On-site repair method and system for high-voltage cable metal sheath

Abstract

The invention belongs to the technical field of cable repair, and particularly relates to an on-site repair method and system for a high-voltage cable metal sheath. The repairing method comprises the following steps: firstly, pretreating a defect part of a metal sheath, and then depositing a first layer of cold additive material on the defect part; a second layer of cold additive is deposited on the defect portion where the first layer of cold additive is deposited, and finally a third layer of cold additive is deposited on the defect portion where the second layer of cold additive is deposited; wherein the temperature of the base material of the high-voltage cable metal sheath does not exceed 110 DEG C in the deposition process. According to the repairing method, in-situ repairing is carried out on the metal sheath through low-pressure cold additive equipment, the repairing process does not need to be carried out at high temperature and high pressure, defects cannot be caused to the cable and the adjacent metal sheath, meanwhile, the repairing method is friendly to an operator, and the repaired metal sheath has the advantages of being high in mechanical strength and low in resistance; and the subsequent safe operation of the cable can be realized.

Description

Technical Field

[0001] The invention belongs to the technical field of cable repair, and in particular relates to an on-site repair method and system for a high-voltage cable metal sheath. Background Art

[0002] In modern society, power supply has become one of the basic needs of people's daily life. As one of the important means of power transmission, power cable lines undertake the important task of transmitting power from power plants to user terminals. However, in the process of power transmission, the lines are often affected by various external environments and human factors, such as lightning strikes, short circuits, ground faults, etc. These problems may cause line damage, power outages and safety accidents. Therefore, metal protective covers are often installed on power cable lines, which can not only improve the reliability and stability of the lines, but also ensure the continuity of power supply.

[0003] The metal protective sheath is a device used to protect cables, usually made of metal. Its main functions are as follows:

[0004] 1. Lightning protection function: The metal protective cover can provide a low-resistance path to conduct lightning current into the ground, reduce the impact of lightning on the line, and protect the line from damage by lightning.

[0005] 2. Anti-short circuit function: The metal protective cover can provide a low-resistance, low-voltage loop for the short-circuit current, help to disconnect the short-circuit current, reduce the impact of the short-circuit current on the line equipment, and prevent equipment damage.

[0006] 3. Function of preventing the spread of insulation faults: The metal protective cover can timely extinguish the sparks and arcs generated by line insulation faults, prevent the expansion of insulation faults, and protect line equipment.

[0007] However, the metal protective sheath of the cable and the lead seal of the cable terminal are placed outdoors for a long time. When there are strong corrosive substances such as acid rain in the environment, the lead material at the connection seal will corrode and become brittle, and even the cable sheath will break, causing insulation breakdown and other problems. Figure 1 Therefore, it is very important to repair the damaged metal protective sleeve in time and ensure that the repaired metal protective sleeve has similar performance to the original metal protective sleeve.

[0008] Most of the metal sheath repair processes currently used use hot lead brazing, and there are usually two methods: lead touching method and lead pouring method. The lead touching method is to heat the lead sealing part with a burner flame, melt the lead sealing solder at the same time, stick it firmly, and then use a wiper to shape the lead sealing; the lead pouring method is to heat and melt the lead bar in a lead cylinder, scoop it with an iron spoon, and pour it on the lead sealing part, or melt the lead bar on the wiper through the burner flame, and then apply it to the sealing repair part, and finally shape it.

[0009] However, these two repair methods usually require a high temperature and high pressure environment during the repair process, which can easily cause damage to the cable and the protective sheath connected to the defective part. Therefore, they have the disadvantages of complex operation, high cost, long construction period, and poor electrical performance of the repaired metal sheath. Summary of the invention

[0010] Based on the above technical background, the main purpose of the present invention is to provide an on-site repair method and system for a high-voltage cable metal sheath to overcome the deficiencies in the prior art.

[0011] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes:

[0012] According to a first aspect of the present invention, there is provided an on-site repair method for a metal sheath of a high voltage cable, the on-site repair method comprising the following steps:

[0013] Step 1, pre-treating the defective part of the metal sheath, and then depositing the first layer of cold additive material on the defective part;

[0014] Step 2, depositing a second layer of cold additive material on the defective portion where the first layer of cold additive material is deposited;

[0015] Step 3, depositing a third layer of cold additive material on the defective portion where the second layer of cold additive material is deposited;

[0016] Wherein, the base material temperature of the high-voltage cable metal sheath does not exceed 110° C. during the deposition process.

