CN-122025238-A - Crosslinked polyethylene insulated steel wire armored medium-voltage power cable and preparation method thereof

CN122025238ACN 122025238 ACN122025238 ACN 122025238ACN-122025238-A

Abstract

The invention relates to the technical field of power cables, in particular to a crosslinked polyethylene insulated steel wire armored medium-voltage power cable and a preparation method thereof, wherein the crosslinked polyethylene insulated steel wire armored medium-voltage power cable comprises a plurality of wire cores which are tangent to each other in pairs and a filling structure filled between the wire cores, and the wire cores are wrapped by wrapping belts to form cable cores with circular cross sections; the cable comprises a cable core, an elastic isolation layer, a first steel wire sparse winding layer, a composite belt waterproof layer, a second steel wire sparse winding layer and a composite belt waterproof layer, wherein the cable core is extruded on the outer wall of the cable core, the first steel wire sparse winding layer is tightly pressed on the outer wall of the elastic isolation layer, the composite belt waterproof layer is coated on the first steel wire sparse winding layer and the outer wall of the elastic isolation layer, and the second steel wire sparse winding layer is tightly pressed on the outer wall of the composite belt waterproof layer. The invention realizes dynamic self-adaptive radial waterproof sealing through the synergistic effect of the rigid polygonal constraint frame formed by internally and externally aligned sparse winding steel wires, the composite belt waterproof layer with the prefabricated reinforced structure and the internal and external high-elasticity layers.

Inventors

SHI MINGPENG
WU MINGLIANG
WU CHUNZHONG
SUN SHUGUANG
PAN LONG
LI ZHIYUAN
WANG WENHUAN
WU BIN

Assignees

江苏中超电缆股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260313

Claims (10)

