How to determine whether to use 6 / 10 or 8.7/10 for cable selection

When selecting cables, the power cable line design, installation and operation departments shall consider four factors, such as cable service conditions, insulation level, AAAC Cable type and conductor section, which are divided as follows.
1. Cable service conditions
(1) cable rated voltage / u () shall meet the following requirements:
1) the voltage shall meet the requirements of neutral grounding mode of power system, that is, in the neutral ungrounded power system, the voltage of non fault phase increases by times in case of single-phase grounding fault, which is related to the troubleshooting time of system grounding fault.


In IEC standard, power system is divided into three categories. Class a means that any phase conductor of the system is grounded and can be separated from the system within lmin; Class B refers to the grounding of single-phase conductor in the system, the allowable grounding fault time shall not exceed 8h, and the annual cumulative time shall not exceed 125h; Class C is a system that does not belong to classes a and B.
when the cable is used in the neutral effective grounding system, u takes the phase voltage value of the system. For example, 6 / 10kV cable is selected for 10kV system and 21 / 35kV Cable is selected for 35kV system.
When the cable is used for neutral non effective grounding system, the cable with one level higher than the system phase voltage shall be selected. For example, 8.7/10kv cable shall be selected for 10kV system and 26 / 35kV Cable shall be selected for 35kV system.
When the cable is used in class C system and single-phase grounding is allowed for long-term operation, u shall select the line voltage of the system, such as 6 / 6kV cable in 6kV system.
2) the voltage U and shall be equal to or greater than the rated voltage and maximum working voltage of the system where the ACSR Cable is located.
(2) cable transmission capacity. The cable line must meet the transmission capacity of the power system, that is, the selected cable shall have long-term allowable current carrying capacity to meet the system requirements.
For longer cable lines, the line voltage drop of the cable shall also be considered.
(3) cable laying conditions. Cables shall adapt to different laying methods, arrangement methods, metal sheath grounding methods and surrounding medium temperature, etc. The conductor of XLPE cable used for underwater laying shall have longitudinal water resistance. In order to meet the requirements of various laying environments, such as tension, compression, fire prevention, termite prevention and rodent prevention, the armor layer and outer sheath of the cable shall be made of corresponding structural materials.


2. Basic insulation level of cable
the peak value of lightning impulse withstand voltage between each conductor of the cable and the shield or metal sheath, i.e. the basic insulation level bil, shall comply with the provisions in table 1-13.
picture
in table 1-13, the lightning impulse withstand voltage of 220kV and above cable lines has two values, which can be selected according to the protection characteristics of arrester, the characteristic length of impulse wave of cable line and the lightning impulse insulation level of connected equipment.
3. Cable type
(1) comparison of insulation properties between XLPE and oil paper cables. XLPE insulated cable has the advantages of simple production process, short manufacturing cycle, easy installation and maintenance, excellent electrical performance and large transmission capacity. In recent 30 years, the technology of XLPE insulated cable has developed very fast and has been widely used. In terms of insulation performance, compared with oil paper insulation, cross-linked polyethylene insulation has some different characteristics, which are listed in table 1-14.
picture
Note: “air raid” should be “gap”
Oil paper insulated cable has the advantages of excellent electrical performance and long service life. It can be used in general occasions. However, compared with XLPE cable, the manufacturing and installation process of oil paper ABC Cable is more complex and the cost is higher.
oil filled cable with paper plastic composite insulation with low dielectric loss and alkylbenzene synthetic oil with good aging resistance as insulation structure, suitable for voltage levels of 220kV and above. In addition, oil paper insulated cables are also suitable for HVDC transmission lines.
(2) for cable lines of 110kV and below, XLPE insulated cable is generally the preferred variety. For distribution cables of 1kV and below, in addition to polyvinyl chloride (PVC) insulated cables for lines with light load, cross-linked polyethylene insulated cables shall also be selected.
Note: at present, 1-500 cables are mainly XLPE cables, and only some stocks of oil paper insulated cables and oil filled cables are left.


