A high-voltage cable with a nozzle and its application method

Abstract

The present invention discloses a high-voltage cable with air nozzles and an application method thereof. The high-voltage cable with air nozzles of the present invention includes a cable body. Both ends of the cable body are closed, and more than two air nozzles with valves are provided on the outer wall of the cable body. The air nozzles are communicated with the cavity inside the cable body, and the valves are arranged on the pipeline channels where the air nozzles are communicated with the cavity. The application method of the high-voltage cable with air nozzles of the present invention includes dehumidification and degassing. The high-voltage cable of the present invention can achieve on-line dehumidification under the operating state, without disconnecting both ends of the high-voltage cable, and can realize the stable and reliable flow of gas inside the high-voltage cable, which is beneficial to improving the dehumidification efficiency and effect, and timely and thoroughly discharging the moisture or water vapor in the cable in a short time.

Description

Technical Field

[0001] The present invention relates to an improvement in the structure of high-voltage cables, and particularly to a high-voltage cable with air nozzles and an application method thereof. Background Art

[0002] During the construction process and the use process of cables, the problem of moisture absorption may occur. Once moisture or water enters the cable, it will longitudinally penetrate through the gaps between the outer copper tape shield of the cable insulation and the gaps between the conductors. Seriously, it will lead to unqualified test results and the inability to supply power as scheduled. Under the action of a strong electric field, "water trees" will occur in the cable, resulting in a decline in the insulation performance of the cable, and even the cable insulation may be punctured within 5 to 10 years. Therefore, if the moisture in the damp cable is not treated or not treated thoroughly, it will leave potential safety hazards for the power supply system and may cause accidents during operation, resulting in economic losses and even endangering lives.

[0003] The harm of moisture absorption or water ingress in cables is relatively hidden, and the treatment process is relatively complex. The existing cable moisture removal methods generally involve disconnecting both ends of the damp cable and then injecting nitrogen from one end for moisture removal. However, this method has the following problems: First, this method requires disconnecting both ends of the cable, which is not suitable for cables in on-line operation; Second, this method requires disconnecting both ends of the cable, which makes it difficult to seal both ends of the cable. If the sealing is not good, it will affect the reliability of injecting nitrogen. Since the internal cavity of the cable is small, in the case of poor sealing, the monomer may leak at the end where nitrogen is injected and cannot flow reliably to the other end. Summary of the Invention

[0004] The technical problem to be solved by the present invention: In view of the above problems of the prior art, a high-voltage cable with air nozzles and an application method thereof are provided. The high-voltage cable of the present invention can achieve on-line moisture removal in the operating state, without disconnecting both ends of the high-voltage cable, and can realize the stable and reliable flow of gas inside the high-voltage cable, which is beneficial to improving the moisture removal efficiency and effect, and timely and thoroughly discharging the moisture or water vapor in the cable in a short time.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0006] A high-voltage cable with air nozzles, including a cable body, both ends of the cable body are closed, and two or more air nozzles with valves are provided on the outer wall of the cable body. The air nozzles are communicated with the internal cavity of the cable body, and the valves are arranged on the pipeline channels where the air nozzles are communicated with the cavity.

[0007] Optionally, some or all of the air nozzles are also installed with detachable one-way valves.

[0008] Optionally, the cable body includes a conductor, an inner insulating sheath, and an outer insulating sheath. The conductor is disposed within the inner insulating sheath, and the inner insulating sheath is disposed within the outer insulating sheath with a cavity formed therebetween.

[0009] Optionally, the inner insulating sheath includes an insulating inner semi-conductive shield, a main insulation, an insulating outer semi-conductive shield, and a buffer layer, which are arranged in layers from the inside to the outside in sequence.

[0010] Optionally, the outer insulating sheath includes a metal sheath and an insulating outer sheath, which are arranged in layers from the inside to the outside in sequence. The metal sheath and the insulating outer sheath are mutually adhered and both are in a corrugated shape.

