WO2022048012A1 - Lightweight corrosion-resistant energy-saving aluminium conductor, preparation method therefor, and medium-voltage power cable - Google Patents

Abstract

A lightweight corrosion-resistant energy-saving aluminum conductor, a preparation method therefor, and a medium-voltage power cable. The preparation method for the lightweight corrosion-resistant energy-saving aluminum conductor comprises the following steps: S1, weighing raw materials according to the following mass percentages of components: 100 parts of Al, 0.03 to 0.04 parts of Si, 0.09 to 0.10 parts of Fe, 0.08 to 0.13 parts of Cu, 0.005 to 0.007 parts of Zn, 0.0008 to 0.001 parts of La, 0.015 to 0.03 parts of Be, 0.001 to 0.002 parts of Ti, 0.007 to 0.008 parts of V, 0.01 to 0.02 parts of Zr, 0.003 to 0.005 parts of Mn, and 0.001 to 0.002 parts of Mg; S2, adding all the raw materials into a melting furnace for melting, and performing stirring to make molten aluminum uniform; S3, casting the molten aluminum obtained in step S2 to obtain an aluminium ingot; and S4, performing induction-heating on the aluminium ingot, and performing rolling when the temperature reaches 520℃ to 540℃, so as to obtain the lightweight corrosion-resistant energy-saving aluminum conductor. The lightweight corrosion-resistant energy-saving aluminum conductor has conductivity of 62.5% IACS to 63.0% IACS, and improves the creep resistance of the aluminum conductor.

Description

Lightweight, corrosion-resistant, energy-saving aluminum conductor, preparation method thereof, and medium-voltage power cable

This application claims the priority of the patent application with the application number 202010910355.X filed with the State Intellectual Property Office of China on September 2, 2020.

technical field

The invention relates to the technical field of aluminum alloy materials, in particular to a lightweight, corrosion-resistant, energy-saving aluminum conductor, a preparation method thereof, and a medium-voltage power cable.

Background technique

Power cables are wire products used to transmit and distribute electrical energy in power systems. Cables are widely used in various power plants and underground transmission and distribution lines. At present, power transmission and distribution lines mainly use copper conductor power cables. Due to the large proportion of copper materials, due to the influence of transportation and installation restrictions, the length of the cable section is short, and there are many intermediate connections, which increases the hidden danger of operation safety. Especially in wind farms, photovoltaic power stations and other power generation sites, due to the large temperature difference between day and night and heavy humidity, copper core cables are prone to oxidation and corrosion, causing potential safety hazards. Coupled with the steady rise of copper prices in recent years, the economic cost of using copper core cables from project investment to operation and maintenance is increasing.

At present, the conductivity of conventional aluminum conductors in China is 61% IACS (28.264Ω·mm ² /km), and the content of iron and silicon in the aluminum rod is as high as 0.45%. Under the same resistance requirements, the cross-sectional area needs to be larger. At the same time, due to the poor creep resistance of ordinary aluminum conductor cables, there will be cable connection problems, affecting the stability of the power system and shortening the service life. According to statistics, the line faults caused by cable intermediate joints and terminal installation problems account for 7.6% of cable line faults, which is also the biggest obstacle restricting the application of aluminum cables. Although the 8000 series aluminum alloy conductor has solved the creep resistance, due to the addition of the annealing process, its price is nearly 15% higher than that of the ordinary aluminum conductor, and the cost is higher.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a lightweight and corrosion-resistant energy-saving aluminum conductor.