[0017] In step 1,

[0018] Preferably, the carrier gas pressure when depositing the first layer of cold additive is 0.5-1.5 MPa, and the gas flow rate is 20-30 m / s. 3 / h, the distance between the nozzle and the defective part is 5-20mm, and the horizontal moving speed of the nozzle is 0.01m / s-0.1m / s.

[0019] Preferably, the deposition material of the first layer of cold additive is a copper-based material, and the mass percentage of the deposition material is: based on the total weight of the raw materials as 100%, Al: 30-40%, Zn: 5-15%, Mn: 1.0-1.5%, Mg: 0.2-0.6%, Cr: 0.1%, Ti: 0.1%, Si: 0.6%, Cu: balance.

[0020] In step 2,

[0021] Preferably, the carrier gas pressure when depositing the second layer of cold additive is 0.5-1.5 MPa, and the gas flow rate is 20-30 m / s. 3 / h, the distance between the nozzle and the defective part is 5-20mm, and the horizontal moving speed of the nozzle is 0.01m / s-0.1m / s.

[0022] Preferably, the deposition material of the second layer of cold additive is a copper-based material, and the mass percentage of the deposition material is: based on the total weight of the raw materials as 100%, Al: 7-18%, Zn: 3-10%, Cr: 10%, Mn: 1.3-1.8%, Mg: 0.1-0.5%, Ti: 0.2%, Si: 0.8%, Cu: balance.

[0023] In step 3,

[0024] Preferably, the carrier gas pressure when depositing the third layer of cold additive is 0.5-1.5 MPa, and the gas flow rate is 20-30 m / s. 3 / h, the distance between the nozzle and the defective part is 5-20mm, and the horizontal moving speed of the nozzle is 0.01m / s-0.1m / s.

[0025] Preferably, the deposition material of the third layer of cold additive is a copper-based material, and the mass percentage of the deposition material is: based on the total weight of the raw materials as 100%, Al: 10-15%, Sn: 8-13%, Mn: 1.0-2.0%, Mg: 0.5-1.0%, Cr: 0.2%, Ti: 0.1%, Si: 0.6%, Cu: balance.

[0026] According to a second aspect of the present invention, there is provided an on-site repair system for a high voltage cable metal sheath using the method of the first aspect of the present invention. The system comprises: a carrier gas bottle, a first gas passage, a second gas passage, a first control valve, a second control valve, a powder feeder, a gas heater and a nozzle;

[0027] The carrier gas bottle is connected to the nozzle via the first gas passage and the second gas passage respectively; the first control valve and the micron alloy powder feeder are arranged on the first gas passage and are arranged in sequence between the carrier gas bottle and the nozzle; the second control valve and the gas heater are arranged on the second gas passage and are arranged in sequence between the carrier gas bottle and the nozzle; the gases in the first gas passage and the second gas passage are merged in the nozzle and sprayed out through the nozzle of the nozzle to be deposited on the metal sheath of the high-voltage cable.

[0028] Furthermore, the powder feeder is a micron alloy powder feeder.

[0029] Furthermore, the gas heater has a temperature control and display module.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) Low-pressure cold additive equipment is used to repair the metal sheath in situ. By using metal alloy powders of different proportions to deposit cold additives layer by layer on the defective parts of the high-voltage cable metal sheath, high temperature and high pressure are not required during the repair process. The base material temperature of the metal sheath does not exceed 110°C during the entire repair process. After the repair is completed, there is no need for annealing treatment to release stress, and no damage will be caused to the cable and the protective sheath connected to the defective part. The repaired metal sheath has the advantages of high tensile strength, high density and low resistance. Compared with the original metal sheath, the resistance is not increased, which can ensure the subsequent safe operation of the cable;

[0032] (2) The technical solution of the present invention is simple and easy to operate, has a short repair period, low cost, and will not cause harm to the operator. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Photographs showing cracking and corrosion of the metal sheath;

[0034] Figure 2 A flow chart showing the on-site repair method of the high voltage cable metal sheath of the present invention;

[0035] Figure 3 The photos show the metal sheath before repair, after copper-based material is deposited on the metal sheath, and after the metal sheath is deposited and polished;

[0036] Figure 4 The structural diagram of the on-site repair system of the high-voltage cable metal sheath of the present invention is shown. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described in this application are only part of the embodiments of the present invention, not all of them. Based on the spirit of the present invention, other embodiments obtained by ordinary technicians in this field without creative work are all within the scope of protection of the present invention.

