Nuclear power coaxial cable

Abstract

The utility model relates to a nuclear power coaxial cable, which comprises a central conductor, an insulating layer, a grounding layer and an outer coating layer which are sequentially arranged from inside to outside, the central conductor is bare copper, and the usage amount of the central conductor is 45 kg / km to 55 kg / km; the insulating layer is made of crosslinked polyethylene, and the thickness of the insulating layer is 2 mm to 2.5 mm; the grounding layer is formed by weaving a plurality of strands of conductive wires, each strand of conductive wire comprises a plurality of bare copper wires, the diameter of a single bare copper wire is 0.15 mm-0. 17 mm, the weaving pitch of the grounding layer is 63 mm-67 mmm, the shielding rate of the grounding layer is 92%-98%, and the direct current resistance of the grounding layer is 1.4 ohm / km-1. 65 ohm / k. According to the nuclear power coaxial cable, the grounding resistance can be reduced under the condition that the diameter of the center conductor is small, and the electrical safety of the nuclear power coaxial cable is improved.

Description

Technical Field

[0001] This utility model relates to the field of cable technology, specifically to a nuclear power coaxial cable. Background Technology

[0002] Nuclear power coaxial cables are widely used in control, monitoring, and communication systems of nuclear power plants, such as external nuclear measurement systems and signal transmission inside and outside the containment. They play a crucial role in ensuring the safe operation of nuclear power plants and accurate signal transmission. Compared to conventional applications, nuclear power plant applications place higher demands on the electrical, mechanical, extreme environment resistance, and safety performance of coaxial cables. Coaxial cables typically include a center conductor, the size of which, such as its diameter, is related to the current carrying capacity required for the actual application. When existing nuclear power coaxial cables are modified to reduce the size of their center conductors to meet practical application needs, it often results in a higher grounding resistance. A high grounding resistance can easily lead to leakage, causing the outer casing to become electrified or resulting in electric shock, and can also damage equipment and increase energy loss. Utility Model Content

[0003] In view of the shortcomings of the prior art, the purpose of this utility model is to provide a nuclear power coaxial cable that can reduce grounding resistance and improve electrical safety with a smaller center conductor diameter.

[0004] To achieve the objectives of this utility model, a nuclear power coaxial cable is provided, comprising a center conductor, an insulation layer, a grounding layer, and an outer sheath arranged sequentially from the inside out. The center conductor is bare copper, and the amount of the center conductor is 45 kg / km to 55 kg / km. The insulation layer is cross-linked polyethylene, and the thickness of the insulation layer is 2 mm to 2.5 mm. The grounding layer is braided from multiple strands of conductive wire, each strand containing multiple bare copper wires, the diameter of a single bare copper wire being 0.15 mm to 0.17 mm, the braiding pitch of the grounding layer being 63 to 67 mm, the shielding rate of the grounding layer being 92% to 98%, and the DC resistance of the grounding layer being 1.4 Ω / km to 1.65 Ω / k.

[0005] In some embodiments of this utility model, the pitch of the grounding layer is 64.5~65.5mm, and the DC resistance of the grounding layer is 1.4Ω / km~1.6Ω / km.

[0006] In some embodiments of this utility model, the grounding layer is a double layer, with the first grounding layer being closer to the insulating layer than the second grounding layer; the first grounding layer is braided from 15 to 17 strands of conductive wire, with each strand containing 10 to 12 bare copper wires; the second grounding layer is braided from 15 to 17 strands of conductive wire, with each strand containing 11 to 13 bare copper wires.

[0007] In some embodiments of this utility model, the total thickness of the grounding layer is 1.2mm to 1.5mm.

[0008] In some embodiments of this utility model, the thickness of the first grounding layer is 0.6mm~0.9mm, and the thickness of the second grounding layer is 0.5mm~0.9mm.

[0009] In some embodiments of this utility model, the grounding layer is a single layer, which is woven from 22 to 26 strands of conductive wire, and each strand of conductive wire contains 8 to 10 bare copper wires.

[0010] In some embodiments of this utility model, the thickness of the grounding layer is 0.9~1.3mm.