(3) ethylene propylene rubber (EPR) insulated cable is suitable for 35kV and below lines. This kind of cable is suitable for underwater laying because of its good moisture resistance, but its price is expensive.
4. Conductor section
copper conductors are generally used for power cables. The selection of conductor section shall meet the requirements of cable line transmission capacity and maximum short-circuit thermal stability of the system at the same time. And comply with “economic optimization of cable conductor size”.
in urban low-voltage power grid, four core cable is generally used, that is, in addition to three-phase conductor, there is a neutral line passing through three-phase unbalanced current and having protective grounding effect. The section of neutral wire shall generally be 30% ~ 60% of the conductor section of each phase. In the low-voltage power grid with large three-phase unbalanced current, four core low-voltage cables with equal cross-section shall be selected. The three core cable plus another insulated conductor cannot be used as the neutral wire to connect to the three-phase four wire low-voltage power grid, because in this way, there will be unbalanced current passing through the metal sheath and armor layer of the three core cable to heat it, thus affecting the transmission capacity of the cable.

Completion of laying of high temperature AC superconducting cable

The transmission capacity of superconducting AAC Cable is much larger than that of conventional cable. The power transmission capacity of a 10KV three-phase coaxial high temperature AC superconducting cable is greater than that of a conventional 110kV cable, but the transmission loss is only one fourth to one fifth of that of a conventional cable, which is very suitable for power supply in high load density areas. However, due to the great difficulty of project implementation, at present, the above application scenarios are still blank in China and even in the world.
The superconducting cable laid this time passes through the busy roads, subway areas and core business districts in the central urban area of Shenzhen. The laying environment space is narrow. There are special complex working conditions such as 24.2m vertical drop, more than 10 turns less than 90 degrees, short-span S-shaped corners and staggered height of transmission pipelines. There is almost no precedent experience to follow. It is a typical “small corridor” of complex transmission in large cities, Even laying conventional cables is challenging.


In the face of such special and complex working conditions, in order to ensure the smooth completion of superconducting cable laying, the superconducting cable project team of Shenzhen Power Supply Bureau has conducted dozens of field surveys and discussions in the past three months, and formulated a special research scheme of “remote simulation laying + on-site pre laying”. The project team built a simulation site at the location of the manufacturer, restored various special and complex working conditions, carried out many simulation laying drills, obtained a large amount of valuable data, accumulated on-site experience and laid a solid foundation for on-site laying. In the project site, analog cables of the same size and weight are pre laid twice, which provides the most direct reference for formal laying.
During the laying process, in addition to the conveyor and winch required for conventional AAAC Cable laying, the project team has developed special auxiliary guidance, turning radius limit protection, nozzle center positioning, well shaped conveying wheel set and other laying tools and instruments to ensure the safe and reliable laying of superconducting cable body.
Next, the project will enter the installation, test and commissioning stage of superconducting cable accessories, supporting low-temperature refrigeration system, measurement and control protection system, etc. When the project is put into operation, it is expected to “package” solve many problems and challenges such as the difficulty of power grid construction land in large cities, the continuous growth of power grid load demand and the saturation of urban transmission and distribution corridors, so as to provide a new scheme for solving the problem of regional power supply with high load density in mega cities around the world
Other media reports:
The first 10kV three-phase coaxial high temperature AC superconducting cable in China has been laid
Xinhua news agency, Shenzhen, July 30 (reporter Wang Feng) – the reporter learned from the Shenzhen Power Supply Bureau of China Southern Power Grid on the 30th that the first 10kV three-phase coaxial high-temperature AC superconducting cable in China was laid in Shenzhen on the 28th, laying the foundation for the first demonstration project of this type of superconducting cable to be put into operation within the year. It is expected to “package” solve the difficulty of power grid construction land and the continuous growth of power grid load demand in big cities There are many problems and challenges such as the saturation of urban transmission and distribution corridors.
It is reported that the project is a major science and technology project of China Southern Power Grid Corporation. It is developed by Shenzhen Power Supply Bureau of China Southern Power Grid and connects 220 kV Binhe substation and 110 kV Xinghe substation in Futian central area of Shenzhen. The cable length is 400 meters. It will supply power to important loads such as Shenzhen landmark Ping’an building.
High temperature superconducting power transmission refers to the use of the superconducting properties of superconducting materials to make the power transmission medium close to zero resistance and the power transmission loss close to zero in the liquid nitrogen environment close to minus 200 ℃ relative to absolute zero, so as to realize high-capacity power transmission at low voltage level. A 10KV three-phase coaxial high temperature AC superconducting cable has the power transmission capacity equivalent to a conventional 110kV cable.
It is understood that at present, most domestic superconducting ACSR Cable demonstration projects are experimental in nature, and the importance level of line load is low. The demonstration project plans to apply superconducting cable to the high load density power supply area in the city center to supply power to important loads, which will be a big test for the application of superconducting cable.
Next, the project will enter the installation, test and commissioning stage of superconducting cable accessories, supporting low-temperature refrigeration system, measurement and control protection system, etc. When the project is put into operation, it will provide a new scheme and model for solving the power supply problem in high load density areas of mega cities.

