Anti-torsion cable for photovoltaic system

Abstract

The invention relates to the technical field of photovoltaic cables, in particular to an anti-torsion cable for a photovoltaic system, which comprises a plurality of wire cores distributed in an annular array; the plurality of heat dissipation pipes are respectively arranged between two adjacent wire cores and are attached to the wire cores; the inner winding layer is used for wrapping the wire core and the radiating pipe; the structural layers are distributed on the outer side of the inner winding layer in an annular array mode and correspond to the heat dissipation pipes one to one; the outer sides form a circle after the plurality of structural layers are combined; the reinforcing rings are distributed at intervals in the axial direction of the structural layer; each reinforcing ring is in a spiral shape wrapping all the structural layers, and the spiral shape has at least one complete circle; the structural layer is clamped after each reinforcing ring is mounted; the outer protection layer wraps the reinforcing ring and the structural layer; a groove is formed in the inner wall of the outer protection layer, and the width of the groove is gradually increased from one side to the other side; the outer side of the reinforcing ring extends into the groove and is attached to the side wall of the groove. According to the invention, the problem of poor torsion resistance of the photovoltaic cable in the background art can be effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic cables, and in particular to an anti-torsion cable for a photovoltaic system. Background Art

[0002] Photovoltaic cables are specialized power transmission cables for photovoltaic systems. They are primarily used to connect photovoltaic modules, inverters, combiner boxes, and other equipment, carrying the power. Because photovoltaic systems are typically installed outdoors, photovoltaic cables are often exposed to the elements for extended periods of time. The cables must ensure high electrical conductivity and sufficient environmental adaptability.

[0003] During the installation and use of photovoltaic cables, they are easily affected by torsional stress, mainly including: mechanical stress during installation (it is difficult to avoid twisting the cable during operation when adjusting the cable direction), environmental influences during use (such as wind force causing the cable to swing continuously and twist), and influences from external objects (such as external objects hooking or hitting the cable, causing the cable to twist). Torsion problems will directly lead to a decrease in conductivity, insulation failure or short circuit risks, so photovoltaic cables need to have a certain degree of torsion resistance.

[0004] In existing photovoltaic cables, the main method for torsion resistance is to strengthen the overall cable structure, such as adding fillers to provide support. However, these structures not only seriously affect the heat dissipation capacity of the cable, but also have little effect on improving the cable's torsion resistance. A better torsion resistance structure for photovoltaic cables is needed. Summary of the Invention

[0005] The present invention provides a torsion-resistant cable for a photovoltaic system, which can effectively solve the problem of poor torsion resistance of photovoltaic cables in the background art.

[0006] The present invention provides an anti-torsion cable for a photovoltaic system, comprising: Multiple cores are distributed in a ring array; A plurality of heat dissipation pipes are respectively arranged between two adjacent wire cores and are fitted with the wire cores; Inner winding layer, used to wrap the wire core and heat dissipation tube; Multiple structural layers are distributed in a circular array outside the inner winding layer and correspond one to one with the heat pipes; the outer side of each structural layer is a curved surface, and the outer side forms a circle after the multiple structural layers are combined; Multiple reinforcement rings are spaced apart along the axial direction of the structural layer; each reinforcement ring is in a spiral shape that surrounds all the structural layers, and the spiral shape has at least one complete circle; each reinforcement ring clamps the structural layer after installation; The outer protective layer wraps the reinforcement ring and the structural layer; the inner wall of the outer protective layer is provided with a groove, the width of the groove gradually increases from one side to the other side; the outer side of the reinforcement ring extends into the groove and fits with the side wall of the groove.

[0007] Furthermore, the diameter of the heat dissipation pipe is set so that the cross section of the inner winding layer forms a convex polygon.

[0008] Furthermore, a V-shaped groove is provided on the inner side of the structural layer and is in contact with the inner winding layer, and the heat dissipation pipe extends into the V-shaped groove.

[0009] Furthermore, the heat dissipation pipe is a metal braided hose.

[0010] Furthermore, the reinforcement ring includes bending sections at both ends and a curved surface section in the middle, and a bending groove is provided between the bending section and the curved surface section.