[0038] The present invention will be described in detail below, and the characteristics and advantages of the present invention will become clearer and more distinct with the description.

[0039] The present invention provides an on-site repair method for a high voltage cable metal sheath. Figure 2 , the high voltage cable repair method comprises the following steps:

[0040] Step 1, pre-treating the defective part of the metal sheath, and then depositing the first layer of cold additive material on the defective part;

[0041] Step 2, depositing a second layer of cold additive material on the defective portion where the first layer of cold additive material is deposited;

[0042] Step 3, depositing a third layer of cold additive material on the defective portion where the second layer of cold additive material is deposited;

[0043] The base material temperature of the high-voltage cable metal sheath does not exceed 110° C. during the deposition process to prevent damage to the cable and the protective sheath connected to the defective portion.

[0044] The above steps are described in detail below.

[0045] In step 1, the pretreatment includes: grinding, cleaning, sandblasting, and cleaning the defective parts of the metal sheath (such as Figure 1 The surface of the defective part is polished (as shown) to remove the oxide layer until the opening presents a smooth conical transition, and then cleaned to ensure that there is no obvious debris in the defective fracture and adjacent areas. After polishing and cleaning, the defective part is sandblasted.

[0046] Low-pressure cold additive equipment is used to perform cold additive processing on the defective parts of the metal sheath. Figure 2 As shown in the figure, cold additive technology mainly accelerates the material in powder form to a very high speed and realizes the conversion of kinetic energy into plastic deformation energy at the moment of impacting the substrate, thereby forming a molding method on the surface of the target substrate with performance basically equivalent to that of a bulk material.

[0047] When depositing the first layer of cold additive material, the carrier gas pressure is 0.5-1.5 MPa, preferably 1.2 MPa; the gas flow rate is 20-30 m 3 / h, the preferred gas flow rate is 27m 3 / h; the distance between the nozzle and the defective part is 5 to 20 mm, preferably 20 mm; the horizontal moving speed of the nozzle is 0.01 m / s to 0.1 m / s, preferably the horizontal moving speed is 0.1 m / s. Selecting the above deposition parameters is conducive to uniformly depositing the metal alloy powder on the substrate of the metal sheath to form an additive with sufficiently high tensile strength and density.

[0048] The deposition material of the first layer of cold additive is a copper-based material, and the mass percentage of the deposition material is: based on the total weight of the raw materials as 100%, Al: 30-40%, Zn: 5-15%, Mn: 1.0-1.5%, Mg: 0.2-0.6%, Cr: 0.1%, Ti: 0.1%, Si: 0.6%, Cu: balance.

[0049] Preferably, the mass percentages of the first layer of deposition material are: based on the total weight of the raw materials as 100%, Al: 35%, Zn: 5%, Mn: 1.0%, Mg: 0.2%, Cr: 0.1%, Ti: 0.1%, Si: 0.6%, and Cu: balance.

[0050] The first layer of cold additive material deposited by controlling the above parameter conditions can establish a tight and reliable bond with the metal sheath, laying a good foundation for the deposition of subsequent layers of cold additive material.

[0051] In step 2, when depositing the second layer of cold additive material: the carrier gas pressure is 0.5-1.5 MPa, preferably 1 MPa; the gas flow rate is 20-30 m 3 / h, the preferred gas flow rate is 27m 3 / h; the distance between the nozzle and the defective part is 5 to 20 mm, preferably 12 mm; the horizontal moving speed of the nozzle is 0.01 m / s to 0.1 m / s, preferably 0.05 m / s. Selecting the above deposition parameters is conducive to uniformly depositing the metal alloy powder on the substrate of the metal sheath to form an additive with sufficiently high tensile strength and density.

[0052] The deposition material of the second layer of cold additive is a copper-based material, and the mass percentage of the deposition material is: based on the total weight of the raw materials as 100%, Al: 7-18%, Zn: 3-10%, Cr: 10%, Mn: 1.3-1.8%, Mg: 0.1-0.5%, Ti: 0.2%, Si: 0.8%, Cu: balance.

[0053] Preferably, the mass percentages of the second layer of deposition material are: based on the total weight of the raw materials as 100%, Al: 7%, Zn: 3%, Cr: 10%, Mn: 1.3%, Mg: 0.1%, Ti: 0.2%, Si: 0.8%, Cu: balance.