Why do low-voltage power cables use four cores?

The low-voltage power grid in urban residential areas generally adopts the three-phase four wire system. The four core cable used in the low-voltage power grid, except for the three-phase conductor, is called the neutral wire. It can pass through the unbalanced current of three-phase AC and has the function of protective grounding. Three core cable and one conductor cannot be used as neutral wire to connect to three-phase four wire low-voltage power grid, because in this case, part of the three-phase unbalanced current will pass through the armor of three-core ABC Cable, which will heat the armor layer and reduce the current carrying capacity of the cable.


The measured load data of low-voltage power grid in some sections show that the difference of three-phase load may be several times. Due to the unbalanced power load of household appliances and the different timing of household appliance load, the three-phase load is unbalanced, which is difficult for the power department to grasp and manage. At the beginning of the 20th century, in some low-voltage power grids in urban residential areas, accidents of ACSR Cable damage caused by neutral line overload occurred from time to time, especially the low-voltage cable insulated with polyvinyl chloride (PVC), sometimes even burning out the PVC insulation of the whole cable due to overheating. After analysis, the cause of the accident is that when the unbalanced current of the power grid is too large, the neutral line of the low-voltage cable is seriously overloaded due to too small section. Therefore, the power department requires cross-linked polyethylene as the insulation of low-voltage cables, and appropriately increase the cross-section of low-voltage cables. At the same time, the cable factory is required to produce four core low-voltage cables with equal cross-section. Under the condition of extremely unbalanced three-phase load, the cable neutral line can have sufficient ability to pass through unbalanced current.


3.5 number of power cable cores
3.5.1 when the neutral point of 1kV and below power supply is directly grounded, the number of cable cores of three-phase circuit shall comply with the following provisions:
1. When the protective conductor is connected with the exposed conductive part of the power receiving equipment for grounding, the following provisions shall be met:
1) For TN-C system, when the protective conductor and neutral conductor share the same conductor, 4-core cable shall be selected;
2) For TN-S system, when the protective conductor and neutral conductor are independent, 5-core cable should be selected; When the provisions of article 5.1.16 of this standard are met, it can also be composed of 4-core cable and another protective conductor laid close to the phase conductor;
3) When TN-S system is not equipped with neutral conductor or the circuit does not need neutral conductor to be led to the power receiving equipment, 4-core cable should be selected; When the provisions of article 5.1.16 of this standard are met, the 3-core cable can also be composed of another protective conductor laid close to the phase conductor.
2 for TT system, when the protective grounding of the exposed conductive part of the power receiving equipment is independent of the neutral point grounding of the power supply system, 4-core cable shall be selected; When the neutral conductor is not provided or the circuit does not need the neutral conductor to be led to the power receiving equipment, 3-core cable should be selected.
3 for TN system, when the exposed conductive parts of power receiving equipment are reliably connected to the public grounding grid distributed in the whole plant and station, 3-core cables should be selected for motors and other electrical equipment that are fixedly installed and do not need neutral conductors.
4 when the section of phase conductor is greater than 240mm2, single core cable can be selected, and the section of neutral conductor and protective conductor of its circuit shall comply with the provisions of articles 3.6.9 and 3.6.10 of this standard.
3.5.2 when the neutral point of 1kV and below power supply is directly grounded, the number of ACAR Cable cores of single-phase circuit shall comply with the following provisions:
1. When the protective conductor is connected with the exposed conductive part of the power receiving equipment for grounding, the following provisions shall be met:
1) For TN-C system, when the protective conductor and neutral conductor share the same conductor, 2-core cable shall be selected;


