High-voltage cable

Abstract

The present invention provides a high-voltage cable, which includes a conductor, a semiconductive tape sleeved outside the conductor, a conductor shielding layer sleeved outside the semiconductive tape, an insulating layer sleeved outside the conductor shielding layer, an insulation shielding layer sleeved outside the insulating layer, a semiconductive buffer water-blocking layer sleeved outside the insulation shielding layer, a corrugated aluminum sheath sleeved outside the semiconductive buffer water-blocking layer, an anticorrosion layer sleeved outside the corrugated aluminum sheath, a sheath sleeved outside the anticorrosion layer, and a conductive layer sleeved outside the sheath. A temperature measurement unit is arranged in the semiconductive buffer water-blocking layer, and the temperature measurement unit includes a stainless steel tube optical cable and support members arranged on both sides of the stainless steel tube optical cable. The high-voltage cable provided by the present invention has good insulation performance, can realize real-time and accurate temperature measurement, accurately locate the fault position, has good water-blocking performance, and can effectively prevent termite gnawing, etc., and can operate safely in a high-voltage environment.

Description

Technical Field

[0001] The present invention relates to the field of cable manufacturing, and particularly to a high-voltage cable. Background Art

[0002] In the process of building the "new generation power grid" by the State Grid system, it is particularly important to adopt technical measures to effectively solve the problem of the safe operation of high-voltage cables. High-voltage cables with an optical fiber composite structure are the development direction of new technologies, which helps to promote the high-end development of China's cable engineering and also meets the requirements of "intrinsic safety" of the new generation power grid. High-voltage cable failures are often caused by a decrease in insulation level, an increase in leakage current, an increase in losses, resulting in a temperature rise. The temperature rise further ages the insulation, increases the leakage current, and raises the temperature again, ultimately leading to insulation breakdown and even fire. The temperature rise is a major factor causing cable accidents, so it can be used as a parameter to reflect the operating conditions of the cable. Whether from the perspective of the safe operation of power cables themselves or from the perspective of the needs of power system dispatching, it is necessary to monitor the operating temperature of power cables in real time. Traditional temperature measurement is to lay a temperature measurement optical cable on the surface of the cable outer sheath. It is difficult to accurately measure the temperature of the insulation surface in this way, and it is also affected by the external environment. Therefore, this method has certain limitations. The optical cable is also subject to external forces, and the optical fiber breaks after mechanical damage and cannot measure temperature. The manufacturing, installation, laying, and maintenance of temperature measurement optical cables require a large amount of costs. At the same time, in southern China, the cases of high-voltage cables being damaged by termites and causing defects are on the rise. Termite damage to cables can reduce the insulation resistance of the cable sheath and allow water to penetrate into the cable through the perforated metal sheath, seriously threatening the safe operation of the cable. Summary of the Invention

[0003] In view of this, it is necessary to provide a high-voltage cable, which has better insulation performance, can achieve real-time temperature monitoring, has good water-blocking performance, and the cable is not easily damaged by termites, so as to ensure the safe operation of the cable.

[0004] A high-voltage cable includes a conductor, a semiconductive tape, a conductor shield layer, an insulating layer, an insulation shield layer, a semiconductive buffer water-blocking layer, a corrugated aluminum sheath, an anticorrosion layer, a sheath, and a conductive layer, which are sequentially coated from the inside out. A temperature measurement unit is provided in the semiconductive buffer water-blocking layer. The temperature measurement unit includes a stainless steel tube optical cable and support members arranged on both sides of the stainless steel tube optical cable.

[0005] Further, the stainless steel tube optical cable includes an optical fiber unit and a stainless steel tube, and the stainless steel tube is sleeved outside the optical fiber unit.

[0006] Further, the outer diameter of the support member is greater than the outer diameter of the stainless steel tube.

[0007] Further, the support member is one of copper wire, aluminum wire, or a semiconductive strip.

[0008] Further, the optical fiber unit includes two single-mode optical fibers and two multi-mode optical fibers.

[0009] Further, the sheath includes an inner sheath and an anti-termite outer sheath covering the inner sheath.

[0010] Further, the anti-termite outer sheath and the inner sheath are co-extruded into a double layer.

[0011] Further, the insulating layer is a cross-linked polyethylene insulating layer.

[0012] Further, the anti-termite outer sheath is a polyolefin sheath with a Shore hardness greater than 70.

[0013] Further, the temperature measurement unit and the support member are spirally wound inside the high-voltage cable.