In order to solve the above technical problems, the present invention provides a method for preparing a lightweight, corrosion-resistant, energy-saving aluminum conductor, comprising the following steps:

S1, according to the mass percentage of the following ingredients to prepare the ingredients: Al 100 parts, Si 0.03-0.04 parts, Fe 0.09-0.10 parts, Cu 0.08-0.13 parts, Zn 0.005-0.007 parts, La 0.0008-0.001 parts, Be 0.015- parts 0.03 part, Ti 0.001～0.002 part, V 0.007～0.008 part, Zr 0.01～0.02 part, Mn 0.003～0.005 part, Mg 0.001～0.002 part;

S2. Add each raw material into the melting furnace to melt, and stir to make the aluminum liquid uniform;

S3, the molten aluminum obtained in the casting step S2, obtains an aluminum ingot;

S4. Induction heating is performed on the aluminum ingot, and when the temperature rises to 520-540° C., rolling is performed to obtain the lightweight, corrosion-resistant, energy-saving aluminum conductor.

Further, in step S1, Al99.70 aluminum ingot, AlSi ₁₂ , AlFe ₂₀ , AlCu ₅₀ , AlZn ₁₀ , AlRe ₁₀ , AlBe ₁₀ , AlZr ₁₀ , and AlMg ₁₀ are selected as raw materials for batching.

Further, in step S2, the molten aluminum liquid is kept at 750-780° C. for heat preservation, fully stirred until uniform, the stirring time is ≥30 min, and the molten aluminum is kept at rest to obtain aluminum melt.

Further, in step S3, the casting temperature is 690-700°C.

The present invention also provides a lightweight, corrosion-resistant, energy-saving aluminum conductor prepared by the method.

Further, the resistivity of the aluminum conductor is 27.367-27.577 Ω·mm ² /km.

The present invention also provides a medium-voltage power cable, which includes the light-weight, corrosion-resistant, energy-saving aluminum conductor.

Further, the medium voltage power cable includes an aluminum conductor, a semiconducting conductor shielding layer, a cross-linked polyethylene insulating layer, a semiconducting insulating shielding layer, a metal shielding layer, a filling layer, a tape layer, an isolation sleeve, an armoring layer and It consists of an outer sheath layer; the aluminum conductor is formed by twisting aluminum monofilaments, and the semiconducting conductor shielding layer, the cross-linked polyethylene insulating layer, the semiconducting insulating shielding layer, and the metal shielding layer are sequentially coated from the inside to the outside. On the outer side of the aluminum conductor, a cable core is formed; the tape layer, the isolation sheath, the armor layer and the outer sheath layer are sequentially wrapped on the outer side of the cable core from the inside to the outside, and the filling layer is filled in the outer side of the cable core. The gap between the cable core and the tape layer.

Further, when the aluminum monofilament is twisted into an aluminum conductor, the stranding direction of the outermost aluminum monofilament of the aluminum conductor is the left direction, and the stranding direction of the adjacent aluminum monofilament is opposite. Pitch diameter ratio.

Further, the semiconducting conductor shielding layer, the cross-linked polyethylene insulating layer and the semiconducting insulating shielding layer are extruded on the aluminum conductor through a three-layer co-extrusion process, and a step is used in the process of installing the extrusion die. Shaft-shaped centering pin to control the eccentricity of the insulating screen within 6%.

Beneficial effects of the present invention:

1. The present invention improves the electrical conductivity of the aluminum conductor by controlling the content of iron and silicon in the aluminum conductor to be below 0.30%; by adding the Be element, it is beneficial to improve the strength of the aluminum alloy; The creep resistance of aluminum conductors is 300% higher than that of pure aluminum cables. The metal structure of the high-conductivity aluminum rod of the present invention is obviously improved, the tensile strength and elongation are greatly improved after production tests and subsequent wire drawing, and the electrical conductivity is increased to between 62.5% IACS and 63.0% IACS.

2. In the medium-voltage power cable of the present invention, by using the light-weight, corrosion-resistant, energy-saving aluminum conductor, the electrical conductivity of the conductor is higher, and the cross-sectional area of the aluminum conductor is reduced by about 3% under the condition that the standard resistance is met. ; At the same time, the creep resistance of the conductor is also improved, so that the safety of the conductor connection can be improved.

