High-voltage shielding insulation downlead with long service life

Abstract

The utility model discloses a high-voltage shielding insulation down lead with long service life. The insulation down lead comprises a central radiating tube, a concentric conductor, a conductor belting layer, a semi-conductive conductor shielding layer, a cross-linked polyethylene insulating layer, a semi-conductive insulation shielding layer, a metal belt shielding layer and a sheath layer from inside to outside in sequence, the central radiating tube is a hollow tube made of polyethylene, and the concentric conductors are evenly distributed on the outer surface of the central radiating tube. According to the utility model, the impedance of the conductor of the down lead is reduced, the weight is light, the down lead cable is generally vertically laid, the dead weight of the cable is reduced, the installation and laying are convenient, the longitudinal tensile force of the dead weight of the cable can be reduced, and the stability of the product is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of electric wires and cables, and relates to an insulated down conductor, in particular to a high-life high-voltage shielded insulated down conductor. Background Art

[0002] The direct lightning protection system can use copper strips and flat steel as down conductors. However, if ordinary copper wires or flat steel are used as down conductors, when lightning current leaks, "flashover" will cause harm to nearby personnel and equipment.

[0003] The existing insulated down conductor is a round solid copper conductor or a round stranded copper conductor with a layer of cross-linked polyethylene insulation extruded on the surface. This structure can significantly reduce the generation of leakage current. However, if this product is installed and laid in a building with metal structures around it, the strong lightning current and the electromagnetic field generated will cause damage to the surrounding communication equipment and power equipment. In addition, after a lightning strike, the conductor will instantly generate high temperature, and a large amount of heat energy inside the insulation cannot be dissipated in time, causing the insulation to age or even be damaged, and unable to withstand multiple consecutive lightning strikes.

[0004] The insulated down conductor consists of a high thermal conductivity polyethylene pipe, a wound aluminum alloy wire concentric conductor, an extruded conductor shield, an extruded cross-linked polyethylene insulation, an extruded insulation shield, a wound composite metal wire shield, and an extruded long-life polyolefin outer sheath.

[0005] However, the existing insulated down conductor has the following defects:

[0006] 1. When ordinary copper wire or flat steel is used as a lightning conductor, when lightning current leaks, "flashover" will cause harm to nearby personnel and equipment.

[0007] 2. The existing insulated lightning protection down conductor cannot effectively suppress strong electromagnetic fields.

[0008] 3. The characteristics of direct lightning strikes are short duration and high voltage. In the case of such a sudden voltage change, the skin effect produced in the down conductor is obvious, which leads to a decrease in the effective current conduction of the conductor, an increase in impedance, and more heat generated by the conductor, which damages the insulator. Utility Model Content

[0009] In order to solve the above problems, the utility model provides a high-life high-voltage shielded insulated down conductor. The utility model can improve the service life of the down conductor cable: when the direct lightning passes through the down conductor, a large amount of heat is generated. If the heat cannot be diffused in time, it will cause the insulation material adjacent to the down conductor conductor to age and be damaged, thereby losing the insulation performance. By reducing the generation of heat and accelerating the diffusion of heat, the damage caused by the direct lightning current to the cable is reduced. The utility model reduces the impedance of the down conductor conductor and is lightweight. The down conductor cable is usually laid vertically, which reduces the cable's own weight and is easy to install and lay. At the same time, it can reduce the longitudinal tensile force of the cable under its own weight, thereby improving the stability of the product.

[0010] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0011] The utility model provides a high-life high-voltage shielded insulated down conductor, which comprises, from the inside to the outside, a central heat dissipation pipe, a concentric conductor, a conductor tape layer, a semi-conductive conductor shielding layer, a cross-linked polyethylene insulation layer, a semi-conductive insulation shielding layer, a metal tape shielding layer and a sheath layer; the central heat dissipation pipe is a hollow pipe made of polyethylene, and the concentric conductors are evenly distributed on the outer surface of the central heat dissipation pipe.

