China Zhenglan Cable Technology Co., Ltd Company News

Aluminum alloy cables and aluminum core cables are two common power transmission line materials. Their conductor materials are different, so their prices are also different. Generally speaking, the price of aluminum alloy cables is relatively high. The following are some factors that affect the price: 1. Conductor material: The conductor of aluminum alloy cable is made of aluminum alloy, while the aluminum core cable is made of ordinary aluminum. The manufacturing cost of aluminum alloy is relatively high, which makes aluminum alloy cables relatively expensive. 2. Performance differences: Aluminum alloy cables usually have better electrical conductivity and mechanical properties and can meet some special requirements, which is one of the reasons for their higher price. 3. Manufacturing process: The production and manufacturing process of aluminum alloy cables is relatively complex and requires a higher level of technology and equipment, which will also affect its price.

Dear users,   Thank you for your continued support and trust! On this special Christmas season, we would like to extend our warmest wishes and greetings to you.   Christmas is a time filled with love and joy, and we hope you enjoy a cozy and joyful holiday season with your family, loved ones, and friends. May you feel an abundance of warmth and happiness during this festive time and have a wonderful New Year ahead.   As a token of appreciation for your ongoing support, we will continue to strive to provide you with high-quality services and products that cater to your needs. In the coming year, we will keep innovating and improving to bring you more surprises and convenience.   Wishing you and your family an unforgettable Christmas and a prosperous New Year! May the new year bring you endless happiness, health, and success!   Once again, thank you for your support, and Merry Christmas!   Warmest regards Zhenglan Cable    

Medium voltage power cables mostly use cross-linked polyethylene insulation. Ordinary cross-linked polyethylene insulation cables are damaged by mechanical stress or external forces during installation and operation, or the cables are operated for a long time in a humid and watery environment, which can cause external moisture to penetrate into the interior of the cables. The chance of forming water trees under the action of the electric field is greatly increased, and water trees are transformed into permanent electrical trees under the action of the electric field, Causing insulation breakdown in a relatively short period of time. Once the outer protective layer of the cable is damaged, water ingress into the cable can cause corrosion of the steel strip and copper strip, decrease the insulation performance, and greatly shorten the service life of the cable. Therefore, the industry recommends using water resistant cross-linked polyethylene cables.

23. Where are the inner shielding layer and outer shielding layer of power cables located? What materials are used? What does it do? Answer: In order to have better contact between the insulation layer and the cable conductor and eliminate the increase in electric field intensity on the conductor surface caused by the roughness of the conductor surface, the conductor surface is generally covered with an inner shielding layer of metallized paper or semiconductor paper tape. In order to ensure better contact between the insulation layer and the metal sheath, an outer shielding layer is generally wrapped around the insulation layer. The outer screen layer is made of the same material as the inner screen layer, and sometimes it is also bound with copper tape or braided copper wire tape.   24. What should we pay attention to during the transportation, loading and unloading of cables? Answer: (1) During transportation, loading and unloading, cables and cable drums should not be damaged. It is strictly forbidden to push cable drums directly off the vehicle. Cables should generally not be transported or stored flat. (2) Before transporting or rolling the cable drum, it must be ensured that the cable drum is firm and the cable is wound tightly. The oil pipe between the oil-filled cable and the pressure oil tank should be fixed and not damaged. The pressure oil tank should be secure and the pressure indication should meet the requirements. 25. What aspects should be considered when selecting the cross-section of power cables? Answer: The following aspects should be considered: (1) The long-term operating current allowed by the cable; (2) Thermal stability in the event of short circuit; (3) The voltage drop on the line cannot exceed the allowable working range. 26. What are the advantages of power cables compared with overhead lines? Answer: (1) Reliable operation. Because it is installed in hidden places such as underground, it is less damaged by external forces and has fewer chances of failure. The power supply is safe and will not cause harm to people; (2) The maintenance workload is small and frequent inspections are not required; (3) No need to erect poles and towers; (4) Helps improve power factor.   27. What measures are taken to prevent cable fire? Answer: (1) Use flame-retardant cables; (2) Use fireproof cable brackets; (3) Use fire retardant coatings; (4) Fire partition walls and fire baffles should be installed at cable tunnels, mezzanine exits, etc.; (5) Overhead cables should avoid oil pipelines and explosion-proof doors. Otherwise, local pipe penetration or heat insulation and fire prevention measures should be taken.   28. What is a cable failure? How many common types are there? Answer: Cable failure refers to the failure of insulation breakdown of the cable during preventive testing or the failure of the cable line to cause a power outage due to insulation breakdown, wire burnout, etc. during operation. Common faults include ground faults, short circuit faults, disconnection faults, flashover faults and mixed faults.   29. According to the "Regulations on Safety in Electrical Industry", what are the conditions that electrical workers must meet? Answer: The following conditions must be met: (1) Healthy as determined by a doctor, with no illness that would hinder work; (2) Have necessary electrical knowledge, master relevant procedures, professional techniques and safe operation techniques according to their duties and nature of work, and pass the examination; (3) Be proficient in first aid methods for electric shock.   30. Where are the inner shielding layer and outer shielding layer of power cables located? What materials are used? What does it do? Answer: In order to have better contact between the insulation layer and the cable conductor and eliminate the increase in electric field intensity on the conductor surface caused by the roughness of the conductor surface, the conductor surface is generally covered with an inner shielding layer of metallized paper or semiconductor paper tape. In order to ensure better contact between the insulation layer and the metal sheath, an outer shielding layer is generally wrapped around the insulation layer. The outer screen layer is made of the same material as the inner screen layer, and sometimes it is also bound with copper tape or braided copper wire tape.

