High-voltage cable filled with elastic semi-conductive buffer layer

Abstract

The utility model belongs to the field of cables, and provides a high-voltage cable filled with an elastic semi-conductive buffer layer, which comprises a conductor; the insulating layer coats the outer surface of the conductor to ensure the stability of electric energy transmission; the conductor and the insulating layer are combined to form an insulating wire core, and liquid semiconductive foaming liquid is sprayed outside the insulating wire core through an argon arc welding process so as to foam outside the insulating wire core and form a semiconductive foaming buffer layer; and a metal aluminum sheath, an asphalt anti-corrosion layer, a non-metal sheath and a sheath outer semi-conductive layer are sequentially coated outside the semi-conductive foaming buffer layer from inside to outside. Compared with the prior art, the utility model has the advantages that the semi-conductive foaming buffer layer is sprayed on the surface of the insulation shielding layer in the production process of the argon arc welding process, so that on one hand, the process link of wrapping a buffer strip is omitted, the production efficiency is improved, and the production cost is reduced; and on the other hand, the important quality problem caused by damping of the buffer water-blocking tape is effectively avoided.

Description

Technical Field

[0001] This utility model belongs to the field of cables, specifically relating to a high-voltage cable filled with an elastic semi-conductive buffer layer. Background Technology

[0002] In the manufacturing process of 66kV and above high-voltage cables, a water-blocking buffer strip is typically used between the aluminum sheath and the insulation shield to achieve a water-blocking structure. While this method can meet the cable's buffering and waterproofing requirements to a certain extent, its inherent drawbacks also bring some problems to the overall cable performance and the production process.

[0003] 1. Additional steps: Wrapping the buffer tape requires specialized equipment and processes, which increases the complexity of the entire production process. Each step requires precise control to ensure that the buffer tape is correctly wound around the cable core, a process that is both time-consuming and labor-intensive.

[0004] 2. Material Costs: The wrapping cushioning tape itself is an additional material, which undoubtedly increases the cost of raw materials. Moreover, in some cases, in order to ensure quality, it may be necessary to use higher quality or specially treated cushioning tape, further increasing the cost.

[0005] 3. Operational Hazards: When the cable is in operation, if the buffer water-blocking strip is damp, it may cause the buffer layer to burn. This is because moisture reduces the electrical insulation performance of the buffer layer, making partial discharge more likely to occur, which in turn triggers a thermal effect. In the most severe cases, it may even lead to cable insulation breakdown, seriously affecting the safe and stable operation of the cable and shortening its service life. Utility Model Content

[0006] In view of the above-mentioned shortcomings of the existing technology, the technical problem to be solved by this utility model is to propose a high-voltage cable with a filled elastic semi-conductive buffer layer that has a simple overall structure, improves production efficiency, and avoids quality problems caused by moisture in the buffer water-blocking strip.

[0007] The technical solution adopted by this utility model to solve its technical problem is to propose a high-voltage cable filled with an elastic semi-conductive buffer layer, comprising: a conductor;

[0008] An insulating layer covers the outer surface of the conductor to ensure the stability of electrical energy transmission;

[0009] The conductor and the insulating layer are combined to form an insulated wire core. The outside of the insulated wire core is sprayed with liquid semi-conductive foaming liquid by argon arc welding process to foam and form a semi-conductive foaming buffer layer on the outside of the insulated wire core.

[0010] The semiconductive foamed buffer layer is sequentially covered from the inside out with a metal aluminum sheath, an asphalt anti-corrosion layer, a non-metallic sheath, and an outer semiconductive layer.

[0011] In the aforementioned high-voltage cable filled with an elastic semi-conductive buffer layer, the semi-conductive foamed buffer layer is made by spraying polypropylene, foaming agent, and carbon black onto the insulated core.

[0012] In the aforementioned high-voltage cable filled with an elastic semi-conductive buffer layer, the thickness of the semi-conductive foamed buffer layer after the insulation core is foamed is in the range of 5mm-10mm.

[0013] In the aforementioned high-voltage cable filled with an elastic semi-conductive buffer layer, the conductor is wrapped with a semi-conductive nylon tape with a 47%-49% overlap.

[0014] In the aforementioned high-voltage cable filled with an elastic semi-conductive buffer layer, the conductor is covered with a conductor shielding layer, the insulation layer is covered with the conductor shielding layer, and an insulation shielding layer is provided outside the insulation layer. Liquid semi-conductive foaming liquid is sprayed onto the insulation shielding layer.

