Crosslinked polyethylene insulated smooth aluminum sheath power cable

Abstract

The utility model relates to the technical field of power cables, in particular to a cross-linked polyethylene insulated smooth aluminum sheath power cable, which comprises a stranded conductor comprising a plurality of layers of stranded oxygen-free copper conductors or aluminum alloy conductors; the inner shielding layer, the insulating layer and the outer shielding layer are co-extruded and coated on the outer wall of the stranded conductor from inside to outside; the inner waterproof layer wraps the outer wall of the outer shielding layer; and the smooth aluminum sleeve water-blocking layer is coated on the outer wall of the inner water-blocking layer. According to the utility model, the inner waterproof layer, the smooth aluminum sleeve and the outer waterproof layer are adopted to form a waterproof structure, and the inner waterproof layer, the smooth aluminum sleeve and the outer waterproof layer form surface contact, so that the three layers of structures are connected compactly, the axial propagation of water vapor is not easy to form, meanwhile, the heat transfer from inside to outside is facilitated, a good heat dissipation effect is formed, and the current-carrying capacity is improved.

Description

Technical Field

[0001] This utility model relates to the field of power cable technology, and more specifically to a cross-linked polyethylene insulated smooth aluminum-sheathed power cable. Background Technology

[0002] High-voltage power cables (66kV-500kV) are the core of main transmission lines, and their stability and safety are of paramount importance. Traditional cross-linked polyethylene insulated high-voltage cables mostly use a corrugated aluminum sheath structure, which has good bending performance, but suffers from insufficient water resistance and low heat dissipation efficiency.

[0003] Specifically, the air gap between the corrugated aluminum sheath and the insulated core results in poor longitudinal water resistance, allowing moisture to easily penetrate the insulation layer along the gap, leading to water tree growth and insulation breakdown. Simultaneously, the high thermal resistance of the air gap in the corrugated structure reduces the cable's current carrying capacity and limits transmission efficiency. Utility Model Content

[0004] To address the technical problems existing in high-voltage power cables in the prior art, this utility model proposes a cross-linked polyethylene insulated smooth aluminum-sheathed power cable, comprising:

[0005] Stranded conductors, including multilayer stranded oxygen-free copper conductors or aluminum alloy conductors;

[0006] The inner shielding layer, the insulating layer, and the outer shielding layer are co-extruded from the inside out and covered on the outer wall of the stranded conductor.

[0007] An inner water-blocking layer covers the outer wall of the outer shielding layer;

[0008] A smooth aluminum sleeve water-blocking layer covers the outer wall of the inner water-blocking layer;

[0009] An outer water-blocking layer covers the surface of the smooth aluminum sleeve water-blocking layer;

[0010] The outer sheath is extruded onto the outer wall of the outer water-resistant layer;

[0011] The inner water-blocking layer, the smooth aluminum sleeve water-blocking layer, and the outer water-blocking layer are in contact. The inner water-blocking layer includes a water-blocking tape wrapping structure, and the outer water-blocking layer includes an adhesive layer.

[0012] Preferably, the water-blocking tape wrapping structure includes a single-layer expansion water-blocking tape with a butt joint wrapping structure.

[0013] Preferably, the expansion water-blocking tape includes a semi-conductive butyl tape layer, and the semi-conductive butyl tape layer has a water-absorbing resin coating on the side facing the outer shielding layer.

[0014] Preferably, the water-absorbing resin coating comprises water-absorbing resin powder with a particle size of less than 50 micrometers.

[0015] Preferably, the water-blocking tape wrapping structure includes an elastic wrapping layer and a longitudinal water-blocking wrapping layer. The elastic wrapping layer includes a semi-conductive elastic tape wrapping structure layer, and the longitudinal water-blocking wrapping layer includes a semi-conductive buffer water-blocking tape wrapping structure layer.

[0016] Preferably, the elastic wrapping layer comprises two layers of semi-conductive elastic strip wrapping layer, with each wrapping layer having a wrapping overlap rate of 45-50%.

