CN115101256A - Novel 220kV crosslinked polyethylene insulated power cable production process - Google Patents

Abstract

The invention relates to the technical field of cable production, and discloses a novel production process of a 220kV crosslinked polyethylene insulated power cable, which comprises the following steps of 1) increasing certain pressure on the cable by adopting a dry-type crosslinking method and an electric heating mode to wind the cable to the outer side of a vulcanization pipe, then concentrating heat on the cable insulation to enable the cable to generate vulcanization reaction, and taking nitrogen in the pipe as a pressurized medium; 2) in the cross-linking process, different spectrum ultraviolet light is used as a light source, the running power of the ultraviolet light with different spectrum for irradiation is set to be 2KW, and the irradiation time is set to be 20-25S, so that the irradiation effect of the ultraviolet light is ensured. This novel 220kV crosslinked polyethylene insulation power cable production technology extrudes simultaneously through the three-layer and can guarantee that conductor shield surface is smooth, and is protruding little, and conductor shield, insulation and insulation shield three-layer cooperation are inseparable to improve the electrical properties of cable, double plate receive and releases line equipment and conductor and store up line equipment, can adapt to the production of linking in batches.

Description

Production Technology of New 220kV XLPE Insulated Power Cable

technical field

The invention relates to the technical field of cable production, in particular to a production process for a novel 220kV cross-linked polyethylene insulated power cable.

Background technique

A cable is a power or signal transmission device, usually composed of several or several groups of wires, made of one or more mutually insulated conductors and an outer insulating protective layer, which transmit power or information from one place to another. Conductor, usually a rope-like cable consisting of several or several groups of conductors twisted at least two in each group. Each group of conductors is insulated from each other and often twisted around a center. The covering layer of the cable has the characteristics of inner energization and outer insulation. The cables include power cables, control cables, compensation cables, shielded cables, high temperature cables, computer cables, signal cables, coaxial cables, fire-resistant cables, marine cables, and mining cables. and aluminum alloy cables, etc., they are all composed of single or multi-strand wires and insulating layers. They are used to connect circuits, electrical appliances and other power cables. According to the properties of insulating materials, they can be divided into three types: oil-paper insulation, plastic insulation, and rubber insulation. Plastic insulation is divided into PVC insulation type and XLPE insulation type. Among them, oil-paper insulated cable products were developed earlier, but the disadvantage is that oil is easy to drip, so it is not suitable for high drop laying; the allowable working field strength is low, and it is not suitable for If it is used at too high voltage, even if there is no dripping impregnated oil-paper insulated cable in oil-paper insulation, it can overcome the problem of oil dripping, but the cost is higher than that of general oil-paper insulation, so the production of oil-paper insulated cable products has been gradually phased out; The working temperature of the conductor is 700C. Although it has certain flame retardant or flame retardant properties, polyvinyl chloride contains halogen. Once an electrical fire occurs and burns, not only a large amount of smoke but also a large amount of acidic toxic gas will be generated. It does not meet the technical requirements of fire protection at all, so the production and usage are not large; although the rubber insulated cable has good flexibility, easy bending, good electrical properties and chemical stability, it is resistant to corona, ozone and oil. The performance is poor, and it is not suitable for use at too high voltage, so the production and usage are not large, so the cross-linked polyethylene cable came into being.

Compared with traditional cables, XLPE cables have unparalleled advantages, which make their use quantity and radiation density increase day by day, but with the improvement of people's living standards, the use and safety performance of XLPE insulated cable products are also proposed Higher requirements, in physical cross-linking, both electron beam radiation cross-linking and silane cross-linking do not need to increase pressure. The former only needs to use electron rays to remove part of the hydrogen atoms in polyethylene to achieve the cross-linking goal, while the latter requires The chemical method is used to cross-link polyethylene molecules, which is more suitable for the production of thin insulated control cables or 1kV cross-linked polyethylene cables. Chemical cross-linking requires pressure to generate water and gas. The wet method can increase the moisture in polyethylene. At the same time, the size of the micropores becomes larger, so they all have certain limitations, so that the power does not have good electrical performance, so the stability of the cable is relatively low during operation.

SUMMARY OF THE INVENTION

(1) Technical problems solved

Aiming at the deficiencies of the prior art, the present invention provides a new production process for a 220kV cross-linked polyethylene insulated power cable, which has the advantages of stable operation and the like, and solves the problem of not having good electrical performance.