[0011] Optionally, an end sealing kit is provided at the end of the cable body. The end sealing kit includes an accessory tail pipe and a metal sheath seal disposed inside the accessory tail pipe. A through hole is provided in the middle of the metal sheath seal. The end of the cable body is inserted into the accessory tail pipe, and the inner insulating sheath after removing the outer insulating sheath and the buffer layer passes through the through hole in the middle of the metal sheath seal and extends out to be arranged outside the end sealing kit. A lead seal is provided between the outer wall of the accessory tail pipe and the outer wall of the cable body.

[0012] Optionally, the nozzle includes a nozzle rod. A bottom plate extending radially around is provided at the inner end of the nozzle rod. The bottom plate and the metal sheath are fixedly sealed by welding or bonding. The nozzle rod penetrates through the outer insulating sheath and extends out to be arranged outside the outer insulating sheath. An insulating material sleeve is wrapped outside the nozzle rod. The insulating material sleeve is integrally connected with the insulating outer sheath, and a connecting flange is provided at the end of the nozzle rod.

[0013] Optionally, the nozzle is connected to an air pump. Connecting flanges for connecting with the nozzle are provided at the air inlet and the air outlet of the air pump. At least one of an air dehumidifier and an air heater is also connected in series on the pipeline where the air inlet or the air outlet of the air pump is located.

[0014] The present invention also provides a method for applying the aforementioned high-voltage cable with a nozzle, including a step of dehumidifying the high-voltage cable: A1) Select one nozzle at each end of the high-voltage cable to be dehumidified, and connect one of the selected two nozzles to the air supply port of the air pump; A2) Open the valves corresponding to the selected two nozzles, and continuously inject dry air into the cavity inside the cable body from the connected nozzle through the air pump, so that the dry air flows along the cavity inside the cable body and discharges the moisture in the cavity through the other nozzle to achieve the dehumidification operation; A3) After completing the dehumidification operation, close the valves corresponding to the selected two nozzles to keep the cavity inside the cable body isolated from the outside.

[0015] The present invention also provides an application method for the aforementioned high-voltage cable with a nozzle, including the step of degassing the high-voltage cable: B1) Select a nozzle for the high-voltage cable to be dehumidified, and connect the selected nozzle to the air inlet of the air pump; B2) Open the valve corresponding to the selected nozzle, and extract the gas in the cavity inside the cable body from the connected nozzle through the air pump to achieve degassing operation; B3) After completing the degassing operation, close the valve corresponding to the selected nozzle to keep the cavity inside the cable body isolated from the outside.

[0016] Compared with the prior art, the present invention has the following advantages: The present invention includes a cable body, the two ends of the cable body are closed, and there are more than two nozzles with valves on the outer wall of the cable body. The nozzles are communicated with the cavity inside the cable body, and the valves are arranged on the pipeline channel where the nozzles are communicated with the cavity. The present invention can realize online dehumidification under the operating state, without disconnecting the two ends of the high-voltage cable, and can realize the stable and reliable flow of gas inside the high-voltage cable, which is beneficial to improving the dehumidification efficiency and effect, and timely and thoroughly discharging the moisture or water vapor in the cable in a short time. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic structural diagram of the cable body in the embodiment of the present invention.

[0018] Figure 2 is Figure 1 A partial enlarged structural diagram of area A in

[0019] Figure 3 It is a schematic transverse sectional structure diagram of the cable body in the embodiment of the present invention.

[0020] Figure 4 It is a schematic structural diagram of the end sealing kit in the embodiment of the present invention.

[0021] Legend: 1. Cable body; 10. Cavity; 11. Conductor; 12. Inner insulation sheath; 121. Insulating inner semi-conductive shield; 122. Main insulation; 123. Insulating outer semi-conductive shield; 124. Buffer layer; 13. Outer insulation sheath; 131. Metal sheath; 132. Insulating outer sheath; 14. End sealing kit; 141. Accessory tail pipe; 142. Metal sheath seal; 15. Lead seal; 2. Nozzle; 20. Valve; 21. Nozzle rod; 211. Insulating material sleeve; 212. Connecting flange; 22. Base plate; 33. Air dehumidifier; 34. Air heater. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] Below, taking a single-core 66 kV high-voltage cable as an example, the high-voltage cable with a nozzle and its application method of the present invention will be further described in detail.

