CN212322655U - Medium-voltage prefabricated branch power cable - Google Patents

Abstract

The utility model discloses a prefabricated branch power cable of middling pressure, including copper conductor, semi-conductor shielding layer, crosslinked polyethylene insulating layer, copper C clamp, electric field homogenization layer, water blocking layer and oversheath. The electric field homogenization layer is formed by winding a semi-conductive self-adhesive tape, and the water resistance layer is formed by winding a radiation cross-linked polyethylene film.

Description

Medium-voltage prefabricated branch power cable

Technical Field

The utility model relates to a power cable, in particular to prefabricated branch power cable of middling pressure belongs to electrical engineering technical field.

Background

With rapid development of science and technology and economy, ultra-high landmark buildings, cross-sea tunnels are continuously increased, high-power equipment is increased, low-voltage pre-branching power cables cannot meet the requirements of the low-voltage pre-branching power cables, and particularly in long-distance high-power transmission and distribution projects, transmission power can only be increased by adopting a mode of improving voltage grade to solve the problems of line loss and heating. The method has the advantages that the medium-voltage cable is reliably prefabricated and branched, the problems can be effectively solved, the space is saved, and the complexity and high cost of medium-voltage cable joint construction can be avoided. The difficulty of the existing prefabricated branch of the medium-voltage cable is that under high voltage, burrs and sharp corners at the joint of a conductor can generate higher electric field concentration and point discharge; and the medium voltage cable insulation material is a cross-linked polyethylene material, and is difficult to be tightly combined with other materials after cross-linking, so that the branch head can not be effectively sealed, water trees are easy to generate when water vapor enters, the service life of the cable is shortened, and the cable is even punctured.

SUMMERY OF THE UTILITY MODEL

The utility model provides a prefabricated branch power cable of middling pressure provides a prefabricated branch power cable of novel middling pressure through the selection of material, structure and technology, solves conductor burr and closed angle problem, avoids appearing electric field concentration and closed angle discharge phenomenon, solves the waterproof problem between branch's first sheath and insulation core simultaneously, makes the cable have good compressive property and stability, the effectual problem of having solved existence among the prior art.

In order to solve the technical problem, the utility model provides a following technical scheme:

the utility model relates to a prefabricated branch power cable of middling pressure, including copper conductor, semi-conductive conductor shielding layer, crosslinked polyethylene insulating layer, copper C clamp, electric field homogenization layer, water blocking layer and oversheath, copper conductor, semi-conductive conductor shielding layer, crosslinked polyethylene insulating layer, copper C clamp, electric field homogenization layer, water blocking layer and oversheath from interior to exterior set gradually.

As an optimized technical scheme of the utility model, the connector portion of the whole middling pressure prefabricated shaping branch cable of cable is Y shape, lays when the space of being convenient for is limited.

As an optimal technical scheme of the utility model, trunk cable and branch cable sticiss copper conductor sinle silk and adopt copper C clamp to compress tightly side by side.

As an optimal technical scheme of the utility model, the position of the exposed conductor of trunk cable and branch cable closely twines 4 layers of semi-conductive self-adhesive tape at least, and takes to cover at least 10mm on insulating to the most advanced and the burr of homogenization conductor eliminate inside electric field and concentrate and most advanced discharge.

As an optimized technical scheme of the utility model, be located the trunk cable of branch head of moulding plastics and branch cable insulation wrap 3 layers at least radiation crosslinking polyethylene thermal contraction membrane outward to it heats makes its inseparable bonding on the XLPE insulating layer.

As the utility model discloses an optimal technical scheme carries out polyethylene branch support cover injection moulding in arranging the injection mould around the branch connector after the package in, and high temperature melting state's polyethylene and radiation crosslinking polyethylene thermal contraction membrane closely adhere simultaneously, make branch head whole have waterproof performance.

The utility model discloses the beneficial effect who reaches is: the utility model discloses a material is chooseed for use, cable structure and suitable process design guarantee that the inside electric field of this cable is balanced, can not puncture because of the most advanced discharge of branch crimping conductor to possess bear higher voltage, divide branch in advance to lay advantages such as convenience, economic nature, temperature resistant level can reach 90 ℃.