(2) Technical solutions

In order to achieve the above-mentioned purpose of stable operation, the present invention provides the following technical solutions: the production process of a novel 220kV cross-linked polyethylene insulated power cable, comprising the following steps:

1) The dry cross-linking method is used to add a certain pressure to the cable to wind the cable to the outside of the vulcanized tube by means of electric heating, and then the heat is concentrated on the cable insulation to cause a vulcanization reaction, and the inner part of the tube is vulcanized. Nitrogen as pressurized medium;

2) In the process of cross-linking, different spectrum ultraviolet light is used as the lamp source, the operating power of different spectrum ultraviolet light is set to 2KW, and the irradiation time is 20-25S to ensure the irradiation effect of ultraviolet light;

3) Then use three extruders to extrude the conductor shielding layer, insulating layer and insulating shielding layer to one head at the same time, set the extruded plastic to be 1-2m per second, and the extrusion temperature to be 100 to 100 degrees. fifth degree;

4) Degas the insulating layer, place it in the drying room for rest, set the temperature in the drying room to be between 50 and 70 degrees, and set the degassing time to 80-90 hours. Then coat copper wire on the outer layer, and then coat the flame-retardant cloth strip on the outer side of the copper wire layer;

5) Set up double-disc take-up and pay-off equipment and conductor storage equipment for continuous production, and use computer online control to automatically control the production speed according to the vulcanization speed in the vulcanized tube to ensure the quality of cable production.

Preferably, the simultaneous extrusion of the conductor shielding layer, the insulating layer and the insulating shielding layer can ensure that the conductor shielding surface is smooth, the protrusions are small, and the three layers of the conductor shielding, insulating and insulating shielding are closely matched, so as to improve the electrical performance of the cable.

Preferably, the double-reel take-up and pay-out equipment and the conductor storage equipment can adapt to mass production, which can not only ensure the quality of the cables, but also reduce waste products, reduce the consumption of raw materials, and reduce the cost of cables.

Preferably, the semiconductive material dryer reduces the number of micropores and the size of the micropores in the extruded semiconductive shielding layer, improves the shielding layer, and the material sealing and feeding system prevents the clean material from being polluted by impurities in the air, thereby improving Electrical properties of cables.

Preferably, the use of ultraviolet light with different spectrums as the light source effectively increases the intensity of the light source, ensures that the photocrosslinking reaction can proceed smoothly, and makes the light source produced by the process more stable.

Preferably, the cross-linking reaction requires the participation of ultraviolet light to provide sufficient radiation intensity for polyethylene to ensure that the ultraviolet light cross-linking reaction can proceed smoothly. The polyethylene cross-linking reaction needs to be carried out in a molten state, and ultraviolet light is required. Irradiation can increase the temperature to a certain extent.

(3) Beneficial effects

Compared with the prior art, the present invention provides a new 220kV cross-linked polyethylene insulated power cable production process, which has the following beneficial effects:

1. The production process of the new 220kV XLPE insulated power cable can ensure that the conductor shielding surface is smooth, the protrusions are small, and the three layers of conductor shielding, insulation and insulation shielding are closely matched by extruding three layers at the same time, so as to improve the electrical performance of the cable. Double-reel take-up and pay-off equipment and conductor storage equipment can adapt to mass production, which can not only ensure cable quality but also reduce waste, reduce raw material consumption, and reduce cable costs. The semi-conductive material dryer makes the extruded semi-conductive shielding. The number of micropores in the layer is reduced and the size of the micropores is reduced, the shielding layer is improved, the material sealing feeding system makes the clean material not polluted by impurities in the air, thereby improving the electrical performance of the cable, the cross-linking production line has computer online control, is based on vulcanized pipes The medium vulcanization speed automatically controls the production speed to ensure the quality of the product.

2. The production process of this new 220kV cross-linked polyethylene insulated power cable is to add a photoinitiator to the polyolefin, and use different spectrum ultraviolet light as a light source for irradiation, and absorb the ultraviolet light of a specific wavelength through the photoinitiator to generate a polymer. olefin free radicals, and undergo a polymerization reaction, and finally generate a cross-linked polyolefin with a three-dimensional network structure. The material formed through the above reaction process has the advantages of strong heat resistance, solvent resistance, etc. Replacing mercury lamps with light can effectively improve the purity of ultraviolet light, significantly enhance the efficiency of the light source, and ensure that the cross-linking reaction is more efficient.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to 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.