2) For TN-S system, when the protective conductor and neutral conductor are independent, 3-core cable should be selected; When the provisions of article 5.1.16 of this standard are met, it can also be composed of 2-core cable and another protective conductor laid close to the phase conductor.
2. For TT system, when the protective grounding of exposed conductive parts of power receiving equipment is independent of the neutral point grounding of power supply system, 2-core cable shall be selected.
3 for TN system, when the exposed conductive parts of power receiving equipment are reliably connected to the public grounding grid distributed in the whole plant and station, the fixed electrical equipment should use 2-core cable.
3.6 conductor section of power cable
3.6.9 when the neutral point of 1kV and below power supply is directly grounded, the section of cable neutral conductor or protective grounding neutral conductor of three-phase four wire system shall not be less than the minimum section required for continuous operation according to the maximum unbalanced current of the line; The circuit affected by harmonic current shall comply with the following provisions:
1. For the circuit with gas discharge lamp as the main load, the neutral conductor section shall not be less than the phase conductor section.
2 when there is high-order harmonic current, the current of neutral conductor shall be calculated and the effect of harmonic current shall be included. When the neutral conductor current is greater than the phase conductor current, the cable phase conductor section shall be selected according to the neutral conductor current. When there is harmonic current in the three-phase balance system, and the materials of neutral conductor and phase conductor in 4-core or 5-core cable are the same and the section is the same, the reduction coefficient of cable ampacity shall be determined according to the provisions of table 3.6.9.

Introduction of conductor calculation formula of wire and cable

1、 Wire and AAC Cable material consumption
The conventional calculation method of copper weight without conversion: sectional area * 8.89 = kg / km
For example: 120 * 8.89 = 1066.8kg/km
1. Quantity of Conductor:
(Kg/Km)=d^2 * 0.7854 * G * N * K1 * K2 * C /
D = diameter of copper wire, g = specific gravity of copper wire, n = number of wires, K1 = twisting rate of copper wire, K2 = twisting rate of core wire, C = number of insulated core wires
2. Insulation amount:
(Kg/Km)=(D^2 – d^2)* 0.7854 * G * C * K2
D = outer diameter of insulation d = outer diameter of conductor g = specific gravity of insulation K2 = twisting rate of core wire C = number of insulation core wires
3. Dosage of external coating:
(Kg/Km)= ( D1^2 – D^2 ) * 0.7854 * G
D1 = finished outer diameter d = upper process outer diameter g = insulation specific gravity


4. Amount of wrapping tape:
(Kg/Km)= D^2 * 0.7854 * t * G * Z
D = outer diameter of upper process t = thickness of cladding g = specific gravity of cladding z = overlap ratio (1 / 4lap = 1.25)
5. Winding amount:
(Kg/Km)= d^2 * 0.7854 * G * N * Z
D = copper wire diameter n = number of wires g = specific gravity z = twist in rate
6. Weaving amount:
(Kg/Km)= d^2 * 0.7854 * T * N * G / cos θ
θ = Atan (2 * 3.1416 * (D + D * 2)) * mesh / 25.4/t
D = diameter of braided copper wire t = number of ingots n = number of bars per ingot g = specific gravity of copper
Specific gravity of material:
89; Cu -8; 50; Ag -10; Aluminum – 2.70; Zinc-7.05; 90; Ni -8; 30; tin-7; Steel -7.80; Lead-11.40; Aluminum foil mylar-1.80; 35; Myra -1.37
PVC-1.45; LDPE-0.92; HDPE-0.96; PEF (foaming) – 0.65; FRPE-1.7; Teflon(FEP)2.2; Nylon-0.97; PP-0.97; PU-1.21
55; cotton belt -0; PP rope -0.55; Cotton yarn-0.48
2、 Calculation formula of material outside conductor
1. Sheath thickness: outer diameter before extrusion × 035 + 1 (for power cables, the nominal thickness of sheath of single core ABC Cable shall not be less than 1.4mm, and that of multi-core cable shall not be less than 1.8mm)
2. On line measurement of sheath thickness: sheath thickness = (perimeter after sheath extrusion – Perimeter before sheath extrusion) / 2 π
Or sheath thickness = (perimeter after sheath extrusion – Perimeter before sheath extrusion) × zero point one five nine two


3. Thinnest point of insulation thickness: nominal value × 90%-0.1
4. Thinnest point of single core sheath: nominal value × 85%-0.1
5. Thinnest point of multi-core sheath: nominal value × 80%-0.2
6. Steel wire armor: number=
{π ×( Outer diameter of inner sheath + diameter of steel wire) ×λ)
Weight = π × Wire diameter? ×ρ× L × Number of roots ×λ
7. Weight of insulation and sheath = π ×( Pre extrusion outer diameter + thickness) × thickness × L ×ρ
8. Weight of steel strip = {π ×( Outer diameter before wrapping + 2 × Thickness – 1) × two × thickness ×ρ× L}/(1+K)
9. Weight of tape = {π} ×( Outer diameter + number of layers before wrapping × Thickness) × Number of layers × thickness ×ρ× L}/(1±K)
Where: K is the overlap rate or gap rate, if it is overlap, it is 1-k; In case of gap, it is 1 + K
ρ Is the specific gravity of the material; L is the length of cable; λ Stranding coefficient

Teach you to choose high quality wire through insulating layer!