[0011] Furthermore, the installation angle of each reinforcement ring is different from the installation angles of its two adjacent reinforcement rings.

[0012] Furthermore, a flexible wrapping layer is provided on the outer side of the reinforcement ring, and both ends of the flexible wrapping layer extend to the structural layers on both sides of the reinforcement ring.

[0013] Furthermore, the flexible wrapping layer is a heat shrinkable film wrapping layer.

[0014] Furthermore, the wire core includes a conductor, an insulating layer, and a metal shielding layer which are arranged in sequence from the inside to the outside.

[0015] Furthermore, it is characterized in that the insulating layer has a double-layer structure, including an inner cross-linked polyethylene layer and an outer flame-retardant polyolefin layer.

[0016] The technical solution of the present invention can achieve the following technical effects: This cable ensures efficient heat dissipation of the cable core through the alternating layout of the core and the heat dissipation tube; and through the cooperation of the reinforcing ring and the gradually expanding groove of the outer protective layer, when the cable is torsionally subjected to the force, part of the external force can be converted into the energy of the reinforcing ring deformation, and the deformation support of the reinforcing ring can isolate the inner and outer layers of the cable, effectively improving the cable's anti-torsion ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1Schematic diagram of the structure of the anti-torsion cable for the photovoltaic system of the present invention; Figure 2 This is a schematic diagram of the structure of the anti-torsion cable for the photovoltaic system of the present invention after removing the outer protective layer; Figure 3 This is a schematic diagram of the structure of the anti-torsion cable for the photovoltaic system of the present invention after removing the outer protective layer and the flexible wrapping layer; Figure 4 This is a schematic diagram of the structure before and after the reinforcement ring is installed in the present invention; Figure 5 Schematic diagram of the structure of the outer protective layer in the present invention.

[0019] Figure numerals: 1, wire core; 2, heat dissipation pipe; 3, inner winding layer; 4, structural layer; 5, reinforcement ring; 51, bending section; 52, curved section; 53, bending groove; 6, outer protective layer; 61, groove; 7, flexible winding layer. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0021] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by “center”, “up”, “down”, “left”, “right”, “vertical”, “horizontal”, “inside” and “outside” are 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, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0022] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; they may refer to mechanical or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0023] The present invention relates to a torsion-resistant cable for a photovoltaic system. Figures 1-3 As shown, from the inside to the outside, it includes a wire core 1, a heat dissipation tube 2, an inner winding layer 3, a structural layer 4, a reinforcement ring 5 and an outer protective layer 6. The following is the specific structure of each component and its arrangement method: Multiple cores 1 are located in the center of the cable and are distributed in a ring array, with adjacent cores 1 fitting together. Inside the cores are conductors made of multiple twisted copper wires, which realize the power transmission function of the cable.

[0024] Multiple hollow heat dissipation tubes 2 are located in the center of the cable and are also distributed in a circular array. The number of heat dissipation tubes 2 is the same as the number of cores 1, so that each heat dissipation tube 2 can be embedded between two adjacent cores 1, and the outer wall of each heat dissipation tube 2 is in contact with the outer walls of the two adjacent cores 1; the outer surfaces of the cores 1 and the heat dissipation tubes 2 are sprayed with a thermal conductive layer (such as silicone grease, etc.) and are tightly fitted with the winding layer 3 to form a direct heat transfer path, which is used to absorb the heat generated by the core 1 during power transmission and transfer it outward to achieve heat dissipation.

[0025] The inner winding layer 3 is made of aramid fiber tape and polyester film alternately wound in a spiral manner to form a flame retardant layer and a waterproof layer; the inner winding layer 3 can be used to wrap the wire core 1 and the heat dissipation tube 2, so that the wrapped wire core 1 and the heat dissipation tube 2 are tightly attached to each other to prevent the two from loosening, and the other space in the inner winding layer 3 can be vacated, thereby providing heat dissipation space for the wire core 1 and reducing the overall weight of the cable.

[0026] Multiple structural layers 4 are distributed in a ring array outside the inner winding layer 3. The number of structural layers 4 is the same as the number of heat pipes 2, and corresponds one-to-one with the heat pipes 2. The center of each structural layer 4 is aligned with the heat pipe 2. The outer side of each structural layer 4 is an arc-shaped surface, and after multiple structural layers 4 are combined, the multiple outer sides form a circle.

