An overhead insulated cable with a steel-cored aluminum stranded conductor and its manufacturing process

Abstract

The invention discloses a preparation process of a steel-cored aluminum stranded conductor overhead insulated cable, which comprises the following steps: stranding aluminum single wires outside a magnetic strengthening element to form a conductor core, with the magnetic strengthening element arranged intermittently; extruding a non-metallic semi-conductive layer and an insulating layer on the surface of the conductor core; using a strong magnet to find out the magnetic strengthening elements at intervals and marking on the insulating layer, and dividing the anchor section from the marked position. The invention also discloses a steel-cored aluminum stranded conductor overhead insulated cable, which comprises a conductor core, and a semi-conductive nylon tape, a non-metallic semi-conductive layer and an insulating layer are sequentially arranged outside the conductor core; the overhead insulated cable prepared by the invention enables multi-anchor-section and large-length continuous production to be possible, and reduces the number of steel core joints in large-length production; the intervals of the magnetic strengthening elements can solve the problems that in a cross-linked pipeline, due to different linear expansion coefficients of steel and aluminum at high temperature, incremental changes cause the aluminum layer to bulge and form lantern flowers.

Description

Technical Field

[0001] The present invention relates to the technical field of insulated wires, and particularly to a steel core aluminum stranded conductor overhead insulated cable and a preparation process thereof. Background Art

[0002] For a steel core aluminum stranded conductor overhead insulated cable, due to this structure, it has both the mechanical properties of an overhead conductor and good electrical insulation properties, and there is a large demand in the construction and transformation of line distribution networks. During the compacting process of a combined conductor of two different metal materials, it is easy to become loose. After standing for a period of time, the outer diameter of the conductor will significantly increase. When implementing the subsequent cross-linking process under high temperature and high pressure, the conductor is likely to bulge into a "lantern flower", forcing the production to stop. It can neither meet the requirement of a fixed-length anchor section nor cause production waste. For continuous large-length production, the steel core anchor section needs to be crimped multiple times. Due to the crimping of different materials, it is also easy to cause the conductor to bulge into a "lantern flower" and also easily cause waste. Summary of the Invention

[0003] The purpose of the present invention is to provide a steel core aluminum stranded conductor overhead insulated cable and a preparation process thereof in view of the above-mentioned deficiencies of the prior art.

[0004] To solve the above problems, the technical solutions adopted by the present invention are as follows:

[0005] A preparation process of a steel core aluminum stranded conductor overhead insulated cable includes the following steps:

[0006] Step 1) Stranding aluminum single wires outside a magnetic strengthening element to form a conductor core. When stranding the aluminum single wires, the magnetic strengthening elements are arranged intermittently;

[0007] Step 2) Extruding a non-metallic semi-conductive layer on the surface of the conductor core;

[0008] Step 3) Extruding an insulating layer outside the non-metallic semi-conductive layer;

[0009] Step 4) Using a strong magnet to find out the magnetic strengthening elements at intervals and marking on the insulating layer, and dividing the anchor section from the marked position.

[0010] Further, in the step 1), a non-metallic water-blocking tape is tightly wound in the same direction on the outer surface of the magnetic strengthening element.

[0011] Further, in the step 1), a semi-conductive nylon tape is wound in the opposite direction on the outer surface of the conductor core.

[0012] Further, in the step 1), the distance between two adjacent magnetic strengthening elements is 50 - 200 mm.

[0013] A steel-cored aluminum stranded conductor overhead insulated cable prepared by the above-described preparation method, comprising a conductor core containing magnetic strengthening elements, an extruded non-metallic semi-conductive layer outside the conductor core, and an extruded insulating layer outside the non-metallic semi-conductive layer.

[0014] Further, the conductor core is formed by stranding magnetic strengthening elements and aluminum single wires, the magnetic strengthening elements are located at the center of the conductor core, and the aluminum single wires are stranded outside the magnetic strengthening elements.

[0015] Further, the magnetic strengthening elements are stranded by multiple aluminum-clad steel wires or galvanized steel wires containing magnetism.

[0016] Further, the magnetic strengthening elements are wrapped with a non-metallic water-blocking tape.

[0017] Further, the conductor core is wrapped with a semi-conductive nylon tape.

[0018] Further, 1-3 layers of aluminum single wires are stranded outside the magnetic strengthening elements.

[0019] The beneficial effects produced by adopting the above technical solutions are as follows:

[0020] In the present invention, the magnetic strengthening elements are arranged at intervals, making it possible for multi-anchor-section and large-length continuous production, reducing the number of steel core joints in large-length production. The intervals of the magnetic strengthening elements can solve the problem of the formation of bulges and lantern flowers in the aluminum layer caused by the incremental changes due to different linear expansion coefficients of steel and aluminum at high temperatures in the cross-linked pipeline.

