Low-voltage modified polypropylene insulated power cable and preparation method thereof
By using modified polypropylene insulating materials, combined with toughening materials and low-pressure extruder manufacturing technology, the problem of existing cable materials being unable to be recycled and stable operation under high temperature conditions is solved, and high-performance, recyclable and low-cost low-voltage power cables are achieved.
Patent Information
- Application Number
- CN202311401850.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-10-27
- Publication Date
- 2025-04-29
AI Technical Summary
The existing 1kV low-voltage cable insulation layer materials have problems such as inability to recycle and high-temperature decomposition products to the environment, and it is difficult to meet the stable operation under high temperature and high field strength conditions.
It is made of modified polypropylene insulating material and is mixed with toughening materials. It is used to make low-voltage 0.6/1kV power cables and is manufactured using a low-voltage extruder.
It realizes low-cost, high-performance, and recyclable insulated power cables, improves the electrical, anti-aging and mechanical and physical properties of the cables, and can operate stably under high temperature and high field strength conditions.
Smart Images
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Abstract
Description
Technical Field
[0001] The patent of this invention relates to the field of power cables, and in particular to a low-voltage 1kV modified polypropylene insulated power cable, including the main structure, application materials and manufacturing method of the power cable. Background Art
[0002] Power cables are an important part of the power system and the main artery of urban energy. At present, the insulation layer of 1kV low-voltage cables generally uses silane cross-linked polyethylene materials. Polyethylene is turned into a thermosetting polymer through steam cross-linking, which cannot be recycled, and its high-temperature decomposition products are extremely harmful to the environment. Therefore, in order to simplify the production process of cables, improve the final quality of cable insulation, and eliminate the possible harm to the environment, it is necessary to find a new type of thermoplastic recyclable cable insulation material and its preparation process to replace the traditional polyethylene material and its cross-linking process, so as to realize the manufacturing and engineering application of low-cost, high-performance, recyclable insulated power cables.
[0003] Polypropylene insulated power cables are environmentally friendly power cables that have emerged in recent years. Polypropylene cables are not only environmentally friendly because their materials can be recycled after retirement, but also have many advantages in manufacturing and application: for example, in the manufacturing of low-voltage cables, the energy consumption caused by steam cross-linking can be saved; polypropylene materials are cheap, and the production of cables has cost advantages; and the operating temperature of polypropylene cables is nearly 15% higher than that of silane cross-linked polyethylene cables. At the same time, they have the technical advantage of long-term and long-length continuous extrusion production, which will become an important option for the next generation of power cables. Summary of the invention
[0004] The purpose of the present invention is to overcome the problem that existing cable products cannot meet the requirements of stable operation under high temperature and high field strength, and to provide a modified polypropylene cable.
[0005] Another problem to be solved by the present invention is to provide a method for preparing the above-mentioned low-voltage 1 kV power cable using thermoplastic modified polypropylene insulation as an insulating material.
[0006] The present invention provides a solution to the above problem: using one or more of random, syndiotactic and isotactic polypropylenes and mixing one or more toughening materials to prepare a modified polypropylene insulation material. Using the polypropylene as the insulation material, a low-voltage 0.6 / 1kV power cable is manufactured by a low-voltage extruder.
[0007] A low-voltage modified polypropylene insulated power cable and a manufacturing method thereof, characterized in that the cable material used is a modified polypropylene cable material containing 10% to 80% of a polypropylene component. Preferably, the polypropylene is a combination of one or more random copolymers, homopolymers, and block copolymers. The polypropylene cable material can be a combination of one or more elastomer toughening systems, dynamically cross-linked rubber systems, and graft toughening systems, and does not require semi-conductive inner and outer semi-conductive shielding materials.
[0008] The low-voltage modified polypropylene insulated power cable and its manufacturing method have the following characteristic structures: Figure 1 As shown, it includes: a main line core, a cable wrap, an inner sheath, a steel belt armor and an outer sheath. Compared with the commonly used silane cross-linked polyethylene insulation material, the modified polypropylene insulation material has excellent electrical properties, anti-aging properties and mechanical and physical properties. Preferably, the inner sheath and the outer sheath are both polymer materials, and more preferably, they can be low-density polyethylene, high-density polyethylene, polyvinyl chloride and other similar polymer materials.
[0009] The low-voltage modified polypropylene insulated power cable and its manufacturing method are characterized in that the manufacturing method of the main core includes copper wire drawing and copper wire twisting. The equipment used includes a wire drawing machine, a frame twisting machine, a single-screw extruder, a traction machine, a vulcanizing pipe, a cooling water tank, etc.
[0010] In order to highlight the characteristics and advantages of the present invention, the present invention will be further described below in conjunction with some specific embodiments. However, the described embodiments are only some examples of the present invention, not all embodiments, and the protection scope of the present invention is not limited to the following examples.