1. A crosslinked polyethylene insulated wire-armored medium voltage power cable, comprising: The cable cores (10) are wrapped and fixed into a circular section by wrapping belts (3) together with filling structures (2) filled between the cable cores (1) along with a plurality of tangent line cores (1) in pairs; An elastic isolation layer (4) which is extruded on the outer wall of the cable core (10); The first steel wire sparse winding layer (5) is tightly pressed and sparse wound on the outer wall of the elastic isolation layer (4); a composite belt waterproof layer (6) which is coated on the outer walls of the first steel wire sparse winding layer (5) and the elastic isolation layer (4); the second steel wire sparse winding layer (7) is tightly pressed and sparse wound on the outer wall of the composite belt waterproof layer (6); an elastic sheath layer (8) is extruded on the outer walls of the second steel wire sparse winding layer (7) and the composite belt waterproof layer (6); the outer sheath layer (9) is extruded on the outer wall of the elastic sheath layer (8); The first steel wires in the first steel wire sparse winding layer (5) are distributed at equal intervals, the second steel wires in the second steel wire sparse winding layer (7) are distributed at equal intervals, the sparse winding angles of the first steel wires and the second steel wires are the same, and the circumferential positions of the first steel wires and the second steel wires are configured to enable the composite belt waterproof layer (6) to form a stable convex polygon profile at any axial position of a cable under the clamping of the first steel wires and the second steel wires; The composite belt waterproof layer (6) comprises a wrapping structure formed by a composite belt (61) according to a preset wrapping coverage rate, the composite belt (61) is provided with at least one reinforcement structure (611) distributed along the length direction of the composite belt, and part of the reinforcement structure (611) is positioned in a coverage area (6 a) when the composite belt (61) is wrapped to form the wrapping structure; The first steel wire forms outward pressure by the inner side of the wrapping structure to the wrapping structure, the second steel wire forms inward pressure by the outer side of the wrapping structure to the wrapping structure, a cover area (6 a) of the wrapping structure forms a high pressure area (6 b) at the position of the reinforcement structure (611), and the wrapping structure is radially compressed, so that the cover area (6 a) of the wrapping structure is kept sealed.
2. The crosslinked polyethylene insulated wire armored medium voltage power cable according to claim 1, wherein the composite tape (61) comprises a metal base layer (601) and a friction layer (602) coated on the surface of the metal base layer (601), the metal base layer (601) is a copper tape or an aluminum alloy tape, the friction layer (602) is a hydrogenated nitrile rubber, fluororubber or thermoplastic polyurethane elastomer coating, and the surface of the reinforcement structure (611) is provided with a water-absorbing expansion coating (603) arranged on the surface of the friction layer (602).
3. The crosslinked polyethylene insulated wire armored medium voltage power cable according to claim 1, wherein the reinforcement structure (611) is a rib formed on the belt body of the composite belt (61) and having a sinusoidal waveform, trapezoidal waveform or zigzag cross section, 3-4 reinforcement structures (611) are provided on the belt body of the composite belt (61), and the reinforcement structures (611) are arranged at positions such that at least two reinforcement structures (611) are located in the overlapping region (6 a) when the composite belt (61) is wrapped according to an overlapping rate of 35-40%.
4. The crosslinked polyethylene insulated wire armored medium voltage power cable according to claim 1, wherein the elastic isolation layer (4) comprises thermoplastic polyurethane or high elastomer silicone rubber, the compression elastic modulus under normal state is 10-30 mpa, the elastic sheath layer (8) comprises a high-hardness silicone rubber layer, the elastic sheath layer (8) is extruded and covered on the surfaces of the plurality of second steel wires and the wrapping structure, and a seamless connection interface is formed on the surfaces of the plurality of second steel wires and the wrapping structure.
5. The crosslinked polyethylene insulated steel wire armored medium voltage power cable according to claim 4, wherein a gap formed between the elastic isolation layer (4) and the wrapping structure is filled with water-blocking sealant, two sides of the first steel wire are filled with water-blocking ropes (51), and the water-blocking ropes (51) are polyester fiber ropes coated with water-swelling powder.
6. The crosslinked polyethylene insulated wire armored medium voltage power cable of claim 1, wherein the first and second wires have the same wire diameter and a diameter greater than the thickness of the composite tape (61), the first and second wires are evenly distributed along the circumferential direction of the cable, and the circumferential diameter of the first wire is smaller than the circumferential diameter of the second wire.
7. The crosslinked polyethylene insulated wire armored medium voltage power cable according to any of claims 1-6, wherein the wrapping structure has a stable polygonal profile in cross-sectional shape under the constraint of the first and second wires, and each angle of the polygonal profile is an angle smaller than 180 °, the convex polygonal structure is used for dispersing stress by smooth variation of included angles of respective apex angles when the cable is bent or thermally deformed, maintaining stability of the high pressure region (6 b) of the overlapping region (6 a), and preventing local plastic deformation or circumferential slip of the composite tape.
8. The crosslinked polyethylene insulated wire-armored medium voltage power cable of claim 1, wherein the number of the first wires or the second wires is 6-10.
9. The method of producing a crosslinked polyethylene insulated wire-armored medium voltage power cable according to any of claims 1-8, comprising the steps of: S1, sequentially co-extruding and coating a conductor shielding layer (12), an insulating layer (13) and an insulating shielding layer (14) on a conductor (11), and then coating a metal shielding layer (15) to form a single wire core (1); s2, twisting the three wire cores and the longitudinal water-blocking material into a cable, and wrapping the cable by using a wrapping belt (3) to form a cable core (10); S3, extruding and wrapping the cable core (10) to form the elastic isolation layer (4); s4, a plurality of first steel wires are wound on the surface of the elastic isolation layer (4) in a sparse mode at a first spiral angle to form a first steel wire winding layer (5); S5, spirally wrapping the composite belt (61) pre-pressed with the reinforcement structure (611) on the surfaces of the first steel wire sparse winding layer (5) and the elastic isolation layer (4), and ensuring the reinforcement structure (611) in the overlapping region (6 a) to form a composite belt water-resisting layer (6); S6, a second steel wire is wound on the surface of the composite belt water-resisting layer (6) in a sparse mode through a first spiral angle, a second steel wire winding-free layer (7) is formed on the composite belt water-resisting layer (6), and the first steel wire and the second steel wire apply radial pressure to the composite belt water-resisting layer (6) together and are pressed on the surface of the elastic isolation layer (4); s7, sequentially extruding an elastic sheath layer (8) and an outer sheath layer (9) on the outer layer of the second steel wire sparse winding layer (7).
10. The method for manufacturing a crosslinked polyethylene insulated wire-armored medium voltage power cable according to claim 9, wherein in step S5, the wrapping covering rate of the composite tape (61) is 35-40%, the wrapping tension is controlled to be 5-20 n, in steps S4 and S6, the loose winding tension of the first wire and the second wire is independently controlled, and the loose winding tension of the second wire is not greater than the loose winding tension of the first wire.

