Longitudinal water-blocking and water-resistant tree type medium-voltage cable insulation wire core

Abstract

The utility model discloses a longitudinal water-blocking and water-tree-resistant medium-voltage cable insulation wire core, which sequentially comprises a conductor and a co-extrusion insulation layer from inside to outside, and is characterized in that the conductor comprises a central circular monofilament and a tile-shaped monofilament layer which is arranged around the circular monofilament and consists of a plurality of tile-shaped monofilaments; and a waterproof layer is arranged between the central circular monofilament and the tile-shaped monofilament layer. The tile-shaped monofilament layers and the waterproof layers are distributed in a crossed mode. The water-blocking layer comprises a water-blocking paste layer and a semi-conductive water-blocking tape layer. The co-extrusion insulating layer comprises a water-tree-resistant conductor shielding layer, a water-tree-resistant insulating layer and a water-tree-resistant insulating shielding layer. The co-extrusion insulating layer is formed by cross-linking a water-tree-resistant semi-conductive conductor shielding material, a water-tree-resistant insulating material and a water-tree-resistant semi-conductive insulating shielding material through a co-extrusion dry method. Water vapor can be prevented from leaking inwards, and the longitudinal water blocking performance of the cable insulation wire core is improved. The insulation water tree forming time is effectively prolonged, the insulation water tree aging phenomenon is reduced, and the insulation performance and the service life of the cable are improved.

Description

Technical Field

[0001] The utility model relates to the field of cable structures, in particular to a longitudinal water-blocking and water-tree-resistant medium-voltage cable insulation core. Background Art

[0002] With the vigorous development of my country's power construction, medium-voltage cross-linked cables have been widely used. With the construction of green energy, wind and photovoltaic power generation have developed rapidly. The number of photovoltaic power generation projects with complementary fisheries and photovoltaics in lake areas and wind power projects on the coast and islands has also increased. This has put forward higher requirements on the waterproof and water-blocking properties of cables and the anti-water tree performance of cable insulation.

[0003] Cross-linked power cables in photovoltaic projects in lake areas and wind power projects on the seaside and lakeside are mostly laid by direct burial, on water bridges or on underwater buoys. Water vapor and moisture can easily invade the interior of the cable through the cable terminals and damaged parts. If the conductor does not have a good water-blocking structure, water vapor will slowly penetrate into the cable. In high humidity and high electric field conditions, the cable will quickly produce insulating water trees. When the water trees grow to a certain extent, the insulation layer will be punctured.

[0004] Traditional medium-voltage cross-linked power cables utilize a circular, compressed monofilament structure with gaps between the individual filaments. This results in a maximum conductor compression coefficient of approximately 0.9. In very humid environments, moisture can easily enter terminals and damaged cable areas, and then penetrate the conductors through gaps in the conductors. The conventional cross-linked polyethylene insulation in medium-voltage cross-linked cables rapidly develops water trees under the influence of moisture and electric fields, causing insulation degradation. After a certain period of time and when the water trees reach a certain level, the cable insulation can be broken down. Some cables utilize polyethylene sheaths with inner and outer layers for waterproofing, but these only provide radial waterproofing and have little effect on insulation degradation caused by water ingress to the terminals. Utility Model Content

[0005] The purpose of the utility model is to provide a longitudinal water-blocking and water-resistant tree-type medium-voltage cable insulation core to solve the problems of low longitudinal water-blocking performance and low insulation performance of the conductor, so as to improve the safety and reliability of power cable operation in a humid environment.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: a longitudinally water-blocking and water-tree-resistant medium-voltage cable insulated core, which includes a conductor and a co-extruded insulation layer from the inside to the outside, wherein the conductor includes a central circular monofilament and a tile-shaped monofilament layer composed of a plurality of tile-shaped monofilaments arranged around the central circular monofilament, and a water-blocking layer is arranged between the circular monofilament and the tile-shaped monofilament layer.

[0007] As a further improvement of the above technical solution:

[0008] The plurality of tile-shaped monofilament layers and the water-blocking layers are cross-distributed.

[0009] The water-blocking layer includes a water-blocking paste layer and a semi-conductive water-blocking tape layer.

[0010] The insulating shielding layer includes an anti-water tree conductor shielding layer, an anti-water tree insulation layer and an anti-water tree insulation shielding layer. The co-extruded insulation layer is formed by co-extruding and dry-crosslinking three layers of anti-water tree semi-conductive conductor shielding material, anti-water tree insulation material and anti-water tree semi-conductive insulation shielding material.

[0011] The thickness of the water-blocking layer between the tile-shaped monofilament layer and the central circular monofilament is 0.1-0.3 mm.

[0012] Compared with the prior art, the beneficial effects of the present invention are:

[0013] The utility model discloses a longitudinally water-blocking and water-tree-resistant medium-voltage cable insulated core. In the conductor structure design, in addition to the central monofilament, tile-shaped monofilaments are used instead of round monofilaments. By twisting, the monofilaments are embedded in each other and compressed to a certain extent, eliminating the gaps between the monofilaments. The conductor compression coefficient is increased from the original 0.9 to over 0.95. During the conductor twisting process, each layer is coated with waterproof paste and longitudinally wrapped with semi-conductive water-resistant tape, which can completely prevent water vapor from penetrating inward along the conductor gaps, further improving the conductor's water-blocking performance. It can fully meet the water permeability test in the standard. The conductor is wrapped with a layer of semi-conductive water-resistant tape and then three layers are co-extruded, dry-crosslinked, and extruded to form a water-tree-resistant conductor shield, insulation, and insulation shielding material. This can effectively extend the formation time of insulating water trees and improve the insulation performance and service life of the cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the overall structure of the utility model;

[0015] Figure 2 For this utility model Figure 1 Enlarged structural diagram at point A in the middle.