[0027] Multiple reinforcement rings 5 are distributed along the axial direction of the structural layer 4 (i.e., the axial direction of the cable), with a certain interval between two adjacent reinforcement rings 5; each reinforcement ring 5 is made of metal, and the reinforcement ring 5 is in the shape of a spiral wrapped around the outer side of a circle formed by all the structural layers 4, and the spiral has at least one complete circle, usually within 1 to 1.5 circles, so that each reinforcement ring 5 can achieve elastic compression deformation like a spring; after each reinforcement ring 5 is installed, the inner side of the reinforcement ring 5 will clamp the structural layer 4.

[0028] The outer protective layer 6 is a relatively thick rubber layer used to wrap the reinforcement ring 5 and the structural layer 4; the inner wall of the outer protective layer 6 is provided with a groove 61, such as Figure 5 As shown, the width of the groove 61 gradually increases from one side to the other; a circle outside the reinforcement ring 5 will extend into the groove 61, and both sides of the part of the reinforcement ring 5 extending into the groove 61 are in contact with the side walls of the groove 61.

[0029] The main reason why traditional photovoltaic cables have poor torsional resistance is that their internal conductor and outer protective layer are basically integrated. Therefore, no matter how the outer protective layer is structurally strengthened, it will still twist when subjected to force, and the internal conductor will inevitably rotate along with it, affecting the normal operation of the conductor. Therefore, the torsional resistance is always poor.

[0030] This cable adopts the form of internal and external separation during torsion to solve the problem of poor torsion resistance of existing structures. The specific principle is as follows: When torsion occurs in the axial vertical direction, due to the arrangement of the grooves 61 on the outer protective layer 6, the outer protective layer 6 is divided into multiple small segments, and the two ends of each small segment are against the metal reinforcement ring 5 that is difficult to deform. In this way, the deflection of each small segment will be reduced and it is not easy to bend. Moreover, after the external force acts on the outer protective layer 6, if the outer protective layer 6 is a complete long segment, the entire force will act on the outer protective layer 6 to cause it to deform greatly. However, after the outer protective layer 6 of the cable is subjected to force, part of the force will be transmitted to the end face of each small segment and then to the reinforcement ring 5. This part The force will be used to compress the reinforcement ring 5, thereby reducing the force used to deform the outer protective layer 6. At the same time, after the reinforcement ring 5 is compressed, not only can its reaction force further limit the deformation of the cable, but the diameter of the reinforcement ring 5 will also increase with the compression of the reinforcement ring 5, thereby separating the interior of the reinforcement ring 5 from the structural layer 4, and the exterior will move outward to support the outer protective layer 6, thereby isolating the internal core 1 from the external force, and the core 1, heat pipe 2, inner winding layer 3, and structural layer 4 as a whole can have a slight rotation space, thereby reducing the deformation inside the cable and achieving the purpose of protecting the core 1; When axial torsion occurs, the structure in which the width of the groove 61 gradually increases from one side to the other is originally intended to adapt to the outer shape of the reinforcement ring 5. When subjected to external force and causing the outer protective layer 6 to rotate, the reinforcement ring 5 will initially not rotate due to the restriction of the internal structure. Then, as the groove 61 rotates, the widest side of the reinforcement ring 5 will move from the place where the groove 61 is the widest to the place where the width is smaller, thereby compressing the reinforcement ring 5. Similarly to the above, as the reinforcement ring 5 is compressed, the internal structure of the cable has a slight rotation space, thereby reducing the deformation inside the cable and achieving the purpose of protecting the core 1; and the deformation of the reinforcement ring 5 can also generate a reaction force to prevent the outer protective layer 6 from rotating, thereby further reducing the twisting of the cable.

[0031] Preferably, when setting the heat pipe 2, it is necessary to control the diameter of the heat pipe 2. If the diameter of the heat pipe 2 is too small, the inner winding layer 3 can only be wound on the wire core 1, and the heat pipe 2 will be in a free swinging state in the inner winding layer 3, affecting the heat conduction function; therefore, it is necessary to set the diameter of the heat pipe 2 to be large enough so that the cross-section of the inner winding layer 3 can form a convex polygon after winding. A convex polygon is a polygon with an internal angle of less than 180°. In this way, the heat pipe 2 can be pressed against the wire core 1 through the inner winding layer 3.

