A method for connecting conductors of high-voltage cable flexible joints and a high-voltage cable

Abstract

The present invention discloses a method for connecting conductors of a high-voltage cable flexible joint and a high-voltage cable. The conductors of the high-voltage cable flexible joint include an aluminum conductor for a submarine cable section and a copper conductor for a landing cable section. The connection between the aluminum conductor for the submarine cable section and the copper conductor for the landing cable section includes the following steps: Step S1, cutting the conductor connection end into a conical structure; Step S2, arranging micropores on the conical surface of the conductor; Step S3, filling the micropores with metal powder; Step S4, positioning the conductor; Step S5, heating and melting the connection end; Step S6, welding the conductor; and Step S7, shaping the welded section. After heating and welding, the present invention converts the aluminum conductor connection section from pure aluminum to an aluminum alloy containing copper, greatly improving the hardness of the connection section after welding and resolving the problem of low mechanical strength of the aluminum material after welding. The present invention also fills the micropores on the conical surface of the copper conductor connection end of the landing cable section with aluminum powder, and uses a copper-aluminum alloy as the welding material to form a copper-aluminum alloy transition section after welding, thereby improving the welding strength between the copper and aluminum.

Description

Technical Field

[0001] The present invention relates to the technical field of high-voltage cable connection, in particular to a method for connecting conductors of a high-voltage cable flexible joint and a high-voltage cable. Background Art

[0002] DC cables offer high transmission efficiency, low line losses, easy current regulation and power transmission direction change, independent interference between different grid frequencies, and relatively low costs for long-distance lines. They may be the only solution for long-distance submarine power transmission. However, due to limitations in production length and transportation conditions, the length of DC submarine cables may not fully meet the required line length. Therefore, appropriate submarine cable connections must be employed to meet the required line length.

[0003] Cables consist of a submarine section, located on the seabed, and a land-based section. Although copper conductors outperform aluminum conductors in both physical and electrical properties, aluminum is significantly cheaper than copper in the market, offering significant cost advantages and lighter weight. The lower ocean temperatures further enhance aluminum's conductivity, making aluminum more economical for the submarine section. However, the land-based section, where temperatures are relatively high, makes copper a better choice for electrical performance. Therefore, using aluminum conductors for submarine cables and copper conductors for land-based cables offers both a high cost-performance ratio and a certain degree of practicality. For this type of cable structure, when the submarine cable is connected to the landing cable, the aluminum conductor and the copper conductor need to be connected. For the welding between the copper conductor and the aluminum conductor, in order to ensure the welding strength between the copper conductor and the aluminum conductor, the announcement number CN115255706B discloses a patent document of a method for welding copper conductors and aluminum conductors for a high-voltage submarine power cable flexible joint. It first prefabricates an aluminum-copper transition joint, welds a solid aluminum column and a solid copper column to form an aluminum-copper transition joint, and then welds the aluminum conductor of the submarine cable in the submarine section to the aluminum column end of the aluminum-copper transition joint, and welds the copper conductor of the cable in the landing section to the copper column end of the aluminum-copper transition joint. The welding strength is improved by welding between the same materials.

[0004] The above-mentioned patent document has the following defects: First, after welding and annealing the aluminum conductor and the aluminum column end, the aluminum material at the connection becomes brittle and less flexible, with a material strength of only 70-80, significantly reducing the mechanical strength and making it easy to break at the aluminum conductor connection; Second, welding the solid aluminum column and the solid copper column to form an aluminum-copper transition joint is essentially welding between aluminum and copper, which has no effect on improving the welding strength and does not truly solve the problem of welding strength between aluminum and copper. Moreover, after adding the aluminum-copper transition joint, the number of welding times increases from one welding to three welding times without solving the problem. Therefore, the technical solution adopted in the above-mentioned patent document does not significantly improve the welding strength. Therefore, how to improve the mechanical strength of the aluminum material after welding and how to improve the welding strength between aluminum and copper remain technical problems that need to be solved urgently. Summary of the Invention

[0005] The object of the present invention is to provide a method for connecting conductors of a high-voltage cable flexible joint and a high-voltage cable, which can improve the mechanical strength of the connection.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A method for connecting high-voltage cable flexible joint conductors, wherein the high-voltage cable flexible joint conductors include an aluminum conductor for a submarine cable and a copper conductor for a landing cable. The connection of the aluminum conductor for the submarine cable and the copper conductor for the landing cable comprises the following steps:

