CN214336392U - High-voltage special power cable capable of running stably - Google Patents

Abstract

A high-voltage special power cable capable of running stably is structurally characterized in that: the insulating layer comprises a copper conductor, an inner insulating layer, a middle insulating layer, an outer insulating layer, a buffer protective layer, an aluminum sheath, a high-electric polyethylene sheath and a conductive polyolefin sheath; the inner insulating layer, the middle insulating layer and the outer insulating layer are of a three-layer co-extrusion structure to form an insulating wire core; the high-electric polyethylene sheath and the conductive polyethylene sheath are of a double-layer co-extrusion structure to form an integrated outer sheath; the inner insulating layer is formed by extruding a semiconductive polyolefin mixture; the middle insulating layer is formed by extruding cross-linked polyethylene material; the outer insulating layer is formed by extruding a semiconductive polyolefin mixture; coating an asphalt anti-corrosion protective layer outside the aluminum sheath; the high-electric polyethylene sheath is formed by extruding high-electric polyethylene sheath materials; the conductive polyolefin sheath is formed by extruding semiconductive polyolefin sheath materials. The cable meets the use requirements of various scenes, and ensures the stability of the operation of the cable.

Description

High-voltage special power cable capable of running stably

Technical Field

The technical scheme is a high-voltage special power cable which runs stably, and belongs to the technical field of ultrahigh-voltage power cables.

Background

The extra-high voltage cable is a common power transmission cable, and needs to meet the requirement of long-term stable operation. In the use process, due to complex line working conditions, very complex and delicate relations exist among functional structure layers of the cable, and after long-term use, performance parameters of the functional structure layers are changed, which directly influence the use reliability. With the technical progress, the cable structure needs to have wider applicability, which has higher requirements on the reliability of the cable.

Disclosure of Invention

In order to satisfy the high reliability requirement of extra-high voltage cable, the utility model provides a widely suitable cable structure, particularly:

a high-voltage special power cable capable of running stably is structurally characterized in that: the insulating layer comprises a copper conductor, an inner insulating layer, a middle insulating layer, an outer insulating layer, a buffer protective layer, an aluminum sheath, a high-electric polyethylene sheath and a conductive polyolefin sheath;

the inner insulating layer, the middle insulating layer and the outer insulating layer are of a three-layer co-extrusion structure to form an insulating wire core; the high-electric polyethylene sheath and the conductive polyethylene sheath are of a double-layer co-extrusion structure to form an integrated outer sheath;

the inner insulating layer is formed by extruding a semiconductive polyolefin mixture, and the average thickness of the inner insulating layer is 1.5-2.5 mm; the middle insulating layer is formed by extruding a cross-linked polyethylene material, and the nominal thickness of the middle insulating layer is 16.0-31.0 mm; the outer insulating layer is formed by extruding a semiconductive polyolefin mixture, and the average thickness of the outer insulating layer is 1.0-1.5 mm;

the thickness of the aluminum sheath is 2.0-3.3 mm; an asphalt anti-corrosion protective layer is coated outside the aluminum sheath, and the thickness of the asphalt anti-corrosion protective layer is 0.2-0.4 mm;

the high-electric polyethylene sheath is formed by extruding high-electric polyethylene sheath materials, and the thickness of the high-electric polyethylene sheath is 5.0-6.0 mm; the conductive polyolefin sheath is formed by extruding semiconductive polyolefin sheath materials, and the thickness of the conductive polyolefin sheath is not less than 0.2 mm.

1. For 2500mm resistant to 110kV²The cable of (2):

the copper conductor is resistant to 110kV and has a section of 2500mm²The conductor of (1); the copper conductor structure is formed by twisting 5 fan-shaped strand blocks, and the center angle 72 of each fan-shaped strand block^oEach fan-shaped strand block is formed by twisting 91 copper monofilaments with the diameter of 2.82mm, and an insulating crepe paper tape with the thickness of 0.3mm is longitudinally wrapped between each two strand blocks; the 91 copper monofilaments are divided into 6 layers, and the number of the copper monofilaments in each layer from inside to outside is 1, 6, 12, 18, 24 and 30;

the average thickness of the inner insulating layer is 1.5 mm; the insulation core displacement degree of the middle insulation layer is less than 4%, and the nominal thickness of the middle insulation layer is 18.0 mm; the average thickness of the outer insulating layer is 1.0 mm;

the buffer protective layer is a buffer water-blocking layer and is composed of two layers of semi-conductive buffer water-blocking tapesOverlapping and lapping; the thickness of the semi-conductive buffer water-blocking tape is 2.3mm, the width of the semi-conductive buffer water-blocking tape is 80mm, and the overlapping rate of overlapping lapping is 48-52%; the thickness deviation range of the semi-conductive buffer water-blocking tape is 0.3mm, and the volume resistivity is not more than 10⁴Omega.cm, the surface resistance is not more than 400 omega, and the water absorption expansion speed is not less than 10mm/1st min;