[0032] Preferably, a V-shaped groove is provided on the inner side of the structural layer 4 to fit the inner winding layer 3, so as to facilitate heat conduction outward; the V-shaped groove can also limit the position of the heat dissipation tube 2, and the heat dissipation tube 2 will extend into the V-shaped groove and be stuck in the V-shaped groove, thereby preventing the heat dissipation tube 2 from being skewed and shaking.

[0033] Preferably, the heat dissipation tube 2 is set as a metal braided hose. The metal braided hose is a tubular structure formed by weaving stainless steel wire into a mesh tube wall. It can produce slight deformation after being compressed, increasing the contact area between the heat dissipation tube 2 and the wire core 1 and the inner winding layer 3, improving the heat dissipation efficiency, and the metal braided hose will not deform again after being deformed to a certain extent, ensuring that the heat dissipation tube 2 is always hollow and the heat dissipation effect is guaranteed.

[0034] Under normal circumstances, the entire cable is processed continuously, so the reinforcement ring 5 is not convenient to be installed in a set manner; in this cable, the reinforcement ring 5 is preferably designed to include bending sections 51 located at both ends and a curved section 52 located in the middle, and a bending groove 53 is provided between the bending section 51 and the curved section 52, and the opening of the bending groove 53 faces the interior of the reinforcement ring 5.

[0035] Before the reinforcement ring 5 is installed, its structure is as follows Figure 4 As shown, the bending sections 51 at both ends bend outward, forming the reinforcement ring 5 into a U-shape. This allows for large-scale, low-cost manufacturing of the reinforcement ring 5 through stamping. During installation, the reinforcement ring 5 is simply placed over the cable component through the U-shaped opening. The bending sections 51 at both ends of the U-shape are then bent inward using a tool. The tool is used to limit the bent position of the bending sections 51, forming a spiral shape to complete the reinforcement ring installation. The bending groove 53 can be used to determine the bending rotation center of the bending section 51, preventing the reinforcement ring 5 from changing into other shapes.

[0036] Preferably, when setting the reinforcement ring 5, the installation angle of each reinforcement ring 5 is different from the installation angles of the two adjacent reinforcement rings 5. For example, taking Figure 3 as an example, from the angle at which the same end of each reinforcement ring 5 is located, there will be: the first reinforcement ring 5 is installed at the 0° position, the second reinforcement ring 5 is installed at the 120° position, the third reinforcement ring 5 is installed at the 240° position, the fourth reinforcement ring 5 is installed at the 0° position... and so on. In this way, no matter from which direction the outer protective layer 6 is subjected to force, the reinforcement ring 5 can be at the optimal working angle, thereby ensuring the overall torsion resistance of the cable.

[0037] The outer protective layer 6 is typically formed by extruding molten rubber material directly onto the internal structure of the cable. Therefore, it is difficult to form the groove 61 through post-processing, especially when the installation angle of each reinforcement ring 5 is different from the installation angles of the two adjacent reinforcement rings 5. This makes it even more difficult to ensure the fit between the groove 61 and the reinforcement ring 5. Therefore, in this cable, a flexible wrapping layer 7 is provided on the outside of the reinforcement ring 5. Both ends of the flexible wrapping layer 7 need to extend onto the structural layer 4 on both sides of the reinforcement ring 5. After the flexible wrapping layer 7 wraps around the reinforcement ring 5, it automatically forms a shape identical to the desired groove 61. Furthermore, the flexible wrapping layer 7 completely seals the reinforcement ring 5. When the molten rubber material reaches the reinforcement ring 5, it is blocked by the flexible wrapping layer 7 and formed into the groove 61. After the cable is processed, the flexible wrapping layer 7 will not interfere with the deformation function of the reinforcement ring 5, ensuring the normal anti-torsion function of the cable.