[0021] In the present invention, multiple strands of unequal magnetic steel wires are used to form magnetic strengthening elements, increasing the strength and facilitating the winding of the water-blocking tape. The water-blocking tape can not only prevent moisture (vapor) from migrating and penetrating along the conductor gap to the insulating layer, but also be used to absorb and eliminate the axial stress changes caused by different linear expansion coefficients of the strengthening elements and aluminum single wires during the high-temperature processing and forming of the insulation, reducing the problems of conductor bulges and lantern flowers; the semi-conductive nylon tape is reversely wound on the surface of the aluminum single wires, making all the aluminum single wires closer, which can reduce the problems of conductor bulges and lantern flowers, and at the same time avoid the non-metallic semi-conductive layer and insulating layer extruded during the cross-linking process from embedding into the conductor core.

[0022] In the present invention, a conductor core with magnetic strengthening elements is selected. By the different sensitivities of the steel core and the aluminum layer to magnetic properties and using the magnetic attraction principle, the segmentation points of the anchor section can be accurately found, and the problem of difficult finding of the segmentation points caused by the metering error can be solved. Description of the Drawings

[0023] Figure 1 It is a schematic cross-sectional view of the cable in Embodiment 1 of the present invention;

[0024] Figure 2 It is a schematic cross-sectional view of the cable in Embodiment 2 of the present invention;

[0025] Figure 3 It is a schematic cross-sectional view of the cable in Embodiment 3 of the present invention;

[0026] Figure 4 It is a schematic cross-sectional view of the cable in Embodiment 4 of the present invention;

[0027] Figure 5 It is a schematic longitudinal cross-sectional view of the cable strengthening element in Embodiment 4 of the present invention.

[0028] In the figure: 1, magnetic strengthening element; 2, aluminum single wire; 3, non-metallic water-blocking tape; 4, non-metallic semi-conductive layer; 5, insulating layer; 6, semi-conductive nylon tape. Specific embodiments

[0029] The following further describes the embodiments of the present invention in detail in conjunction with the drawings and embodiments. The following embodiments are used to illustrate the present invention, but cannot be used to limit the scope of the present invention.

[0030] As Figures 1-5 shown, it is a schematic structural view of the steel-core aluminum stranded conductor overhead insulated cable in the present invention;

[0031] Embodiment 1

[0032] As Figure 1 shown, it is the first embodiment of a steel-core aluminum stranded conductor overhead insulated cable of the present invention. This embodiment includes a conductor core containing a magnetic strengthening element 1. The conductor core is formed by stranding a magnetic strengthening element 1 and three layers of aluminum single wires 2. The magnetic strengthening element 1 is located at the center of the conductor core, and the aluminum single wires 2 are stranded outside the magnetic strengthening element 1. The magnetic strengthening element 1 is formed by stranding 7 magnetic aluminum-clad steel wires or galvanized steel wires. An outer non-metallic semi-conductive layer 4 is extruded on the conductor core, and an insulating layer 5 is extruded outside the non-metallic semi-conductive layer 4.

[0033] Embodiment 2

[0034] As Figure 2 shown, it is the second embodiment of the present invention. The difference from the above Embodiment 1 is that a non-metallic water-blocking tape 3 is wrapped outside the magnetic strengthening element 1. The water-blocking tape can not only prevent moisture (vapor) from migrating and penetrating along the conductor gap to the insulating layer, but also be used to absorb and eliminate the axial stress change due to different linear expansion coefficients of the strengthening element and the aluminum single wire during the high-temperature processing and forming of the insulation, reducing problems such as bulging and lantern flower.

[0035] Embodiment 3

[0036] As Figure 3As shown in the figure, this is the third embodiment of the present invention. The difference from the above-mentioned Embodiment 1 is that a semiconductive nylon tape 6 is wrapped around the conductor core. The semiconductive nylon tape 6 makes all the aluminum single wires 2 more compact, which can reduce the problems of wire bulging and lantern flower, and at the same time avoid the extrusion of the extruded non-metallic semiconductive layer 4 and the insulating layer 5 into the conductor core during the cross-linking process.

[0037] Embodiment 4

[0038] As Figures 4-5 shown in the figure, this is the fourth embodiment of the present invention. The difference from the above-mentioned Embodiment 1 is that a non-metallic water-blocking tape 3 is wrapped around the magnetic strengthening element 1, and a semiconductive nylon tape 6 is wrapped around the conductor core; the water-blocking tape can not only prevent moisture (vapor) from migrating and penetrating along the conductor gap to the insulating layer, but also be used to absorb and eliminate the change of axial stress caused by different linear expansion coefficients of the strengthening element and the aluminum single wire during the high-temperature processing and forming of the insulation, reducing the problems of wire bulging and lantern flower; wrapping the semiconductive nylon tape reversely on the surface of the conductor core makes all the aluminum single wires more compact, which can reduce the problems of wire bulging and lantern flower, and at the same time avoid the extrusion of the extruded non-metallic semiconductive layer and the insulating layer into the conductor core during the cross-linking process.