[0011] Embodiment: This embodiment is a power cable product with a rated voltage of 0.6 / 1kV and below, which is produced using modified polypropylene (PP) insulation material. It has a five-core insulated wire core structure. The outer side of the conductor of each insulated wire core is sequentially extruded with an insulating layer of polypropylene (PP) as the base material from the inside to the outside. After the insulated wire core is cabled, it is covered with a lining layer and a sheath. For details, see Figure 1 . ; 5-core cable is yellow, green, red, blue, yellow / green two-color; yellow / green two-color wire can also be included in any cable core according to customer requirements. The proportion of green in the yellow / green two-color wire should be no less than 30%, but not more than 70%. The preparation process of the above-mentioned power cable with a rated voltage of 0.6 / 1kV and below includes the processing steps of copper single wire, conductive core, PP insulation layer, cabling and outer sheath, specifically including:
[0012] (1) Use a wire drawing machine to draw an oxygen-free copper rod with a diameter of 8 mm into a copper wire with a diameter of 1-5 mm, and anneal it to make a copper single wire.
[0013] (2) Multiple copper wires are concentrically twisted to form a conductive structure, and a nano-diamond coated twisting die is used to interweave and press the wires in a clockwise direction to form a conductor core.
[0014] (3) Using a low-voltage cable extruder, extrude a PP insulation layer on the outer surface of the conductor. After the eccentricity of the insulation core is adjusted, immerse it in a water tank for cooling, blow dry it, and then reel it in. The engineering parameters designed in Example 1 are: screw speed: 15 rpm; screw zone temperatures: 120°C, 140°C, 160°C, 170°C, 180°C, 180°C.
[0015] The insulated cores are arranged in the order of yellow, green, red, blue, and yellow / green, and the cabling direction is right. 50mm 2 The gaps between the following cable cores are filled with flame-retardant filling ropes, and the gaps between the remaining cable cores are filled with PP (polypropylene film or rope). The filling amount can be adjusted based on the filling circle.
[0016] The non-armored cable is wrapped with halogen-free low-smoke tape in the left direction, and the armored cable is 50mm 2 The following non-woven tapes, 50mm 2 The CPP tape (inner layer) and non-woven tape (outer layer) are used for left overlapping wrapping. The wrapping should be flat, tight and continuous, without looseness or leakage. The average overlapping width of the wrapping tape shall not exceed the maximum value specified by the process.
[0017] The outer sheath should be tightly extruded, continuous, and uniform in thickness. The surface should be flat and smooth, free of impurities, burnt particles, poor seams, wrinkles, bamboo knots, fingerprints and other defects. There should be no visible pores on the cross section. Water should not enter the two ends of the cable. The minimum thickness of the outer sheath of the non-armored cable should not be less than 85%-0.1mm of the specified nominal thickness, and the minimum thickness of the outer sheath of the armored cable should not be less than 80%-0.2mm of the specified nominal thickness. The cable out-of-roundness should not exceed 10%.
[0018] The results obtained in this embodiment are measured by the eccentricity of the outer dimensions of the cable main core and the maximum production speed. The results are as follows: the dimensions of the main insulation are: maximum diameter: 12.8 mm, minimum diameter 10.6 mm, average 12.7 mm, eccentricity 1.5%. Maximum production speed: 3 m / min; mechanical properties of the main insulation - tensile strength / elongation at break: 17 MPa / 480%. BRIEF DESCRIPTION OF THE DRAWINGS The embodiments of the present invention are described in more detail with reference to the accompanying drawings. Figure 1 This is a schematic diagram of a cable structure in a specific implementation manner of the present invention. Figure 2 The present invention provides a cable production device. Description of Reference Numerals 1- conductor; 2- PP insulation; 3- cabling wrapping; 4- inner sheath; 5- steel belt armor; 6- outer sheath; 7- cable extruder; 8- extruder control cabinet; 9- cooling water tank; 10- traction machine.
Claims
1. A low voltage 1kV modified polypropylene insulated power cable and a manufacturing method thereof, characterized in that: The modified polypropylene cable material used in the cable, the main structure of the cable and the manufacture of the cable core are also characterized in that the voltage level is 1kV and below.
2. A low-voltage modified polypropylene insulated power cable and a method for manufacturing the same according to claim 1, characterized in that: The cable insulation material used is modified polypropylene, in which the content of polypropylene is 10% to 80%.
3. The polypropylene according to claim 2 is one or more combinations of a random copolymer, a homopolymer, and a block copolymer.
4. The modified polypropylene insulating material according to claim 2 needs to contain an anti-copper agent.
5. A low-voltage modified polypropylene insulated power cable and a method for manufacturing the same according to claim 1, characterized in that: Low voltage 1kV modified polypropylene insulated power cable includes main line core, cabling wrap, inner sheath, steel tape armor and outer sheath.
6. A low-voltage modified polypropylene insulated power cable and a method for manufacturing the same according to claim 4, characterized in that: The main insulation of the copper wire core is produced by adopting an extrusion die head.
7. A low-voltage modified polypropylene insulated power cable and a method for manufacturing the same according to claim 1, characterized in that: The manufacturing method of the main line core includes copper wire drawing, copper wire stranding, extrusion, and cabling. The method is characterized in that the equipment used includes a wire drawing machine, a frame stranding machine, a single screw extruder, a traction machine, a cooling water tank, etc.