the aluminum sheath is formed by extrusion or longitudinal wrapping, and the thickness of the aluminum sheath is 2.6 mm; the aluminum sheath is seamlessly connected or welded and then pressed into spiral embossing, and the depth of the spiral embossing is designed to be 5.0 +/-0.2 mm;

the volume resistivity of the high-electric polyethylene sheath material is not less than 1.0 multiplied by 10¹⁴Omega cm, the dielectric strength is not less than 26 kV/mm; the nominal thickness of the high-electric polyethylene sheath is 5.0 mm; the volume resistivity of the semiconductive polyolefin sheath material at 20 ℃ is not more than 50 omega cm, and the elongation at break is not less than 450%; the conductive polyolefin jacket has a nominal thickness of no less than 0.3 mm.

The outer diameter of the insulated wire core is 105.0 +/-0.2 mm; the outer diameter is 116.0 mm plus or minus 0.3mm after wrapping the buffer water-resistant layer; the overall outer diameter of the cable is 142 mm.

2. For copper ribbon structure high voltage cables:

the sectional area of the copper conductor is 800mm²The copper conductor is formed by regularly pressing and twisting 91 copper monofilaments with the diameter of 3.45mm, and a layer of semiconductive nylon belt with the thickness of 0.14mm is wrapped outside the copper conductor; the outer diameter of the conductor wrapped with the semiconductive nylon tape is 34.0 mm; the 91 copper monofilaments are divided into 6 layers, and the number of the copper monofilaments in each layer from inside to outside is 1, 6, 12, 18, 24 and 30;

the copper conductor has a cross-sectional area of 1600mm²The copper conductor is formed by twisting 5 fan-shaped strand blocks; center angle 72 of fan-shaped strand block^oEach fan-shaped strand block is formed by twisting 61 copper monofilaments with the diameter of 2.76mm, and an insulating crepe paper tape with the thickness of 0.3mm is longitudinally wrapped between each two strand blocks; the 61 copper monofilaments are divided into 5 layers, and the number of the copper monofilaments in each layer from inside to outside is 1, 6, 12, 18 and 24; five 72^oThe outer diameter phi of the twisted fan-shaped strand block is 49.5 +/-0.2 mm.

The average thickness of the inner insulating layer is 1.5 mm; 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 mm; the average thickness of the outer insulating layer is 1.0 mm;

the buffer protection layer is formed by overlapping and wrapping a semiconductive copper wire shielding tape, and the overlapping rate of the overlapping and wrapping is 48% -52%; the nominal thickness of the semiconductive copper wire shielding belt is 0.5 +/-0.02 mm, the width is 80mm-100mm, the diameter of a copper wire on the semiconductive copper wire shielding belt is 0.2 +/-0.01 mm, and no less than 20 copper wires are arranged in a horizontal gap manner in the width direction; the surface resistance of the semiconductive copper wire shielding belt is less than 120 omega, the volume resistivity is less than 200 omega-cm, the water content is not more than 5 percent, the instantaneous temperature resistance is 230 ℃, the water absorption expansion speed is more than or equal to 8mm/1st min, and the expansion height is more than or equal to 12mm/3 min;

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 formed by seamless connection or welding connection;

the volume resistivity of the high-electric polyethylene sheath material is not less than 1.0 multiplied by 10¹⁴Omega cm, the dielectric strength is not less than 26 kV/mm; the nominal thickness of the high-electric polyethylene sheath is 5.0 mm;

the volume resistivity of the semiconductive polyolefin sheath material at 20 ℃ is not more than 50 omega cm, and the elongation at break is not less than 450%; the thickness of the conductive polyolefin sheath is not less than 0.2 mm.

3. For a 500kV power cable:

the sectional area of the copper conductor is 2500mm²The copper conductor is formed by twisting 5 fan-shaped strand blocks, and the central angle of the fan-shaped strand blocks is 72 degrees^o(ii) a Each fan-shaped strand block is formed by twisting 91 copper monofilaments with the diameter of 2.82mm, and an insulating crepe paper tape with the thickness of 0.3mm and the width of 62.0mm is longitudinally wrapped between each fan-shaped strand block; the 91 copper monofilaments are divided into 6 layers, and the number of the copper monofilaments in each layer from inside to outside is 1, 6, 12, 18, 24 and 30;