The novel 220kV XLPE insulated power cable production process in this embodiment includes the following steps:

1) The dry cross-linking method is used to add a certain pressure to the cable to wind the cable to the outside of the vulcanized tube by means of electric heating, and then the heat is concentrated on the cable insulation to cause a vulcanization reaction, and the inner part of the tube is vulcanized. Nitrogen as pressurized medium;

2) In the process of cross-linking, different spectrum ultraviolet light is used as the lamp source, the operating power of different spectrum ultraviolet light is set to 2KW, and the irradiation time is 20-25S to ensure the irradiation effect of ultraviolet light;

3) Then use three extruders to extrude the conductor shielding layer, insulating layer and insulating shielding layer to one head at the same time, set the extruded plastic to be 1-2m per second, and the extrusion temperature to be 100 to 100 degrees. fifth degree;

4) Degas the insulating layer, place it in the drying room for rest, set the temperature in the drying room to be between 50 and 70 degrees, and set the degassing time to 80-90 hours. Then coat copper wire on the outer layer, and then coat the flame-retardant cloth strip on the outer side of the copper wire layer;

5) Set up double-disc take-up and pay-off equipment and conductor storage equipment for continuous production, and use computer online control to automatically control the production speed according to the vulcanization speed in the vulcanized tube to ensure the quality of cable production.

Extrusion of conductor shielding layer, insulating layer and insulating shielding layer at the same time can ensure that the conductor shielding surface is smooth, the protrusions are small, and the three layers of conductor shielding, insulating and insulating shielding are closely matched to improve the electrical performance of the cable. Wire storage equipment, which can adapt to mass production, can not only ensure the quality of cables but also reduce waste, reduce the consumption of raw materials, and reduce the cost of cables. The size of the micropores, the shielding layer is improved, and the material sealing and feeding system makes the clean materials free from contamination by impurities in the air, thereby improving the electrical performance of the cable. The use of different spectrum ultraviolet light as the light source effectively increases the intensity of the light source and ensures that the light is crossed. The linking reaction can be carried out smoothly, making the light source produced by the process more stable. The cross-linking reaction requires the participation of ultraviolet light to provide sufficient radiation intensity for polyethylene to ensure that the ultraviolet light cross-linking reaction can proceed smoothly. It needs to be carried out in a molten state, and it needs to be irradiated with ultraviolet light, which can improve the temperature to a certain extent. The extruder, drying room, double-disc take-up and pay-out equipment and conductor storage equipment used in the embodiment It is an existing device on the market, and it is not necessary to describe how it works and how to use the computer to control it online.

The principle of ultraviolet light crosslinking is mainly to add a photoinitiator to polyolefin and irradiate it with ultraviolet light. The photoinitiator absorbs ultraviolet light of a specific wavelength to generate polyolefin free radicals, and a polymerization reaction occurs, and finally a three-dimensional network is formed. The cross-linked polyolefin with a cross-linked polyolefin-like structure, the material formed through the above reaction process, has the advantages of strong heat resistance, solvent resistance, etc. Life and other aspects are slightly better, which is more in line with the development needs of electric power modernization. The photo-crosslinking method is similar to the high-energy electron beam irradiation method in terms of technical principle, but in terms of process flow, it is similar to the chemical reaction induced by peroxide heat. The cross-linking method has the same purpose, and draws on the advantages of different methods. As a new cross-linking process with low cost and high product quality, UV cross-linking technology, as a new technology after chemical and physical cross-linking, makes up for the first two. At the same time, it has made breakthroughs on the original basis.

Therefore, the main advantage of cross-linked polyethylene cable in practical application is that it has superior heat resistance, even if the temperature is as high as 300 ℃, it will not decompose or carbonize, and the long-term working temperature can reach 90 ℃, and its thermal life It can reach 40 years. While maintaining the original insulation, the insulation resistance is improved. Due to the chemical bonds established between macromolecules, the hardness, stiffness and wear resistance have been improved, effectively making up for the natural resistance of traditional cables. The cracking problem caused by environmental impact has its own acid resistance and oil resistance, and its combustion products are mainly water and carbon dioxide, which have less environmental pollution and are in line with modern energy conservation and emission reduction requirements.