Drawings

The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention, and together with the description serve to explain the invention and not to limit the invention. In the drawings:

fig. 1 is a schematic structural diagram of the present invention.

In the figure: 1. a copper conductor; 2. a semiconductive conductor shield layer; 3. a crosslinked polyethylene insulating layer; 4. c-shaped clips are made of copper; 5. an electric field homogenization layer; 6. a water resistant layer; 7. an outer sheath.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

Example (b): as shown in fig. 1, the utility model relates to a prefabricated branch power cable of middling pressure, including copper conductor 1, semiconduction conductor shielding layer 2, crosslinked polyethylene insulating layer 3, copper C clamp 4, electric field homogenization layer 5, water blocking layer 6 and oversheath 7, copper conductor 1, semiconduction conductor shielding layer 2, crosslinked polyethylene insulating layer 3, copper C clamp 4, electric field homogenization layer 5, water blocking layer 6 and oversheath 7 set gradually from inside to outside, electric field homogenization layer 5 is formed by the winding of semiconduction self-adhesive tape, water blocking layer 6 is formed by the winding of radiation crosslinked polyethylene heat shrink film.

The copper conductor 1 adopts a round compacted oxygen-free copper conductor 1, the outer diameter is relatively small, and the electrical property and the oxidation resistance are excellent.

The semi-conductive conductor shielding layer 2 and the crosslinked polyethylene insulating layer 3 are formed by co-extruding three layers of 35kV semi-conductive shielding material and 35kV crosslinked polyethylene insulating material, and then the insulating shielding layer is stripped to obtain an insulating wire core.

And at the position of the branch joint, removing the insulating layer and the conductor shielding layer of the insulating wire core, keeping the notch smooth and burr-free, and not damaging the conductor and the conductor shielding and insulating structure outside the notch.

When in compression joint, the copper C-shaped clamp 4 is positioned in the middle of the exposed conductor of the trunk cable, the branch line is in complete contact with the C-shaped clamp, and the compression joint is stable and tight.

The electric field homogenization layer 5 is composed of semi-conductive self-adhesive tapes, 4 layers of semi-conductive self-adhesive tapes are at least tightly wound at the exposed conductor parts of the main cable and the branch cable after crimping, and the main cable and the branch cable are covered on the insulation by at least 10mm so as to homogenize the tip and the burr of the conductor and eliminate the concentration of an internal electric field and the tip discharge.

The water-proof layer 6 is formed by winding and wrapping the radiation cross-linked polyethylene heat-shrinkable film, and the implementation method comprises the steps of wrapping at least 3 layers of radiation cross-linked polyethylene heat-shrinkable films outside the main cable and the branch cable insulation positioned in the injection molding branch head, and heating the radiation cross-linked polyethylene heat-shrinkable films to enable the radiation cross-linked polyethylene heat-shrinkable films to be tightly adhered to the XLPE insulation layer.

The branch connecting body wrapped with the water-resistant layer 6 is placed in an injection mould, medium-density injection moulding is adopted to form an outer sheath 7, meanwhile, polyethylene in a high-temperature molten state is tightly bonded with the radiation crosslinking polyethylene heat-shrinkable film, and the XLPE insulating layer, the radiation crosslinking polyethylene heat-shrinkable film water-resistant layer 6 and the outer sheath 7 in the branch head are tightly combined, so that the whole branch head has waterproof performance.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims (3)

1. The medium-voltage prefabricated branch power cable is characterized by comprising a copper conductor (1), a semi-conductive conductor shielding layer (2), a cross-linked polyethylene insulating layer (3), a copper C-shaped clamp (4), an electric field homogenization layer (5), a water blocking layer (6) and an outer sheath (7), wherein the copper conductor (1), the semi-conductive conductor shielding layer (2), the cross-linked polyethylene insulating layer (3), the copper C-shaped clamp (4), the electric field homogenization layer (5), the water blocking layer (6) and the outer sheath (7) are sequentially arranged from inside to outside.

2. A medium voltage prefabricated branch power cable according to claim 1, characterized in that said electric field homogenization layer (5) is wound from a semi-conductive self-adhesive tape.

3. A medium voltage prefabricated branch power cable according to claim 1, characterized in that said water-blocking layer (6) is wrapped with a radiation crosslinked polyethylene heat-shrinkable film.

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