[0023] Such asFigure 1 and Figure 2 As shown in Figure 2 , the high-voltage cable with a nozzle in this embodiment includes a cable body 1. Both ends of the cable body 1 are closed, and there are two or more nozzles 2 with valves 20 provided on the outer wall of the cable body 1. The nozzles 2 communicate with the cavity 10 inside the cable body 1, and the valves 20 are arranged on the pipeline channels where the nozzles 2 communicate with the cavity 10.

[0024] As Figure 1 , Figure 2 and Figure 3 As shown in Figure 1 , Figure 2 and Figure 3 , in this embodiment, the cable body 1 includes a conductor 11, an inner insulating sheath 12 and an outer insulating sheath 13. The conductor 11 is inserted into the inner insulating sheath 12, and the inner insulating sheath 12 is inserted into the outer insulating sheath 13 and forms a cavity 10 with the outer insulating sheath 13.

[0025] As Figure 1 , Figure 2 and Figure 3 As shown in Figure 1 , Figure 2 and Figure 3 , in this embodiment, the inner insulating sheath 12 includes an insulating inner semi-conductive shield 121, a main insulation 122, an insulating outer semi-conductive shield 123 and a buffer layer 124 which are arranged in layers from the inside to the outside. It should be noted that for different types of high-voltage cables, the inner insulating sheath 12 may be different.

[0026] As Figure 1 , Figure 2 and Figure 3 As shown in Figure 1 , Figure 2 and Figure 3 , in this embodiment, the outer insulating sheath 13 includes a metal sheath 131 and an insulating outer sheath 132 which are arranged in layers from the inside to the outside. The metal sheath 131 and the insulating outer sheath 132 are mutually attached and both are in a corrugated shape. It should be noted that for different types of high-voltage cables, the outer insulating sheath 13 may be different.

[0027] As Figure 4As shown in the figure, in this embodiment, an end sealing kit 14 is provided at the end of the cable body 1. The end sealing kit 14 includes an accessory tail pipe 141 and a metal sheath seal 142 disposed inside the accessory tail pipe 141. A through hole is provided in the middle of the metal sheath seal 142. The end of the cable body 1 is inserted into the accessory tail pipe 141, and the inner insulation sheath 12 after removing the outer insulation sheath 13 and the buffer layer 124 passes through the through hole in the middle of the metal sheath seal 142 and extends out to be arranged outside the end sealing kit 14. A lead seal 15 is provided between the outer wall of the accessory tail pipe 141 and the outer wall of the cable body 1. Through the above structure, the sealing of the end can be ensured on the basis of the existing interconnection structure of high-voltage cables, ensuring the stable and reliable flow of gas inside the high-voltage cables, which is beneficial to improving the dehumidification efficiency and effect, and timely and thoroughly discharging the moisture or water vapor in the cables in a short time. The metal sheath seal 142 can be made of an elastic material such as rubber or silica gel as needed, and a reliable seal between the inner insulation sheath 12 and the metal sheath seal 142 is achieved through interference fit during installation.

[0028] As Figure 2 shown in the figure, in this embodiment, the air nozzle 2 includes an air nozzle rod 21. A bottom plate 22 extending radially around is provided at the inner end of the air nozzle rod 21. The bottom plate 22 and the metal sheath 131 are hermetically fixed by welding or bonding. The air nozzle rod 21 passes through the outer insulation sheath 13 and extends out to be arranged outside the outer insulation sheath 13. An insulating material sleeve 211 is wrapped outside the air nozzle rod 21. The insulating material sleeve 211 is connected to the insulating outer sheath 132 to form an integral body, and a connecting flange 212 is provided at the end of the air nozzle rod 21. Through the setting of the bottom plate 22, the structural strength of the air nozzle 2 can be improved, preventing the air nozzle 2 from being damaged due to external force and resulting in air leakage; the insulating material sleeve 211 is connected to the insulating outer sheath 132 to form an integral body, which can make the contact area between the air nozzle 2 and the outer wall of the cable body 1 larger and the seal more secure and reliable.

[0029] In addition, an air pump is connected to the air nozzle 2 in this embodiment. Connecting flanges for connecting to the air nozzle 2 are provided at the air inlet and outlet of the air pump. The air source of the air pump can be ordinary air or nitrogen as needed.