Burning test for ACSR Conductor production

There are two key links in the wire and cable manufacturing industry, namely theAluminum conductors steel-reinforced production link and the wire and cable testing link, especially the wire and cable testing link. This is the last stop for quality control and a comprehensive assessment of the performance of wires and cables.
The burning test of the cable is an extremely important one of its many tests. The national cable performance classification has special grade requirements for it, such as the number GB/T31248-2014. This standard divides the burning of the cable into 4 grades, A Class (non-flammable cable or optical cable, equivalent to metal sheathed cable or optical cable), Class B1 (flame-retardant B1 cable or optical cable, equivalent to halogen-free low-smoke flame-retardant cable or optical cable), Class B2 (flame-retardant B2 cable or Optical cable, equivalent to low-halogen, low-smoke flame-retardant cable or optical cable) and Class B3 (ordinary cable or optical cable).


Especially for fire-resistant and flame-retardant special cables, the burning test is a very important test for their professional performance. These fire-resistant and flame-retardant cables are required to have certain flame-retardant properties, and they must also have a certain flame-retardant performance. The characteristics of normal operation for a certain period of time, so the burning test is also a test of the performance of this type of cable.
In addition, there are a number of data for various combustion conditions. The values ​​need to be tested. For example, the heat release rate of the cable is the heat energy released by the combustion of the cable within a certain period of time under the specified conditions. This value is the normal combustion of the cable. Detect the data, and the value of the data will be affected by many factors, such as the combustion state, and the amount of non-metallic materials.


There is also an average heat release rate, which refers to the average heat release rate within 30 seconds. The average heat release rate during the combustion process is also a value that changes with the continuation of the combustion time. The peak heat release rate is the maximum value of the average heat release rate during the entire combustion period. The standard stipulates that the combustion time is 1200 seconds, which is the maximum value among the 40 average heat release rates. This value is related to the combustion state of Aerial Bundled Cable during combustion. If the flame is particularly large in a certain period of time within 1200 seconds, the peak heat release rate may not meet the requirements. The total amount of heat release refers to the integral value of the heat release rate within a specified time.
The various test data of the cable in the flame combustion can reflect the performance and influence of the cable in the flame, and can fully reflect whether the cable is qualified and up to the standard, and whether the fire performance of the fire-resistant cable meets the requirements, these are extremely important Therefore, the burning test is also one of the routine tests of wire and cable manufacturers.

Factors Affecting Cable Performance and Placement in Wiring

Factors affecting Aerial Bundled Cable (ABC) SANS 1418 Standard and placement in the wiring six factors affecting cable performance:

  • Ultraviolet (UV)– Do not use cables without UV protection in direct sunlight.
  • Heat — The temperature of the cable in the metal tube or groove is very high, and many polymeric materials will degrade their service life at this temperature.
  • Water — moisture in a twisted-pair cable on a LAN can increase the capacitance of the cable, thereby reducing the impedance and causing near-end crosstalk problems.
  • Mechanical damage (repair cost)– Cable repair is very expensive and requires at least two terminations at each break point.
  • Grounding — If the shielding of the cable needs to be grounded, the appropriate standards must be complied with.
  • Total length of routing (not just between buildings)– Outdoor LAN twisted pair cables are used between buildings and the total length is limited to 90 meters. For 100Mbps or 1000Mbps networks, the paved distance cannot exceed this limit. If the laying distance is between 100 meters and 300 meters, optical cable should be chosen.

Is the cable placed in:

1.Under the eaves. 4/0 Aluminum Cable can only be used when they are not directly exposed to sunlight or ultra-high temperatures. Standard LAN cables are recommended.

  1. Exterior wall. Avoid direct sunlight exposure to the wall and man-made damage.
  2. In pipes (plastic or metal).If in pipes, pay attention to the damage of plastic pipes and the heat conduction of metal pipes.
  3. Hanging applications/overhead cables. Consider cable sag and pressure. What kind of binding do you plan to use? Whether the cable is exposed to direct sunlight.

