Jack knowledge about cable:Distinguish between wire and cable

People often think of wire and cable be confused, the Jack will give you the difference between the wire and cable!

Wire
Carrier conduction electricity use.

Wire and cable
For transmission (magnetic) energy, information and realize electromagnetic energy conversion of wire products.

Distinguish between wire and cable

The wire is composed of one or a plurality of soft wire, wrapped with a protective layer of light; cable is composed of one or a plurality of insulating coating wire, wrapped with metal or rubber tough outer. Cables and wires are generally consists of a core wire, insulating sheath and the protecting scarfskin consists of three parts. The following characteristics of common cable: CEF — ethylene propylene rubber insulated rubber chloroprene, flame retardant power cable for ship. CVV — PVC insulation, flame retardant power cable with PVC sheath for ship. Oxygen line often use BV, BX, RV, RVV series wire, wherein: BV — copper core PVC insulated wires, long-term permissible temperature 65 ℃, the lowest temperature of -15 ℃, working voltage 500V AC, DC 1000V, fixed laid indoor, outside, can be laid can also be concealed. BX — copper core rubber insulated wire, the highest use temperature is 65 ℃, apply to indoor. RV — Polyvinyl chloride insulated single core cable, the highest use temperature is 65 ℃, the minimum temperature -15 ℃, working voltage 250V AC, DC 500V, used as a instrument and equipment internal wiring. RVV — copper core PVC insulated and sheathed flexible cords, allowing long-term working temperature is 105 ℃, the working voltage 500V AC, DC 1000V, used in wet, mechanical protection requirements high, often moving and bending of the occasion. In fact, “the wire” and “cable” and there is no strict boundaries. Usually the core number less, products with small diameter, simple structure of the product called wires, no insulation called bare wire, the other called cables; conductor cross-sectional area of the larger (greater than 6 mm2) called the high wire, the smaller (less than or equal to 6 mm2) called small wires, insulated wire, also known as wire cloth that is relatively simple, easy to understand!! cable generally have 2 layers of insulation, most of them are multi core structure, around the cable tray, usually more than 100 meters in length. The wire is usually single layer insulation, single core, 100 meters roll, radio disc. Cable common type: VV said: PVC insulated (first V), PVC sheath (second V) YJV22 said: crosslinking PVC insulation, PVC sheath (YJ) (V), steel tape armored (22) and add “ZR” or “FR” for flame retardant cable (wire). Add “L” to aluminum wire type is simple: BVV– PVC insulated and sheathed copper core PVC insulated copper wire, BV–, BYJ– copper core crosslinked polyolefin insulation wire, PVC insulated copper wire BVR–, BX– rubber insulated copper wire, RHF– chloroprene rubber copper core wire.

(2) small diameter called “line”; large diameter is called “cable”.

(3) is called the “line” has the advantages of simple structure; complex called “cable”.

But with the expanding usage, many varieties of “line cable”, “cable cable”. So there is no need to distinguish strictly.

In daily habits, the household cloth wire is house wire, the power cable referred to as cable.

Wire and cable mainly includes bare wire, winding wires, power cables, communication cables and optical cables, electrical equipment with.

keep learning and working hard!

The new week began, a month is about to begin!

Summarize the work this month, found that doing a lot, also got a lot of!

Plan for the future, have to do a lot of, keep learning and working hard!

Jack knowledge about cable:knowledge of control cable

Power cables for transmission and distribution of electrical energy in the power system features a large trunk, the control cables from the distribution point of the power system to power transmission lines connected directly to the power supply of various electrical equipment appliances. Rated voltage power cables 0.6/1kV and more generally, control cables mainly for 450/750V. The same specifications as power cables and control cables in the production, power cable insulation and sheathing thickness thicker than the control cables. Control cables for the mining industry, energy and transportation sectors, for AC rated voltage of 450/750 volts control, protection circuit and other occasions of PVC insulated, PVC sheathed control cable.

Features

1. DC resistance:. 20 ℃, 0.4mm copper, less than or equal 148Ω/km, 0.5mm copper, less than or equal 95Ω/km.
2.insulated electrical strength: 1min 1kv no breakdown between the conductor and shield conductor 1min 3kv no breakdown
3 Insulation resistance: each wire with the rest of the grounding wire core, control cables greater than 10000MΩ.km, HYAT cable than 3000MΩ.km.
4 Capacitance: mean 52 ± 2nF/km
5 FEXT defense degree: the average power is greater than the specified combinations 150kHZ 69dB/km.

And the performance difference between the power cable

(A) control cables are cables for electrical equipment, cables and power cables are five categories of the two.
(B) The standard is 9330 control cable, power cable is standard GB12706.
(C) control cable color insulated cores are generally black and white printing, and low-voltage power cables are generally separations.
(D) control cable cross section are generally not more than 10 square feet, the main

power cable transmission of electricity, are generally large cross-section.
Due to the above reasons we talked about, power cable specifications generally large, large 500 square (conventional manufacturers can produce a range), then a large cross-section of the manufacturers generally do relatively little, while the control cable cross-section is generally small, generally not more than 10 square maximum.

Speaking from the cable core power cable according to claim grid, typically up to 5 cores, and the control signal transmission control cable, the number of cores is more, according to the standard in terms of number of core 61, but can also be produced according to the user requirements .