[0017] Preferably, the semiconductive buffer water-blocking tape wrapping structure layer includes two layers of semiconductive water-blocking tape wrapping layers, with each wrapping layer having a wrapping overlap rate of 45-50%.

[0018] Preferably, the outer water-blocking layer further includes an aramid braided layer, which covers the outer wall of the smooth aluminum sleeve water-blocking layer.

[0019] Preferably, the adhesive layer is coated on the surface of the aramid braided layer.

[0020] Preferably, the thickness of the smooth aluminum sleeve water-blocking layer is 2.0 to 2.3 mm.

[0021] Compared with the prior art, the significant advantages of the cross-linked polyethylene insulated smooth aluminum sheathed power cable proposed in this utility model are:

[0022] This utility model of cross-linked polyethylene insulated smooth aluminum sheathed power cable is designed with an inner water-blocking layer, a smooth aluminum sheath, and an outer water-blocking layer to form a water-blocking structure. The inner water-blocking layer, the smooth aluminum sheath, and the outer water-blocking layer form a surface contact, making the connection between the three layers tight and preventing the axial propagation of water vapor. At the same time, it is also conducive to the transfer of heat from the inside to the outside, forming a good heat dissipation effect and improving the current carrying capacity. In addition, the smooth aluminum sheath itself has good longitudinal water-blocking performance, giving the cable a better overall water-blocking ability, reducing the probability of water treeing-induced breakdown, and improving the reliability and service life of the cable. Attached Figure Description

[0023] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown in the various figures may be denoted by the same reference numeral. For clarity, not every component is labeled in each figure. Embodiments of various aspects of the present invention will now be described by way of example and with reference to the accompanying drawings, wherein:

[0024] Figure 1 This is a schematic diagram of the structure of the cross-linked polyethylene insulated smooth aluminum-sheathed power cable shown in this utility model;

[0025] Figure 2 This is a schematic diagram showing the relative positions of the inner water-blocking layer, the smooth aluminum sleeve water-blocking layer, and the outer water-blocking layer as illustrated in this utility model. Detailed Implementation

[0026] To better understand the technical content of this utility model, specific embodiments are provided below in conjunction with the accompanying drawings.

[0027] Combination Figure 1 As shown, this utility model proposes a cross-linked polyethylene insulated smooth aluminum sheath power cable, including a stranded conductor 1, an inner shielding layer 2, an insulation layer 3, an outer shielding layer 4, an inner water-blocking layer 5, a smooth aluminum sheath water-blocking layer 6, an outer water-blocking layer 7, and an outer sheath 8.

[0028] The stranded conductor 1 includes multi-layer stranded oxygen-free copper conductors or aluminum alloy conductors, and the multi-layer stranded conductors conform to the second type of compacted stranded circular structure of GB / T3956.

[0029] Furthermore, a semi-conductive tertrolene tape and a semi-conductive polypropylene tape are wrapped around the outer wall of the stranded conductor 1.

[0030] Optionally, the semi-conductive terylene tape has two wrapping layers, both right-handed, with a wrapping overlap rate of 45-50%, while the semi-conductive polypropylene tape has one wrapping layer, left-handed, with a wrapping overlap rate of 15-20%.

[0031] In an optional embodiment, an inner shielding layer 2, an insulating layer 3, and an outer shielding layer 4 are formed by co-extrusion of three layers from the inside to the outside on the outer wall of the stranded conductor 1.

[0032] Among them, the thinnest point of the inner shielding layer 2 is not less than 1.1mm, the thinnest point of the insulation layer 3 is not less than 22.8mm, the thickest point is not greater than 25.2mm, and the thinnest point of the outer shielding layer 4 is not less than 0.8mm.

[0033] Furthermore, the inner water-blocking layer 5 covers the outer wall of the outer shielding layer 4, the smooth aluminum sleeve water-blocking layer 6 covers the outer wall of the inner water-blocking layer 5, and the outer water-blocking layer 7 covers the surface of the smooth aluminum sleeve water-blocking layer 6.