[0012] As a preferred solution of the utility model, the central heat dissipation tube is a hollow circular tube, and the extension line of the center of the circle of the concentric conductor is arranged parallel to the extension line of the center of the circle of the central heat dissipation tube.

[0013] As a preferred solution of the utility model, the diameter ratio of the central heat dissipation pipe to the concentric conductor is 0.8-0.9.

[0014] As a preferred solution of the present invention, the conductor tape layer tightly covers the concentric conductor, and the thickness of the conductor tape layer is 0.1 mm.

[0015] As a preferred embodiment of the utility model, the semi-conductive conductor shielding layer covers the conductor tape layer, and the thickness is 0.5±0.1mm. The cross-linked polyethylene insulation layer covers the semi-conductive conductor shielding layer, and the thickness is 5.5±0.2mm. The semi-conductive insulation shielding layer covers the cross-linked polyethylene insulation layer, and the thickness is 0.5±1mm.

[0016] As a preferred solution of the utility model, the metal tape shielding layer is wrapped around the outer surface of the semi-conductive insulating shielding layer, with a thickness of 0.1 mm and an overlap rate of 10% to 15%.

[0017] As a preferred solution of the utility model, the sheath layer is uniformly extruded and arranged on the outer surface of the metal belt shielding layer, and has a thickness of 3.2±0.3 mm.

[0018] As a preferred solution of the present utility model, the number of the concentric conductors is 30 to 38.

[0019] Compared with the prior art, the utility model has the following beneficial effects:

[0020] 1) The utility model improves the service life of the down conductor cable: when direct lightning strikes through the down conductor, a large amount of heat is generated. If the heat cannot be dissipated in time, the insulating material adjacent to the down conductor conductor will be aged and damaged, thereby losing its insulating properties. By reducing the generation of heat and accelerating the diffusion of heat, the damage to the cable caused by direct lightning current is reduced.

[0021] 2) The utility model reduces the impedance of the down conductor; the central conductor adopts a concentric winding method to reduce the high-frequency impedance of the down conductor, thereby reducing the heat energy generated by the down conductor.

[0022] 3) The utility model eliminates the flashover generated when the lightning current passes through the down conductor: a high-voltage arc (air breakdown phenomenon) is generated between the charged down conductor conductor and the adjacent metal components, and the high-voltage arc may cause damage to buildings or personal injury.

[0023] 4) The utility model eliminates the electromagnetic field generated by the lightning current passing through the down conductor: the current change in a very short time will generate a strong magnetic field, and the communication equipment and power system around the down conductor will be disturbed by the magnetic field, resulting in communication abnormalities and even equipment damage. The down conductor cable is usually laid vertically to reduce the cable's own weight and facilitate installation and laying. At the same time, it can reduce the longitudinal tensile force of the cable under its own weight, thereby improving the stability of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0025] Figure 1 It is a schematic diagram of the utility model.

[0026] In the figure, 1. Central heat dissipation pipe; 2. Concentric conductors; 3. Conductor tape layer; 4. Semi-conductive conductor shielding layer; 5. Cross-linked polyethylene insulation layer; 6. Semi-conductive insulation shielding layer; 7. Metal tape shielding layer; 8. Sheath layer. DETAILED DESCRIPTION

[0027] In order to further understand the content of the utility model, the utility model is described in detail in conjunction with the accompanying drawings and embodiments.

[0028] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are only used to explain the relevant utility model, rather than to limit the utility model. It should also be noted that, for the convenience of description, only the parts related to the utility model are shown in the accompanying drawings. The words "first", "second", etc. described in the present utility model are set for the convenience of describing the technical solution of the present utility model, and have no specific limiting effect. They are all general references and do not constitute a limiting effect on the technical solution of the present utility model. It should be noted that, in the absence of conflict, the embodiments and features in the embodiments in the present application can be combined with each other. In the description of the present utility model, it should be noted that the orientation or position relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present utility model 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 cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be a connection between the insides of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances. Multiple technical solutions in the same embodiment, and multiple technical solutions in different embodiments, can be arranged and combined to form new technical solutions that do not have contradictions or conflicts, all of which are within the scope of protection required by the present utility model.