[0016] Figure numerals: 1, conductor; 11, central circular monofilament; 12, tile-shaped monofilament layer; 13, water-blocking layer; 131, water-blocking paste layer; 132, semiconductor water-blocking tape layer; 2, co-extruded insulating layer; 21, anti-water-tree conductor shielding layer; 22, anti-water-tree insulating layer; 23, anti-water-tree insulating shielding layer. DETAILED DESCRIPTION

[0017] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.

[0018] In the description of this utility model, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," "the other end," and the like, indicating directions or positions, are based on the directions or positions shown in the accompanying drawings and are intended solely to facilitate the description of this utility model and simplify the description. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0019] In the description of this utility model, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "provided with," "connected," etc. should be understood in a broad sense. For example, "connected" can mean a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be internal communication between two components. Those skilled in the art will be able to understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] like Figure 1 and Figure 2 As shown, the longitudinal water-blocking and water-resistant tree-type medium-voltage cable core of this embodiment comprises, from the inside out, a conductor 1, a co-extruded insulation layer 2, a multi-layer tile-shaped monofilament layer 12, and a water-blocking layer 13 interlaced therewith. The water-blocking layer 13 comprises a water-blocking paste layer 131 and a semi-conductive water-resistant tape layer 132.

[0022] Conductor 1 comprises a central circular monofilament 11 and a tile-shaped monofilament layer 12 composed of several tile-shaped monofilaments arranged around the central circular monofilament 11. A water-blocking layer 13 is disposed between the central circular monofilament 11 and the tile-shaped monofilament layer 12. The conductor comprises a single circular monofilament at the center of the conductor, serving as the central circular monofilament 11. Multiple tile-shaped monofilaments are arranged in layers, one above the other, and then twisted and compacted in layers to form a circular, compacted conductor. The tile-shaped monofilaments are interwoven, and each layer is further compacted in layers, minimizing gaps between the individual filaments. This results in a conductor compaction coefficient greater than 0.95. By reducing the twist-in pitch-to-diameter ratio, the conductor's bending properties are fully guaranteed. During the twisting process, each layer of conductor is evenly coated with a waterproof paste and longitudinally wrapped with a semi-conductive waterproof tape, effectively preventing moisture from penetrating through the gaps between the individual filaments, forming a water-blocking conductor. The water-blocking layer 13 between the tile-shaped monofilament layer 12 and the central circular monofilament 11 has a thickness of 0.1-0.3 mm.

[0023] The co-extruded insulation layer 2 includes a water-tree-resistant conductor shielding layer 21, a water-tree-resistant insulation layer 22, and a water-tree-resistant insulation shielding layer 23. The co-extruded insulation layer 2 is formed by co-extruding and dry-crosslinking three layers of water-tree-resistant semiconductive conductor shielding material, water-tree-resistant insulation material, and water-tree-resistant semiconductive insulation shielding material. This effectively prolongs the formation of water trees in the insulation, reduces water tree aging, and improves the insulation performance and service life of the cable.

[0024] The above is only an embodiment of the present invention, and common knowledge such as the specific structure and characteristics of the scheme are not described in detail here. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is limited by the appended claims rather than the above description, and it is intended that all changes that fall within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claim involved.

Claims

1. A longitudinal water-blocking and water-tree-resistant medium-voltage cable insulated core, comprising, from the inside out, a conductor (1) and a co-extruded insulation layer (2), characterized in that: The conductor (1) comprises a central circular monofilament (11) and a tile-shaped monofilament layer (12) composed of a plurality of tile-shaped monofilaments arranged around the central circular monofilament (11), and a water-blocking layer (13) is provided between the central circular monofilament (11) and the tile-shaped monofilament layer (12).

2. The longitudinal water-blocking and water-tree-resistant medium-voltage cable insulated core according to claim 1, characterized in that: The multiple layers of tile-shaped monofilament layers (12) and water-blocking layers (13) are cross-distributed.

3. The longitudinal water-blocking and water-tree-resistant medium-voltage cable insulated core according to claim 1 or 2, characterized in that: The water-blocking layer (13) comprises a water-blocking paste layer (131) and a semi-conductive water-blocking tape layer (132).

4. The longitudinal water-blocking and water-tree-resistant medium-voltage cable insulated core according to claim 3, characterized in that: The co-extruded insulating layer (2) comprises an anti-water tree conductor shielding layer (21), an anti-water tree insulating layer (22) and an anti-water tree insulating shielding layer (23), and the co-extruded insulating layer (2) is formed by co-extruding and dry-crosslinking three layers of anti-water tree semi-conductive conductor shielding material, anti-water tree insulating material and anti-water tree semi-conductive insulating shielding material.

5. The longitudinal water-blocking and water-tree-resistant medium-voltage cable insulated core according to claim 3, characterized in that: The thickness of the water-blocking layer (13) between the tile-shaped monofilament layer (12) and the central circular monofilament (11) is 0.1-0.3 mm.

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