Precautions

Control wiring cable installation considerations:
1 roof. Cables are not only exposed to direct sunlight or ultra-high temperature, a standard LAN cable can be applied, it is recommended to use the pipeline. Ultraviolet (UV) - do not apply to cable without UV protection within direct sunlight environment.
2 external walls. Avoid direct sunlight walls and man-made damage. Heat - the temperature in a metal cable duct or trunking is high, many polymeric materials at such temperatures will reduce the service life.
3 pipes (plastic or metal). As in the pipeline, attention to thermal damage and metal pipes plastic pipe. Mechanical damage (Zhi ڮ f cost??) - Cable repair is very expensive, at least every two discontinuous point terminated.
4 vacant application / aerial cable. Consider sag and tension cables. Whether the cable is exposed to direct sunlight.
5 directly in the trench laying underground cables, control of this environment is minimal. To install the cable channel regularly check the extent of dry or wet. Grounding - If you need to control the cable shield grounding must comply with the appropriate standards.
6. Underground pipes. In order to facilitate future upgrades, cable replacement and surface pressure and ambient isolation to isolate the pipeline paved, paved the pipeline is a better way. But do not hope the pipeline will always be kept dry, it will affect the cable types to choose from. Water - Water twisted pair cable LAN cable capacitance will increase, thereby reducing the resistance and cause problems in the near-end crosstalk.

Maintenance

Control cable price formula as follows: Weight of copper in copper calculated X: silk warp ÷ 2 = square root of the number 1.25X1.25X3.14 = X then copper wire X0.89X +10% processing fee.

Calculation of cost price control cables

Square X1.83 = X then the weight of copper in copper + armored price (weight X0.4 yuan / kg) = cost price +10% processing fee

The price of the cable = manufacturing material costs + fixed costs + taxes + service fee + profit
Manufacturing materials cost = material costs * (1 + material consumption) (material cost is the theoretical value calculated)
Fixed costs vary according to each company's situation, generally including production wages, management salaries, utilities, repairs, depreciation, rent costs, transportation costs
Control cable line failures are common mechanical damage, insulation damage, wet insulation, insulation aging deterioration, over-voltage, cable overheating failure. The failure occurs when the line should be cut off the power cable fault, find the point of failure, the fault inspection and analysis, and repair and testing, the mutilation of circumcision, upon failure to eliminate before power is restored.

Above to introduce the performance characteristics of the control cables, precautions and maintenance of knowledge, as well as more control cable inspection knowledge to understand a lot of hope that we own!

Learn a little progress every day

Yesterday went to a meeting!

All the things that I knew would be speaking, but still learned a lot of new things!

As such, open to new ideas, new knowledge, learning a little progress every day, So wonderful!

Jack knowledge about cable:knowledge of high voltage cable

During electric power transmission transmission, the higher the voltage, the less the loss of power! With the development of insulating materials and technology, and now has a large number of high-voltage cable production and extensive application! Here jack'll tell you about the structure of high-voltage cables, usage characteristics, Construction and other knowledge!

High voltage cable is a power cable, means for transmitting the power cable 10KV-35KV (1KV = 1000V) between the power transmission and more used in the main road.

The structure of high-voltage cables

High voltage cable from the inside to the outside components include: conductor, insulation, inner sheath, fillers (armored), external insulation. Of course, armored high-voltage underground cables are mainly used, can resist the oppression of high intensity on the ground, while preventing other external damage.

High-voltage cable to use features

The product is suitable for AC rated voltage 35KV and below for power transmission and distribution lines with a fixed set granary, the maximum long-term working temperature of conductor 90 degrees, short circuit (the longest time not to exceed 5S), the cable conductor maximum temperature does not exceed 250 degrees.

Construction

Like other power cables, high-voltage cables have the structural elements of one or more conductors, insulation, and a protective jacket. High-voltage cables differ from lower-voltage cables in that they have additional internal layers in the insulation jacket to control the electric field around the conductor.

For circuits operating at or above 2,000 volts between conductors, a conductive shield may surround each insulated conductor. This equalizes electrical stress on the cable insulation. This technique was patented by Martin Hochstadter in 1916;[1] the shield is sometimes called a Hochstadter shield. The individual conductor shields of a cable are connected to earth ground at the ends of the shield, and at splices. Stress relief cones are applied at the shield ends.

Cables for power distribution of 10 kV or higher may be insulated with oil and paper, and are run in a rigid steel pipe, semi-rigid aluminum or lead sheath. For higher voltages the oil may be kept under pressure to prevent formation of voids that would allow partial discharges within the cable insulation.

Sebastian Ziani de Ferranti was the first to demonstrate in 1887 that carefully dried and prepared paper could form satisfactory cable insulation at 11,000 volts. Previously paper-insulated cable had only been applied for low-voltage telegraph and telephone circuits. An extruded lead sheath over the paper cable was required to ensure that the paper remained absolutely dry.

Vulcanized rubber was patented by Charles Goodyear in 1844, but it was not applied to cable insulation until the 1880s, when it was used for lighting circuits.Rubber-insulated cable was used for 11,000 volt circuits in 1897 installed for the Niagara Falls Power Generation project.