[0011] In some embodiments of this utility model, the central conductor is composed of a single copper wire core or multiple copper wire cores, the diameter of the central conductor is 2.6mm~2.8mm, the material of the central conductor is bare copper, and the DC resistance of the central conductor is 2Ω / km~3Ω / km.

[0012] In some embodiments of this utility model, the thickness of the outer layer is 0.8mm~1mm, and the material is halogen-free flame retardant material, polyvinyl chloride or thermoplastic polyurethane elastomer.

[0013] In some embodiments of this invention, the insulating layer is made of modified cross-linked polyolefin, and the volume resistivity of the insulating layer is ≥10 Ω·cm. 15 Ω·m.

[0014] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0015] The nuclear power coaxial cable of this utility model has a center conductor weight of 45kg / km to 55kg / km. Matching the center conductor, a grounding layer is made of multiple strands of conductive wire containing multiple bare copper wires. With appropriate braiding spacing and shielding rate, the grounding layer has low resistance, which can effectively prevent the equipment casing from becoming live or personnel from being electrocuted, protect the equipment, reduce energy loss, and improve electrical safety. Attached Figure Description

[0016] Figure 1 This is a structural diagram of the first embodiment of the nuclear power coaxial cable of this utility model.

[0017] Figure 2 This is a structural diagram of the second embodiment of the nuclear power coaxial cable of this utility model.

[0018] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Detailed Implementation

[0019] like Figure 1 As shown, this utility model provides a first embodiment of a nuclear power coaxial cable. This nuclear power coaxial cable can be used for control, monitoring, or communication in nuclear power plants, as well as in other fields and scenarios. The nuclear power coaxial cable of this utility model is particularly suitable for scenarios with low current-carrying capacity requirements, such as when the amount of the center conductor 10 is below 60 kg / km. Even with a reduction in the size of the center conductor 10, a low grounding resistance can still be guaranteed, improving the electrical safety of the nuclear power coaxial cable.

[0020] Specifically, the nuclear power coaxial cable of this embodiment includes a center conductor 10, an insulation layer 20, a grounding layer 30, and an outer sheath 40 arranged sequentially from the inside out. Adjacent center conductors 10, insulation layers 20, grounding layers 30, and outer sheaths 40 are in contact with each other; that is, they are directly adjacent without any other functional layers separating them. The center conductor 10, insulation layer 20, grounding layer 30, and outer sheath 40 are concentrically or substantially concentrically arranged, with a concentricity of not less than 80%.

[0021] The center conductor 10 is bare copper, which is copper without any surface treatment, coating, or other materials. It is pure copper directly exposed to the air, possessing good conductivity and readily available raw materials. The amount of center conductor 10 used is 45 kg / km to 55 kg / km, for example, 45 kg / km, 46 kg / km, 47 kg / km, 48 kg / km, 49 kg / km, 50 kg / km, 51 kg / km, 52 kg / km, 53 kg / km, 54 kg / km, 55 kg / km, etc. When the amount of center conductor 10 is within the above range, it can meet the current carrying capacity requirements of some cables for control, monitoring, or communication in nuclear power plants, and can save conductive materials.

[0022] The insulation layer 20 is made of cross-linked polyethylene. Cross-linked polyethylene has good gas and liquid barrier properties as well as insulation properties, which can effectively protect the center conductor 10 from corrosion and prevent faults such as short circuits between the center conductor 10 and the grounding layer 30. The thickness of the insulation layer 20 is 2mm to 2.5mm, for example, it can be 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, etc. When the thickness of the insulation layer 20 is within the above range, it can provide sufficient insulation performance.