[0054] The second layer of cold additive material deposited by controlling the above parameter conditions can form a dense current-carrying layer, so that the repaired metal sheath has high tensile strength and high density while having low resistance.

[0055] In step 3, when depositing the third layer of cold additive material, the carrier gas working pressure is 0.5-1.5 MPa, preferably 1.2 MPa; the gas flow rate is 20-30 m 3 / h, the preferred gas flow rate is 25m 3 / h; the distance between the nozzle and the defective part is 5 to 20 mm, preferably 10 mm; the horizontal moving speed of the nozzle is 0.01 m / s to 0.1 m / s, preferably 0.04 m / s. Selecting the above deposition parameters is conducive to uniformly depositing the metal alloy powder on the substrate of the metal sheath to form an additive with sufficiently high tensile strength and density.

[0056] The deposition material of the third layer of cold additive is a copper-based material, and the mass percentage of the deposition material is: based on the total weight of the raw materials as 100%, Al: 10-15%, Sn: 8-13%, Mn: 1.0-2.0%, Mg: 0.5-1.0%, Cr: 0.2%, Ti: 0.1%, Si: 0.6%, Cu: balance.

[0057] Preferably, the mass percentages of the third layer of deposition material are: based on the total weight of the raw materials as 100%, Al: 10, Sn: 8%, Mn: 1.0, Mg: 0.5, Cr: 0.2%, Ti: 0.1%, Si: 0.6%, Cu: balance.

[0058] The third layer of cold additive material deposited by controlling the above parameter conditions can make the repaired part have good weather resistance and sealing, ensuring that the repaired high-voltage cable metal sheath has a long service life.

[0059] At the same time, the deposition material ratio of the above three layers of cold additive is carefully designed based on material stress considerations to ensure that the deposited material has high tensile strength and high density, and the stress between each layer of additive is minimal, so that after the repair is completed, there is no need to release stress through annealing treatment, so as to minimize the damage of high temperature and high pressure to the cable and the protective cover connected to the defective part.

[0060] Preferably, the high voltage cable repair method further comprises:

[0061] Step 4: After depositing the third layer of cold additive, the repaired metal sheath is polished.

[0062] By grinding, the surface of the repaired metal sheath can be made smoother and burrs can be reduced.

[0063] The present invention is further described below by specific examples, which are limited to illustrating the present invention but not to limiting the scope of the present invention. The raw materials used in the examples of the present invention were all purchased.

[0064] Example 1

[0065] The defective part (opening position) of the metal sheath is ground until the taper at the opening has a smooth transition to ensure that there are no obvious debris in the fracture and adjacent areas. After grinding, the defective part is sandblasted.

[0066] Low-pressure cold additive equipment is used to perform cold additive processing on the defective parts of the metal sheath. The carrier gas pressure when depositing the first layer of cold additive is 1MPa, and the gas flow rate is 25m 3 / h, the distance between the nozzle and the defective part during deposition is 12mm, the horizontal moving speed during deposition is 0.05m / s, and the mass percentage of the deposited material of the first layer of cold additive is: based on the total weight of the raw materials as 100%, Al: 35%, Zn: 10%, Mn: 1.2%, Mg: 0.4%, Cr: 0.1%, Ti: 0.1%, Si: 0.6%, Cu: balance.

[0067] After the first layer of cold additive material is deposited, the second layer of cold additive material is deposited. The carrier gas pressure during the deposition of the second layer of cold additive material is 1.2 MPa and the gas flow rate is 27 m 3 / h, the distance between the nozzle and the defective part during deposition is 12mm, the horizontal moving speed during deposition is 0.05m / s, the second layer of deposition material is copper-based powder, and the mass percentage of the second layer of deposition material is: based on the total weight of the raw materials as 100%, Al: 15%, Zn: 5%, Cr: 10%, Mn: 1.5%, Mg: 0.3%, Ti: 0.2%, Si: 0.8%, Cu: balance.