  1. It is directly laid in the underground cable trench, which is the least controlled environment. The installation of cable trench should be checked regularly for dryness or humidity.
  2. Underground pipes. In order to facilitate future upgrades, cable replacement and isolation from surface pressure and surrounding environment, auxiliary pipe isolation, auxiliary pipe is a better method. But don’t expect the pipes to stay dry forever, which will affect the type of cable you choose.

Plastic Extrusion and Traction Speed of Cable Technology

The rate of plastic extrusion

According to the flow rate analysis of the viscous fluid in the material conveying and homogenizing section of the ABC conductor,  the flow rate of the plastic (that is, the extrusion speed) is proportional to the screw speed, and the screw speed is an important operating variable to characterize the extrusion speed in the extrusion process because of the convenience of adjustment. Therefore, in general, increasing the screw speed is an important means to improve the production capacity of modern plastic extruder and realize high-speed extrusion. But the analysis of the plastic melting length shows that the increase of the screw speed, on the one hand, increases the viscous dissipation heat due to the enhanced shear effect; On the other hand, in the absence of head pressure control, the screw speed increases, the flow rate increases, and the material stays in the machine time is shortened. Moreover, the influence of the latter is more than that of the former, and the normal extrusion process will be destroyed due to the extension of the melt length to the homogenizing section. Therefore, it is necessary to increase the screw speed to improve the extrusion speed, but also to increase the heating temperature or use the control of the head pressure to achieve the purpose.

Plastic extrusion speed or the quality of plasticizing is related to the use of plastic material and temperature control, the plasticizing temperature of various plastics is different. If you want to quickly extrude plastic, only the material is good, the temperature is appropriate, to achieve. In addition, the extrusion speed is closely related to the extrusion thickness. In the normal extrusion process, the amount of glue is large and the extrusion speed is slow. On the contrary, the extrusion speed is fast, on the premise of ensuring the quality, the extrusion speed can be appropriately improved.

Traction speed

Extruded products are dragged through the machine head by traction device, in order to ensure the quality of products, the traction speed is required to be uniform and stable, in coordination with the screw speed, to ensure the uniformity of extrusion thickness and outer diameter of products. If the traction speed is not stable, the extrusion layer is easy to form bamboo joints, and the extrusion thickness is large when the traction speed is too slow, and the phenomenon of glue stacking or empty pipe occurs. When the traction speed is too fast, it is easy to cause extruding and thinning, or even the phenomenon of degumming and leakage. Therefore, in the normal extrusion process, we must control the traction speed.

Cable Knowledge: Classification, Use and Function of Armoured Cables

ABC cable is made of conductors of different materials mounted in insulated metal bushing, which is processed into a flexible and solid assembly.Armoured cable is generally fixed power cable, generally speaking, is fixed in a place and basically do not move, power line transmission of electric energy.The armoured cable includes armoured thermocouple, armoured thermal resistor, armoured heater and armoured lead, which are mainly used for temperature measurement, signal transmission and special heating in chemical industry, metallurgy, machinery manufacturing, power generation and scientific experiments. The largest amount of armoured thermocouple is used.

Classification of Armoured Cables

Armoring is classified into steel tape armoring (22,23), fine steel wire armoring (32,33) and coarse steel wire armoring (42,43).

Steel tape armoured cable models are VV22, VVP22, ZRVV22, NH-VV2;

Control cable steel tape armoured cable, models are KVV22, KVVP2, KVVP22, ZR-KVV22

Steel wire armoured power cable, model VV32, YJV32, ZR-VV32

Steel wire armoured control cable Cable model KVV32 KVVP32

Armored communication cable models: HYA53, HYAT53, HYA23, HYV22, HYA22(rat proof, buried)

 

