Field
The utility model relates to a 110kV power cable of fire-retardant structure of A class belongs to high tension line cable technical field, is applicable to tunnel, shaft, cable pit etc. and requires higher environment of laying to flame retardant property.
Background
The 110kV power cable is mainly laid in a power tunnel, a cable trench and the like. The power tunnel has the advantages of strong line transmission capacity, small occupied area and high space utilization rate, and is a main transmission channel of a power cable in the development of an urban power grid.
However, because the tunnel space is large, the cable lines are arranged in a centralized manner, potential fire sources are more, once a fire occurs in the tunnel, the influence range is wide, and large-area power failure is easily caused. Especially, a 110kV power cable tunnel with multiple loops is laid, and the safe and stable operation of the whole power grid can be endangered even when a fire disaster occurs. Because the cable insulation and the sheath are made of plastics, when a fire disaster happens to the cable in the tunnel, smoke is large, the temperature is high, the cable is easy to spread along the tunnel, and the fire is difficult to extinguish. Statistically, the cable itself causes fewer fires, and most fires are caused by external reasons. So the flame retardant property of the 110 kV-class power cable is particularly concerned.
Flame retardant cables are generally classified into A, B, C categories based on their flame retardant properties (the characteristic of flame action under certain test conditions causing the cable to rapidly self-extinguish after being burned off after removal of the source of fire) and must pass the corresponding type of bundled cable burn test. The volume of combustible (non-metallic substances) of the A-type combustion test cable is not less than 7L, and the fire supplying time is 40 min; the volume of combustible (non-metallic substances) of the cable for the B-type combustion test is not less than 3.5L, and the fire supplying time is 40 min; the volume of combustible (non-metallic substances) of the cable for the C-type combustion test is not less than 1.5L, and the fire supplying time is 20 min.
Disclosure of Invention
The utility model aims at providing an electric, mechanical properties are good, can satisfy various 110kV flame retardant power cable who lays the environmental requirement, and its fire-retardant grade can reach the fire-retardant requirement of A class.
The technical scheme of the utility model is that: a110 kV power cable with an A-type flame-retardant structure is characterized in that an inner shielding layer, a middle insulating layer and an outer shield are wrapped outside a copper conductor from inside to outside to form an insulating wire core;
wrapping a buffered semi-conductive shielding layer on the periphery of the insulated wire core;
an aluminum sheath is wrapped outside the semi-conductive shielding layer, a flame-retardant asphalt anti-corrosion protective layer is coated outside the aluminum sheath to improve the flame-retardant performance, the thickness is 0.2mm-0.4mm, and a (red) high-electric flame-retardant polyethylene sheath and a (black) flame-retardant conductive polyolefin sheath are sequentially wrapped outside the asphalt anti-corrosion protective layer;
the volume resistivity of the high-electric flame-retardant polyethylene sheath layer is not less than 1.0 multiplied by 1014Omega cm, dielectric strength not less than 18kV/mm, elongation at break not less than 400%, oxygen index not less than 26, and nominal thickness of the flame-retardant polyethylene sheath material is 5.0 mm.
The flame-retardant conductive polyolefin sheath layer has volume resistivity not more than 50 omega cm, elongation at break not less than 250%, oxygen index not less than 23, and nominal thickness not less than 0.2 mm.
Further, the sectional area is 800mm2And the structure of the copper conductor is a round twisted and compacted structure. For example, 91 (1+6+12+18+24+30) monofilaments with the diameter of 3.45mm are adopted, and the conductor is formed by layering, pressing and regularly twisting, and the outer diameter of the conductor is 34.0 mm.
The cross section area is 1000mm2And the above copper conductor, the junction thereofThe structure is a five-division no-center-unit twisted structure. Wherein the cross section is 1600mm2The conductor is taken as an example, and the structure of the conductor is formed by twisting 5 fan-shaped strand blocks, and the center angle of the fan-shaped strand blocks is 72 degrees. Each fan-shaped strand block is formed by twisting 61 (1+6+12+18+24) monofilaments with the diameter of 2.74mm, and two edge surfaces of each fan-shaped strand block are insulated by longitudinally wrapping a layer of crepe paper with the thickness of 0.3mm, so that the adjacent strand blocks are ensured to be insulated from each other.