Mass-impregnated paper-insulated medium voltage cables were commercially practical by 1895. During World War II several varieties of synthetic rubber and polyethylene insulation were applied to cables.Modern high-voltage cables use polymers or polyethylene, including (XLPE) for insulation.

Enjoy life, work hard and look forward to the remaining days of 2014, getting better and better!

March 27, and today is a beautiful sunny day!

Unconsciously, we should have passed in March 2014, immediately after a 1/3 of 2014!

Enjoy life, work hard and look forward to the remaining days of 2014, getting better and better!

Jack knowledge about cable:knowledge of Wire and cable manufacturing process

Hello everyone, It’s time to share my knowledge of cable now,Today I will share the knowledge of Wire and cable manufacturing process.

Process

Wire and cable manufacturing and production of most of the mechanical and electrical products are completely different. Another commonly used mechanical and electrical products will be assembled into component parts , multiple parts and then assembled into a single product , the product measured by number of units or pieces . Wire and cable is the basic unit of measurement of length . All are from the conductor wire and cable processing began , with the insulation layer by layer in the periphery of the conductor, shielded cabling , protection layer made ​​of wire and cable products. The more complex structure of the product , the more superimposed layers.

Technological Characteristics

1. large length of continuous overlay combination mode of production , the impact on the global wire and cable production and controllability , which involves and affects:

( 1 ) production process and equipment layout

Various equipment production plant product requirements must be reasonable discharge process , so that the various stages of semi-finished products , sequential flow. Device configuration to be considered and balanced production capacity of different production efficiency , and some equipment may have to configure two or more , in order to make the production capacity of the production line can be balanced . Thus a combination of reasonable matching device layout and production sites , must be based on the product and production to balance considered.

( 2) The production organization and management

Production organization and management must be scientific and reasonable, accurate and careful , meticulous , scrupulous operator must perform according to process requirements , any link problems will affect the process of smooth, affect product quality and delivery. Especially multi -core cable , one pair or the basic unit length is short , or quality problems , the entire length of cable will be enough to cause scrapped. Conversely, if a cell is too long , must be sawn waste.

( 3 ) Quality Management

Large continuous length superimposed combination of production, so that any one part of the production process , some problems occur instantaneously , it will affect the quality of the entire cable . The more quality defects occur in the inner layer , but did not discover the termination of production, then the greater the losses . Because unlike the production of wire and cable products assembled , you can open other pieces of heavy equipment and replacement ; either a part or the wire and cable process quality problems, these cables is almost irreversible and irreparable. Post- processing is very negative , not sawn downgrade is either scrap the entire cable . It is not open to reload.

Quality Management wires and cables must be run through the entire production process . Quality inspection departments to manage the entire production process inspection tour , the operator self-inspection, mutual inspection process from top to bottom , this is to ensure product quality , and means an important guarantee for improving economic efficiency of enterprises .

2 . Production process multiple categories , material flow

Wire and cable manufacturing process involving a wide range of categories , and pressure from the non-ferrous metal smelting and processing, to plastics , rubber, paint and other chemical technology ; fiber material wrapping , weaving and other textile technology , the metal strip around the bag and metal materials the longitudinally welded metal forming process , and so on .

Wire and cable manufacturing a variety of materials used , not only classes , varieties , specifications, and large quantities. Therefore, the amount of various materials , spare capacity , batch and batch cycle must be approved . Meanwhile , the decomposition of waste treatment, recycling , reuse and waste disposal , as an important part of management , good material quota management , attention to conservation work .

Wire and cable production, from raw materials and various auxiliary materials and out of storage , the process of transfer to the semi-finished product storage, factory , material flow, must be rational distribution , dynamic management .

3 . Special equipment and more

Wire and cable manufacturing industry that has the technological characteristics of specialized production equipment , in order to adapt the structure , performance requirements of cable products to meet the large length of continuous high-speed production requirements as much as possible , so as to form a cable manufacturing equipment series. Such as extrusion machine, cable machine, stranding machine, around the charter series.

Closely related to the development of wire and cable manufacturing processes and equipment , and promote each other. The new process requirements, to promote the emergence and development of new specialized equipment ; conversely , the development of new equipment , but also to improve the promotion of the development and application of new technology . Such as drawing, annealing , tandem extrusion line ; physical foaming production lines and other special equipment , wire and cable manufacturing process to promote the development and improvement , improve product quality and production efficiency of the cable.
Second, the main craft wire and cable\

Power cables

Wires and cables through : drawing , stranding , covering three processes to produce finished , the more complex model specifications , the higher reproducibility.

1 . Drawn

In the external force so that the metal in the metal working pressure is forced through the die ( pressure roller ) , a metal cross-sectional area is compressed to obtain technical processing method and the shape and size of the cross-sectional area required called metal drawing .

Drawing process of : single strands system and stranding drawn .

2 . Stranding

To improve the flexibility of wire and cable , the overall degree , so two or more single-wire , interwoven according to a predetermined direction called stranding .

Stranding process points : Conductor stranding , cabling , weaving , wire armouring and winding .

3 . Coated

According to the different performance requirements of the wire cable , the use of special equipment in the outside conductor covering a different material . Coating process points :

A. Squeeze bag : rubber, plastic, lead, aluminum and other materials.
B. Longitudinal package : rubber , wrinkles aluminum material.
C. Wrapping: ribbon tape , mica , E-glass fiber tape, non-woven fabrics , plastic tapes , linear cotton , silk and other fibrous materials.
D. Dip : insulating paint , asphalt , etc.

