Anti-interference water-blocking medium-voltage cable for maglev traffic

Abstract

The invention discloses an anti-interference water-blocking medium-voltage cable for maglev traffic, which comprises a cable core, an insulating layer, an outer water-blocking layer, a shielding layer and a sheath layer, the cable core is a plurality of strands of stranded guide wires, gaps are filled with water-blocking powder, the insulating layer, the outer water-blocking layer, the shielding layer and the sheath layer are sequentially arranged outside the cable core, and the outer water-blocking layer is arranged outside the sheath layer. The cable has good water-blocking performance and excellent anti-interference performance, is suitable for a magnetic suspension traffic system, and has a huge potential market prospect.

Description

Technical Field

[0001] The invention relates to the technical field of cables, in particular to the technical field of anti-interference water-blocking medium-voltage cables for magnetic suspension transportation. Background Art

[0002] With the rapid development of maglev transportation technology, people have put forward higher requirements on the supporting cables; the operating environment of maglev transportation is complex, there are strong electromagnetic interference fields, and there may be risks of water vapor intrusion under some special environments; traditional medium-voltage cables are difficult to meet the strict requirements of maglev transportation in terms of anti-interference and water-blocking performance; the shielding structure of ordinary cables has limited shielding effect when facing the high-frequency strong electromagnetic interference generated by the maglev system, which may cause signal transmission errors or unstable power transmission; in addition, when the cable is damaged or in a humid environment, moisture can easily penetrate along the gaps or voids inside the cable, affecting the insulation performance and service life of the cable, and thus endangering the safe and stable operation of maglev transportation; therefore, it is of great significance to develop an anti-interference and water-blocking medium-voltage cable specifically for maglev transportation. Summary of the invention

[0003] The purpose of the present invention is to solve the problems in the prior art and to propose an anti-interference and water-blocking medium-voltage cable for magnetic levitation transportation, which has good water-blocking performance and excellent anti-interference performance, is suitable for magnetic levitation transportation systems, and has huge potential market prospects.

[0004] To achieve the above-mentioned purpose, the present invention proposes an anti-interference, water-blocking medium-voltage cable for magnetic levitation transportation, comprising a cable core, an insulation layer, an outer water-blocking layer, a shielding layer and a sheath layer. The cable core is a multi-strand twisted guide wire and the gap is also filled with water-blocking powder. The insulation layer, outer water-blocking layer, shielding layer and sheath layer are sequentially arranged outside the cable core.

[0005] Preferably, the guide wire is a copper wire, and the water-blocking powder is a mixed powder of metal powder and water-swellable powder.

[0006] Preferably, the insulating layer is a cross-linked polyethylene sheath extruded and coated outside the cable core.

[0007] Preferably, the outer water-blocking layer is composed of a water-absorbing and swelling coating film coated on the outside of the insulating layer and a waterproof film wrapped around the water-absorbing and swelling coating film.

[0008] Preferably, the shielding layer comprises a copper wire braided sleeve woven outside the outer water-blocking layer and a copper wrapping tape wrapped around the copper wire braided sleeve.

[0009] Preferably, the sheath layer is a polyvinyl chloride sheath or a low-smoke halogen-free flame-retardant polyolefin sheath extruded and coated outside the shielding layer.

[0010] Preferably, an inner water-resistance layer and a conductor shielding layer are sequentially provided between the cable core and the insulation layer.

[0011] Preferably, the inner water-resistance layer is a semi-conductive water-resistance tape wrapped around the cable core.

[0012] Preferably, the conductor shielding layer is a semi-conductive sleeve extruded and coated outside the inner water-resistant layer.

[0013] Preferably, adhesive is coated between every two adjacent layers of the cable.

[0014] Beneficial effects of the present invention: 1) Excellent anti-interference performance: The double shielding structure of copper wire braided sleeve and copper wrapped tape can effectively resist high-frequency and low-frequency electromagnetic interference in the operation environment of magnetic levitation transportation, ensure the stability of power transmission and the accuracy of signal transmission, and avoid system failures caused by electromagnetic interference; 2) Good water-blocking performance: Multi-layer water-blocking layer design (the gaps in the cable core are filled with water-blocking powder; the cable core is directly wrapped with a semi-conductive water-blocking tape; the cable core is indirectly wrapped with an outer water-blocking layer composed of a water-absorbing and swelling coating and a waterproof film) can effectively prevent moisture from invading the cable. Even if the cable is damaged or in a high humidity environment, it can continue to maintain the insulation performance of the cable for a certain period of time, thereby extending the service life of the cable and improving the operational reliability of the maglev transportation system. 3) Reliable electrical performance: The use of high-quality copper conductors and cross-linked polyethylene insulation ensures low loss and high insulation performance of the cable during medium-voltage power transmission, which can meet the strict requirements of the maglev transportation system for power supply; 4) Excellent protective performance: Weather resistance, corrosion resistance, good sheath layer and tightly bonded structure between layers enable the cable to resist the influence of adverse factors such as external mechanical damage, chemical corrosion and ultraviolet radiation, while reducing the generation of smoke and harmful gases in the event of a fire, providing all-round protection for the safe operation of maglev transportation.