[0015] In the aforementioned high-voltage cable filled with an elastic semi-conductive buffer layer, both the conductor shielding layer and the insulating shielding layer are made of semi-conductive cross-linkable shielding material.

[0016] In the aforementioned high-voltage cable filled with an elastic semi-conductive buffer layer, the thickness of the semi-conductive cross-linkable shielding material ranges from 1.0 mm to 1.5 mm.

[0017] In the aforementioned high-voltage cable with a filled elastic semi-conductive buffer layer, the non-metallic sheath is made of polyvinyl chloride, polyethylene, or low-smoke halogen-free material.

[0018] In the aforementioned high-voltage cable with a filled elastic semi-conductive buffer layer, the outer semi-conductive layer of the sheath can be connected to the positive and negative poles of the metallic aluminum sheath to detect whether the non-metallic sheath has copper breakage or damage.

[0019] In the aforementioned high-voltage cable filled with an elastic semi-conductive buffer layer, the conductor is either a split conductor or made of stranded copper wire.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The present invention provides a high-voltage cable filled with an elastic semi-conductive buffer layer. By spraying a semi-conductive foamed buffer layer on the surface of the insulation shield during the production process of argon arc welding, the process of wrapping the buffer tape is eliminated, which improves production efficiency and reduces production costs. On the other hand, it effectively avoids the important quality problems caused by the moisture of the buffer water-blocking tape.

[0022] (2) By applying a moving voltage to the two electrodes formed by the outer semiconductive layer of the sheath and the aluminum sheath, it is possible to detect whether the sheath is intact and whether the insulation resistance of the sheath meets the required usage requirements, thereby improving the safety of the cable during use.

[0023] (3) The semi-conductive foamed buffer layer formed by foaming can absorb the change in outer diameter caused by thermal expansion and contraction of insulation, and has the function of longitudinal water blocking. Attached Figure Description

[0024] Figure 1 This is a structural diagram of this application.

[0025] In the diagram, 1 is the conductor; 10 is the conductor shielding layer; 2 is the insulation layer; 20 is the insulation shielding layer; 3 is the semi-conductive foamed buffer layer; 4 is the aluminum sheath; 5 is the asphalt anti-corrosion layer; 6 is the non-metallic sheath; and 7 is the outer semi-conductive layer of the sheath. Detailed Implementation

[0026] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0027] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0028] like Figure 1 As shown, this utility model discloses a high-voltage cable filled with an elastic semi-conductive buffer layer, comprising: a conductor 1; an insulation layer 2, which covers the outer surface of the conductor 1 to ensure the stability of power transmission; the conductor 1 and the insulation layer 2 are combined to form an insulated core, and the outside of the insulated core is sprayed with liquid semi-conductive foaming liquid through argon arc welding process to foam and form a semi-conductive foamed buffer layer 3; the semi-conductive foamed buffer layer 3 is covered from the inside out with a metal aluminum sheath 4, an asphalt anti-corrosion layer 5, a non-metallic sheath 6, and an outer semi-conductive layer 7.

[0029] Currently, in 66KV and above high-voltage cables, the aluminum sheath and the insulation shield 20 often employ a buffer water-blocking structure with a wrapped buffer water-blocking tape. The solution in this embodiment makes further improvements, specifically, as follows: Figure 1As shown, in this embodiment, an insulating layer 2 is uniformly coated on the outer surface of conductor 1. This insulating layer 2 is preferably made of ultra-clean cross-linked polyethylene insulating material to ensure the stability of power transmission. The insulation thickness is controlled according to different voltage levels, while ensuring that the eccentricity of the insulating layer 2 does not exceed 5%. After conductor 1 and insulating layer 2 are combined to form an insulated wire core, a liquid semi-conductive foaming liquid is directly sprayed onto the insulating shield surface through an argon arc welding process. During the spraying process, due to the high temperature of the argon arc welding, the liquid semi-conductive foaming liquid rapidly foams and solidifies, ultimately forming a coating on the insulating layer 2. The external semi-conductive foamed buffer layer 3 eliminates the traditional production step of wrapping buffer tape, and also reduces the need for additional materials (i.e., buffer water-blocking tape), lowering raw material costs (and of course, reducing investment and maintenance costs for related production equipment). Overall, this significantly reduces production costs, simplifies the production process, and improves production efficiency. Furthermore, the use of argon arc welding effectively avoids significant quality problems caused by moisture in the buffer water-blocking tape, thereby reducing the risk of cable insulation breakdown due to buffer layer burning and improving the stability and reliability of cable operation. In addition, the designed aluminum sheath 4, asphalt anti-corrosion layer 5, and non-metallic sheath 6 provide multiple protective measures, enhancing the cable's resistance to external environmental factors (such as corrosion and mechanical damage) and extending its service life.