[0008] Step S1, cutting the conductor connection ends into a conical structure: cutting the connection ends of the aluminum conductor of the submarine cable and the copper conductor of the landing cable into a conical structure;

[0009] Step S2, arranging micropores on the conical surface of the conductor: arranging micropores on the conical surface of the connecting end of the aluminum conductor of the submarine cable so that the micropores cover the entire conical surface of the conductor;

[0010] Step S3, filling metal powder in the micropores: filling copper powder in the micropores on the conical surface of the connecting end of the aluminum conductor of the submarine cable;

[0011] Step S4, conductor positioning: fixing the aluminum conductor of the submarine cable and the copper conductor of the landing cable so that the connecting end of the aluminum conductor of the submarine cable contacts the connecting end of the copper conductor of the landing cable, and forming an annular welding groove between the two connecting ends;

[0012] Step S5, heating and melting the connection end: using a flame spray gun to perform flame heating on the conical surface of the connection end of the aluminum conductor of the submarine cable;

[0013] Step S6, conductor welding: using welding equipment to perform welding at the annular welding groove until the welding material fills the entire annular welding groove to form a welding section;

[0014] Step S7, welding section shaping: shaping the welding section so that the welding section meets the roundness requirement and the diameter of the welding section is equal to the diameter of the aluminum conductor of the fixed submarine section cable and the copper conductor of the landing section cable.

[0015] Furthermore, in step S2, micropores are arranged on the conical surface of the connecting end of the copper conductor of the landing section cable, so that the micropores cover the entire conical surface of the conductor.

[0016] Furthermore, in step S3, aluminum powder is filled into the micropores on the conical surface of the connecting end of the copper conductor of the landing section cable.

[0017] Furthermore, in step S5, flame heating is performed on the conical surface of the connecting end of the copper conductor of the landing section cable using a flame spray gun.

[0018] Furthermore, in step S6, the welding material selected for welding is a copper-aluminum alloy material, so that the welding section forms a copper-aluminum transition connection section.

[0019] Furthermore, the copper-aluminum alloy material is formed by uniformly mixing 50% by weight of copper powder and 50% by weight of aluminum powder.

[0020] Furthermore, the temperature of the flame spray gun when performing flame heating on the conical surface of the connection end of the aluminum conductor of the submarine cable is controlled between 600-650°C.

[0021] Furthermore, the temperature of the flame spray gun when performing flame heating on the conical surface of the connecting end of the copper conductor of the landing section cable is controlled between 950-1000°C.

[0022] Furthermore, in step S6, the welding equipment used is arc welding equipment, and the welding temperature is controlled between 1100-1500°C.

[0023] A high-voltage cable comprises a cable flexible joint made by the method for connecting high-voltage cable flexible joint conductors of the present application.

[0024] The beneficial effects of the present invention are:

[0025] The present invention arranges holes on the conical surface of the connecting end of the aluminum conductor and fills the micropores with copper powder. After heating and welding, the connecting section of the aluminum conductor is changed from pure aluminum to an aluminum alloy containing copper, which greatly improves the hardness of the connecting section after welding and solves the problem of low mechanical strength of the aluminum material after welding.

[0026] The present invention also fills aluminum powder in the micropores on the conical surface of the connecting end of the copper conductor of the landing section cable, and uses copper-aluminum alloy material as welding material. After welding, a copper-aluminum alloy transition section is truly formed in the connecting section, thereby improving the welding strength between copper and aluminum. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a flow chart of a method for connecting conductors of a high-voltage cable flexible connector according to the present invention;

[0028] Figure 2 This is a schematic diagram of the structure of the conductor after welding of the present invention. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features therein can be combined with each other unless there is a conflict.

[0030] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper surface", "lower surface", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "forward", "reverse", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0031] Example 1:

[0032] like Figure 1 、 2 As shown, a method for connecting high-voltage cable flexible joint conductors, wherein the high-voltage cable flexible joint conductors include an aluminum conductor of a submarine cable and a copper conductor of a landing cable. The connection of the aluminum conductor of the submarine cable and the copper conductor of the landing cable includes the following steps:

[0033] Step S1, cutting the conductor connection ends into a conical structure: cutting the connection end 2 of the aluminum conductor 1 of the submarine cable and the connection end 4 of the copper conductor 3 of the landing cable into a conical structure.