The range of the sectional area is between the two, and can be alternatively adopted.
Further, the inner shielding layer is formed by extruding and wrapping a semiconductive polyolefin mixture, and the average thickness of the inner shielding layer is 1.5 mm;
the middle insulating layer is formed by extruding cross-linked polyethylene material; the insulation core displacement degree of the middle insulation layer is less than 4%, and the nominal thickness of the middle insulation layer is 16.0-19.0 mm;
the outer shielding layer is formed by extruding and wrapping a semiconductive polyolefin mixture, and the average thickness of the outer shielding layer is 1.2 mm.
Furthermore, the semiconductive shielding layer is formed by overlapping two layers of semiconductive polyester bulky belts, the overlapping rate of the overlapping wrapping of each layer of semiconductive polyester bulky belt is 47% -50%, the average thickness of each layer of semiconductive polyester bulky belt is 2.0mm, and the nominal width is 80 mm. The periphery of the insulated wire core is wrapped with a buffer semi-conductive shielding layer, so that the dual functions of shielding and buffering can be achieved.
Furthermore, the aluminum sheath is formed by extrusion or longitudinal wrapping, and the thickness of the aluminum sheath is 2.0 mm-2.3 mm. The aluminum sheath is a seamless or welded connection.
Further, the inner shielding layer, the middle insulating layer and the outer shielding layer outside the conductor are of a three-layer co-extrusion structure; the red high-electric-property flame-retardant polyethylene sheath and the black flame-retardant conductive polyolefin sheath are of a double-layer co-extrusion structure.
The utility model discloses 110kV power cable selects fire-retardant pitch, the fire-retardant polyethylene sheath of red high electric property and the fire-retardant electrically conductive double-deck crowded structure altogether of black fire-retardant electrically conductive polyolefin sheath seamless or welding aluminium sheath outward, requires to satisfy national standard GB/T11017, GB/T18380 on the one hand, through A type flame retardant test, needs to satisfy the extrusion molding technological requirement of manufacturing simultaneously.
The insulated wire core with the three-layer co-extrusion structure is adopted, so that no impurities are brought into the insulated wire core during production, and the sizes of the impurities, micropores and the like are ensured to meet the requirements of the national standard GB/T11017.
The aluminum sheath adopts a seamless or welding mode and has the functions of metal shielding, magnetic shielding and radial mechanical protection. Therefore, the long-time stable operation of the 110kV flame-retardant power cable can be effectively ensured.
The utility model has the advantages that can satisfy multiple environmental requirement of laying, the fire resistance reaches a 110kV flame retardant power cable of A class.
Drawings
Fig. 1 is a schematic structural diagram of the present invention.
In the figure: 1. the cable comprises a copper conductor, 2, an inner shielding layer, 3, a middle insulating layer, 4, an outer shielding layer, 5, an insulating wire core, 6, a semi-conductive shielding layer, 7, an aluminum sheath, 8, a high-electric-property flame-retardant polyethylene sheath, and 9, a flame-retardant conductive polyolefin sheath.
Detailed Description
The technical solution of the present invention will be described in detail with reference to the accompanying drawings, but the scope of the present invention is not limited to the embodiments.
Referring to fig. 1, the cable structure is suitable for cables with the outer diameter of 100 mm-130 mm, and the 110kV power cable with the A-type flame retardant structure is provided.
An inner shielding layer, a middle insulating layer and an outer shielding layer are wrapped outside the copper conductor from inside to outside to form an insulating wire core;
wrapping a semi-conductive shielding layer around the periphery of the insulated wire core;
wrapping an aluminum sheath outside the semiconductive shielding layer, coating a flame-retardant asphalt anti-corrosion protective layer outside the aluminum sheath, and sequentially wrapping a comprehensive sheath consisting of a high-electric flame-retardant polyethylene sheath and a flame-retardant conductive polyolefin sheath material outside the flame-retardant asphalt anti-corrosion protective layer;
the semiconductive shielding layer is formed by sequentially overlapping and wrapping two layers of semiconductive polyester bulking belts, and the overlapping rate of the overlapping and wrapping of each layer of semiconductive polyester bulking belt is 47-50%.