[0030] In addition, this embodiment also provides a method for applying the aforementioned high-voltage cable with an air nozzle, including the steps of dehumidifying the high-voltage cable:

[0031] A1) Select one air nozzle 2 at each end of the high-voltage cable to be dehumidified, and connect one of the selected two air nozzles 2 to the air supply port of the air pump;

[0032] A2) Open the valves 20 corresponding to the two selected nozzles 2, and continuously inject dry air into the cavity 10 inside the cable body 1 from the connected nozzle 2 through an air pump, so that the dry air flows along the cavity 10 inside the cable body 1 and discharges the moisture in the cavity 10 through the other nozzle 2 to achieve the moisture removal operation;

[0033] A3) After completing the moisture removal operation, close the valves 20 corresponding to the two selected nozzles 2 to keep the cavity 10 inside the cable body 1 isolated from the outside.

[0034] In addition, during the use of high-voltage cables, some gases will be slowly released inside them. If the pressure of the generated gases is too high, it will cause the cable accessories to be displaced. To solve the above technical problems, this embodiment also provides an application method for the aforementioned high-voltage cable with nozzles, including the step of degassing the high-voltage cable:

[0035] B1) Select a nozzle 2 for the high-voltage cable to be dehumidified, and connect the selected nozzle 2 to the air inlet of the air pump;

[0036] B2) Open the valve 20 corresponding to the selected nozzle 2, and extract the gas in the cavity 10 inside the cable body 1 from the connected nozzle 2 through the air pump to achieve the degassing operation;

[0037] B3) After completing the degassing operation, close the valve 20 corresponding to the selected nozzle 2 to keep the cavity 10 inside the cable body 1 isolated from the outside.

[0038] Embodiment 2:

[0039] This embodiment is a further improvement on Embodiment 1. In Embodiment 1, when the nozzle 2 with the valve 20 is in use, once the valve 20 is opened, it may cause external air or moisture to enter the cavity 10, resulting in the inside of the cable body 1 getting damp. To solve the above problem, as a further improvement on Embodiment 1, a detachable one-way valve is also installed on the nozzle 2 in this embodiment. Through the one-way valve, the gas in the nozzle 2 can only flow in one direction, preventing external air or moisture from entering the cavity 10. The nozzle 2 with the one-way valve installed can be either partial or all. Due to its detachable structure, it will not affect the functions of the nozzle 2, including air supply or air extraction. It should be noted that in the case of partial installation of the one-way valve, the one-way valve can not only be installed on the nozzle 2 in a detachable structure, but also be installed in the air flow channel of the nozzle 2 in an embedded manner to achieve an integrated design, making the device structure more compact and occupying less volume.

[0040] Embodiment 3:

[0041] This embodiment is a further improvement on Embodiment 1.

[0042] Considering the cost issues of nitrogen storage and transportation. As a further improvement to the first embodiment, in this embodiment, an air dehumidifier is also connected in series on the pipeline where the air inlet or air outlet of the air pump is located. Through the air dehumidifier, the air sent to the cavity 10 can be dehumidified, and the low-cost dehumidification effect can also be achieved. In addition, on this basis, an air heater can be further connected in series on the pipeline where the air inlet or air outlet of the air pump is located. Through the air heater, the air sent to the cavity 10 can be heated, which can further enhance the dehumidification effect. In addition, an air heater can also be connected in series separately on the pipeline where the air inlet or air outlet of the air pump is located, and only the air heating is used to enhance the dehumidification effect.

[0043] The above is only the preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions within the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and retouches should also be regarded as the protection scope of the present invention.