Third, the basic plastic wire and cable manufacturing process

1 . Copper, aluminum, single strands system

Commonly used copper wire cable , aluminum material , at room temperature , the tensile drawing machine using a die or a number of channels through the die orifice to reduce the cross section , increasing the length , strength. Drawing is the first procedure of each wire and cable companies , the main process parameters are brushed with mold technology.

2 . Annealed monofilament

Copper, aluminum filaments heated to a certain temperature , recrystallization of the monofilament way to improve the toughness and reduce the strength of the monofilament to meet the conductive core wire and cable requirements . The key is to prevent oxidation annealing process copper wire .

3 . Stranding conductor

In order to improve the flexibility of wire and cable in order to facilitate the laying of installation , conductive core to take a plurality of monofilaments twisted together . From the conductive core stranded form, can be divided into rules and irregular strands twisted . Irregular Stranded Stranded divided into concentric complex twist, twisted and so special .

To reduce the area occupied by wire , cable geometries shrink , while using the stranded conductor pressed form, so that variation of ordinary semi circular , fan-shaped, W -shaped and pressed round . Such conductors mainly used in the power cable.

4 . Extruded insulation

Plastic wire and cable type used mainly extruded solid insulation , plastic insulation extruded main technical requirements :

4.1. Eccentricity : extruded insulation thickness deviation is reflected important symbol extrusion process level , most of the product structure size and standard deviation values ​​are clearly defined.

4.2 . Smoothness: the surface of the insulating layer extrusion requires smooth , with no rough surface, charred , poor quality of impurities

4.3 . Density : a cross-sectional extruded insulation layer to be dense and firm, not allowed to have visible pinhole to eliminate the presence of air bubbles.

5. Cabling

For multi -core cables in order to ensure molding degrees , reducing the appearance of the cable, generally need to be twisted round . Mechanism of stranded conductor stranding similar, larger diameter section due stranding , they use no way back twist . Cabling technical requirements : First, eliminate shaped stand up and lead insulated cores twisted cables ; second is to prevent insulation from being scratched.

Most of the cable into the cable accompanied by the completion of the other two processes : one is filled to ensure stability after round into the cable and the cable ; one is lashing ensure no loose cable core .

6. Inner sheath

To protect the insulation core is not the pimple armored injury , the need for appropriate protection insulating layer , the protective layer of : extruded inner sheath ( isolation units ) and wrap the sheath ( cushion ) . Wrapping cushion with a cable instead of banding with processes simultaneously.

7 . Armouring

Laying underground cables , the work may be subject to certain positive pressure, choose the steel tape armored structure. Cable laying there in both the positive pressure pulling force occasions ( such as water , drop a large vertical shaft or soil ) , should be used with structured inner wire armouring .

8. Sheath

Structural part of the outer sheath to protect wire and cable insulation to prevent the erosion of environmental factors . The main role of the outer sheath is to improve the mechanical strength of the wire and cable , anti-chemical corrosion, moisture, water immersion , prevents cable burning capabilities. According to the different requirements of the cable directly to the use of an extruder extruded plastic sheath .

Just this today,welcome to talk about cable knowledge together!

Start exercising, strong up!

Yesterday afternoon, I went out for dinner at noon, too many people crowded elevator, so I chose to go down the stairs!

19th floor, quickly go and eat, go to work, as usual!

This morning it was felt that leg! Sour leg pain when walking, especially uncomfortable!

Hey, it seems that they wanted to exercise regularly, and be sure to make yourself stronger together!

Jack knowledge about cable:knowledge of AAC(Aluminum alloy cable) cable

Like the same day to share my life, and then to share my knowledge of the cable ! Today we give Aluminum alloy cable to share materials , advantages and performance of such knowledge !

Conductor materials and their characteristics

Aluminum alloy cable is AA 8030 series aluminum alloy conductor , power cables using new materials and special annealing process to squeeze other advanced technology inventions .
Alloying element in Aluminum alloy cable electrician aluminum , but through the process of adjustment , so that the mechanical properties of aluminum alloy conductor greatly improved , to avoid low elongation aluminum conductors , poor creep resistance , the problem of poor flexibility , increase cable system connection reliability. In addition , maintaining the electrical properties of aluminum alloys and aluminum electrical conductor flat at 61% IACS or more.

DC resistance of aluminum electrical conductor assessment indicators refer to GB/T3956-2008 " the cable conductor " in the solid conductor or stranded conductor DC resistance . Alloy power cable to make up for past deficiencies Aluminum alloy cables , although no increase in the conductivity of the cable , but the bending properties, creep resistance and corrosion resistance , etc. has increased greatly , to ensure that the cable in a long time to maintain a continuous overload and overheating stable performance , using AA-8000 series aluminum alloy conductors , can greatly improve the conductivity of Aluminum alloy cable , high temperature resistance, while addressing the aluminum conductor electrochemical corrosion , creep and other issues.