[0034] Step S2, arranging micropores on the conical surface of the conductor: Arranging micropores 5 on the conical surface of the connecting end of the aluminum conductor of the submarine cable so that the micropores 5 cover the entire conical surface of the conductor; and arranging micropores 6 on the conical surface of the connecting end of the copper conductor of the landing cable so that the micropores 6 cover the entire conical surface of the conductor.

[0035] Step S3, filling metal powder in the micropores: filling copper powder in the micropores on the conical surface of the aluminum conductor connection end of the submarine cable; filling aluminum powder in the micropores on the conical surface of the copper conductor connection end of the landing cable.

[0036] Step S4, conductor positioning: fix the aluminum conductor of the submarine cable and the copper conductor of the landing cable so that the connecting end of the aluminum conductor of the submarine cable contacts the connecting end of the copper conductor of the landing cable, and form an annular welding groove between the two connecting ends.

[0037] Step S5, heating and melting the connection end: flame heating is performed on the conical surface of the connection end of the aluminum conductor of the submarine cable using a flame spray gun; the temperature of the flame spray gun when performing flame heating on the conical surface of the aluminum conductor connection end of the submarine cable is controlled between 600-650° C.; flame heating is performed on the conical surface of the connection end of the copper conductor of the landing cable using a flame spray gun; the temperature of the flame spray gun when performing flame heating on the conical surface of the copper conductor connection end of the landing cable is controlled between 950-1000° C.

[0038] Step S6, conductor welding: welding is performed at the annular welding groove using welding equipment until the welding material fills the entire annular welding groove to form a welding section 7; the welding material selected for welding is a copper-aluminum alloy material, so that the welding section 7 forms a copper-aluminum transition connection section. After the copper-aluminum transition connection section is formed, the micropores no longer exist. Figure 2 The micropores in the figure only indicate their specific distribution before welding. The copper-aluminum alloy material is formed by uniformly mixing 50% by weight of copper powder and 50% by weight of aluminum powder. In step S6, the welding equipment used is an arc welding device, and the welding temperature is controlled between 1100°C and 1500°C.

[0039] Step S7, welding section shaping: shaping the welding section so that the welding section meets the roundness requirement and the diameter of the welding section is equal to the diameter of the aluminum conductor of the fixed submarine section cable and the copper conductor of the landing section cable.

[0040] The technical solution of Example 1 solves two problems: first, by changing the connecting section of the aluminum conductor from pure aluminum to an aluminum-copper alloy, the problem of low mechanical strength of the aluminum material after welding is solved; second, by forming a copper-aluminum alloy transition section through welding, the problem of low welding strength between aluminum and copper is solved.

[0041] Example 2:

[0042] like Figure 1 As shown, a method for connecting high-voltage cable flexible joint conductors, wherein the high-voltage cable flexible joint conductors include an aluminum conductor of a submarine cable and a copper conductor of a landing cable. The connection of the aluminum conductor of the submarine cable and the copper conductor of the landing cable includes the following steps:

[0043] Step S1, cutting the conductor connection ends into a conical structure: cutting the connection ends of the aluminum conductor of the submarine cable and the connection ends of the copper conductor of the landing cable into a conical structure.

[0044] Step S2, arranging micropores on the conical surface of the conductor: arranging micropores on the conical surface of the connecting end of the aluminum conductor of the submarine cable so that the micropores cover the entire conical surface of the conductor.

[0045] Step S3, filling metal powder in micropores: filling copper powder in the micropores on the conical surface of the connecting end of the aluminum conductor of the submarine cable.

[0046] Step S4, conductor positioning: fix the aluminum conductor of the submarine cable and the copper conductor of the landing cable so that the connecting end of the aluminum conductor of the submarine cable contacts the connecting end of the copper conductor of the landing cable, and form an annular welding groove between the two connecting ends.

[0047] Step S5, heating and melting the connection end: using a flame spray gun to flame heat the conical surface of the connection end of the aluminum conductor of the submarine cable; the temperature of the flame spray gun when performing flame heating on the conical surface of the connection end of the aluminum conductor of the submarine cable is controlled between 600-650°C.

[0048] Step S6, conductor welding: welding is performed at the annular welding groove using welding equipment until the welding material fills the entire annular welding groove to form a welding section. The copper-aluminum alloy material is formed by uniformly mixing 50% by weight of copper powder and 50% by weight of aluminum powder.