[0014] Compared with the prior art, in the high-voltage cable of the present invention, the semi-conductive buffer water-blocking layer is provided with a temperature measurement unit. The temperature measurement unit includes a stainless steel tube optical cable and support members arranged on both sides of the stainless steel tube optical cable. The stainless steel tube optical cable can be used as a sensor to monitor the operating temperature of the high-voltage cable in real time, accumulate data, and find the temperature change conditions of the high-voltage cable in different seasons and different time periods of each day, so as to effectively master the operating conditions of the cable, avoid the occurrence of serious accidents. At the same time, the optical fiber sensing technology can also be used for rapid cable fault location, and the measurement is simple and the location is accurate. Description of the Drawings

[0015] Figure 1 It is a schematic cross-sectional structure diagram of a high-voltage cable in an embodiment of the present invention.

[0016] Description of the Main Element Symbols

[0017]

[0018]

[0019] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. Specific Embodiments

[0020] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0021] It should be noted that when a component is referred to as being "fixed to" another component, it can be directly on the other component or there may also be an intermediate component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intermediate component at the same time. When a component is considered to be "disposed on" another component, it can be directly disposed on the other component or there may be an intermediate component at the same time.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this invention belongs. The terms used in the description of the present invention herein are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "or / and" as used herein includes any and all combinations of one or more of the related listed items.

[0023] Please refer to Figure 1 , Figure 1Schematic diagram of the structure of a high-voltage cable 100 in an embodiment of the present invention. The high-voltage cable 100 includes a conductor 11 and a semiconductive tape 12 sleeved outside the conductor. A conductor shielding layer 13 is sleeved outside the semiconductive tape 12 to achieve a shielding effect. An insulating layer 14 is sleeved outside the conductor shielding layer 13 to achieve an insulating effect. In one embodiment, the insulating layer 14 is a cross-linked polyethylene insulating layer. An insulating shielding layer 15 is sleeved outside the insulating layer 14. A semiconductive buffer water-blocking layer 16 is sleeved outside the insulating shielding layer 15. A corrugated aluminum sheath 17 is sleeved outside the semiconductive buffer water-blocking layer 16. The corrugated aluminum sheath 17 can be formed by welding or extrusion. An anticorrosion layer 18 is sleeved outside the corrugated aluminum sheath 17. In one embodiment, the anticorrosion layer 18 is asphalt. A sheath 19 is sleeved outside the anticorrosion layer 18. The sheath 19 includes an inner sheath 191 and an anti-termite outer sheath 192 coated on the inner sheath 191. In this embodiment, the inner sheath 191 is a high-density polyethylene sheath, and the anti-termite outer sheath 192 is an ultra-high hardness anti-termite polyolefin sheath with a Shore hardness greater than 70. Using physical hardness to prevent termites, the anti-termite outer sheath 192 has good corrosion resistance, wear resistance, and elasticity. The anti-termite performance meets the national standard requirements, and according to the termite nest method, it reaches the first-level corrosion grade. At the same time, using the physical termite prevention method has no pollution to the environment and does not harm human health. Comparing with the chemical termite prevention method of adding repellents in the sheath to achieve the effect of killing termites, but the repellents will penetrate into the soil and volatilize into the air over time, polluting the environment and harming the human body, and the termite prevention performance also decreases day by day. Therefore, adopting this structure for termite prevention is environmentally friendly, has good effects, and is harmless to the human body. The anti-termite outer sheath 192 and the inner sheath 191 are co-extruded and formed. A conductive layer 20 is provided outside the anti-termite outer sheath 192. In one embodiment, the conductive layer 20 is graphite. In one embodiment, the rated voltage of the high-voltage cable 100 is 66 kV to 500 kV.

[0024] A temperature measuring unit 21 is provided in the semiconductive buffer water-blocking layer 16, and the temperature measuring unit 21 is spirally wound around the high-voltage cable 100. The temperature measuring unit 21 includes a stainless steel tube optical cable 211 and support members 212 provided on both sides of the stainless steel tube optical cable 211. The stainless steel tube optical cable 211 is very convenient during the installation process. The stainless steel tube optical cable 211 includes an optical fiber unit 2110 and a stainless steel tube 2111 sleeved outside the optical fiber unit 2110. The optical fiber unit 2110 is used to monitor the operating temperature of the high-voltage cable 100 in real time and accurately locate the fault position. In an embodiment, the stainless steel tube 2111 is a non-magnetic metal. The support members 212 are provided on both sides of the stainless steel tube 2111, and the outer diameter of the support members 212 is greater than the outer diameter of the stainless steel tube 2111 to reduce the impact of external force on the stainless steel tube 2111. The support members 212 can be one of copper wires, aluminum wires or semiconductive strips. In an embodiment, the support members 212 are copper wires. In an embodiment, the optical fiber unit 2110 has 2 multimode optical fibers (not shown in the figure) and 2 single-mode optical fibers (not shown in the figure). The single-mode optical fibers are for use, and the multimode optical fibers are for backup. When in use, the multimode optical fibers (not shown in the figure) are used for temperature measurement, and the single-mode optical fibers (not shown in the figure) are used for communication. When realizing the temperature measurement function, the optical fiber unit 2110 can be used as a sensor to monitor the operating temperature of the high-voltage cable 100 in real time, accumulate data, effectively master the operating conditions of the high-voltage cable 100, and avoid the occurrence of serious accidents.