Conductivity

Conductivity of aluminum is the most commonly used benchmark of 61.8% IACS copper material , the carrying capacity of copper is 79% better than standard aluminum . However, in the same volume , the actual weight of the aluminum alloy is about one third of the copper. Therefore, the same weight of Aluminum alloy cable carrying capacity of copper is about half . Replace copper with Aluminum alloy cable , the cable can reduce weight, reduce installation costs , reduce equipment wear and cables to make installation easier.

Weight

Under the premise to meet the same electrical properties , the use of Aluminum alloy cable is half the weight of copper cable , the cross section is 1.1 to 1.25 times that of traditional copper cables , 15 to 30% lower prices than traditional copper cable .

Performance advantages

The above describes the basic structure and materials Aluminum alloy cable , the following describes the safety performance of Aluminum alloy cables , electrical performance, mechanical performance, service life , economic performance and other advantages !

Safety performance

1 , history proved
Aluminum alloy cable U.S. R & D since 1968 , has been in use for 43 years , the product has been quite common, North America market share of 80 %. After 43 years of practice has proved that the use of Aluminum alloy cable has never been any failures , is safe.

2 , testing and certification

Aluminum alloy cable through American UL, Canadian authorities CUL, SAI GLOBAI international authoritative organization certification and China National Wire and Cable Testing Center of Australia, State Grid Wuhan High Voltage Research Institute , National Fire Protection Building Materials Quality Supervision and Inspection Center, testing and certification , aluminum conductor comply with CSA standard C22.2 No. 38 articles on the ACM alloy wire requirements , and GB12706.1--2008 and IEC60502.1 latest version of performance requirements, as well as UL for AA8000 series of standards related .

3 , the role of aluminum components

◆ aluminum conductor ingredients are added after the rare earth and iron and other elements , which greatly improves the performance of its electrical properties and connections , especially when you add iron to produce annealed conductor creep resistance of high strength , when current overload, iron play to continue connecting role in making aluminum conductor creep does not occur.
◆ creep great harm to the cable , if the cable creep , its original point of contact pressure is not tight enough , the pressure is reduced so that the contact resistance increases rapidly after the current flow caused by overheating of the joints , if unscheduled maintenance, there will be security risks. Is very important to solve the problem of cable creep .
◆ Creep: metal temperature , force and its own weight , over time , permanent deformation will not be slow to recover , the phenomenon of creep.

4 , flame retardant

Aluminum retardant cable insulation materials using silane cross -linked polyethylene (XLPE), the use of self-locking armored structure, thermal performance is far superior to PVC jacket material can rapidly heat the process, the flame disappears quickly extinguished the flames , then do not delay other materials , very excellent flame retardant properties . Aluminum alloy cable using new materials and new technology , to ensure its use more secure.

Electrical properties

1 , cable ampacity

◆ alloy conductor cross-sectional area is 1.5 times of copper , copper alloy conductors and electrical properties as a conductor to achieve the same carrying capacity , resistance, and pressure loss .
◆ resistance between the aluminum alloy of aluminum and copper, aluminum slightly higher , but lower than copper , provided at the same flow cross section , the weight of the aluminum alloy conductor of equal length is only half the copper . If the conductivity of the copper at 100 %, the conductivity of the conductor is about 61.2% of the alloy , the proportion of the alloy is 2.7 , the proportion of copper is 8.9 , the (8.9/2.7) × (0.612 / 1) = 2, i.e., 2 the unit weight of the same alloy with a resistor of resistance of copper per unit mass , so that when the cross-sectional area of ??the alloy is 1.5 times that of copper conductors is the same as the electrical properties , i.e. to achieve the same cross-sectional flow and copper , resistance, and voltage loss.
◆ Factors power cables cut a lot of traffic , such as line characteristics ( such as the working electrode , a current type, frequency , load factor ) ; structure of wires and cables ( such as the structure of the conductive core , the core number , the type of insulating material , shield and structures and materials , the outer diameter of the inner and outer sheath of the total ) ; laying conditions ( such as air laying, pipe laying, direct burial, underground laying of the channel , underwater in laying ) ; conductive core maximum allowable operating temperature and ambient conditions ( such as air and soil temperature, soil thermal resistivity , heat around the proximity effect ) and so on .

2, to reduce the outer section of the cable

Aluminum alloy cable production process, pressed Germany's most advanced technology , making it the conductor fill factor can reach 93%. And Aluminum alloy cable uses a silane crosslinked polyethylene , polyvinyl chloride thickness of the insulation just 2/3 can be far more than conventional insulation. But generally only copper fill factor of 80%, is commonly used in PVC insulation , Aluminum alloy cable diameter so on the basis of copper increased by only 11% or less , you can have the same electrical properties of copper . Visible , no need to change the original use of Aluminum alloy cable duct design using copper cables . ( General designer piping size is 150% copper , so wear a tube is not a problem . )

3, to reduce cable damage

A non- magnetic material , no eddy currents can reduce line losses . Even loaded with armor lock aluminum material is non- magnetic , even if the three-phase current imbalance exists , it does not produce a vortex , can reduce the loss of lines.

Mechanical properties

1 , extends the performance of Aluminum alloy cables
Elongation is an important indicator of the mechanical properties of the conductor , the merits of the product and can withstand the force size an important symbol. Also is an important indicator of the mechanical properties of the conductor . Aluminum alloy cable elongation after annealing treatment to achieve 30% elongation of 25% copper , the general elongation of 15% aluminum pole is to replace aluminum with copper cable is an important indicator .