a layer of semi-conductive extra-heavy nylon belt with the nominal thickness of 0.20mm is lapped and wound outside the copper conductor in an overlapping mode, and a layer of semi-conductive nylon belt with the nominal thickness of 0.14mm is lapped and wound in a left-hand overlapping mode; the lapping overlapping rate of the two layers of the semi-conductive super-heavy tangential belts is 48 to 52 percent;

the average thickness of the inner insulating layer is 2.5 mm; the insulation core displacement degree of the middle insulation layer is less than 3%, and the nominal thickness of the middle insulation layer is 31.0 mm; the average thickness of the outer insulating layer is 1.5 mm;

bufferThe protective layer is an electrical contact buffer layer and comprises three layers from inside to outside, wherein the three layers are respectively formed by overlapping and wrapping a layer of semi-conductive butyl rubber buffer tape, overlapping and wrapping a layer of semi-conductive buffer water-blocking tape and overlapping and wrapping a layer of copper wire shielding tape; the thickness of the semiconductive butyl rubber buffer belt is 0.25mm, the width of the semiconductive butyl rubber buffer belt is 80mm, and the overlapping rate of the overlapping wrapping is 47% -50%; the thickness of the semi-conductive buffer water-blocking tape is 2.3mm, the width of the semi-conductive buffer water-blocking tape is 100mm, and the overlapping rate of overlapping wrapping is 47-50%; the thickness of the copper wire shielding belt is 0.5mm, the width of the copper wire shielding belt is 80mm, the overlapping rate of the overlapping wrapping is 20%, and 20 tinned copper wires with the diameter of 0.20mm are uniformly and horizontally placed in the copper wire shielding belt along the width direction of the copper wire shielding belt; the thickness deviation range of the semiconductive butyl rubber buffer belt is 0.05mm, and the volume resistivity is not more than 10⁴Omega.cm; the thickness deviation range of the semi-conductive buffer water-blocking tape is 0.3mm, and the volume resistivity is not more than 10⁴Omega, cm, the water absorption expansion speed is not less than 10mm/1st min; the thickness deviation range of the copper wire shielding tape is 0.05mm, and the volume resistivity is not more than 200 omega cm;

the aluminum sheath is formed by extruding or longitudinally wrapping, the thickness of the aluminum sheath is 3.3mm, the aluminum sheath is formed by seamless connection or welding connection, and then the aluminum sheath is pressed into spiral embossing, and the depth of the spiral embossing is designed to be 8.0 +/-0.5 mm;

the volume resistivity of the high-electric polyethylene sheath material is not less than 1.0 multiplied by 10¹⁴Omega cm, the dielectric strength is not less than 26 kV/mm; the nominal thickness of the high-electric polyethylene sheath is 6.0 mm;

the volume resistivity of the semiconductive polyolefin sheath material at 20 ℃ is not more than 50 omega cm, and the elongation at break is not less than 450%; the conductive polyolefin jacket is nominally no less than 0.3mm thick.

The overall outer diameter of the cable is 180mm, and the single weight is 41.6 kg/m.

The ultrahigh voltage power cable with the structure adopts a specific structure, particularly a specific buffer protective layer, meets the use requirements of various scenes, and ensures the stability of the operation of the cable.

Drawings

Figure 1 is a schematic radial cross-section of the cable of this embodiment,

in the figure: 1. the cable comprises a copper conductor, 2 parts of an inner insulating layer, 3 parts of a middle insulating layer, 4 parts of an outer insulating layer, 5 parts of a buffer protective layer, 6 parts of an aluminum sheath, 7 parts of a high-electric polyethylene sheath, and 8 parts of a conductive polyolefin sheath.

Detailed Description

The technical solution is further described below with reference to specific examples as follows:

the power cable shown in fig. 1 has the following structure from inside to outside in sequence: the insulating layer comprises a copper conductor, an inner insulating layer, a middle insulating layer, an outer insulating layer, a buffer protective layer, an aluminum sheath, a high-electric polyethylene sheath and a conductive polyolefin sheath;

the inner insulating layer, the middle insulating layer and the outer insulating layer are of a three-layer co-extrusion structure to form an insulating wire core; the high-electric polyethylene sheath and the conductive polyethylene sheath are of a double-layer co-extrusion structure to form an integrated outer sheath;

the inner insulating layer is formed by extruding a semiconductive polyolefin mixture, and the average thickness of the inner insulating layer is 1.5-2.5 mm; the middle insulating layer is formed by extruding a cross-linked polyethylene material, and the nominal thickness of the middle insulating layer is 16.0-31.0 mm; the outer insulating layer is formed by extruding a semiconductive polyolefin mixture, and the average thickness of the outer insulating layer is 1.0-1.5 mm;

the thickness of the aluminum sheath is 2.0-3.3 mm; an asphalt anti-corrosion protective layer is coated outside the aluminum sheath, and the thickness of the asphalt anti-corrosion protective layer is 0.2-0.4 mm;

the high-electric polyethylene sheath is formed by extruding high-electric polyethylene sheath materials, and the thickness of the high-electric polyethylene sheath is 5.0-6.0 mm; the conductive polyolefin sheath is formed by extruding semiconductive polyolefin sheath materials, and the thickness of the conductive polyolefin sheath is not less than 0.2 mm.