[0025] A semiconductive buffer water-blocking layer 16 with a suitable thickness is used between the corrugated aluminum sheath 17 and the insulation shielding layer 15 in the high-voltage cable 100. The semiconductive buffer water-blocking layer 16 and the temperature measuring unit 21 are completed simultaneously in the winding process. Two layers of semiconductive buffer water-blocking layer 16 are respectively wound around the upper and lower parts of the temperature measuring unit 21. In addition to being supported by the support members 212 on both sides of the stainless steel tube optical cable 211, there is also a semiconductive buffer water-blocking layer 16 to buffer the impact force of the aluminum sheath on the stainless steel tube 2111 during corrugation, so that the compressive capacity of the temperature measuring unit 21 is enhanced. Furthermore, the troughs of the corrugated aluminum sheath 17 are inserted deeper into the semiconductive buffer water-blocking layer 16, and the insertion depth reaches 2 mm - 3 mm. The peaks of the corrugated aluminum sheath 17 are filled with the semiconductive buffer water-blocking layer 16, and the contact between the two changes from line contact to surface contact, ensuring that the circumferences of the corrugation troughs of the corrugated aluminum sheath 17 are in close contact with the surface of the semiconductive buffer water-blocking layer 16, ensuring that there is a path for the capacitive current in the radial direction, making the corrugated aluminum sheath 17 and the semiconductive buffer water-blocking layer 16 in good electrical continuous contact, keeping the two at the same potential, and not generating gap discharge. At the same time, a semiconductive buffer water-blocking layer 16 with a volume resistivity consistent with that of the insulation shielding layer 15 is used to achieve electric field homogenization, thereby ensuring that the high-voltage cable 100 has good water-blocking performance and is safe and reliable for long-term operation.

[0026] The high-voltage cable provided by the present invention has better insulation performance, can achieve real-time temperature monitoring, has good water-blocking performance, and the high-voltage cable is not easily damaged by termites, thereby ensuring the safe operation of the high-voltage cable.

[0027] Those of ordinary skill in the art of this technology should recognize that the above embodiments are only used to illustrate the present invention and are not used to limit the present invention. As long as appropriate changes and variations made to the above embodiments fall within the scope of the spirit of the present invention, they fall within the scope of protection required by the present invention.

Claims

1. A high-voltage cable, comprising a conductor, a semiconductive tape, a conductor shielding layer, an insulating layer, an insulating shielding layer, a semiconductive buffer water-blocking layer, a corrugated aluminum sheath, an anticorrosive layer, a sheath and a conductive layer which are sequentially coated from the inside to the outside, characterized in that, A temperature measuring unit is provided in the semi-conductive buffer water-blocking layer. The temperature measuring unit includes a stainless steel tube optical cable and support members disposed on both sides of the stainless steel tube optical cable; The stainless steel tube optical cable includes an optical fiber unit and a stainless steel tube, and the stainless steel tube is sleeved outside the optical fiber unit; The outer diameter of the support member is greater than the outer diameter of the stainless steel tube; The optical fiber unit includes two single-mode optical fibers and two multi-mode optical fibers; The outer circumferential surface of the corrugated aluminum sheath is provided with corrugations. The depth of the area of the corrugated aluminum sheath corresponding to the trough of the corrugation embedded in the semi-conductive buffer water-blocking layer is set as the first depth, and the depth of the area of the corrugated aluminum sheath corresponding to the peak of the corrugation embedded in the semi-conductive buffer water-blocking layer is set as the second depth. The first depth is greater than the second depth, so that the area of the corrugated aluminum sheath corresponding to the peak of the corrugation is filled by the semi-conductive buffer water-blocking layer. The first depth reaches 2 mm - 3 mm, and the volume resistivity of the semi-conductive buffer water-blocking layer is consistent with the volume resistivity of the insulation shielding layer.

2. The high-voltage cable according to claim 1, wherein: The support member is one of copper wire, aluminum wire or semi-conductive strip.

3. The high-voltage cable according to claim 1, characterized in that: The sheath includes an inner sheath and an anti-termite outer sheath coated on the inner sheath.

4. The high-voltage cable according to claim 3, wherein: The anti-termite outer sheath and the inner sheath are co-extruded and formed.

5. The high-voltage cable according to claim 1, characterized in that: The insulating layer is a cross-linked polyethylene insulating layer.

6. The high-voltage cable according to claim 3, characterized in that: The anti-termite outer sheath is a polyolefin sheath with a Shore hardness greater than 70.

7. The high-voltage cable according to claim 1, characterized in that: The temperature measuring unit and the support members are spirally wound inside the high-voltage cable.

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