2 , flexible performance Aluminum alloy cables
Torsion test : the main test metal wire toughness, toughness, better able to withstand the more the number of twist . An important disadvantage of ordinary aluminum wire is brittle high, as long as the number of times during the installation angle of twist , the conductor will have cracks, splits will heat , corrosion, is an important reason for the fire. Use Aluminum alloy cable , due to its good toughness, no cracks appeared in the installation to reduce security risks .

3, the bending properties of Aluminum alloy cable
Bending test : The main test of metal bending performance. Material inequality or brittle materials , anti- bending performance is poor.
According to the provisions of GB/T12706 bend radius copper installed copper cable bend radius is 10-20 times the cable diameter , the minimum bend radius Aluminum alloy cable is 7 times the cable diameter , the use of Aluminum alloy cable layout space can be reduced easier laying and reduce installation costs.

4 , rebound performance Aluminum alloy cables
Practice has proved that : at room temperature the copper and Aluminum alloy cable bend of 90 degrees , the stress release , Aluminum alloy cable rebound angle of 60% copper . Because Aluminum alloy cable having no memory , the stability of the connection rebound performance than copper cables, terminals connected to the connector during installation easy pressing , increase the tightness improved .

Life

1 , there are two main conductor portion corrosion : chemical corrosion and electrochemical corrosion

◆ chemical corrosion : refers to the metal in the atmosphere with oxygen , chlorine , sulfur dioxide, hydrogen sulfide and other gases used to make corrosion under .
Metal surface with oxygen , generating different metal oxides.
Can form a dense aluminum oxide has a surface hardness of a protective film.
Loose iron oxide structure , easy to fall off, and continued penetration of the metal inside , diffusion, damage materials.
Copper oxide , commonly known as Pseudomonas , between these two, is a toxic substance .
◆ electrochemical corrosion : metal and dielectric composition defined by the primary cells , the formation of corrosion of metals , where the metal of the two different potentials are connected to the electrodes , but also during the water or other electrolyte , is generated between the two metal forming a primary battery current , wherein the metal is in the positive potential and the other at a negative potential , a negative potential of the metal in the ionic state constantly at a positive potential through the electrolyte to the metal buildup. So that in the negative potential of the metal gradual loss of damage, the formation of electrochemical corrosion. The potential difference between the electrodes of the greater of the two metals , galvanic corrosion , the more intense. The higher the temperature , the corrosion of metals is also more serious.
Different metals have different electrode potential . Common electrode potential of the order of several metals ; metallic Ag ( silver ) Cu ( copper ) Pb ( lead ) Sn ( tin ) Fe ( iron ) Zn ( zinc ) A1 ( aluminum ) . The potential of the negative electrode potential of +0.8 +0.334-0.122-0.16-0.44-0.76-1.33 larger metal ions into the electrolyte become the stronger the tendency , i.e., the more susceptible to corrosion. A more negative electrode potential of aluminum , but the surface layer of oxide film is often a protective layer to improve its corrosion resistance .

Rare earth elements in aluminum alloy material is added to aluminum , which can purify and improve the purity, fill surface defects , grain refinement . Reduce segregation , which led to the elimination of microscopic uneven effect of localized corrosion , but also bring negative electrode potential of aluminum shift with a sacrifice anode effect and excellent electrical properties , thus greatly improving the corrosion resistance of aluminum . For the marine environment, C1- and corrosion problems in petroleum, chemical environment, S, H2S + C02 , etc., this material has a unique anti-corrosion mechanism . Strong reduction of rare earth metals with S, H2S, strong oxidizing C1- effective integration , interaction, generating stable compounds (C1- and rare-earth aluminum to form a stable coordination compounds ) , chemical oxidation and reduction reactions process organic unity , interaction , as the oxidation activity S, H2S, C1- corrosive media such as corrosion caused fundamentally destroyed, thus completely solve the worldwide countries including the United States not well resolved by Beijing Nonferrous Metal Research Institute and other national inspection departments to detect and engineering data analysis examples show that chloride ions , water, ocean-atmosphere , salt spray environment ( alternating wet and dry ) , saturated HzS, sulfur and high-temperature , high-pressure environment conditions corrosion , the rare earth aluminum was zero or nearly zero.

2, the insulating portion

◆ Power cable ampacity is the maximum allowable temperature of the cable allows the maximum current through the conductor . In the design and selection cable , the cable should be made part of the loss of heat generated does not exceed the maximum temperature allowed by cable , in most cases, the transmission capacity of the cable is determined by the maximum temperature limit of the cable , the cable of the maximum permitted temperature mainly depends used in heat aging properties of insulating materials , because the cable operating temperature is too high , will accelerate the aging of insulation materials , large shorten cable life . If the cable runs in the allowable temperature above 30 years of cable safety .
◆ XLPE crosslinked polyethylene Abbreviation Name of the polyethylene is a linear molecular structure , easily deformed at high temperatures . XLPE process it into a mesh structure. This structure is the same even at a high temperature has a strong resistance to deformation .
◆ anti-aging properties of crosslinked polyethylene excellent and superior heat distortion determines the normal operating temperature (90C) short-term failure (130C) and short (250C) conditions can allow a large current. Because of its higher operating temperature than PVC 20C, has excellent thermal properties, to increase the anti -aging properties of the insulation , which greatly increase the life span .