The implementation mode of the tool comprises:

example 1, for a 110kV 2500mm2 power cable.

The copper conductor is resistant to 110kV and has a section of 2500mm²The conductor of (1); the copper conductor structure is formed by twisting 5 fan-shaped strand blocks, and the center angle 72 of each fan-shaped strand block^oEach fan-shaped strand block is formed by twisting 91 copper monofilaments with the diameter of 2.82mm, and an insulating crepe paper tape with the thickness of 0.3mm is longitudinally wrapped between each two strand blocks; the 91 copper monofilaments are divided into 6 layers, and the number of the copper monofilaments in each layer from inside to outside is 1, 6, 12, 18, 24 and 30;

the average thickness of the inner insulating layer is 1.5 mm; the insulation core displacement degree of the middle insulation layer is less than 4%, and the nominal thickness of the middle insulation layer is 18.0 mm; the average thickness of the outer insulating layer is 1.0 mm;

the buffer protective layer is a buffer water-blocking layer and is formed by lapping and overlapping two layers of semi-conductive buffer water-blocking tapes; the thickness of the semi-conductive buffer water-blocking tape is 2.3mm, the width of the semi-conductive buffer water-blocking tape is 80mm, and the overlapping rate of overlapping lapping is 48-52%; the thickness deviation range of the semi-conductive buffer water-blocking tape is 0.3mm, and the volume resistivity is not more than 10⁴Omega.cm, the surface resistance is not more than 400 omega, and the water absorption expansion speed is not less than 10mm/1st min;

the aluminum sheath is formed by extrusion or longitudinal wrapping, and the thickness of the aluminum sheath is 2.6 mm; the aluminum sheath is seamlessly connected or welded and then pressed into spiral embossing, and the depth of the spiral embossing is designed to be 5.0 +/-0.2 mm;

the volume resistivity of the high-electric polyethylene sheath material is not less than 1.0 multiplied by 10¹⁴Omega cm, the dielectric strength is not less than 26 kV/mm; the nominal thickness of the high-electric polyethylene sheath is 5.0 mm; the volume resistivity of the semiconductive polyolefin sheath material at 20 ℃ is not more than 50 omega cm, and the elongation at break is not less than 450%; the conductive polyolefin jacket has a nominal thickness of no less than 0.3 mm.

The outer diameter of the insulated wire core is 105.0 +/-0.2 mm; the outer diameter is 116.0 mm plus or minus 0.3mm after wrapping the buffer water-resistant layer; the overall outer diameter of the cable is 142 mm.

Example 2, high voltage cable with copper ribbon.

The sectional area of the copper conductor is 800mm²The copper conductor is formed by regularly pressing and twisting 91 copper monofilaments with the diameter of 3.45mm, and a layer of semiconductive nylon belt with the thickness of 0.14mm is wrapped outside the copper conductor; the outer diameter of the conductor wrapped with the semiconductive nylon tape is 34.0 mm; the 91 copper monofilaments are divided into 6 layers, and the number of the copper monofilaments in each layer from inside to outside is 1, 6, 12, 18, 24 and 30;

the copper conductor has a cross-sectional area of 1600mm²The copper conductor is formed by twisting 5 fan-shaped strand blocks; center angle 72 of fan-shaped strand block^oEach fan-shaped strand block is formed by twisting 61 copper monofilaments with the diameter of 2.76mm, and an insulating crepe paper tape with the thickness of 0.3mm is longitudinally wrapped between each two strand blocks; 61 copper filamentsThe number of the copper monofilaments is 5, and the number of the copper monofilaments in each layer from inside to outside is 1, 6, 12, 18 and 24; five 72^oThe outer diameter phi of the twisted fan-shaped strand block is 49.5 +/-0.2 mm.