Description

Crosslinked polyethylene insulated steel wire armored medium-voltage power cable and preparation method thereof Technical Field The invention relates to the technical field of power cables, in particular to a crosslinked polyethylene insulated steel wire armored medium-voltage power cable and a preparation method thereof. Background Crosslinked polyethylene (XLPE) insulated medium voltage power cables have become a mainstream choice for urban power grids, industrial parks and various power transmission scenarios due to their excellent electrical and mechanical properties. The three-core cable is compact in structure, can effectively save laying resources in narrow spaces such as underground pipe galleries and the like, and is wide in application. During its long-term operation, especially in direct burial, tunnel or humid environments, the intrusion of external moisture, such as groundwater, moisture, is one of the key factors affecting the insulation life and operational reliability of the cable. XLPE insulation is extremely sensitive to moisture, which under the action of an electric field tends to cause water dendrite aging, resulting in irreversible deterioration of insulation properties. In the industry, a mature technical scheme such as filling water-blocking paste, wrapping water-blocking tape and the like is formed in the aspect of longitudinal water resistance of the cable, however, in the aspect of radial water resistance, particularly for a three-core cable which needs to be compatible with flexibility and economy, a continuous optimization space still exists, and common strategies comprise the adoption of a high-density polyethylene (HDPE) outer jacket, an aluminum/copper plastic composite tape or a metal sealing sleeve (lead sleeve and aluminum sleeve). HDPE jackets rely on their own compactness but may present a risk of penetration under long term environmental stresses, the lap seam area of the aluminum/copper plastic composite tape is a potential weak link, while continuously extruded metal jackets provide excellent radial barriers but add significant rigidity, weight and cost to the cable, which presents challenges for production, transportation and installation. Disclosure of Invention The invention aims to overcome the defects of a medium voltage power cable in the prior art, and provides a crosslinked polyethylene insulated steel wire armored medium voltage power cable, which comprises the following components: the cable cores are wrapped and fixed by wrapping belts together with the filling structures filled between the cable cores, wherein the cable cores are round in section; an elastic isolation layer extruded on the outer wall of the cable core; the first steel wire sparse winding layer is tightly pressed on the outer wall of the elastic isolation layer; The composite belt waterproof layer is coated on the outer walls of the first steel wire sparse winding layer and the elastic isolation layer; the second steel wire sparse winding layer is tightly pressed and sparse wound on the outer wall of the composite belt waterproof layer; the elastic sheath layer is extruded on the outer wall of the second steel wire sparse winding layer and the composite belt waterproof layer; the outer sheath layer is extruded on the outer wall of the elastic sheath layer; The composite belt waterproof layer is arranged on the cable, wherein a plurality of first steel wires in the first steel wire sparse winding layer are distributed at equal intervals, a plurality of second steel wires in the second steel wire sparse winding layer are distributed at equal intervals, the sparse winding angles of the first steel wires and the second steel wires are the same, and the circumferential positions of the first steel wires and the second steel wires are configured to enable the composite belt waterproof layer to form a stable convex polygon profile at any axial position of the cable under the clamping of the first steel wires and the second steel wires; The composite belt waterproof layer comprises a wrapping structure formed by a composite belt according to a preset wrapping coverage rate, the composite belt is provided with at least one reinforcement structure distributed along the length direction of the composite belt, and part of the reinforcement structure is positioned in a coverage area when the composite belt wraps the wrapping structure; The first steel wire forms outward pressure by the package structure inboard to the package structure, the second steel wire by the package structure outside to the package structure forms inward pressure, the area of overlapping of package structure is in the position that the reinforcing structure is located forms high pressure area, radially compresses tightly the package structure, makes the area of overlapping of package structure keeps sealedly. Preferably, the composite belt comprises a metal base layer and a friction layer coated on the surface of the metal base l