Economic Performance

◆ direct procurement costs
Aluminum alloy cable and copper cable price comparison: Aluminum alloy cable with superior safety performance under electrical properties, mechanical properties and longer life premise , the price of Aluminum alloy cable is only about 75% of the copper cables.
◆ reduce installation costs
Saving installation costs : Because Aluminum alloy cable bending performance and light weight, easy to install.

Simple to share knowledge Aluminum alloy cable , and I hope everyone will play a role in the purchase of Aluminum alloy cable , applications.

Time flies,blessing myself all the best!

Yesterday, another friend getting married!

Gradually, my friends are married, and some even have had a baby! Time flies, I think back to the teenagers who are not, the feeling is always some strange!

Think of yourself now no longer young, and immediately have to face these problems, blessing myself all the best!

Jack knowledge about cable:knowledge of xlpe cable

Today, we continue to introduce cable knowledge . Have a blog introduces the history of power cables , in fact, a large part of the development of the cable insulation material development and progress ! Here we give a brief knowledge of XLPE cables !

XLPE cables usually refers to cable insulation layer using crosslinked material. The most commonly used material for the cross -linked polyethylene (XLPE). The crosslinking process is a linear molecular structure of polyethylene (PE) through a specific way of processing the material , to form cross- linked polyethylene cable of the mesh structure of the body . Making long-term allowable working temperature increased from 70 ℃ to 90 ℃ ( or higher ) , short allowable temperature increased from 140 ℃ to 250 ℃ ( or higher ) , while maintaining its original premise of excellent electrical performance , greatly improved actual performance.

Process approach

Currently XLPE cables and cable industry production process is divided into three categories: the first category peroxide crosslinking chemistry , including saturated vapor crosslinked crosslinking inert gas , molten salt crosslinked silicone crosslinking the country are using the first two kinds namely dry chemical crosslinking ; second category silane chemical crosslinking ; third category radiation crosslinking .

Inert gas

Adding peroxide crosslinking agents using the compound polyethylene insulation materials, completed by three co-extruded conductor shield – insulation – extruded insulation shield layer , continuous and uniform through full temperature, high pressure nitrogen seal crosslinked tube complete the crosslinking process. Heat transfer medium is nitrogen ( inert gas ) , cross-linked polyethylene excellent electrical properties, production range up to 500KV class .

Silane chemistry

Using silane coupling agent added polyethylene insulation, extruded through a 1 +2 manner allogeneic shield – insulation – extruded insulation shield layer will have a plate to cool insulated core immersed 85 – of crosslinked for 95 ℃ hot water , since the influence of the insulating layer is wet cross-linking of the water content. Generally only up to a maximum voltage level 10KV.
Irradiation crosslinked

After using the modified polyethylene insulation material is completed by an allogeneic shield +2 extrusion way – insulation – extruded insulation shield , the insulated core cooled , even by high-energy electron accelerator radiation according to the scan window to complete the cross-linking process . Radiation crosslinking cable compound without adding a crosslinking agent , when crosslinked by high-energy electron accelerator to produce high-energy electron beam effectively penetrate the insulation layer , resulting in cross-linking reaction by energy conversion , because the electron with high energy and uniformly through the insulating layer, the formation of crosslinks binding energy , good stability. Exhibit physical properties , heat resistance, superior chemical cross-linking cables. However, due to limitations accelerator energy level ( usually no more than 3.0Mev electron beam effectively penetrate the thickness of 10mm or less , by considering the geometric factor , producing cable voltage level can only reach 10KV, 6KV the following advantages .

Recognition

False identification XLPE cable breakdown methods:

In the course of using the system in a series resonant test voltage cable finished product and high partial discharge test, sometimes during the test due to various causes false sudden breakdown , how to identify the cable itself has a proper breakdown of the true , or other causes of false breakdown occurred cables , cable factory test for improving the efficiency of great significance.

Medium voltage XLPE power cables and high-voltage factory partial discharge test was conducted in a shielded room -by- disc , and then you can consider to replace the insulation core retest , if you replace wires, through the normal voltage test , should be able to determine whether the cable really happened breakdown. Or, re- boost, if the breakdown voltage showed a decreasing trend , you can also determine the cable breakdown really happened , if every breakdown voltage cables are on the same value , you should consider whether the cable ends occur breakdown , this time, partial discharge can be shielded room door door interlock switches , artificially closed, the shielded room door opened, boosting observe breakdown , breakdown soon be able to determine the position of the tip . If, after investigation, the cable ends no breakdown occurs , replace the multi- core insulated wire and cables , and even had qualified to do the exercises had been unloaded cable retest or re-examination , the breakdown voltage value remains the same , it should be recognized when the cable there has been a false breakdown , equipment should be checked , troubleshooting and then tested. But for some length of cross- examination of a large single medium voltage XLPE cables , but also to check whether it has exceeded the allowable load test equipment such cases, the testing process also appears detuning tripping , not the temerity to determine the occurrence of cable the breakdown.

There is a special need in this case also shows that sometimes the cable insulation internal short circuit, series resonance test system may not resonant boost, which also belongs to a special cable breakdown. Encountered this phenomenon, as long as the replacement of insulation good insulated core tests to confirm .