 Model Meaning of Armoured Cable

In order to enable the cable to withstand the radial pressure, double steel tape and gap wrapping technology is adopted, which is called steel tape armoured cable.After the cable is finished, the steel strip is wrapped around the cable core and the plastic sheath is extruded. This type of cable is expressed as control cable KVV22, plastic cable VV22, communication cable SYV22, etc.The two Arabic numerals in the subscript of the cable type, the first one: “2” means double steel tape armoured;The second: “2” represents the PVC sheath, such as the use of polyethylene sheath to change the “2” to “3”. This type of cable is generally used in the bearing pressure is relatively large occasions.For example: through the highway, square and vibration of the highway, railway side, etc., suitable for buried, tunnel and pipeline laying. In order to make the cable able to bear large axial tension, the cable is wrapped with several low carbon steel wires, which is called steel wire armored cable.After the cable is finished, the steel wire is wrapped on the core wire according to the necessary pitch and then the sheath is extruded. The representation method of this cable type is such as control cable KVV32, plastic cable VV32, coaxial cable HOL33, etc. Two Arabic numerals in the model, the first one: “3” represents fine steel wire armor;Second: “2” for PVC sheath, “3” for polyethylene sheath.This type of cable is generally used in large span, laying the occasion of large drop.

Application of Armored Cable

Armour cable mechanical protection layer can be added to any structure of the cable, to increase the mechanical strength of the cable, improve the ability of corrosion resistance, is designed for the vulnerable to mechanical damage and erosion of the area.It can be laid in any way, and it is more suitable for direct buried laying in rock areas. Armoured cable is generally fixed power cable, generally speaking, is fixed in a place and basically do not move, power line transmission of electric energy. In addition to the above purposes, the cable with armoured layer can also enhance the tensile strength, compressive strength and other mechanical protection to extend the service life. Armour has a certain resistance to external force, but also can be wary of rat bite, not through the armor caused by power transmission problems, the bending radius of the armor should be large, the armor layer can be grounded, protect the cable. Foreign armoured cable production is mainly concentrated in several more developed countries, such as the United States, Britain, Japan, Germany, Russia, Southeast Asia has no manufacturers, but as long as there are chemical, metallurgy, machinery manufacturing, power generation and other industries where there is temperature measurement, the need for armoured cable.

The Role of Armoured Cable

Armoured cable refers to the cable with metal armored protective layer. The purpose of the cable with armored layer is not only to enhance the tensile strength, compressive strength and other mechanical protection to extend the service life, but also to improve the anti-interference performance of the cable through shielding protection. The commonly used armoring materials include steel strip, steel wire, aluminum strip and aluminum tube, among which the steel strip and steel wire armoring layer has high magnetic permeability and good magnetic shielding effect, and can be used to resist low frequency interference, and can make the armored cable buried directly without penetrating the pipe, and is cheap and fine, so it is widely used in practice.

What should I pay attention to when buying Aerial Bundled Cable?

As the main carrier of power transmission,Aerial Bundled Cable  HD 626 S1 Standard is widely used in electrical equipment, lighting circuits, household appliances, etc. Its quality directly affects the quality of the project and the safety of consumers’ lives and properties. There are many types of wires in the market, and you must use the appropriate wires according to your own electricity load.
Some of the wires sold in the market are cheaper and some are more expensive, and some people tend to be cheaper first. However, cheap wires often have a lot of performance that does not meet the performance described by him, and they may bring themselves Many security risks. The production technology of the wire is not too high, and the raw materials are not too different. If it is too cheap, either it is cutting corners or the quantity is not enough. How to identify it. Let me tell you several methods that are easier to identify:

  • Take a look at the packaging. National standard wires are often made better, neat, and have a sense of quality when held in hand.
  • Open the package and take a look at the wires inside. The wire thickness (insulation thickness) of the national standard wire of 1.5-6 square meters is 0.7mm. If it is too thick, it is non-standard, and its inner core is definitely not enough. , You can pull the thread hard, the ones that are not easy to tear are generally the national standard.
  • Burn it with fire, the ones that are extinguished within 5s after leaving, and those with certain flame-retardant function are (ABC) ASTM B230 Standard .Look at the inner core, the higher the brightness of the inner core material (copper), the better the copper, and the brightness is uniform, shiny, and without layering. The national standard requires oxygen-free copper to be used in the core. Non-standard, such as black rod copper, may have potential accidents.
  • The thickness of the acsr core has certain national requirements, but it is not very strict. But you can’t go wrong a lot, it’s just a small error, which is generally invisible to the eye.
    The length, the country does not mandate that the rice must be beaten, but many manufacturers have also beaten the rice, and the rice that is beaten is not necessarily the national standard, but the general national standard generally does not. Non-standard rice harvesting is just a means.
  • The country stipulates that there must be a certain mark on the wire, and the maximum size will not exceed 500mm, and the next same mark will be printed. Generally, there are product trademarks, manufacturer names, and implementation standards.