3. The present invention reduces the eccentricity of the insulation and reduces the thickness of the insulation by at least 0.3mm through the use of the centering pin of the insulating three-layer co-extrusion die core, thereby reducing the outer diameter of the insulating wire core, which not only saves materials, but also saves At the same time, the reduction of the outer diameter can reduce the bending radius, save space, and leave more valuable space for customer terminal link equipment.

Description of drawings

1 is a schematic cross-sectional structure diagram of a medium-voltage power cable according to an embodiment of the present invention;

Fig. 2 is the structural representation of centering pin;

Fig. 3 is the preparation process flow chart of the medium voltage power cable of the present invention;

Description of the symbols in the figure: 1, aluminum conductor; 2, semiconducting conductor shielding layer; 3, cross-linked polyethylene insulating layer; 4, semiconducting insulating shielding layer; 5, copper tape shielding layer; 6, PP filling layer; 7, Wrapping tape; 8. Isolation sleeve; 9. Metal armor layer; 10. Outer sheath.

detailed description

The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terms used herein in the description of the present invention are for the purpose of describing specific embodiments only, and are not intended to limit the present invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

As described in the background art, the current domestic conventional aluminum conductor has a conductivity of 61% IACS (28.264Ω·mm ² /km), and the iron and silicon content in the aluminum rod is as high as 0.45%. Under the same resistance requirements, the cross-sectional area needs to be larger. At the same time, due to the poor creep resistance of ordinary aluminum conductor cables, there will be cable connection problems, affecting the stability of the power system and shortening the service life. Although the 8000 series aluminum alloy conductor has solved the creep resistance, due to the addition of the annealing process, its price is nearly 15% higher than that of the ordinary aluminum conductor, and the cost is higher.

In order to solve this technical problem, the present invention provides a method for preparing a lightweight, corrosion-resistant, energy-saving aluminum conductor, comprising the following steps:

S1. According to the mass percentage of the following components, the raw materials are batched: 100 parts of Al, 0.03 to 0.04 parts of Si, 0.09 to 0.10 parts of Fe, 0.08 to 0.13 parts of Cu, 0.005 to 0.007 parts of Zn, 0.0008 to 0.001 parts of La, and 0.015 parts of Be. 0.03 part, Ti 0.001～0.002 part, V 0.007～0.008 part, Zr 0.01～0.02 part, Mn 0.003～0.005 part, Mg 0.001～0.002 part;

S2. Add each raw material into the melting furnace to melt, and stir to make the aluminum liquid uniform;

S3, the molten aluminum obtained in the casting step S2, obtains an aluminum ingot;

S4. Induction heating is performed on the aluminum ingot, and when the temperature rises to 520-540° C., rolling is performed to obtain the lightweight, corrosion-resistant, energy-saving aluminum conductor.

In step S1 of the present invention, Al99.70 aluminum ingot, AlSi ₁₂ , AlFe ₂₀ , AlCu ₅₀ , AlZn ₁₀ , AlRe ₁₀ , AlBe ₁₀ , AlZr ₁₀ , and AlMg ₁₀ are preferably selected as raw materials for batching. Among them, the chemical composition of Al99.70 aluminum ingot is shown in Table 1.

Table 1 Chemical composition of Al99.70 remelted aluminum ingot

In step S2 of the present invention, the molten aluminum is kept at 750-780° C. for heat preservation, fully stirred until uniform, and the stirring time is ≥ 30 minutes, and the molten aluminum is kept at rest to obtain an aluminum melt.

In step S3 of the present invention, the casting temperature is preferably 690-700°C.

The measured values of the components of the aluminum conductor prepared by the present invention are shown in Table 2.

Table 2 Measured value of aluminum conductor composition

The metal structure of the aluminum conductor prepared by the invention is obviously improved, and the tensile strength and elongation rate are greatly improved after production tests and subsequent wire drawing. The resistivity range of 27.367～27.577Ω·mm ² /km.