[0038] It is preferred to set the flexible wrapping layer 7 as a heat shrink film wrapping layer, so that during the production process, the heat shrink film can be quickly wrapped around the approximate position of the reinforcement ring 5, and then as long as hot air is blown on it, the heat shrink film wrapping layer can automatically shrink to form a flexible wrapping layer 7 that wraps and fits the reinforcement ring 5, which greatly facilitates the molding of the flexible wrapping layer 7.

[0039] Core 1 comprises, arranged from the inside out, a conductor, an insulation layer, and a metal shield. The conductor utilizes a layered stranded structure: a single annealed copper wire in the center, the inner copper wires twisted in a right-hand spiral, and the outer layers twisted in a left-hand spiral to offset twisting torque. The insulation layer is a double-layer structure, comprising an inner cross-linked polyethylene layer and an outer flame-retardant polyolefin layer. The rubber layer has axially shaped corrugations extruded on its surface to extend creepage distance. The shielding layer utilizes a composite structure of longitudinally wrapped aluminum foil and braided tinned copper wire. The overlapping edges of the aluminum foil are coated with conductive adhesive to ensure continuous shielding. The braid density gradually decreases from the center of the core to the ends to accommodate bending flexibility.

[0040] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A torsion-resistant cable for a photovoltaic system, characterized in that: include: A plurality of wire cores (1) are distributed in a ring array; A plurality of heat dissipation pipes (2) are respectively arranged between two adjacent wire cores (1) and are fitted with the wire cores (1); An inner winding layer (3) is used for wrapping the wire core (1) and the heat dissipation tube (2); A plurality of structural layers (4) are distributed in a ring array outside the inner winding layer (3) and correspond one-to-one to the heat dissipation pipes (2); the outer side of each structural layer (4) is a curved surface, and the outer sides of the plurality of structural layers (4) are formed into a circle after being combined; A plurality of reinforcement rings (5) are distributed at intervals along the axial direction of the structural layer (4); each reinforcement ring (5) is in a spiral shape surrounding all the structural layers (4), and the spiral shape has at least one complete circle; each reinforcement ring (5) clamps the structural layer (4) after installation; An outer protective layer (6) wraps the reinforcement ring (5) and the structural layer (4); a groove (61) is provided on the inner wall of the outer protective layer (6), and the width of the groove (61) gradually increases from one side to the other side; the outer side of the reinforcement ring (5) extends into the groove (61) and fits with the side wall of the groove (61).

2. The torsion-resistant cable for photovoltaic systems according to claim 1, characterized in that: The diameter of the heat dissipation pipe (2) is set so that the cross section of the inner winding layer (3) forms a convex polygon.

3. The torsion-resistant cable for photovoltaic systems according to claim 2, characterized in that: A V-shaped groove is provided on the inner side of the structural layer (4) and is in contact with the inner winding layer (3), and the heat dissipation pipe (2) extends into the V-shaped groove.

4. The torsion-resistant cable for photovoltaic systems according to claim 2, characterized in that: The heat dissipation pipe (2) is a metal braided hose.

5. The torsion-resistant cable for photovoltaic system according to claim 1, characterized in that: The reinforcement ring (5) comprises bending sections (51) at both ends and a curved section (52) in the middle, and a bending groove (53) is provided between the bending section (51) and the curved section (52).

6. The torsion-resistant cable for photovoltaic systems according to claim 1, characterized in that: The installation angle of each reinforcement ring (5) is different from the installation angles of the two adjacent reinforcement rings (5).

7. The torsion-resistant cable for photovoltaic system according to claim 1, characterized in that: A flexible wrapping layer (7) is provided on the outside of the reinforcement ring (5), and both ends of the flexible wrapping layer (7) extend to the structural layer (4) on both sides of the reinforcement ring (5).

8. The torsion-resistant cable for photovoltaic system according to claim 7, characterized in that: The flexible wrapping layer (7) is a heat shrinkable film wrapping layer.

9. The torsion-resistant cable for photovoltaic systems according to claim 1, characterized in that: The wire core (1) comprises a conductor, an insulating layer, and a metal shielding layer which are arranged in sequence from the inside to the outside.

10. The torsion-resistant cable for photovoltaic system according to claim 9, characterized in that: The insulating layer is a double-layer structure, comprising an inner cross-linked polyethylene layer and an outer flame-retardant polyolefin layer.

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