Claims

1. A high-voltage cable with a nozzle, comprising a cable body (1), characterized in that, The cable body (1) is closed at both ends, and the outer wall of the cable body (1) is provided with two or more gas nozzles (2) with valves (20), the gas nozzles (2) are connected to the cavity (10) inside the cable body (1), the valves (20) are arranged on the pipeline channel connecting the gas nozzle (2) and the cavity (10), and part or all of the gas nozzles (2) are also equipped with a detachable one-way valve, the gas nozzle (2) comprises a gas nozzle rod (21), the inner end of the gas nozzle rod (21) is provided with a bottom plate (22) extending radially in all directions, and the bottom plate (22) and the metal sheath (131) of the cable body (1) are sealed by welding or bonding. The air nozzle rod (21) is fixed, the air nozzle rod (21) penetrates the outer insulating sheath (13) of the cable body (1) and then extends out to be arranged outside the outer insulating sheath (13), and the outside of the air nozzle rod (21) is wrapped with an insulating material sleeve (211), the insulating material sleeve (211) is connected to the insulating outer sheath (132) of the cable body (1) to form a whole, and the end of the air nozzle rod (21) is provided with a connecting flange (212), the air nozzle (2) is connected to an air pump, and the air inlet and air outlet of the air pump are provided with connecting flanges for connecting to the air nozzle (2), and at least one of an air dehumidifier and an air heater is also connected in series to the pipeline where the air inlet or the air outlet of the air pump is located.

2. The high-voltage cable with a nozzle according to claim 1, characterized in that, The cable body (1) comprises a conductor (11), an inner insulating sheath (12) and an outer insulating sheath (13); the conductor (11) is inserted into the inner insulating sheath (12); the inner insulating sheath (12) is inserted into the outer insulating sheath (13) and a cavity (10) is formed between the inner insulating sheath (12) and the outer insulating sheath (13).

3. The high-voltage cable with a nozzle according to claim 2, characterized in that, The inner insulating sheath (12) comprises an insulating inner semi-conductive shield (121), a main insulation (122), an insulating outer semi-conductive shield (123), and a buffer layer (124) which are sequentially stacked from the inside to the outside.

4. The high-voltage cable with a nozzle according to claim 3, characterized in that, The outer insulating sheath (13) comprises a metal sheath (131) and an insulating outer sheath (132) which are sequentially stacked from the inside to the outside, and the metal sheath (131) and the insulating outer sheath (132) are fitted to each other and are both in the shape of a corrugated tube.

5. The high-voltage cable with a nozzle according to claim 4, characterized in that, An end sealing kit (14) is provided at the end of the cable body (1), the end sealing kit (14) comprising an accessory tail tube (141) and a metal sheath seal (142) arranged inside the accessory tail tube (141), a through hole being provided in the middle of the metal sheath seal (142), the end of the cable body (1) being inserted into the accessory tail tube (141) and the inner insulating sheath (12) after removing the outer insulating sheath (13) and the buffer layer (124) passing through the through hole in the middle of the metal sheath seal (142) and then extending out to be arranged outside the end sealing kit (14), and a lead seal (15) being provided between the outer wall of the accessory tail tube (141) and the outer wall of the cable body (1).

6. A method for applying a high-voltage cable with a nozzle according to any one of claims 1 to 5, characterized in that It includes the steps of dehumidifying a high-voltage cable: A1) Select one nozzle (2) at each end of the high-voltage cable to be dehumidified, and connect one of the two selected nozzles (2) to the air supply port of the air pump; A2) Open the valves (20) corresponding to the two selected nozzles (2), and continuously inject dry air into the cavity (10) inside the cable body (1) from the connected nozzle (2) through the air pump, so that the dry air flows along the cavity (10) inside the cable body (1) and discharges the moisture in the cavity (10) through the other nozzle (2) to achieve the dehumidification operation; A3) After completing the dehumidification operation, close the valves (20) corresponding to the two selected nozzles (2) to keep the cavity (10) inside the cable body (1) isolated from the outside.

7. The application method of the high-voltage cable with a nozzle according to claim 6, characterized in that, It includes the steps of degassing a high-voltage cable: B1) Select one nozzle (2) for the high-voltage cable to be dehumidified, and connect the selected nozzle (2) to the air intake port of the air pump; B2) Open the valve (20) corresponding to the selected nozzle (2), and extract the gas in the cavity (10) inside the cable body (1) from the connected nozzle (2) through the air pump to achieve the degassing operation; B3) After completing the degassing operation, close the valve (20) corresponding to the selected nozzle (2) to keep the cavity (10) inside the cable body (1) isolated from the outside.

Images