[0068] After depositing the second layer of cold additive material, continue to deposit the third layer of cold additive material. The carrier gas pressure when depositing the third layer of cold additive material is 1MPa and the gas flow rate is 25m 3 / h, the distance between the nozzle and the defective part during deposition is 12mm, the horizontal moving speed during deposition is 0.04m / s, the third layer of deposition material is copper-based powder, and the mass percentage of the third layer of deposition material is: based on the total weight of the raw materials as 100%, Al: 12%, Sn: 10%, Mn: 1.5%, Mg: 0.7%, Cr: 0.2%, Ti: 0.1%, Si: 0.6%, Cu: balance. After the deposition is completed, the repaired part is polished and smooth, such as Figure 3 shown.

[0069] The tensile strength of the repaired metal sheath was measured to be 88 MPa, the density was 99.6%, and the resistance was detected to be 9.1 μΩ, with no resistance increase problem. Figure 3 The photographs of the metal sheath before repair, after copper-based material is deposited on the metal sheath, and after the metal sheath is deposited and polished in this embodiment are shown.

[0070] Example 2

[0071] The defective part (opening position) of the metal sheath is ground until the taper at the opening has a smooth transition to ensure that there are no obvious debris in the fracture and adjacent areas. After grinding, the defective part is sandblasted.

[0072] Low-pressure cold additive equipment is used to perform cold additive processing on the defective parts of the metal sheath. The carrier gas pressure when depositing the first layer of cold additive is 1.2MPa, and the gas flow rate is 27m 3 / h, the distance between the nozzle and the defective part is 20mm, the horizontal moving speed of the nozzle is 0.1m / s, and the mass percentage of the deposited material of the first layer of cold additive is: based on the total weight of the raw materials as 100%, Al: 38%, Zn: 5%, Mn: 1.0%, Mg: 0.2%, Cr: 0.1%, Ti: 0.1%, Si: 0.6%, Cu: balance.

[0073] After the first layer of cold additive material is deposited, the second layer of cold additive material is deposited. The carrier gas pressure during the deposition of the second layer of cold additive material is 1 MPa and the gas flow rate is 27 m 3 / h, the distance between the nozzle and the defective part during deposition is 12mm, the horizontal moving speed of the nozzle is 0.05m / s, the second layer of deposition material is copper-based powder, and the mass percentage of the second layer of deposition material is: based on the total weight of the raw materials as 100%, Al: 7%, Zn: 3%, Cr: 10%, Mn: 1.3%, Mg: 0.1%, Ti: 0.2%, Si: 0.8%, Cu: balance.

[0074] After depositing the second layer of cold additive material, continue to deposit the third layer of cold additive material. The carrier gas pressure when depositing the third layer of cold additive material is 1.2MPa and the gas flow rate is 25m 3 / h, the distance between the nozzle and the defective part is 10mm, the horizontal moving speed of the nozzle is 0.04m / s, the third layer of deposition material is copper-based powder, and the mass percentage of the third layer of deposition material is: based on the total weight of the raw materials as 100%, Al: 10, Sn: 8%, Mn: 1.0, Mg: 0.5, Cr: 0.2%, Ti: 0.1%, Si: 0.6%, Cu: balance. After the deposition is completed, the repaired part is polished and smooth.

[0075] The tensile strength of the repaired metal sheath was measured to be 89 MPa, the density was 99.5%, and the resistance was detected to be 8.6 μΩ, with no resistance increase problem.

[0076] Example 3

[0077] The defective part (opening position) of the metal sheath is ground until the taper at the opening has a smooth transition to ensure that there are no obvious debris in the fracture and adjacent areas. After grinding, the defective part is sandblasted.

[0078] Low-pressure cold additive equipment is used to perform cold additive processing on the defective parts of the metal sheath. The carrier gas pressure when depositing the first layer of cold additive is 1.5MPa, and the gas flow rate is 30m 3 / h, the distance between the nozzle and the defective part is 5mm, the horizontal moving speed of the nozzle is 0.01m / s, and the mass percentage of the deposited material of the first layer of cold additive is: based on the total weight of the raw materials as 100%, Al: 40%, Zn: 15%, Mn: 1.5%, Mg: 0.6%, Cr: 0.1%, Ti: 0.1%, Si: 0.6%, Cu: balance.

[0079] After the first layer of cold additive material is deposited, the second layer of cold additive material is deposited. The carrier gas pressure during the deposition of the second layer of cold additive material is 1.5 MPa and the gas flow rate is 30 m 3 / h, the distance between the nozzle and the defective part during deposition is 20mm, the horizontal moving speed of the nozzle is 0.01m / s, the second layer of deposition material is copper-based powder, and the mass percentage of the second layer of deposition material is: based on the total weight of the raw materials as 100%, Al: 18%, Zn: 10%, Cr: 10%, Mn: 1.8%, Mg: 0.5%, Ti: 0.2%, Si: 0.8%, Cu: balance.