[0034] The inner water-blocking layer 5, the smooth aluminum sleeve water-blocking layer 6, and the outer water-blocking layer 7 are in surface contact. The inner water-blocking layer 5 includes a water-blocking tape wrapping structure, and the outer water-blocking layer 7 includes an adhesive layer.

[0035] The thickness of the smooth aluminum sleeve water-blocking layer 6 is 2.0 to 2.3 mm, and the smooth aluminum sleeve can be formed by welding or extrusion.

[0036] In an optional embodiment, the water-blocking tape wrapping structure includes a single-layer expansion water-blocking tape seam wrapping structure. Forming a water-blocking layer of uniform thickness through seam wrapping facilitates surface contact between the smooth aluminum sleeve water-blocking layer 6 and the inner water-blocking layer 5.

[0037] The expansion water-blocking tape includes a semi-conductive butyl tape layer, and the semi-conductive butyl tape layer has a water-absorbing resin coating on the side facing the outer shielding layer 4.

[0038] Optionally, the water-absorbing resin coating may include water-absorbing resin powder with a particle size of less than 50 micrometers.

[0039] Thus, the water-absorbing resin powder acts as a water barrier between the smooth aluminum sheath water-blocking layer 6 and the outer shielding layer 4. When the water-absorbing resin powder comes into contact with water, it can absorb water and expand, so that the gap between the outer shielding layer 4 and the smooth aluminum sheath water-blocking layer 6 is filled tightly, preventing water from spreading along the cable axis.

[0040] In other embodiments, the water-blocking tape wrapping structure includes an elastic wrapping layer and a longitudinal water-blocking wrapping layer. The elastic wrapping layer includes a semi-conductive elastic tape wrapping structure layer, and the longitudinal water-blocking wrapping layer includes a semi-conductive buffer water-blocking tape wrapping structure layer.

[0041] The elastic wrapping layer includes two layers of semi-conductive elastic strip wrapping layers, with each wrapping layer having a wrapping overlap rate of 45-50%.

[0042] The semi-conductive buffer water-blocking tape wrapping structure includes two layers of semi-conductive water-blocking tape wrapping layers, with each wrapping layer having a wrapping overlap rate of 45-50%.

[0043] Thus, by setting a semi-conductive elastic layer and a semi-conductive water-resistant layer, the gap between the smooth aluminum sleeve water-resistant layer 6 and the outer shielding layer 4 can be filled tightly to prevent water vapor from entering.

[0044] Furthermore, the outer sheath 8 is extruded onto the outer wall of the outer water-blocking layer 7. Since an adhesive layer is provided on the outer layer of the smooth aluminum water-blocking layer 6, it can be ensured that the outer sheath 8 forms a tight contact with the smooth aluminum water-blocking layer 6 during extrusion, and no air bubbles are generated. Therefore, a better water-blocking effect is achieved.

[0045] In an optional embodiment, to increase the tensile strength of the cable, the outer water-blocking layer 7 further includes an aramid braided layer, which covers the outer wall of the smooth aluminum sheath water-blocking layer 6. An adhesive layer is coated on the surface of the aramid braided layer.

[0046] In this way, the adhesive layer can better adhere to the outer wall of the smooth aluminum sleeve water-blocking layer 6, so that a tight surface contact is formed between the outer sheath 8 and the smooth aluminum sleeve water-blocking layer 6.

[0047] In an optional embodiment, the outer sheath 8 may be a high-density polyethylene outer sheath. The adhesive layer is formed by hot melt adhesive spraying.

[0048] In conjunction with the above embodiments, this utility model employs an inner water-blocking layer, a smooth aluminum sheath, and an outer water-blocking layer to form a water-blocking structure. The inner water-blocking layer, the smooth aluminum sheath, and the outer water-blocking layer form surface contact, making the connection between the three layers tight and preventing the axial propagation of water vapor. At the same time, it is also conducive to the transfer of heat from the inside to the outside, forming a good heat dissipation effect and improving the current carrying capacity. In addition, the smooth aluminum sheath itself has good longitudinal water-blocking performance, giving the cable a better overall water-blocking capability, reducing the probability of water treeing-induced breakdown, and improving the reliability and service life of the cable.