[0029] Example 1

[0030] See also Figure 1 The present embodiment provides a high-life high-voltage shielded insulated down conductor, which includes, from the inside to the outside, a central heat dissipation pipe 1, a concentric conductor 2, a conductor tape layer 3, a semi-conductive conductor shielding layer 4, a cross-linked polyethylene insulation layer 5, a semi-conductive insulation shielding layer 6, a metal tape shielding layer 7 and a sheath layer 8; the central heat dissipation pipe 1 is a hollow tube made of polyethylene, the concentric conductors 2 are evenly distributed on the outer surface of the central heat dissipation pipe 1, the material of the concentric conductors 2 is aluminum alloy, and a plurality of round monofilaments are evenly wound on the surface of the central heat dissipation pipe 1.

[0031] In the utility model, the number of aluminum alloy monofilaments is 30-38, which are evenly wound on the surface of the central heat dissipation tube 1, and the diameter of the aluminum alloy monofilaments is 1.25-1.41 mm.

[0032] The central heat dissipation pipe 1 is a hollow circular tube made of high thermal conductivity polyethylene material, and uses flowing gas to quickly take away the heat generated by direct lightning in the down conductor.

[0033] The composition of high thermal conductivity polyethylene can be 87 parts of high-density polyethylene, 7 parts of boron nitride, 4 parts of aluminum oxide, 1 part of nano titanium dioxide, 0.7 parts of magnesium oxide, and 0.3 parts of antioxidant. Through the reasonable proportion of materials, the thermal conductivity of polyethylene is increased by about 40%, and its stability is improved by adding antibacterial agents, antioxidants and other additives. Immediately after a direct lightning strike occurs, flowing inert gas or coolant is injected into the heat dissipation channel to take away the heat in time and prevent damage to the insulation layer.

[0034] The extension line of the center of the concentric conductor 2 is arranged in parallel with the extension line of the center of the central heat dissipation tube 1 , and the diameter ratio of the central heat dissipation tube to the concentric conductor is 0.8-0.9.

[0035] The conductor tape layer 3 is made of semi-conductive nylon tape, which tightly wraps the concentric conductor 2, wraps it in an overlapping manner, and tightens the conductor to prevent the conductor from loosening and not hinder the electrical connection between the conductor and the inner shield. The thickness of the conductor tape layer 3 is 0.1 mm.

[0036] The semi-conductive conductor shielding layer 4 is made of a thermoplastic inner semi-conductive shielding material, which covers the conductor tape layer 3 and has a thickness of 0.5±0.1 mm.

[0037] The material of the cross-linked polyethylene insulation layer 5 is peroxide cross-linked polyethylene insulation material, covering the semi-conductive conductor shielding layer 4, and having a thickness of 5.5±0.2 mm.

[0038] The semi-conductive insulating shielding layer 6 is made of a thermoplastic outer semi-conductive shielding material, which covers the cross-linked polyethylene insulating layer 5 and has a thickness of 0.5±0.1 mm.

[0039] The semi-conductive conductor shielding layer 4, the cross-linked polyethylene insulation layer 5 and the semi-conductive insulation shielding layer 6 adopt a three-layer co-extrusion structure. The inner and outer semi-conductive structures in the three-layer co-extrusion can make the electric field on the insulation surface evenly distributed, so that the cross-linked polyethylene material can give full play to its insulation performance, with stronger lightning voltage resistance and higher voltage resistance level. The maximum impulse withstand voltage can reach 500kV.

[0040] The semi-conductive conductor shielding layer 4 is the innermost layer of the three-layer co-extruded material, which homogenizes the electric field strength around the conductor and prevents insulation breakdown caused by tip discharge.

[0041] The cross-linked polyethylene insulation layer 5 is a three-layer co-extruded middle layer insulation material with good insulation performance and high voltage resistance level.

[0042] The semi-conductive insulating shielding layer 6 is the outermost layer of the three-layer co-extruded material, which prevents the metal shielding from damaging the insulating layer and causing insulation breakdown due to tip discharge.