The average thickness of the inner insulating layer is 1.5 mm; 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 mm; the average thickness of the outer insulating layer is 1.0 mm;

the buffer protection layer is formed by overlapping and wrapping a semiconductive copper wire shielding tape, and the overlapping rate of the overlapping and wrapping is 48% -52%; the nominal thickness of the semiconductive copper wire shielding belt is 0.5 +/-0.02 mm, the width is 80mm-100mm, the diameter of a copper wire on the semiconductive copper wire shielding belt is 0.2 +/-0.01 mm, and no less than 20 copper wires are arranged in a horizontal gap manner in the width direction; the surface resistance of the semiconductive copper wire shielding belt is less than 120 omega, the volume resistivity is less than 200 omega-cm, the water content is not more than 5 percent, the instantaneous temperature resistance is 230 ℃, the water absorption expansion speed is more than or equal to 8mm/1st min, and the expansion height is more than or equal to 12mm/3 min;

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 formed by seamless connection or welding connection;

the volume resistivity of the high-electric polyethylene sheath material is not less than 1.0 multiplied by 10¹⁴Omega cm, the dielectric strength is not less than 26 kV/mm; the nominal thickness of the high-electric polyethylene sheath is 5.0 mm;

the volume resistivity of the semiconductive polyolefin sheath material at 20 ℃ is not more than 50 omega cm, and the elongation at break is not less than 450%; the thickness of the conductive polyolefin sheath is not less than 0.2 mm.

Example 3, for 500kV power cables.

The sectional area of the copper conductor is 2500mm²The copper conductor is formed by twisting 5 fan-shaped strand blocks, and the central angle of the fan-shaped strand blocks is 72 degrees^o(ii) a Each fan-shaped strand block is formed by twisting 91 copper monofilaments with the diameter of 2.82mm, and an insulating crepe paper tape with the thickness of 0.3mm and the width of 62.0mm is longitudinally wrapped between each fan-shaped strand block; the 91 copper monofilaments are divided into 6 layers, and the number of the copper monofilaments in each layer from inside to outside is 1, 6, 12, 18, 24 and 30;

a layer of semi-conductive extra-heavy nylon belt with the nominal thickness of 0.20mm is lapped and wound outside the copper conductor in an overlapping mode, and a layer of semi-conductive nylon belt with the nominal thickness of 0.14mm is lapped and wound in a left-hand overlapping mode; the lapping overlapping rate of the two layers of the semi-conductive super-heavy tangential belts is 48 to 52 percent;

the average thickness of the inner insulating layer is 2.5 mm; the insulation core displacement degree of the middle insulation layer is less than 3%, and the nominal thickness of the middle insulation layer is 31.0 mm; the average thickness of the outer insulating layer is 1.5 mm;

the buffer protective layer is an electrical contact buffer layer and comprises three layers from inside to outside, wherein the three layers are respectively formed by overlapping and wrapping a layer of semi-conductive butyl rubber buffer tape, overlapping and wrapping a layer of semi-conductive buffer water-blocking tape and overlapping and wrapping a layer of copper wire shielding tape; the thickness of the semiconductive butyl rubber buffer belt is 0.25mm, the width of the semiconductive butyl rubber buffer belt is 80mm, and the overlapping rate of the overlapping wrapping is 47% -50%; the thickness of the semi-conductive buffer water-blocking tape is 2.3mm, the width of the semi-conductive buffer water-blocking tape is 100mm, and the overlapping rate of overlapping wrapping is 47-50%; the thickness of the copper wire shielding belt is 0.5mm, the width of the copper wire shielding belt is 80mm, the overlapping rate of the overlapping wrapping is 20%, and 20 tinned copper wires with the diameter of 0.20mm are uniformly and horizontally placed in the copper wire shielding belt along the width direction of the copper wire shielding belt; the thickness deviation range of the semiconductive butyl rubber buffer belt is 0.05mm, and the volume resistivity is not more than 10⁴Omega.cm; the thickness deviation range of the semi-conductive buffer water-blocking tape is 0.3mm, and the volume resistivity is not more than 10⁴Omega, cm, the water absorption expansion speed is not less than 10mm/1st min; the thickness deviation range of the copper wire shielding tape is 0.05mm, and the volume resistivity is not more than 200 omega cm;

the aluminum sheath is formed by extruding or longitudinally wrapping, the thickness of the aluminum sheath is 3.3mm, the aluminum sheath is formed by seamless connection or welding connection, and then the aluminum sheath is pressed into spiral embossing, and the depth of the spiral embossing is designed to be 8.0 +/-0.5 mm;

the volume resistivity of the high-electric polyethylene sheath material is not less than 1.0 multiplied by 10¹⁴Omega cm, the dielectric strength is not less than 26 kV/mm; the nominal thickness of the high-electric polyethylene sheath is 6.0 mm;

the volume resistivity of the semiconductive polyolefin sheath material at 20 ℃ is not more than 50 omega cm, and the elongation at break is not less than 450%; the conductive polyolefin jacket is nominally no less than 0.3mm thick.

The overall outer diameter of the cable is 180mm, and the single weight is 41.6 kg/m.