[0030] Furthermore, such as Figure 1 As shown, in this embodiment, an asphalt anti-corrosion layer 5 is coated on the outside of the aluminum sheath 4. The asphalt anti-corrosion layer 5 can protect the aluminum sheath 4 and effectively prevent the aluminum sheath from being corroded, thus affecting the stability of the entire high-voltage cable structure.

[0031] Preferably, such as Figure 1 As shown, compared to the traditional process of extruding polypropylene, foaming agent, and carbon black into a strip and then longitudinally wrapping it onto the cable, the semi-conductive foamed buffer layer 3 in this embodiment involves directly spraying polypropylene, foaming agent, and carbon black onto the insulated core, greatly simplifying the process and improving production efficiency. Specifically, workers precisely mix the liquid mixture to ensure the final semi-conductive foamed buffer layer 3 possesses the required physical and electrical properties, while effectively absorbing the outer diameter changes of the insulation layer 2 caused by thermal expansion and contraction, thus enhancing the cable's durability and stability. During the argon arc welding process, the pre-prepared liquid mixture (polypropylene, foaming agent, and carbon black) is uniformly sprayed onto the outer surface of the insulated core using specialized spraying equipment. The high-temperature environment generated during argon arc welding helps the liquid mixture rapidly foam and solidify, forming a uniform semi-conductive foamed buffer layer 3 with a certain thickness (typically 5mm to 10mm).

[0032] More preferably, the conductor 1 in this embodiment can be a segmented conductor 1 or made of stranded copper wire. The segmented conductor 1 is typically composed of multiple small-section copper conductors 1, which are combined together in a specific way to form a whole. This process can employ advanced segmentation technology to ensure good contact and electrical connection between each small section; that is, in the production process, the large-section copper material is first cut into several small sections and then treated (such as cleaning, polishing, etc.) to ensure a smooth and flawless surface, thereby reducing resistance during current conduction. Copper wire stranding involves stranding multiple thin copper wires according to certain rules and directions to form a conductor 1 with a larger cross-sectional area. First, the required thin copper wires are prepared, and then they are stranded into shape using a specialized stranding machine. During the stranding process, the stranding pitch and tension need to be strictly controlled to ensure that the stranded conductor 1 has a tight and uniform structure. The direction and density of stranding can also be adjusted according to requirements to meet the electrical performance requirements of different application scenarios. Therefore, both split conductor 1 and stranded copper wire have better flexibility and tensile strength than a single large-section conductor 1, which makes the cable more durable during installation and use, and able to withstand greater mechanical stress without being easily damaged.

[0033] More preferably, such as Figure 1 As shown, firstly, workers need to select semi-conductive nylon tape with appropriate electrical properties and mechanical strength. This material usually has good conductivity and a certain degree of flexibility, which can provide necessary physical protection while ensuring electrical connection. During the wrapping operation, a special wrapping device is used to wrap the semi-conductive nylon tape around the conductor 1 with an overlap rate of 47%-49%. The overlap rate refers to the proportion of the overlapping part between two adjacent loops of tape. During the wrapping process, the wrapping speed and tension need to be precisely controlled to ensure that the semi-conductive nylon tape is tightly attached to the surface of the conductor 1 and forms a uniform and consistent covering layer. Appropriate tension can avoid slippage caused by the tape being too loose or deformation caused by the tape being too tight.

[0034] Conductor 1 is covered with conductor shielding layer 10, insulation layer 2 is covered with conductor shielding layer 10, and insulation shielding layer 20 is provided outside insulation layer 2. Liquid semi-conductive foaming liquid is sprayed on insulation shielding layer 20.

[0035] More preferably, such as Figure 1 As shown, the presence of conductor shielding layer 10 and insulation shielding layer 20 greatly reduces the risk of partial discharge and improves the electrical continuity inside the cable, thereby enhancing the overall electrical performance. At the same time, a layer of ultra-smooth semi-conductive cross-linkable shielding material is uniformly coated on the outer surface of conductor 1 to form the aforementioned conductor shielding layer 10. The thickness of this shielding material is generally controlled between 1.0mm and 1.5mm to ensure the electrical continuity inside the cable and reduce the possibility of partial discharge.