[0015] The features and advantages of the present invention will be described in detail through embodiments in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic structural diagram of the anti-interference water-blocking medium-voltage cable for magnetic levitation transportation of the present invention; Figure 2 It is a cross-sectional view of the anti-interference water-blocking medium-voltage cable for magnetic levitation transportation of the present invention.

[0017] In the figure: 1-cable core, 2-insulating layer, 3-external water-blocking layer, 31-water-absorbing and swelling resin coating, 32-waterproof film, 4-shielding layer, 5-jacket layer, 6-inner water-blocking layer, 7-conductor shielding layer. DETAILED DESCRIPTION

[0018] See also Figure 1 and Figure 2 The anti-interference water-blocking medium-voltage cable for magnetic levitation transportation of the present invention comprises a cable core 1, an insulating layer 2, an outer water-blocking layer 3, a shielding layer 4 and a sheath layer 5. The cable core 1 is a multi-strand twisted guide wire and the gap is also filled with water-blocking powder. The insulating layer 2, the outer water-blocking layer 3, the shielding layer 4 and the sheath layer 5 are sequentially arranged outside the cable core 1.

[0019] The guide wire is a copper wire, and the water-blocking powder is a mixture of metal powder and water-swellable powder; wherein the copper wire has good electrical conductivity and can ensure efficient transmission of electricity; the number of strands of the copper wire is 30 to 60 and the twisted pitch-diameter ratio is 12 to 14 times, thereby not only meeting the current carrying capacity requirements of magnetic levitation transportation, but also reducing the influence of the skin effect to a certain extent; in addition, the metal powder can be selected from copper powder, and the water-swellable powder can be selected from water-swellable resin powder, thereby, on the one hand, the conductor resistance can meet the requirements, and on the other hand, it can prevent water molecules from moving in the conductor.

[0020] The insulating layer 2 is a cross-linked polyethylene sheath (made of XLPE material) extruded and coated outside the cable core 1; wherein, the XLPE material has excellent electrical insulation performance, temperature resistance and mechanical properties, can withstand the voltage stress of the medium-voltage system of magnetic levitation transportation, and maintain stable insulation characteristics during long-term operation; in addition, the thickness of the insulating layer 2 can be accurately designed according to the rated voltage of the cable to ensure sufficient insulation strength; when processing the insulating layer 2, the cross-linked polyethylene material can be first melted by a high-temperature extruder and then evenly extruded, and the thickness and concentricity can be controlled by a mold, and then cross-linking treatment is performed after extrusion to allow the XLPE material to form a stable three-dimensional network structure, thereby effectively improving the insulation performance.

[0021] The outer water-blocking layer 3 is composed of a water-swellable coating 31 coated on the outside of the insulating layer 2 and a waterproof film 32 wrapped around the outside of the water-swellable coating 31; wherein the water-swellable coating 31 can be a water-swellable resin film, so that it quickly swells and forms a gel-like substance when it meets water, effectively preventing further penetration of moisture; the waterproof film 32 can be made of a metal foil, so that on the basis of providing good waterproof barrier performance (i.e., preventing external moisture from invading the inside of the cable), it also plays a certain role in shielding electromagnetic interference; when making the outer water-blocking layer 3, the water-swellable resin material can be evenly coated on the surface of the insulating layer 2 to form the water-swellable coating 31, and then the metal foil can be wrapped around the outside of the water-swellable coating 31 with a certain overlap rate (tight fit and flatness must be ensured during the wrapping process).

[0022] The shielding layer 4 includes a copper wire braided sleeve woven outside the outer water-blocking layer 3 and a copper wrapping tape wrapped around the copper wire braided sleeve; wherein the copper wire braided sleeve has a high shielding efficiency and can effectively shield high-frequency electromagnetic interference, and the copper wrapping tape is mainly used to shield low-frequency electromagnetic interference; the copper wire braided sleeve and the copper wrapping tape can work together to greatly improve the anti-interference ability of the cable, ensure that the signal transmission in the magnetic levitation transportation system is not affected by electromagnetic interference, and at the same time ensure the stability of power transmission; when processing the shielding layer 4, copper wire of suitable specifications can be selected first and braided using a braiding machine (control the braiding density and braiding angle) so that it is tightly covered outside the outer water-blocking layer 3, and then the copper wrapping tape is spirally wrapped around the copper wire braided sleeve (pay attention to the tension and overlapping width of the copper wrapping tape when wrapping).