[0080] After depositing the second layer of cold additive material, continue to deposit the third layer of cold additive material. The carrier gas pressure for depositing the third layer of cold additive material is 1.5MPa and the gas flow rate is 30m 3 / h, the distance between the nozzle and the defective part during deposition is 20mm, the horizontal moving speed during deposition is 0.01m / s, the third layer of deposition material is copper-based powder, and the mass percentage of the third layer of deposition material is: based on the total weight of the raw materials as 100%, Al: 15%, Sn: 13%, Mn: 2.0%, Mg: 1.0%, Cr: 0.2%, Ti: 0.1%, Si: 0.6%, Cu: balance. After the deposition is completed, the repaired part is polished and smooth.

[0081] The tensile strength of the repaired metal sheath was measured to be 87 MPa, the density was 99.7%, and the resistance was detected to be 8.3 μΩ, with no resistance increase problem.

[0082] It can be seen that by using metal alloy powders in different proportions to deposit cold additive materials layer by layer on the defective parts of the metal sheath of the high-voltage cable, high temperature and high pressure are not required in the repair process, and the substrate temperature of the metal sheath does not exceed 110°C during the entire repair process. After the repair is completed, there is no need for annealing treatment to release stress, so it will not cause damage to the cable and the protective sheath connected to the defective part. The repaired metal sheath has the advantages of high tensile strength, high density and low resistance. Compared with the original metal sheath, the resistance has not increased, which can ensure the subsequent safe operation of the cable.

[0083] The following describes an on-site repair system for a high voltage cable metal sheath using the above method of the present invention. Figure 4The system includes: a carrier gas bottle 1, a first gas passage 2, a second gas passage 3, a first control valve 4, a second control valve 5, a powder feeder 6, a gas heater 7 and a nozzle 8.

[0084] Among them, the carrier gas bottle 1 is connected to the nozzle 8 via the first gas passage 2 and the second gas passage 3 respectively. The first control valve 4 and the powder feeder 6 are arranged on the first gas passage 2 and are arranged in sequence between the carrier gas bottle 1 and the nozzle 8. The second control valve 5 and the gas heater 7 are arranged on the second gas passage 2 and are arranged in sequence between the carrier gas bottle 1 and the nozzle 8. The gases in the first gas passage 2 and the second gas passage 3 converge in the nozzle 8 and are ejected through the nozzle 9 of the nozzle 8 to be deposited on the metal sheath 10 of the high-voltage cable. By controlling the first control valve 4 and the second control valve 5, the pressure and flow rate of the gases in the first gas passage 2 and the second gas passage 3 can be controlled respectively to meet the requirements of additive deposition.

[0085] The alloy powder for depositing the first, second and third layers of cold additive is fed into the first gas passage 2 via the powder feeder 6, and sprayed onto the surface of the metal sheath 10 via the nozzle 9 of the nozzle 8. Preferably, the powder feeder 6 is a micron alloy powder feeder. Accordingly, the alloy powder for depositing the first, second and third layers of cold additive is preferably a micron alloy powder.

[0086] Preferably, the gas heater 7 has a temperature control and display module for regulating the temperature of the carrier gas, thereby controlling the temperature of the metal alloy powder deposited on the surface of the metal sheath and ensuring that the substrate temperature of the metal sheath does not exceed 110°C during deposition.

[0087] Preferably, the protective gas in the carrier gas bottle 1 can be helium, nitrogen or air.

[0088] It can be seen that compared with the prior art, the beneficial effects of the present invention are: low-pressure cold additive equipment is used to repair the metal sheath in situ, and cold additives are deposited layer by layer on the defective parts of the metal sheath of the high-voltage cable by using metal alloy powders in different ratios, so that high temperature and high pressure are not required in the repair process, and the substrate temperature of the metal sheath does not exceed 110°C during the entire repair process, and there is no need for annealing treatment to release stress after the repair is completed, and no damage is caused to the cable and the protective sheath connected to the defective part. The repaired metal sheath has the advantages of high tensile strength, high density and low resistance. Compared with the original metal sheath, the resistance is not increased, which can ensure the subsequent safe operation of the cable; the technical solution of the present invention has the advantages of simple and easy operation, short repair cycle, low cost, and no harm to the operator.