[0049] Step S7, welding section shaping: shaping the welding section so that the welding section meets the roundness requirement and the diameter of the welding section is equal to the diameter of the aluminum conductor of the fixed submarine section cable and the copper conductor of the landing section cable.

[0050] The technical solution of Example 2 solves one problem: by changing the connecting section of the aluminum conductor from pure aluminum to an aluminum-copper alloy, the problem of low mechanical strength of the aluminum material after welding is solved.

[0051] Working Principle: This invention addresses the issue of low mechanical strength of aluminum after welding. First, by creating holes in the conical surface of the connecting end of the aluminum conductor and filling the holes with copper powder, the connecting section of the aluminum conductor is transformed from pure aluminum to an aluminum alloy containing copper after heating and welding. This significantly improves the hardness of the connecting section after welding and resolves the issue of low mechanical strength of aluminum after welding. Furthermore, this invention addresses the aforementioned issues by adding a new technical feature: aluminum powder is filled into the micropores of the conical surface of the connecting end of the copper conductor of the landing cable, and a copper-aluminum alloy is used as the welding material. After welding, a true copper-aluminum alloy transition section is formed in the connecting section, thereby improving the weld strength between copper and aluminum.

[0052] A high-voltage cable includes a high-voltage cable flexible joint manufactured using the connection method of high-voltage cable flexible joint conductors of Example 1 or Example 2 of the present application.

[0053] In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are mutually inconsistent. Although the embodiments of the present invention have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art may make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for connecting high-voltage cable flexible joint conductors, wherein the high-voltage cable flexible joint conductors include an aluminum conductor of a submarine cable and a copper conductor of a landing cable, characterized in that: The connection between the aluminum conductor of the submarine cable and the copper conductor of the landing cable comprises the following steps: Step S1, cutting the conductor connection ends into a conical structure: cutting the connection ends of the aluminum conductor of the submarine cable and the copper conductor of the landing cable into a conical structure; Step S2, arranging micropores on the conical surface of the conductor: arranging micropores on the conical surface of the connecting end of the aluminum conductor of the submarine cable, so that the micropores cover the entire conical surface of the conductor; and arranging micropores on the conical surface of the connecting end of the copper conductor of the landfall cable, so that the micropores cover the entire conical surface of the conductor; Step S3, filling the micropores with metal powder: filling the micropores on the conical surface of the aluminum conductor connection end of the submarine cable with copper powder; filling the micropores on the conical surface of the copper conductor connection end of the landside cable with aluminum powder; Step S4, conductor positioning: fixing the aluminum conductor of the submarine cable and the copper conductor of the landing cable so that the connecting end of the aluminum conductor of the submarine cable contacts the connecting end of the copper conductor of the landing cable, and forming an annular welding groove between the two connecting ends; Step S5, heating and melting the connection end: using a flame spray gun to perform flame heating on the conical surface of the connection end of the aluminum conductor of the submarine cable; Step S6, conductor welding: welding is performed at the annular welding groove using welding equipment until the welding material fills the entire annular welding groove to form a welding section; the welding material selected for welding is a copper-aluminum alloy material, and the welding section forms a copper-aluminum transition connection section; the copper-aluminum alloy material is formed by uniformly mixing 50% by weight of copper powder and 50% by weight of aluminum powder; Step S7, welding section shaping: shaping the welding section so that the welding section meets the roundness requirement and the diameter of the welding section is equal to the diameter of the aluminum conductor of the fixed submarine section cable and the copper conductor of the landing section cable.

2. The method for connecting a high-voltage cable flexible connector conductor according to claim 1, characterized in that: In step S5, flame heating is performed on the conical surface of the connecting end of the copper conductor of the landing section cable using a flame spray gun.

3. The method for connecting high-voltage cable flexible joint conductors according to claim 2, characterized in that: The temperature of the flame spray gun when performing flame heating on the conical surface of the connection end of the aluminum conductor of the submarine cable is controlled between 600-650°C.

4. The method for connecting high-voltage cable flexible joint conductors according to claim 3, characterized in that: The temperature of the flame spray gun when performing flame heating on the conical surface of the connecting end of the copper conductor of the landing section cable is controlled between 950-1000°C.

5. The method for connecting high-voltage cable flexible joint conductors according to claim 4, characterized in that: In step S6, the welding equipment used is arc welding equipment, and the welding temperature is controlled between 1100-1500°C.

6. A high voltage cable, characterized in that: The invention comprises a flexible cable joint made by utilizing any one of claims 1 to 5.

Images