[0039] For the above-mentioned Embodiment 4, a preparation process of a steel-cored aluminum stranded conductor overhead insulated cable includes the following steps:

[0040] Step 1) Stranding multiple magnetic aluminum-clad steel wires or galvanized steel wires to form a magnetic strengthening element 1;

[0041] Step 2) Tightly wrapping a non-metallic water-blocking tape 3 around the outer surface of the magnetic strengthening element 1 in the same direction;

[0042] Step 3) Stranding aluminum single wires 2 outside the magnetic strengthening element 1 to form a conductor core. When the aluminum single wires 2 are stranded, the magnetic strengthening elements 1 are arranged intermittently, and the distance between two adjacent magnetic strengthening elements 1 is 50 - 200 mm;

[0043] Step 4) Wrapping a semiconductive nylon tape 6 reversely around the outer surface of the conductor core;

[0044] Step 5) Extruding a non-metallic semiconductive layer 4 on the surface of the semiconductive nylon tape 6;

[0045] Step 6) Extruding a cross-linked polyethylene insulating layer 5 outside the non-metallic semiconductive layer 4;

[0046] Step 7) Using a strong magnet to find out the intervals of the magnetic strengthening elements 1 and marking on the insulating layer 5, and dividing the anchor section from the marked position.

[0047] Further, the thickness of the non-metallic water-blocking tape is 0.3 - 0.6 mm, and the expansion rate is 10 - 16 mm / min; the thickness of the semi-conductive nylon tape is 0.12 - 0.15 mm, and the longitudinal tensile strength is not less than 120 N / cm; the thickness of the non-metallic semi-conductive layer is 0.8 - 1.0 mm; the nominal thickness of the insulating layer is 2.5 mm (without the non-metallic semi-conductive layer) or 3.4 mm (with the non-metallic semi-conductive layer).

[0048] Further, according to production requirements, the magnetic strengthening element 1 is preferably composed of 3 - 7 magnetic aluminum-clad steel wires or galvanized steel wires stranded together.

[0049] Further, according to the size, weight, and application site requirements of the wire, 1 layer, 2 layers, 3 layers, or more layers of aluminum single wires 2 are stranded outside the magnetic strengthening element 1.

[0050] Further, the non-metallic water-blocking tape 3 can be a conductive water-blocking tape or a non-conductive water-blocking tape.

[0051] In the preparation process of the overhead insulated cable in other embodiments, the process steps are correspondingly deleted according to different cable layer structures.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A preparation process for an overhead insulated cable with a steel-core aluminum stranded conductor, characterized in that, It includes the following steps: Step 1) Stranding aluminum single wires (2) outside the magnetic strengthening element (1) to form a conductor core. When the aluminum single wires (2) are stranded, the magnetic strengthening element (1) is arranged discontinuously. Step 2) Extruding a non-metallic semi-conductive layer (4) on the surface of the conductor core. Step 3) Extruding an insulating layer (5) outside the non-metallic semi-conductive layer (4). Step 4) Using a strong magnet to find out the magnetic strengthening elements (1) at intervals and marking on the insulating layer (5), and dividing the anchor section from the marked place.

2. The manufacturing process of a steel-cored aluminum stranded conductor overhead insulated cable according to claim 1, characterized in that, In the said Step 1), a non-metallic water-blocking tape (3) is closely wound in the same direction on the outer surface of the magnetic strengthening element (1).

3. The preparation process of an overhead insulated cable with a steel-cored aluminum stranded conductor according to claim 1 or 2, characterized in that, In the said Step 1), a semi-conductive nylon tape (6) is wound in the reverse direction on the outer surface of the conductor core.

4. The manufacturing process of a steel core aluminum stranded conductor overhead insulated cable according to claim 1, characterized in that, In the said Step 1), the distance between two adjacent magnetic strengthening elements (1) is 50 - 200 mm.

5. A steel-cored aluminum stranded conductor overhead insulated cable, which is made by using the preparation process of a steel-cored aluminum stranded conductor overhead insulated cable according to any one of claims 1-4, and is characterized in that, It includes a conductor core containing a magnetic strengthening element (1), with a non-metallic semi-conductive layer (4) extruded outside the conductor core, and an insulating layer (5) extruded outside the non-metallic semi-conductive layer (4).

6. A steel-cored aluminum stranded conductor overhead insulated cable according to claim 5, characterized in that, The said conductor core is formed by stranding a magnetic strengthening element (1) and aluminum single wires (2). The magnetic strengthening element (1) is located at the center of the conductor core, and the aluminum single wires (2) are stranded outside the magnetic strengthening element (1).

7. An overhead insulated cable with a steel-cored aluminum stranded conductor according to claim 5, characterized in that, The said magnetic strengthening element (1) is formed by stranding multiple magnetic aluminum-clad steel wires or galvanized steel wires.

8. An overhead insulated cable with a steel-cored aluminum stranded conductor according to claim 5, characterized in that, The outside of the said magnetic strengthening element (1) is wound with a non-metallic water-blocking tape (3).

9. An overhead insulated cable with a steel-cored aluminum stranded conductor according to claim 5 or 8, characterized in that, The outside of the said conductor core is wound with a semi-conductive nylon tape (6).

10. An overhead insulated cable with a steel-core aluminum stranded conductor according to claim 4, characterized in that, 1 - 3 layers of aluminum single wires (2) are stranded outside the said magnetic strengthening element (1).

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