[0043] The material of the metal belt shielding layer 7 is copper belt, which is overlapped and wrapped on the surface of the semi-conductive insulating shielding layer 6. The shielding layer is designed mainly to eliminate the damage of the electromagnetic field to the surrounding electrical equipment and electrical components, and safely introduce the direct lightning current into the earth. Even if the lightning breaks down the insulation, the excellent conductivity of the copper belt can safely introduce the current into the earth to avoid damage to external equipment. The thickness is 0.1mm, and the overlap rate is 10% to 15%.

[0044] The material of the sheath layer 8 is the commonly used 90°C polyvinyl chloride material, which is evenly extruded and arranged on the outer surface of the metal belt shielding layer 7 to protect the internal functional structure of the cable from external damage and destruction, and to protect the safe and stable operation of the cable. The thickness is 3.2±0.3mm.

[0045] The factors that affect the heat generated by the conductor in the circuit are determined by the current, resistance, and time. Since we cannot intervene in the current and time of lightning, we can only reduce the heat generation by reducing the resistance. The characteristics of lightning current are short time and large current. If a solid conductor is used, the skin effect will reduce the effective cross-section of the conductor and increase the resistance. At the same time, the conductor, insulation, and shielding will produce capacitive reactance and inductive reactance. By calculating the high-frequency impedance of the cable and increasing the outer diameter of the inner conductor, the high-frequency impedance of the cable can be effectively reduced. Therefore, the utility model adopts concentric conductors, which can effectively reduce the heat generated by direct lightning inside the cable.

[0046] The above schematically describes the present invention and its implementation methods, which are not restrictive. The drawings show only one implementation method of the present invention, and the actual structure is not limited thereto. Therefore, if ordinary technicians in this field are inspired by it and design structural methods and embodiments similar to the technical solution without creativity without departing from the purpose of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A high-life high-voltage shielded insulated down conductor, characterized in that: The insulated down conductor includes, from the inside to the outside, a central heat dissipation pipe, a concentric conductor, a conductor tape layer, a semi-conductive conductor shielding layer, a cross-linked polyethylene insulation layer, a semi-conductive insulation shielding layer, a metal tape shielding layer and a sheath layer; the central heat dissipation pipe is a hollow tube made of polyethylene, and the concentric conductors are evenly distributed on the outer surface of the central heat dissipation pipe.

2. The long-life high-voltage shielded insulated down conductor according to claim 1, characterized in that: The central heat dissipation tube is a hollow circular tube, and the extension line of the center of the circle of the concentric conductor is arranged in parallel with the extension line of the center of the circle of the central heat dissipation tube.

3. The long-life high-voltage shielded insulated down conductor according to claim 1, characterized in that: The diameter ratio of the central heat dissipation pipe to the concentric conductor is 0.8-0.

9.

4. The long-life high-voltage shielded insulated down conductor according to claim 1, characterized in that: The conductor tape layer tightly covers the concentric conductor, and the thickness of the conductor tape layer is 0.1 mm.

5. The long-life high-voltage shielded insulated down conductor according to claim 1, characterized in that: The semiconductive conductor shielding layer covers the conductor tape layer, and has a thickness of 0.5±0.1 mm; the cross-linked polyethylene insulation layer covers the semiconductive conductor shielding layer, and has a thickness of 5.5±0.2 mm; the semiconductive insulation shielding layer covers the cross-linked polyethylene insulation layer, and has a thickness of 0.5±0.1 mm.

6. The long-life high-voltage shielded insulated down conductor according to claim 1, characterized in that: The metal tape shielding layer is wrapped around the outer surface of the semi-conductive insulating shielding layer, has a thickness of 0.1 mm, and an overlap rate of 10% to 15%.

7. The long-life high-voltage shielded insulated down conductor according to claim 1, characterized in that: The sheath layer is evenly extruded and arranged on the outer surface of the metal belt shielding layer, and has a thickness of 3.2±0.3 mm.

8. A long-life high-voltage shielded insulated down conductor according to any one of claims 1 to 7, characterized in that: The number of monofilaments of the concentric conductor is 30 to 38.

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