[0023] The grounding layer 30 is braided from multiple strands of conductive wire, with the number of strands ranging from 10 to 30. The grounding layer 30 can be formed by braiding multiple strands of conductive wire around the outer side of the insulating layer 20. Each conductive wire contains multiple bare copper wires, for example, 5 to 30 bare copper wires, and each conductive wire can be formed by twisting multiple bare copper wires together. The diameter of a single bare copper wire is 0.15 mm to 0.17 mm, for example, 0.15 mm, 0.16 mm, 0.17 mm, etc. The manufacturing process for bare copper wires with these diameters is mature and readily available. The braiding pitch of the grounding layer 30 is 63 to 67 mm, for example, 63 mm, 64 mm, 65 mm, 66 mm, 67 mm. The pitch is the distance that each strand of conductive wire moves axially in one revolution. The shielding rate of the grounding layer 30 is 92%~98%, for example, 92%, 93%, 94%, 95%, 96%, 97%, 98%, etc. The shielding rate of the grounding layer 30 refers to the degree to which the grounding layer 30 covers the surface of the insulating layer 20. The DC resistance of the grounding layer 30 is affected by the area of ​​the grounding layer 30, the size of the bare copper wire, the braiding pitch, and the braiding shielding rate. The contact area between the grounding layer 30 and the insulation layer 20 can be determined by the amount of the center conductor 10 and the thickness of the insulation layer 20. In this embodiment, for specific dimensions of the center conductor 10, insulation layer 20, and bare copper wire, the DC resistance of the grounding layer 30 can be reduced to 1.4Ω / km to 1.65Ω / km, such as 1.4Ω / km, 1.45Ω / km, 1.5Ω / km, 1.55Ω / km, 1.6Ω / km, and 1.65Ω / km. This reduces the resistance of the grounding layer, avoids dangerous situations such as live equipment casing or electric shock, and improves the electrical safety of nuclear power coaxial cables.

[0024] In addition, the grounding layer 30 also serves as electromagnetic shielding, preventing external electromagnetic interference from affecting the signal transmission of the central conductor 10. The outer sheath 40 covers the outside of the grounding layer 30, providing better protection against external environmental corrosion.

[0025] Therefore, this embodiment provides a nuclear power coaxial cable that can still ensure a low grounding resistance even with a low amount of center conductor 10, thereby improving the electrical safety of the nuclear power coaxial cable. It can be used for control, monitoring, or communication in nuclear power plants.

[0026] In some examples, the braiding pitch of the grounding layer 30 is 64.5~65.5mm, for example, it can be 64.5mm, 65mm, 65.5mm, etc., which can reduce the DC resistance of the grounding layer 30 to 1.4Ω / km~1.6Ω / km, and the braiding is convenient.

[0027] In some examples, the grounding layer 30 is double-layered, forming a double-layer grounding layer 30 or a double-layer shield, resulting in better electromagnetic shielding. The grounding layer 30 consists of a first grounding layer 31 and a second grounding layer 32. The first grounding layer 31 is closer to the insulating layer 20 than the second grounding layer 32, and the area of ​​the second grounding layer 32 is larger than that of the first grounding layer 31. The first grounding layer 31 is braided from 15 to 17 strands of conductive wire, for example, 15, 16, or 17 strands, with each strand containing 10 to 12 bare copper wires, for example, 10, 11, or 12. The second grounding layer is also braided from 15 to 17 strands of conductive wire, for example, 15, 16, or 17 strands, with each strand containing 11 to 13 bare copper wires, for example, 11, 12, or 13. The second grounding layer 32 can have more strands or more bare copper wires per conductive wire compared to the first grounding layer 31, thereby forming a larger outer grounding layer. When the number of strands and wires used in the first grounding layer 31 and the second grounding layer 32 are within the above-mentioned range, the required resistance range can be obtained.

[0028] In some examples, the total thickness of the grounding layer 30 is 1.2mm to 1.5mm, for example, it can be 1.2mm, 1.3mm, 1.4mm, 1.5mm, etc.

[0029] In some examples, the thickness of the first grounding layer 31 is 0.6mm to 0.9mm, such as 0.6mm, 0.7mm, 0.8mm, 0.9mm, etc. The thickness of the second grounding layer 32 is 0.5mm to 0.9mm, such as 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, etc.

[0030] In some examples, the center conductor is composed of a single copper core or multiple copper cores, and the diameter of the center conductor 10 is 2.6mm to 2.8mm, for example, 2.6mm, 2.7mm, 2.8mm, etc., which has a small size. The DC resistance of the center conductor 10 is 2Ω / km to 3Ω / km, which meets the signal transmission requirements in some scenarios.

[0031] In some examples, the thickness of the outer layer 40 is 0.8mm to 1mm, such as 0.8mm, 0.9mm, 1mm, etc., which can provide good protection. The material of the outer layer 40 is halogen-free flame retardant material, polyvinyl chloride, or thermoplastic polyurethane elastomer. Halogen-free flame retardant material and PVC have good insulation and flame retardancy, while thermoplastic polyurethane elastomer has good insulation and flame retardancy as well as good flexibility. Moreover, the raw materials of the above materials are readily available.