[0036] More preferably, such as Figure 1 As shown, the material of the non-metallic sheath 6 in this embodiment can be selected according to the different application environments and requirements of the cable. Generally, polyvinyl chloride (PVC), polyethylene (PE), or low-smoke halogen-free (LSZH) materials can be used. Of course, flame-retardant PVC or flame-retardant PE materials can also be used. Among them, using low-smoke halogen-free (LSZH) material as the non-metallic sheath 6 can reduce the release of toxic gases in the event of a fire, reducing the harm to human health and the environment. This material is particularly suitable for use in densely populated places or occasions with high environmental protection requirements. Polyethylene (PE) has good weather resistance and anti-aging properties, making it suitable for use in long-term outdoor exposure environments. It can effectively resist the effects of ultraviolet rays, oxidation, and other factors, extending the service life of the cable. Polyvinyl chloride (PVC) is not only low in cost, but also has good mechanical strength and wear resistance, which can protect the cable from external physical damage such as scratches and friction to a certain extent. By flexibly selecting different materials for the non-metallic sheath 6, various complex application scenarios can be met. Whether it is indoor wiring requiring flame-retardant properties or outdoor laying to withstand harsh weather conditions, the most suitable solution can be found.

[0037] More preferably, such as Figure 1 As shown, the aluminum sheath 4 designed in this embodiment protects the cable from external damage and also shields the electric field, capacitor current, and short-circuit current. A semi-conductive layer (i.e., the outer semi-conductive layer 7) is extruded or coated on the outermost layer of the sheath. This semi-conductive layer acts as an electrode, forming two electrodes together with the aluminum sheath 4. Applying a certain voltage to these two electrodes and periodically detecting the resistance between the positive and negative electrodes can effectively prevent current leakage caused by holes or severe damage to the non-metallic sheath. This helps to identify potential safety hazards in advance, avoid short circuits or other electrical accidents caused by sheath damage, and ensure the safe and stable operation of the power transmission system.

[0038] It should be noted that in this invention, the use of terms such as "first," "second," and "a" is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified. The terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two elements or the interaction between two elements, unless otherwise explicitly specified. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0039] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0040] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A high voltage cable filled with an elastomeric semiconductive buffer layer, characterized in that, It comprises: a conductor; an insulating layer which is coated on the outer surface of the conductor to ensure the stability of electric energy transmission; the conductor and the insulating layer are combined into an insulated core, and the outer surface of the insulated core is sprayed with liquid semiconductive foaming liquid by argon arc welding process to foam and form a semiconductive foaming buffer layer outside the insulated core; the semiconductive foaming buffer layer is coated with a metal aluminum sheath, an asphalt anticorrosive layer, a non-metal sheath and a semiconductive layer outside the sheath in turn from inside to outside.

2. A high voltage cable filled with an elastomeric semiconductive buffer layer according to claim 1, characterized in that, The semiconductive foaming buffer layer is formed by spraying polypropylene, foaming agent and carbon black onto the insulated core.

3. A high voltage cable filled with an elastomeric semiconductive buffer layer according to claim 1, characterized in that, The thickness of the semiconductive foaming buffer layer after foaming outside the insulated core ranges from 5mm to 10mm.

4. A high voltage cable filled with an elastomeric semiconductive buffer layer according to claim 2, characterized in that, The conductor is wrapped with a semiconductive nylon belt with a lap coverage rate of 47%-49% outside the conductor.

5. A high voltage cable filled with an elastomeric semiconductive buffer layer according to claim 1, characterized in that, The conductor is coated with a conductor shielding layer, the insulating layer is coated on the conductor shielding layer, and an insulating shielding layer is arranged outside the insulating layer, and the liquid semiconductive foaming liquid is sprayed on the insulating shielding layer.

6. A high voltage cable filled with an elastomeric semiconductive buffer layer according to claim 5, characterized in that The conductor shielding layer and the insulating shielding layer both adopt semiconductive cross-linkable shielding material.

7. A high voltage cable filled with an elastomeric semiconductive buffer layer according to claim 6, characterized in that The thickness of the semiconductive cross-linkable shielding material ranges from 1.0mm to 1.5mm.

8. A high voltage cable filled with an elastomeric semiconductive buffer layer according to claim 1, characterized in that, The non-metal sheath adopts polyvinyl chloride, polyethylene or low-smoke halogen-free material.

9. A high voltage cable filled with an elastomeric semiconductive buffer layer according to claim 1, characterized in that, The semiconductive layer outside the sheath can be connected to the positive and negative poles of the metal aluminum sheath to detect whether the non-metal sheath is damaged or broken.

10. A high voltage cable filled with an elastomeric semiconductive buffer layer according to claim 1, characterized in that, The conductor is a split conductor or is made of twisted copper wires.

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