Through detection, the cable of example 1 has the following characteristics:

(1) rated system voltage Uo/U: 64kV/110kV, maximum operating voltage Um: 126 kV;

(2) the conductor allows long-term working temperature when the cable normally runs as follows: 90 ℃;

(3) in the case of short circuits (maximum duration of not more than 5 seconds), the maximum temperature allowed for the cable conductor is 250 ℃.

(4) Insulating structure size: eccentricity (tmax-tmin)/tmax is less than or equal to 4%, tmin is greater than or equal to 0.95tn (tn is the nominal thickness, and the minimum thickness and the maximum thickness of any same section of tmin and tmax) (which is superior to the requirement of less than or equal to 10% specified by national standard);

(5) indexes of partial discharge test: 1.5U0 (96 kV) voltage, without any detectable discharge produced by the cable under test that exceeds the sensitivity of the claim test (96 kV, the sensitivity of the claim test is less than 2 pC);

(6) 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);

(7) 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;

(8) 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).

(9) Bending test: the diameter of the cylinder is 12 (D + D) +5%, which is higher than 25 (D + D) +5% required by GB/T11017 standard.

Through detection, the characteristics of the cable of example 2 include:

(1) rated system voltage Uo/U: 290kV/500kV, maximum operating voltage Um: 550 kV;

(2) the conductor allows long-term working temperature when the cable normally runs as follows: 90 ℃;

(3) in the case of short circuits (maximum duration of not more than 5 seconds), the maximum temperature allowed for the cable conductor is 250 ℃.

(4) Indexes of partial discharge test: 1.5U0 (435 kV) voltage, without any detectable discharge produced by the cable under test that exceeds the sensitivity of the claim test (435 kV, the sensitivity of the claim test is less than 1.2pC, better than the 5pC specified by the national standard);

(5) insulating structure size: eccentricity (tmax-tmin)/tmax is less than or equal to 3%, tmin is greater than or equal to 0.95tn (tn is the nominal thickness, and the minimum thickness and the maximum thickness of any same section of tmin and tmax) (which is superior to the requirement of less than or equal to 8% specified by national standard);

(6) power frequency withstand voltage test: applying 2.0Uo (580 kV) voltage for 60min to prevent insulation breakdown;

(7) and (3) outer sheath electrical test: and applying a direct current voltage of 25kV between the metal sheath and the conducting layer on the surface of the outer sheath by using a metal sleeve to connect with a cathode for 1min, wherein the outer sheath is not broken down.

(8) 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);

(9) 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 standard requirement of GB/T22078;

micropores greater than 0.05 mm: is free of

0.025mm to 0.05mm of micropores: less than or equal to 18 pieces/10 cm³

Opaque impurities greater than 0.125 mm: is free of

Opaque impurities with the diameter of 0.05mm to 0.125mm are less than or equal to 6 per 10cm³

Translucency greater than 0.16 mm: is free of

(10) And in the impulse voltage test, the conductor temperature is 95-100 ℃, the positive polarity voltage is applied for 10 times, the negative polarity voltage is applied for 10 times, and the cable is not broken down.

Through detection, the characteristics of the cable of example 3 include:

(1) indexes of partial discharge test: 1.5U0 (96 kV) voltage, without any detectable discharge produced by the cable under test that exceeds the sensitivity of the claim test (96 kV, the sensitivity of the claim test is less than 1.2 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 12 (D + D) +5%, which is higher than 25 (D + D) +5% required by GB/T11017 standard.

(7) And (3) water permeability test: according to the GB/T11017 test method, a section of cable with the length of 3m is cut from the cable after a bending test, the cable is horizontally placed, a section of ring with the width of about 30mm is cut at the middle part of the cable, a water column with the height of 1m is adopted, heating cycles are applied for 10 times, and no moisture seeps out from two ends of a cable sample.

Claims (1)

1. The utility model provides a high-pressure special power cable of steady operation which characterized by is from inside to outside in proper order: the insulating layer comprises a copper conductor, an inner insulating layer, a middle insulating layer, an outer insulating layer, a buffer protective layer, an aluminum sheath, a high-electric polyethylene sheath and a conductive polyolefin sheath;

the inner insulating layer, the middle insulating layer and the outer insulating layer are of a three-layer co-extrusion structure to form an insulating wire core; the high-electric polyethylene sheath and the conductive polyethylene sheath are of a double-layer co-extrusion structure to form an integrated outer sheath;

the inner insulating layer is formed by extruding a semiconductive polyolefin mixture, and the average thickness of the inner insulating layer is 1.5-2.5 mm; the middle insulating layer is formed by extruding a cross-linked polyethylene material, and the nominal thickness of the middle insulating layer is 16.0-31.0 mm; the outer insulating layer is formed by extruding a semiconductive polyolefin mixture, and the average thickness of the outer insulating layer is 1.0-1.5 mm;