[0032] In some examples, the insulating layer 20 is made of modified cross-linked polyolefin, wherein the volume resistivity of the insulating layer 20 is ≥10 Ω·cm. 15Ω·m, providing good insulation. Modified cross-linked polyolefins, such as halogen-free flame-retardant cross-linked polyethylene, improve the overall flame retardancy of the cable. Halogen-free flame-retardant cross-linked polyethylene is an existing material, for example, made by cross-linking polyethylene with added halogen-free flame retardants.

[0033] This utility model also provides a second embodiment of a nuclear power coaxial cable. The nuclear power coaxial cable in this embodiment is basically the same as the first embodiment, except that the grounding layer 30 in the second embodiment is a single layer, and is braided from 22 to 26 strands of conductive wire, such as 22, 23, 24, 25, or 26 strands. Each strand contains 8 to 10 bare copper wires, such as 8, 9, or 10. When the number of strands and wires used in the grounding layer 30 is within the above range, the required resistance range can be obtained.

[0034] In some examples, the thickness of the grounding layer 30 is 0.9mm to 1.3mm, such as 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, etc.

[0035] Finally, it should be emphasized that the above description is only a preferred embodiment of this utility model and is not intended to limit this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A nuclear power coaxial cable, characterized in that... The device comprises, from the inside out, a central conductor, an insulating layer, a grounding layer, and an outer sheath. The central conductor is bare copper, and the amount of the central conductor used is 45 kg / km to 55 kg / km. The insulating layer is cross-linked polyethylene, and the thickness of the insulating layer is 2 mm to 2.5 mm. The grounding layer is braided from multiple strands of conductive wire, each strand containing multiple bare copper wires. The diameter of a single bare copper wire is 0.15 mm to 0.17 mm. The braiding pitch of the grounding layer is 63 mm to 67 mm. The shielding rate of the grounding layer is 92% to 98%, and the DC resistance of the grounding layer is 1.4 Ω / km to 1.65 Ω / km.

2. The nuclear power coaxial cable according to claim 1, characterized in that... The grounding layer has a braided pitch of 64.5mm to 65.5mm and a DC resistance of 1.4Ω / km to 1.6Ω / km.

3. A nuclear power coaxial cable according to claim 1 or 2, characterized in that... The grounding layer is a double layer, with the first grounding layer being closer to the insulating layer than the second grounding layer; the first grounding layer is braided from 15 to 17 strands of conductive wire, with each strand containing 10 to 12 bare copper wires; the second grounding layer is braided from 15 to 17 strands of conductive wire, with each strand containing 11 to 13 bare copper wires.

4. A nuclear power coaxial cable according to claim 3, characterized in that... The total thickness of the grounding layer is 1.2mm to 1.5mm.

5. A nuclear power coaxial cable according to claim 3, characterized in that... The thickness of the first grounding layer is 0.6mm~0.9mm, and the thickness of the second grounding layer is 0.5mm~0.9mm.

6. A nuclear power coaxial cable according to claim 1 or 2, characterized in that... The grounding layer is a single layer, which is woven from 22 to 26 strands of conductive wire, and each strand of conductive wire contains 8 to 10 bare copper wires.

7. A nuclear power coaxial cable according to claim 3, characterized in that... The thickness of the grounding layer is 0.9mm to 1.3mm.

8. A nuclear power coaxial cable according to claim 1 or 2, characterized in that... The center conductor is composed of a single copper wire core or multiple copper wire cores, the diameter of the center conductor is 2.6mm~2.8mm, and the DC resistance of the center conductor is 2Ω / km~3Ω / km.

9. A nuclear power coaxial cable according to claim 1 or 2, characterized in that... The outer layer has a thickness of 0.8mm to 1mm and is made of halogen-free flame-retardant material, polyvinyl chloride, or thermoplastic polyurethane elastomer.

10. A nuclear power coaxial cable according to claim 1 or 2, characterized in that... The insulating layer is made of modified cross-linked polyolefin, and the volume resistivity of the insulating layer is ≥10. 15 Ω·m.

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