Referring to FIG. 1, the present invention also provides a medium-voltage power cable, including an aluminum conductor, a semiconducting shielding layer, a cross-linked polyethylene insulating layer, a semiconducting insulating shielding layer, a metal shielding layer, a filling layer, and a tape layer , isolation sheath, armor layer and outer sheath layer; the aluminum conductor is formed by twisting aluminum monofilaments, the semiconducting conductor shielding layer, the cross-linked polyethylene insulating layer, the semiconducting insulating shielding layer, the metal The shielding layer is sequentially wrapped on the outside of the aluminum conductor from the inside to the outside to form a cable core; the wrapping layer, the isolation sleeve, the armor layer and the outer sheath layer are sequentially wrapped on the outside of the cable core from the inside to the outside. , the filling layer fills the gap between the cable core and the tape layer. The preparation process of the medium voltage power cable is shown in FIG. 3 .

In the present invention, when the monofilament is twisted into a conductor, the stranding direction of the outermost monofilament of the conductor is the left direction, and the monofilament stranding direction of the adjacent layer is opposite, and the outermost layer adopts 12 times the small pitch ratio when stranding, Such a structure can ensure the flexibility of the conductor, so that the cable has a smaller bending radius when in use, saving space.

In the present invention, the semiconducting shielding layer preferably adopts 35kV semiconducting inner screen material, the insulating layer preferably adopts 35kV XLPE insulating material, and the semiconducting insulating shielding layer preferably adopts 35kV peelable semiconducting outer screen material. All meet the requirements of the IEC 60502 standard.

In the present invention, the semiconducting conductor shielding layer, the cross-linked polyethylene insulating layer and the semiconducting insulating shielding layer are preferably extruded on the aluminum conductor through a three-layer co-extrusion process. Centering pins are centered to reduce insulation eccentricity. According to different specifications and different voltage levels, each set of cores is equipped with centering pins. The centering pins are stepped cylindrical bodies with different diameters at both ends (see Figure 2). The small diameter end is the same as the diameter of the core, and the large diameter The end is the same as that of the second mold core, which can ensure that the first and second mold cores are coaxial, so as to achieve the purpose of controlling the eccentricity of the insulation. Among them, the definition of insulation eccentricity is as follows:

Insulation eccentricity = (the thickest point of the insulation - the thinnest point of the insulation) / the thickest point * 100%

By using the centering pin, the eccentricity of the insulation can be controlled within 6%, so that the thickness of the insulation can be reduced by at least 0.3mm, thereby reducing the outer diameter of the insulated core, and the overall diameter of the cable will also be reduced, saving materials, making the The cost of the cable is reduced, which saves the cost for the customer; the reduction of the outer diameter of the cable can also reduce the bending radius, save space, and leave more valuable space for the customer's terminal link equipment.

In the present invention, the metal shielding layer is preferably annealed copper tape, and the filling layer is preferably a PP filling structure to fill the gap between the cores; after the cores are cabled, the wrapping tape is used for winding and tightening; the isolation sleeve can be PVC or Halogen-free and low-smoke sheathing material plays a role in mechanical protection of the inner core, and at the same time isolates copper tape shielding and steel tape armor to prevent electrochemical corrosion; the armor can be made of galvanized steel tape or galvanized steel wire. Protect the inner core from external extrusion; the outer sheath can be made of PVC or halogen-free low-smoke sheath material. The properties of the above raw materials are in line with the requirements of the IEC 60502 standard.

In summary, the medium-voltage power cable of the present invention has a conductivity of 62.5% IACS to 63.0% IACS, the creep performance is also improved, and the safety of the conductor connection is improved; at the same time, the use of the centering pin reduces the The outer diameter of the insulated wire core not only saves materials and costs, but also reduces the footprint of the cable.

The above-mentioned embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or transformations made by those skilled in the art on the basis of the present invention are all within the protection scope of the present invention. The protection scope of the present invention is subject to the claims.