[0089] The present invention has been described in detail above in conjunction with specific implementations and exemplary examples, but these descriptions cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, a variety of equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its implementation methods, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the attached claims.

Claims

1. A method for repairing a high voltage cable metal sheath on site, characterized in that: The method comprises the following steps: Step 1, pre-treating the defective part of the metal sheath, and then depositing the first layer of cold additive material on the defective part; Step 2, depositing a second layer of cold additive material on the defective portion where the first layer of cold additive material is deposited; Step 3, depositing a third layer of cold additive material on the defective portion where the second layer of cold additive material is deposited; Wherein, the base material temperature of the high-voltage cable metal sheath does not exceed 110° C. during the deposition process.

2. The on-site repair method for the high-voltage cable metal sheath according to claim 1 is characterized in that: In step 1, The carrier gas pressure when depositing the first layer of cold additive is 0.5-1.5 MPa, and the gas flow rate is 20-30 m 3 / h, the distance between the nozzle and the defective part is 5-20mm, and the horizontal moving speed of the nozzle is 0.01m / s-0.1m / s.

3. The on-site repair method for the high-voltage cable metal sheath according to claim 1 is characterized in that: In step 1, The deposition material of the first layer of cold additive is a copper-based material, and the mass percentage of the deposition material of the first layer of cold additive is: based on the total weight of the raw materials as 100%, Al: 30-40%, Zn: 5-15%, Mn: 1.0-1.5%, Mg: 0.2-0.6%, Cr: 0.1%, Ti: 0.1%, Si: 0.6%, Cu: balance.

4. The on-site repair method for the high-voltage cable metal sheath according to claim 1, characterized in that: In step 2, The carrier gas pressure when depositing the second layer of cold additive is 0.5-1.5MPa, and the gas flow rate is 20-30m 3 / h, the distance between the nozzle and the defective part is 5-20mm, and the horizontal moving speed of the nozzle is 0.01m / s-0.1m / s.

5. The on-site repair method for the high-voltage cable metal sheath according to claim 1, characterized in that: In step 2, The deposition material of the second layer of cold additive is a copper-based material, and the mass percentage of the deposition material of the second layer of cold additive is: based on the total weight of the raw materials as 100%, Al: 7-18%, Zn: 3-10%, Cr: 10%, Mn: 1.3-1.8%, Mg: 0.1-0.5%, Ti: 0.2%, Si: 0.8%, Cu: balance.

6. The on-site repair method for the high-voltage cable metal sheath according to claim 1, characterized in that: In step 3, The carrier gas pressure when depositing the third layer of cold additive is 0.5-1.5 MPa, and the gas flow rate is 20-30 m 3 / h, the distance between the nozzle and the defective part is 5-20mm, and the horizontal moving speed of the nozzle is 0.01m / s-0.1m / s.

7. The on-site repair method for the high-voltage cable metal sheath according to claim 1, characterized in that: In step 3, The deposition material of the third layer of cold additive is a copper-based material, and the mass percentage of the deposition material of the third layer of cold additive is: based on the total weight of the raw materials as 100%, Al: 10-15%, Sn: 8-13%, Mn: 1.0-2.0%, Mg: 0.5-1.0%, Cr: 0.2%, Ti: 0.1%, Si: 0.6%, Cu: balance.

8. An on-site repair system for a high voltage cable metal sheath using the method according to any one of claims 1 to 7, characterized in that: It includes: a carrier gas bottle, a first gas passage, a second gas passage, a first control valve, a second control valve, a powder feeder, a gas heater and a nozzle; The carrier gas bottle is connected to the nozzle via the first gas passage and the second gas passage respectively; the first control valve and the powder feeder are arranged on the first gas passage and are arranged in sequence between the carrier gas bottle and the nozzle; the second control valve and the gas heater are arranged on the second gas passage and are arranged in sequence between the carrier gas bottle and the nozzle; the gases in the first gas passage and the second gas passage are merged in the nozzle and sprayed out through the nozzle of the nozzle to be deposited on the metal sheath of the high-voltage cable.

9. The on-site repair system for the high-voltage cable metal sheath according to claim 8, characterized in that: The powder feeder is a micron alloy powder feeder.

10. The on-site repair system for the high voltage cable metal sheath according to claim 8, characterized in that: The gas heater has a temperature control and display module.

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