The thickness of the flame-retardant asphalt anti-corrosion protective layer is 0.2mm-0.4 mm. The flame-retardant asphalt product adopted in the embodiment is obtained by adding a composite flame retardant into No. 10 asphalt in GB/T494-2010 construction petroleum asphalt, and the composite flame retardant has the functions of heat insulation, oxygen insulation and prevention of combustible gas from escaping outwards under the high-temperature condition, thereby achieving the purpose of flame retardance.
The thickness of the high-electric flame-retardant polyethylene sheath ranges from 4.8mm to 5.2mm, and in this example, the nominal thickness is 5.0 mm.
The flame retardant conductive polyolefin jacket has a thickness in the range of 0.2mm to 0.3mm, in this case a nominal thickness of 0.2 mm.
In this example, the average thickness of the semiconductive polyester bulk tapes in the semiconductive shield layer was 2.0mm, and the nominal width was 80 mm. The semi-conductive polyester bulk tape of the embodiment is purchased from the prior art, is formed by sequentially compounding semi-conductive polyester fiber non-woven fabric, high water absorption expansion material and semi-conductive polyester fiber non-woven fabric, and has the function of water resistance.
The aluminum sheath is formed by extruding or longitudinally wrapping, the thickness of the aluminum sheath is 2.0 mm-2.3 mm, and the aluminum sheath is of a seamless connection structure or a welding connection structure.
The sheath material for forming the high-electric flame-retardant polyethylene sheath layer can be a ZRPE sheath material with the volume resistivity not less than 1.0 multiplied by 1014Omega cm, dielectric strength not less than 18kV/mm, oxygen index not less than 26;
the sheath material for forming the flame-retardant conductive polyolefin sheath layer can be a selected number of ZRBDPE sheath material, and has volume resistivity not greater than 50 omega-cm, elongation at break not less than 250% and oxygen index not less than 23.
The high-electric-property flame-retardant polyethylene sheath (oxygen index OI is more than or equal to 26) and the flame-retardant conductive polyolefin sheath (oxygen index OI is more than or equal to 23) adopt the plastic extruding machine to carry out double-layer co-extrusion structure, so that the cable structure is kept complete all the time during the bundled combustion test, the sheath forms a shell shape after the test, the flame is prevented from further expanding to the cable body, the carbonization height of the plastic sheath after combustion and the integrity of the cable body are ensured, and the integrity of the cable body is ensured during fire. The cable is ensured to have good operation of the whole electrical performance and mechanical performance.
The sectional area of the copper conductor is 1000mm2And the structure of the copper conductor is a five-division no-center-unit stranded structure. Alternatively, the copper conductor has a cross-sectional area of 800mm2And the copper conductor is a round twisted and compacted structure.
In this example, the copper conductor has a cross-sectional area of 1600mm2The copper conductor is formed by twisting 5 fan-shaped strand blocks, and the central angle of each fan-shaped strand block is 72 degrees; each fan-shaped strand block is formed by twisting 61 (1+6+12+18+24, namely the innermost layer is 1 monofilament, and each layer from inside to outside is 6, 12, 18 and 24 monofilaments in sequence), and two edge surfaces of each strand block are insulated by longitudinally wrapping a layer of crepe paper with the thickness of 0.3mm, so that the adjacent fan-shaped strand blocks are ensured to be mutually insulated; the monofilament diameter was 2.74 mm.
The inner shielding layer is formed by extruding and wrapping a semi-conductive polyolefin mixture, and the average thickness of the inner shielding layer is 1.5 mm;
the middle insulating layer is formed by extruding cross-linked polyethylene (XLPE) materials, the insulating core displacement degree of the middle insulating layer is less than 4%, and the nominal thickness of the middle insulating layer is 16.0-19.0 mm;
the outer shielding layer is formed by extruding a semiconductive polyolefin mixture, and the average thickness of the outer shielding layer is 1.2 mm.