[0049] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Those skilled in the art to which this invention pertains can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of this invention shall be determined by the claims.

Claims

1. A crosslinked polyethylene insulated smooth aluminium sheath power cable, characterized in that, It comprises: a stranded conductor (1) comprising a plurality of layers of stranded oxygen-free copper conductors or aluminum alloy conductors; an inner shielding layer (2), an insulation layer (3) and an outer shielding layer (4) co-extruded on the outer wall of the stranded conductor (1) from inside to outside; an inner water-blocking layer (5) coated on the outer wall of the outer shielding layer (4); a smooth aluminum sleeve water-blocking layer (6) coated on the outer wall of the inner water-blocking layer (5); an outer water-blocking layer (7) coated on the surface of the smooth aluminum sleeve water-blocking layer (6); an outer sheath (8) extruded on the outer wall of the outer water-blocking layer (7); wherein the inner water-blocking layer (5), the smooth aluminum sleeve water-blocking layer (6) and the outer water-blocking layer (7) are in surface contact, the inner water-blocking layer (5) comprises a water-blocking tape wrapping structure, and the outer water-blocking layer (7) comprises an adhesive layer; the water-blocking tape wrapping structure comprises a single-layer expanded water-blocking tape wrapping structure, the expanded water-blocking tape comprises a semi-conductive butyl tape layer, and the semi-conductive butyl tape layer is provided with a water-absorbing resin coating on one side facing the outer shielding layer (4).

2. The crosslinked polyethylene insulated smooth aluminium sheath power cable according to claim 1, characterized in that, The water-absorbing resin coating comprises water-absorbing resin powder.

3. The crosslinked polyethylene insulated smooth aluminium sheath power cable according to claim 2, characterized in that, The particle size of the water-absorbing resin powder is less than 50 microns.

4. The crosslinked polyethylene insulated smooth aluminum sheath power cable according to claim 1, characterized in that, The water-blocking tape wrapping structure comprises an elastic wrapping layer and a longitudinal water-blocking wrapping layer, the elastic wrapping layer comprises a semi-conductive elastic tape wrapping structure layer, and the longitudinal water-blocking wrapping layer is a semi-conductive buffer water-blocking tape wrapping structure layer.

5. The crosslinked polyethylene insulated smooth aluminium sheath power cable according to claim 4, characterized in that, The elastic wrapping layer comprises two layers of semi-conductive elastic tape wrapping layers, and the wrapping coverage rate of each layer of semi-conductive elastic tape wrapping layer is 45-50%.

6. The crosslinked polyethylene insulated smooth aluminium sheath power cable according to claim 5, characterized in that, The semi-conductive buffer water-blocking tape wrapping structure layer comprises two layers of semi-conductive water-blocking tape wrapping layers, and the wrapping coverage rate of each layer of semi-conductive water-blocking tape wrapping layer is 45-50%.

7. The crosslinked polyethylene insulated smooth aluminum sheath power cable according to claim 1, characterized in that, The outer water-blocking layer (7) further comprises an aramid woven layer, and the aramid woven layer is coated on the outer wall of the smooth aluminum sleeve water-blocking layer (6).

8. The crosslinked polyethylene insulated smooth aluminium sheath power cable according to claim 7, characterized in that, The adhesive layer is coated on the surface of the aramid woven layer.

9. The crosslinked polyethylene insulated smooth aluminum sheath power cable of claim 1, wherein, The thickness of the smooth aluminum sleeve water-blocking layer (6) is 2.0-2.3 mm.

10. The crosslinked polyethylene insulated smooth aluminium sheath power cable according to claim 9, characterized in that, The smooth aluminum sleeve water-blocking layer (6) can be formed by welding or extrusion.

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