the thickness of the aluminum sheath is 2.0-3.3 mm; an asphalt anti-corrosion protective layer is coated outside the aluminum sheath, and the thickness of the asphalt anti-corrosion protective layer is 0.2-0.4 mm;

the high-electric polyethylene sheath is formed by extruding high-electric polyethylene sheath materials, and the thickness of the high-electric polyethylene sheath is 5.0-6.0 mm; the conductive polyolefin sheath is formed by extruding semiconductive polyolefin sheath materials, and the thickness of the conductive polyolefin sheath is not less than 0.2 mm;

the high-voltage special power cable which stably runs is resistant to 110kV and 2500mm²The cable, the high-voltage cable with the copper wire ribbon structure or the 500kV power cable;

for 2500mm resistant to 110kV²The cable of (2):

the copper conductor is resistant to 110kV and has a section of 2500mm²The conductor of (1); the copper conductor structure is formed by twisting 5 fan-shaped strand blocks, the central angle of each fan-shaped strand block is 72 degrees, each fan-shaped strand block is formed by twisting 91 copper monofilaments with the diameter of 2.82mm, and an insulating crepe paper tape with the thickness of 0.3mm is longitudinally wrapped between every two strand blocks; the 91 copper monofilaments are divided into 6 layers, and the number of the copper monofilaments in each layer from inside to outside is 1, 6, 12, 18, 24 and 30;

the average thickness of the inner insulating layer is 1.5 mm; the insulation core displacement degree of the middle insulation layer is less than 4%, and the nominal thickness of the middle insulation layer is 18.0 mm; the average thickness of the outer insulating layer is 1.0 mm;

the buffer protective layer is a buffer water-blocking layer and is formed by lapping and overlapping two layers of semi-conductive buffer water-blocking tapes; the thickness of the semi-conductive buffer water-blocking tape is 2.3mm, the width of the semi-conductive buffer water-blocking tape is 80mm, and the overlapping rate of overlapping lapping is 48-52%; the thickness deviation range of the semi-conductive buffer water-blocking tape is 0.3mm, and the volume resistivity is not more than 10⁴Omega.cm, the surface resistance is not more than 400 omega, and the water absorption expansion speed is not less than 10mm/1st min;

the aluminum sheath is formed by extrusion or longitudinal wrapping, and the thickness of the aluminum sheath is 2.6 mm; the aluminum sheath is seamlessly connected or welded and then pressed into spiral embossing, and the depth of the spiral embossing is designed to be 5.0 +/-0.2 mm;

the volume resistivity of the high-electric polyethylene sheath material is not less than 1.0 multiplied by 10¹⁴Omega cm, the dielectric strength is not less than 26 kV/mm; the nominal thickness of the high-electric polyethylene sheath is 5.0 mm; the volume resistivity of the semiconductive polyolefin sheath material at 20 ℃ is not more than 50 omega cm, and the elongation at break is not less than 450%; the nominal thickness of the conductive polyolefin sheath is not less than 0.3 mm;

the outer diameter of the insulated wire core is 105.0 +/-0.2 mm; the outer diameter is 116.0 mm plus or minus 0.3mm after wrapping the buffer water-resistant layer; the overall outer diameter of the cable is 142 mm;

for copper ribbon structure high voltage cables:

the sectional area of the copper conductor is 800mm²The copper conductor is formed by regularly pressing and twisting 91 copper monofilaments with the diameter of 3.45mm, and a layer of semiconductive nylon belt with the thickness of 0.14mm is wrapped outside the copper conductor; the outer diameter of the conductor wrapped with the semiconductive nylon tape is 34.0 mm; the 91 copper monofilaments are divided into 6 layers, and the number of the copper monofilaments in each layer from inside to outside is 1, 6, 12, 18, 24 and 30;

the copper conductor has a cross-sectional area of 1600mm²The copper conductor is formed by twisting 5 fan-shaped strand blocks; the central angle of the fan-shaped strand blocks is 72 degrees, each fan-shaped strand block is formed by twisting 61 copper monofilaments with the diameter of 2.76mm, and an insulating crepe paper tape with the thickness of 0.3mm is longitudinally wrapped between every two strand blocks; the 61 copper monofilaments are divided into 5 layers, and the number of the copper monofilaments in each layer from inside to outside is 1, 6, 12, 18 and 24; the outer diameter phi of five 72-degree fan-shaped strand blocks after being twisted is 49.5 +/-0.2 mm;

the average thickness of the inner insulating layer is 1.5 mm; 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 mm; the average thickness of the outer insulating layer is 1.0 mm;