[0023] The sheath layer 5 is a polyvinyl chloride sheath (PVC sheath) or a low-smoke halogen-free flame-retardant polyolefin sheath extruded and coated on the outside of the shielding layer 4; wherein, the sheath layer 5 is prepared by using polyvinyl chloride material or low-smoke halogen-free flame-retardant polyolefin material with good weather resistance and corrosion resistance, which can not only protect the internal structure of the cable from damage by external factors such as mechanical damage, chemical corrosion and ultraviolet radiation, but also when a fire occurs, the low-smoke halogen-free flame-retardant polyolefin sheath can reduce the generation of smoke and harmful gases, which is beneficial to personnel evacuation and fire rescue; during the period of heating, melting and extruding the polyvinyl chloride material or low-smoke halogen-free flame-retardant polyolefin material in the extruder, it is necessary to control the thickness, surface finish and outer diameter of the sheath layer 5 in real time to ensure the overall appearance quality and mechanical protection performance of the cable.

[0024] An inner water-resistance layer 6 and a conductor shielding layer 7 are sequentially arranged between the cable core 1 and the insulating layer 2 .

[0025] The inner water-resistance layer 6 is a semiconductive water-resistance tape wrapped around the cable core 1, and the conductor shielding layer 7 is a semiconductive sleeve extruded and wrapped around the inner water-resistance layer 6; wherein, the semiconductive water-resistance tape can further improve the water resistance of the cable core; in addition, since the inner water-resistance layer 6 and the conductor shielding layer 7 are both made of semiconductive materials, the electric field can be evenly distributed, thereby avoiding the problem of insulation breakdown caused by local electric field concentration.

[0026] An adhesive is coated between each two adjacent layers of the cable; the adhesive can ensure that the layers are tightly bonded to prevent moisture from penetrating between the layers, and can also improve the overall mechanical strength of the cable to a certain extent.

[0027] The above embodiments are intended to illustrate the present invention, not to limit the present invention. Any solution that is a simple transformation of the present invention belongs to the protection scope of the present invention.

Claims

1. Anti-interference water-blocking medium-voltage cable for magnetic levitation transportation, characterized by: The cable core (1) comprises a cable core (1), an insulating layer (2), an outer water-blocking layer (3), a shielding layer (4) and a sheath layer (5); the cable core (1) is a plurality of twisted guide wires and the gaps are filled with water-blocking powder; the insulating layer (2), the outer water-blocking layer (3), the shielding layer (4) and the sheath layer (5) are sequentially arranged outside the cable core (1).

2. The anti-interference water-blocking medium-voltage cable for magnetic levitation transportation according to claim 1, characterized in that: The guide wire is a copper wire, and the water-blocking powder is a mixed powder of metal powder and water-absorbing and expanding powder.

3. The anti-interference water-blocking medium-voltage cable for magnetic levitation transportation according to claim 1, characterized in that: The insulating layer (2) is a cross-linked polyethylene sheath that is extruded and coated on the outside of the cable core (1).

4. The anti-interference water-blocking medium-voltage cable for magnetic levitation transportation according to claim 1, characterized in that: The outer water-blocking layer (3) is composed of a water-absorbing and swelling coating (31) coated on the outside of the insulating layer (2) and a waterproof film (32) wrapped around the outside of the water-absorbing and swelling coating (31).

5. The anti-interference water-blocking medium-voltage cable for magnetic levitation transportation according to claim 1, characterized in that: The shielding layer (4) comprises a copper wire braided sleeve braided outside the outer water-blocking layer (3) and a copper wrapping tape wrapped around the copper wire braided sleeve.

6. The anti-interference water-blocking medium-voltage cable for magnetic levitation transportation according to claim 1, characterized in that: The sheath layer (5) is a polyvinyl chloride sheath or a low-smoke halogen-free flame-retardant polyolefin sheath that is extruded and coated outside the shielding layer (4).

7. The anti-interference water-blocking medium-voltage cable for magnetic levitation transportation according to any one of claims 1 to 6, characterized in that: An internal water-resistance layer (6) and a conductor shielding layer (7) are sequentially arranged between the cable core (1) and the insulating layer (2).

8. The anti-interference water-blocking medium-voltage cable for magnetic levitation transportation according to claim 7, characterized in that: The inner water-resistance layer (6) is a semi-conductive water-resistance tape wrapped around the cable core (1).

9. The anti-interference water-blocking medium-voltage cable for magnetic levitation transportation according to claim 7, characterized in that: The conductor shielding layer (7) is a semi-conductive sleeve extruded and coated outside the inner water-resistance layer (6).

10. The anti-interference water-blocking medium-voltage cable for magnetic levitation transportation according to claim 7, characterized in that: Adhesive is also coated between each two adjacent layers of the cable.

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