Claims (10)

1. A method for preparing a lightweight, corrosion-resistant, energy-saving aluminum conductor, characterized by comprising the following steps:

   S1, according to the mass percentage of the following ingredients to prepare the ingredients: Al 100 parts, Si 0.03-0.04 parts, Fe 0.09-0.10 parts, Cu 0.08-0.13 parts, Zn 0.005-0.007 parts, La 0.0008-0.001 parts, Be 0.015- parts 0.03 part, Ti 0.001～0.002 part, V 0.007～0.008 part, Zr 0.01～0.02 part, Mn 0.003～0.005 part, Mg 0.001～0.002 part;

   S2. Add each raw material into the melting furnace to melt, and stir to make the aluminum liquid uniform;

   S3, the molten aluminum obtained in the casting step S2, obtains an aluminum ingot;

   S4. Induction heating is performed on the aluminum ingot, and when the temperature rises to 520-540° C., rolling is performed to obtain the lightweight, corrosion-resistant, energy-saving aluminum conductor.
2. The method for preparing a lightweight, corrosion-resistant, energy-saving aluminum conductor according to claim 1, wherein in step S1, Al99.70 aluminum ingot, AlSi ₁₂ , AlFe ₂₀ , AlCu ₅₀ , AlZn ₁₀ , AlRe ₁₀ , and AlBe are selected. ₁₀ , AlZr ₁₀ and AlMg ₁₀ are used as raw materials for batching.
3. The method for preparing a lightweight, corrosion-resistant, energy-saving aluminum conductor according to claim 1, characterized in that, in step S2, the molten aluminum is kept at 750-780°C for heat preservation, and fully stirred until uniform, and the stirring time is ≥30min , stand for heat preservation, and obtain aluminum melt.
4. The method for preparing a lightweight, corrosion-resistant, energy-saving aluminum conductor according to claim 1, characterized in that, in step S3, the casting temperature is 690-700°C.
5. The lightweight, corrosion-resistant, energy-saving aluminum conductor prepared by the method according to any one of claims 1-4.
6. The lightweight, corrosion-resistant, energy-saving aluminum conductor according to claim 5, wherein the aluminum conductor has a resistivity of 27.367 to 27.577 Ω·mm ² /km.
7. A medium-voltage power cable, characterized in that the medium-voltage power cable comprises the lightweight, corrosion-resistant, energy-saving aluminum conductor according to claim 5 or 6.
8. The medium-voltage power cable according to claim 7, wherein the medium-voltage power cable comprises an aluminum conductor, a semiconducting conductor shielding layer, a cross-linked polyethylene insulating layer, a semiconducting insulating shielding layer, a metal shielding layer, a filler layer, tape layer, isolation sheath, armor layer and outer sheath layer; the aluminum conductor is formed by twisting aluminum monofilaments, the semiconducting conductor shielding layer, the cross-linked polyethylene insulating layer, the semiconducting The insulating shielding layer and the metal shielding layer are sequentially wrapped on the outer side of the aluminum conductor from the inside to the outside to form a cable core; the wrapping layer, the isolation sleeve, the armor layer and the outer sheath layer are sequentially wrapped on the outside of the aluminum conductor from the inside to the outside. On the outside of the cable core, the filling layer fills the gap between the cable core and the tape layer.
9. The medium-voltage power cable according to claim 8, wherein when the aluminum monofilament is twisted into an aluminum conductor, the stranding direction of the outermost aluminum monofilament of the aluminum conductor is leftward, and the adjacent layers of the aluminum monofilament are twisted in the left direction. The direction of the wire is opposite, and the outermost layer adopts 12 times the pitch diameter ratio when the wire is twisted.
10. The medium-voltage power cable according to claim 8, wherein the semiconducting conductor shielding layer, the cross-linked polyethylene insulating layer and the semiconducting insulating shielding layer are extruded on the aluminum conductor by a three-layer co-extrusion process. , and use a stepped shaft-shaped centering pin to control the insulation eccentricity within 6% during the installation of the extrusion die.

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