The inner shielding layer, the middle insulating layer and the outer shielding layer outside the copper conductor are of a three-layer co-extrusion structure; the high-electric-property flame-retardant polyethylene sheath and the flame-retardant conductive polyolefin sheath are of a double-layer co-extrusion structure. The two layers of the sheath of this example are of different colors.
The cable is manufactured by extruding an inner shielding layer, a middle insulating layer and an outer shielding layer on a copper core conductor in a production mode of three-layer co-extrusion, dry-process crosslinking and continuous vulcanization. The copper core conductor and the three insulating layers form an insulating wire core. And a buffer semi-conductive shielding layer is wrapped on the periphery of the insulated wire core. And a layer of aluminum sheath is extruded at the periphery of the semi-conductive shielding layer. And a layer of flame-retardant anti-corrosion asphalt is coated on the periphery of the aluminum sheath. Then a double-layer co-extrusion structure of a red high-electric-property flame-retardant polyethylene sheath and a black flame-retardant conductive polyolefin sheath is adopted.
In this example: in order to enable the 110kV power cable to meet the requirements of a bundled A-type flame-retardant test, the cable adopts flame-retardant asphalt, a crust-type (red) high-electric-property flame-retardant polyethylene sheath (the oxygen index is not less than 26) and a (black) flame-retardant conductive polyolefin sheath (the oxygen index is not less than 23), and realizes a double-layer sheath co-extrusion structure of flame-retardant materials with different colors, so that the extrusion process is simplified, the sheath forms a shell shape when the cable is bundled and burnt, flame is prevented from further expanding to the cable body, and the carbonization height of the burnt plastic sheath and the integrity of the cable body are ensured.
800mm2The copper conductor with the lower cross section adopts a 1000mm round stranding and pressing structure2And the copper conductor with the section adopts a five-division type non-central-unit stranded structure. The conductor between the two cross-sectional areas can be in both structures.
The thickness of the medium insulating layer meets the requirements of GB/T11017 standard. The thickness of the aluminum sheath meets the requirements of GB/T11017 standard regulation. The thickness of the high-electric flame-retardant polyethylene sheath layer meets the requirements of GB/T11017 standard regulation.
Through detection, the main performance parameters of the cable are as follows:
(1) indexes of partial discharge test: 1.5U0(96kV) voltage, without any detectable discharge produced by the cable under test that exceeds the sensitivity of the claim test (96kV, the sensitivity of the claim test is less than 2 pC);
(2) insulating structure size: eccentricity (tmax-tmin)/tmax is less than or equal to 4%, tmin is more than or equal to 0.95tn (tn is the nominal thickness; tmin and tmax have the minimum thickness and the maximum thickness of any same section);
(3) insulation heat elongation test: the maximum elongation under load is less than or equal to 100 percent (which is better than the requirement of less than or equal to 175 percent specified by the national standard), and the permanent elongation after cooling is less than or equal to 5 percent (which is better than the requirement of less than or equal to 15 percent specified by the national standard);
(4) insulating micropore and impurity test: the ultra-clean XLPE insulating material, an advanced frictionless gravity feeding system and a high-grade insulating and purifying system (100-grade insulating and feeding room) are adopted to control the sizes of insulating impurities and micropores to be optimal and obviously higher than the GB/T11017 standard requirement;
(5) and in the impulse voltage test, the conductor temperature is 95-100 ℃, the positive polarity voltage and the negative polarity voltage are applied for 10 times of 650kV, and the cable is not broken down (which is superior to the 550kV requirement specified by the national standard).
(6) Bending test: the diameter of the cylinder is 15(D + D) + 5%, which is higher than 25(D + D) + 5% specified in GB/T11017 standard.
(7) And (3) flame retardant test: according to the test of GB/T18380, the actual carbonization height does not exceed 1.0m when the A-type bundled burning test is passed.