The beneficial effects of the present invention are: through the simultaneous extrusion of three layers, it can ensure that the conductor shielding surface is smooth, the protrusions are small, and the conductor shielding, insulation and insulation shielding three layers are closely matched, so as to improve the electrical performance of the cable. Wire storage equipment, which can adapt to mass production, can not only ensure the quality of cables but also reduce waste, reduce the consumption of raw materials, and reduce the cost of cables. Micropore size, improve shielding layer, material sealing and feeding system so that clean materials are not polluted by impurities in the air, thereby improving the electrical performance of the cable, the cross-linking production line has computer online control, and the production speed is automatically controlled according to the vulcanization speed in the vulcanized tube , to ensure the quality of the product, by adding a photoinitiator to the polyolefin, and using different spectrum ultraviolet light as the lamp source for irradiation, the photoinitiator absorbs the ultraviolet light of a specific wavelength to generate polyolefin free radicals, and the polymerization reaction occurs , and finally generate a cross-linked polyolefin with a three-dimensional network structure. The material formed through the above reaction process has the advantages of strong heat resistance and solvent resistance, and the use of different spectrum ultraviolet light instead of mercury lamp can effectively Improve the purity of ultraviolet light, so that the efficiency of the light source is significantly enhanced, and the cross-linking reaction is more efficient.

Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, and substitutions can be made in these embodiments without departing from the principle and spirit of the invention and modifications, the scope of the present invention is defined by the appended claims and their equivalents.

Claims (6)

1. the production technology of novel 220kV cross-linked polyethylene insulated power cable, is characterized in that, comprises the following steps, 1) The dry cross-linking method is used to add a certain pressure to the cable to wind the cable to the outside of the vulcanized tube by means of electric heating, and then the heat is concentrated on the cable insulation to cause a vulcanization reaction, and the inner part of the tube is vulcanized. Nitrogen as pressurized medium; 2) In the process of cross-linking, different spectrum ultraviolet light is used as the lamp source, the operating power of different spectrum ultraviolet light is set to 2KW, and the irradiation time is 20-25S to ensure the irradiation effect of ultraviolet light; 3) Then use three extruders to extrude the conductor shielding layer, insulating layer and insulating shielding layer to one head at the same time, set the extruded plastic to be 1-2m per second, and the extrusion temperature to be 100-1000 fifth degree; 4) Degas the insulating layer, place it in the drying room for rest, set the temperature in the drying room to be between 50 and 70 degrees, and set the degassing time to 80-90 hours. Then coat copper wire on the outer layer, and then coat the flame-retardant cloth strip on the outer side of the copper wire layer; 5) Set up double-disc take-up and pay-off equipment and conductor storage equipment for continuous production, and use computer online control to automatically control the production speed according to the vulcanization speed in the vulcanized tube to ensure the quality of cable production. 2. The new 220kV XLPE insulated power cable production process according to claim 1, wherein the simultaneous extrusion of the conductor shielding layer, the insulating layer and the insulating shielding layer can ensure that the conductor shielding surface is smooth and the protrusions are small, The three layers of conductor shield, insulation and insulation shield are closely matched to improve the electrical performance of the cable. 3. The new 220kV XLPE insulated power cable production process according to claim 1, characterized in that, the double-disc take-up and pay-out equipment and the conductor wire storage equipment can be adapted to mass-connected production, and both can ensure that the cable is Quality can also reduce waste, reduce raw material consumption, and reduce cable costs. 4. The new 220kV XLPE insulated power cable production process according to claim 1, wherein the semiconductive material dryer reduces the number of micropores and the size of the micropores in the extruded semiconductive shielding layer , Improve the shielding layer, and the material sealing feeding system makes the clean material free from contamination by impurities in the air, thereby improving the electrical performance of the cable. 5. The production process of the novel 220kV cross-linked polyethylene insulated power cable according to claim 1, wherein the use of different spectrum ultraviolet light as the light source effectively improves the intensity of the light source and ensures that the photocrosslinking reaction can It goes on smoothly, making the light source produced by the process more stable. 6. The new 220kV cross-linked polyethylene insulated power cable production process according to claim 1, wherein the cross-linking reaction requires the participation of ultraviolet light, providing enough radiation intensity for polyethylene to ensure ultraviolet light cross-linking The reaction can be carried out smoothly. The polyethylene crosslinking reaction needs to be carried out in a molten state, and ultraviolet light is required for irradiation, which can increase the temperature to a certain extent.