the buffer protection layer is formed by overlapping and wrapping a semiconductive copper wire shielding tape, and the overlapping rate of the overlapping and wrapping is 48% -52%; the nominal thickness of the semiconductive copper wire shielding belt is 0.5 +/-0.02 mm, the width is 80mm-100mm, the diameter of a copper wire on the semiconductive copper wire shielding belt is 0.2 +/-0.01 mm, and no less than 20 copper wires are arranged in a horizontal gap manner in the width direction; the surface resistance of the semiconductive copper wire shielding belt is less than 120 omega, the volume resistivity is less than 200 omega-cm, the water content is not more than 5 percent, the instantaneous temperature resistance is 230 ℃, the water absorption expansion speed is more than or equal to 8mm/1st min, and the expansion height is more than or equal to 12mm/3 min;

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 formed by seamless connection or welding connection;

the volume resistivity of the high-electric polyethylene sheath material is not less than 1.0 multiplied by 10¹⁴Omega cm, the dielectric strength is not less than 26 kV/mm; the nominal thickness of the high-electric polyethylene sheath is 5.0 mm;

the volume resistivity of the semiconductive polyolefin sheath material at 20 ℃ is not more than 50 omega cm, and the elongation at break is not less than 450%; the thickness of the conductive polyolefin sheath is not less than 0.2 mm;

for a 500kV power cable:

the sectional area of the copper conductor is 2500mm²The 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 91 copper monofilaments with the diameter of 2.82mm, and an insulating crepe paper tape with the thickness of 0.3mm and the width of 62.0mm is longitudinally wrapped between each fan-shaped strand block; the 91 copper monofilaments are divided into 6 layers, and the number of the copper monofilaments in each layer from inside to outside is 1, 6, 12, 18, 24 and 30;

a layer of semi-conductive extra-heavy nylon belt with the nominal thickness of 0.20mm is lapped and wound outside the copper conductor in an overlapping mode, and a layer of semi-conductive nylon belt with the nominal thickness of 0.14mm is lapped and wound in a left-hand overlapping mode; the lapping overlapping rate of the two layers of the semi-conductive super-heavy tangential belts is 48 to 52 percent;

the average thickness of the inner insulating layer is 2.5 mm; the insulation core displacement degree of the middle insulation layer is less than 3%, and the nominal thickness of the middle insulation layer is 31.0 mm; the average thickness of the outer insulating layer is 1.5 mm;

the buffer protective layer is an electrical contact buffer layer and comprises three layers from inside to outside, wherein the three layers are respectively formed by overlapping and wrapping a layer of semi-conductive butyl rubber buffer tape, overlapping and wrapping a layer of semi-conductive buffer water-blocking tape and overlapping and wrapping a layer of copper wire shielding tape; the thickness of the semiconductive butyl rubber buffer belt is 0.25mm, the width of the semiconductive butyl rubber buffer belt is 80mm, and the overlapping rate of the overlapping wrapping is 47% -50%; the thickness of the semi-conductive buffer water-blocking tape is 2.3mm, the width is 100mm, and the weight is heavyThe overlapping rate of the lapping package is 47% -50%; the thickness of the copper wire shielding belt is 0.5mm, the width of the copper wire shielding belt is 80mm, the overlapping rate of the overlapping wrapping is 20%, and 20 tinned copper wires with the diameter of 0.20mm are uniformly and horizontally placed in the copper wire shielding belt along the width direction of the copper wire shielding belt; the thickness deviation range of the semiconductive butyl rubber buffer belt is 0.05mm, and the volume resistivity is not more than 10⁴Omega.cm; the thickness deviation range of the semi-conductive buffer water-blocking tape is 0.3mm, and the volume resistivity is not more than 10⁴Omega, cm, the water absorption expansion speed is not less than 10mm/1st min; the thickness deviation range of the copper wire shielding tape is 0.05mm, and the volume resistivity is not more than 200 omega cm;

the aluminum sheath is formed by extruding or longitudinally wrapping, the thickness of the aluminum sheath is 3.3mm, the aluminum sheath is formed by seamless connection or welding connection, and then the aluminum sheath is pressed into spiral embossing, and the depth of the spiral embossing is designed to be 8.0 +/-0.5 mm;

the volume resistivity of the high-electric polyethylene sheath material is not less than 1.0 multiplied by 10¹⁴Omega cm, the dielectric strength is not less than 26 kV/mm; the nominal thickness of the high-electric polyethylene sheath is 6.0 mm;

the volume resistivity of the semiconductive polyolefin sheath material at 20 ℃ is not more than 50 omega cm, and the elongation at break is not less than 450%; the nominal thickness of the conductive polyolefin sheath is not less than 0.3 mm;

the overall outer diameter of the cable is 180mm, and the single weight is 41.6 kg/m.

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