As mentioned above, although the present invention has been shown and described with reference to certain preferred embodiments, it should not be construed as limiting the invention itself. Various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (8)
1. The utility model provides a 110kV power cable of fire-retardant structure of A class which characterized in that:
an inner shielding layer (2), a middle insulating layer (3) and an outer shielding layer (4) are wrapped outside the copper conductor (1) from inside to outside to form an insulating wire core (5);
a semi-conductive shielding layer (6) is wrapped on the periphery of the insulated wire core;
an aluminum sheath (7) is wrapped outside the semi-conductive shielding layer (6), a flame-retardant asphalt anti-corrosion protective layer is coated outside the aluminum sheath (7), and a comprehensive sheath formed by a high-electric-property flame-retardant polyethylene sheath (8) and a flame-retardant conductive polyolefin sheath (9) is sequentially wrapped outside the flame-retardant asphalt anti-corrosion protective layer;
the semiconductive shielding layer (6) is formed by sequentially overlapping and wrapping two layers of semiconductive polyester bulked belts, and the overlapping rate of the overlapping and wrapping of each layer of semiconductive polyester bulked belt is 47-50%;
the thickness of the flame-retardant asphalt anti-corrosion protective layer is 0.2mm-0.4 mm;
the thickness of the high-electric flame-retardant polyethylene sheath is 4.8 mm-5.2 mm;
the thickness of the flame-retardant conductive polyolefin sheath is 0.2 mm-0.3 mm.
2. The 110kV power cable with a class-A flame-retardant structure according to claim 1, wherein: in the semiconductive shield, the semiconductive polyester bulk tapes all had an average thickness of 2.0mm and a nominal width of 80 mm.
3. The 110kV power cable with a class-A flame-retardant structure according to claim 1, wherein: the aluminum sheath is formed by extruding or longitudinally wrapping, the thickness of the aluminum sheath is 2.0 mm-2.3 mm, and the aluminum sheath is of a seamless connection structure or a welding connection structure.
4. The 110kV power cable with a class-A flame-retardant structure according to claim 1, wherein: forming a sheath material of the high-electric flame-retardant polyethylene sheath layer; the nominal thickness of the high-electric flame-retardant polyethylene sheath layer is 5.0 mm;
a sheath material for forming the flame-retardant conductive polyolefin sheath layer; the nominal thickness of the flame retardant conductive polyolefin jacket is 0.2 mm.
5. The 110kV power cable with a class-A flame-retardant structure according to claim 1, wherein:
the sectional area of the copper conductor (1) is 1000mm2And the above copper conductor, the structure of the copper conductor (1) is a five-division no-center-unit stranded structure;
alternatively, the copper conductor (1) has a cross-sectional area of 800mm2And the following copper conductors, the copper conductor (1) is a round stranded compacted structure.
6. The 110kV power cable with a class-A flame-retardant structure according to claim 1, wherein: the copper conductor (1) has a cross-sectional area of 1600mm2The copper conductor (1) is formed by twisting 5 fan-shaped strand blocks, and the central angle of each fan-shaped strand block is 72 degrees; each fan-shaped strand block is formed by twisting 61 monofilaments, insulating crepe paper is arranged between every two adjacent strand blocks, and the diameter of each monofilament is 2.74 mm.
7. The 110kV power cable with a class-A flame-retardant structure according to claim 1, wherein:
the inner shielding layer is formed by extruding and wrapping a semi-conductive polyolefin mixture, and the average thickness of the inner shielding layer is 1.5 mm;
the middle insulating layer is formed by extruding a cross-linked polyethylene material, the insulating core displacement degree of the middle insulating layer is less than 4%, and the nominal thickness of the middle insulating layer is 16.0-19.0 mm;
the outer shielding layer is formed by extruding a semiconductive polyolefin mixture, and the average thickness of the outer shielding layer is 1.2 mm.
8. The 110kV power cable with a class-A flame-retardant structure according to claim 1, wherein: the inner shielding layer (2), the middle insulating layer (3) and the outer shielding layer (4) outside the copper conductor (1) are of a three-layer co-extrusion structure; the high-electric-property flame-retardant polyethylene sheath (8) and the flame-retardant conductive polyolefin sheath (9) are of a double-layer co-extrusion structure.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202020803889.8U CN212434277U (en) | 2020-05-14 | 2020-05-14 | 110kV power cable with A-type flame-retardant structure |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202020803889.8U CN212434277U (en) | 2020-05-14 | 2020-05-14 | 110kV power cable with A-type flame-retardant structure |
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| CN212434277U true CN212434277U (en) | 2021-01-29 |
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