The function of insulation screen in MV cable:  The insulation and shielding structure of medium voltage cables is relatively complex, usually composed of multiple components such as cable core, insulation layer, semiconductor shielding layer, metal sheath, and outer protective layer. 1. Protect the cable core The insulation shielding of medium voltage cables can effectively protect the cable core from mechanical damage and external electromagnetic interference. 2. Enhance cable durability The semiconductor shielding layer of medium voltage cable insulation can not only balance the electric field and prevent partial discharge, but also enhance the durability of the cable and extend its service life. 3. Improve cable transmission performance The insulation and shielding of medium voltage cables can effectively reduce the transmission loss and crosstalk interference of cables, and improve the transmission performance and stability of cables. 4. Safety The insulation and shielding of medium voltage cables can effectively prevent accidents such as fires and electric shocks, ensuring the safety of the power system and personnel.

18. What are the requirements for the mechanical strength of cable conductor connection points?   Answer: The mechanical strength of the connection point is generally lower than the tensile strength of the cable conductor itself. For fixedly laid power cables, the tensile strength of the connection point is required to be no less than 60% of the tensile strength of the conductor itself. 19. What are the main properties of the insulation layer material of power cables?   Answer: It should have the following main properties: (1) High breakdown strength; (2) Low dielectric loss; (3) Quite high insulation resistance; (4) Excellent discharge resistance; (5) Has certain softness and mechanical strength; (6) The insulation performance is long-term and stable. 20. The applications of wires and cables are mainly divided into three categories:   (1), power system The wire and cable products used in the power system mainly include overhead bare wires, busbars (busbars), power cables (plastic cables, oil-paper power cables (basically replaced by plastic power cables), rubber sheathed cables, overhead insulated cables), branch cables (replacing some busbars), electromagnetic wires, and electrical equipment wires and cables for power equipment, etc.   (2), Information transmission system The wires and cables used in information transmission systems mainly include local telephone cables, television cables, electronic cables, radio frequency cables, optical fiber cables, data cables, electromagnetic wires, power communication or other composite cables, etc.   (3), mechanical equipment, instrumentation systems In addition to overhead bare wires, almost all other products in this section are applied, but mainly power cables, electromagnetic wires, data cables, instrumentation cables, etc.   21. Wire and cable products are mainly divided into five categories:   (1), Bare wires and bare conductor products The main characteristics of this type of product are: pure conductor metal, without insulation and sheath layers, such as steel core aluminum stranded wire, copper aluminum busbar, electric locomotive wire, etc.; the processing technology is mainly pressure processing, such as smelting, rolling, drawing system, stranding/compression stranding, etc.; the products are mainly used in suburban areas, rural areas, user main lines, switch cabinets, etc.   (2), power cable The main features of this type of product are: extruding (winding) the insulation layer on the conductor, such as overhead insulated cables, or twisting several cores (corresponding to the phase line, neutral line and ground wire of the power system), such as overhead insulated cables with more than two cores , or add a sheath layer, such as plastic/rubber sheathed wire and cable. The main process technologies include drawing, stranding, insulation extrusion (wrapping), cabling, armoring, sheath extrusion, etc. There are certain differences in the different process combinations of various products. The products are mainly used in the transmission of strong electric energy in generation, distribution, transmission, transformation and power supply lines, with large currents (tens of tens of amps to thousands of amps) and high voltages (220V to 500kV and above).   (3) Wires and cables for electrical equipment The main features of this type of products are: a wide range of varieties and specifications, a wide range of applications, most of the operating voltages are 1kV and below, and new products are constantly derived for special occasions, such as fire-resistant cables, flame-retardant cables, low-smoke halogen-free/low-smoke Smoke-resistant low-halogen cables, termite-proof, mouse-proof cables, oil-resistant/cold-resistant/temperature-resistant/wear-resistant cables, medical/agricultural/mining cables, thin-walled wires, etc.   (4), communication cables and optical fibers (brief introduction) With the rapid development of the communications industry in the past two decades, products have also developed at an alarming rate. From the simple telephone and telegraph cables in the past, it has developed into thousands of pairs of voice cables, coaxial cables, optical cables, data cables, and even combined communication cables. The structural dimensions of such products are usually small and uniform, and require high manufacturing precision.   (5), electromagnetic wire (winding wire) Mainly used in various motors, instruments, etc. Derivatives/new products of wires and cables are mainly due to different application situations, application requirements, convenience of equipment, and reduction of equipment costs. They use new materials, special materials, or change the product structure, or improve process requirements, or will be different. A variety of products are produced by combining them. Use different materials such as flame-retardant cables, low-smoke halogen-free/low-smoke low-halogen cables, termite-proof, mouse-proof cables, oil-resistant/cold-resistant/temperature-resistant cables, etc.; change the product structure such as: fire-resistant cables, etc.; improve technology Requirements such as: medical cables, etc.; combined products such as: OPGW, etc.; convenient installation and reduced equipment costs, such as: prefabricated branch cables, etc.   22. What requirements should be met when laying cables? Answer: The following requirements should be met: (1) In terms of safe operation, try to avoid all kinds of external damage and improve the power supply reliability of cable lines; (2) Economically, consider the aspect of saving the most investment; (3) In terms of construction, the path of the cable line must be convenient for work and maintenance after operation.