My potted plants: Alocasia amazonica

Hello everyone, a new week began!

Today the meeting, each person’s feelings are good, but Luo teacher gave us each a pot! 
Haha, I picked the skunk cabbage, although she now looks in general, but I know as long as I am careful to take care of the future, she will be a beautiful future together!

Give us a picture of the first to enjoy it:

Jack knowledge about cable:knowledge of fiber optic cable

Front to introduce the the basics knowledge of the cable and power cable ! I think we all feel that the cable is made of metal as a conductor , in fact, with the development of technology, with its somewhat concentric cable has been widely used. Today ‘ll tell you about the history of fiber optic cables , structure, classification and install applications , and more!
An optical fiber cable is a cable containing one or more optical fibers that are used to carry light. The optical fiber elements are typically individually coated with plastic layers and contained in a protective tube suitable for the environment where the cable will be deployed. Different types of cable are used for different applications, for example long distance telecommunication, or providing a high-speed data connection between different parts of a building.

Fiber Optic Cable History

In 1976, the American Institute in Atlanta Bell built the first experimental optical fiber communication system that uses a cable containing 144 fibers manufactured by Western Electric Company .
In 1980 , commercial multi-mode fiber optic cable is made from the beginning of the use of the trunk line between the city and a few long-distance Bureau .
Commercial single-mode fiber optic cable made ​​in the long line began to use in 1983 .
In 1988, the connection between the United States and Britain and France ‘s first successful transatlantic submarine cable laying , and soon built the first submarine cable across the Pacific .
China in 1978, developed a communications cable , using a multimode optical fiber, cable core structure for the layer stranded . Has worked in Shanghai , Beijing , Wuhan and other places to carry out field trials.
Soon after in the local telephone network as interoffice trunks trial , after 1984 , gradually for long-distance lines , and began using single-mode fiber .
Communications cable than copper cables with greater transmission capacity , long- distance relay , small size, light weight, no electromagnetic interference, has developed into a long haul since 1976 after the city’s relay , coastal and transoceanic submarine communications , as well as local area network, a private network , such as a wired backbone transmission lines and areas of the city began to subscriber loop wiring network development, FTTH , broadband integrated services digital network to provide transmission lines.

Fiber optic cable construction

The basic structure of the cable is normally provided by the cable core , strengthen steel , and sheathing filler composed of several parts , as well as needed in addition waterproof layer, a buffer layer , insulated wires and other metal components . Specifically refer to the following figure :

Fiber optic cable construction

Classification of fiber-optic cable

Fiber optic cables can also be in different ways performance , materials, structures, etc. There are many categories :
1 according to the different transmission performance , distance, and use , the cable can be divided into user- optic cable , telephone cable, fiber optic cable and long-distance submarine cable .
2 used according to the type of fiber optic cable within different cable can be divided into single-mode fiber and multimode fiber optic cable.
3 according to the number of core fiber optic cable , fiber optic cable can be divided into single , dual fiber optic cable .
4 reinforcement configuration according to different methods, the cable can be divided into central strength member fiber optic cable, fiber optic cable dispersed reinforcement member , the reinforcing member cable sheath and integrated cable outer sheath .
5 The transmission conductor , media situation is different, can be divided into non- metallic fiber optic cable , general cable, integrated cable ( mainly for railway network communication lines ) .
6 ways according to different laying , fiber optic cable can be divided into the pipe , buried cable, aerial and underwater fiber optic cable .
7 ways according to different structures , fiber optic cable can be divided into flat structure , Stranded cable , skeleton -type cable, armored fiber optic cable and high-density user .

Application of fiber optic cable installation

Long distance cable laying is most important to select a suitable path. Here is the shortest route is not necessarily the best , but also pay attention to the land use rights , the possibility of erecting or buried so on.
When the cable turn, its turning radius is 20 times greater than the diameter of the cable itself .

Buried cable depth standard
Laying lots and soil	Depth (m)
Ordinary clay, hard clay	≥1.2
Gravel, half stone soil, weathered stone	≥1.0
The stone, sand flow	≥0.8
The suburbs, towns and villages	≥1.2
The urban sidewalks	≥1.0
The road side ditch: Stone (stone, soft stone)	Side ditch design depth below 0.4
Other soil	Side ditch design depth below 0.8
Highway shoulder	≥0.8
Crossing the railway (from the road surface), highway (from the pavement basement)	≥1.2
The ditch, pond	≥1.2
Rivers	According to the requirements of submarine cable

Optical fibers are inherently very strong, but the strength is drastically reduced by unavoidable microscopic surface flaws inherent in the manufacturing process. The initial fiber strength, as well as its change with time, must be considered relative to the stress imposed on the fiber during handling ., cabling, and installation for a given set of environmental conditions There are three basic scenarios that can lead to strength degradation and failure by inducing flaw growth: dynamic fatigue, static fatigues, and zero-stress aging.
Telcordia GR-20, Generic Requirements for Optical Fiber and Optical Fiber Cable, contains reliability and quality criteria to protect optical fiber in all operating conditions.The criteria concentrate on conditions in an outside plant (OSP) environment. For the indoor plant, similar criteria are in Telcordia GR-409, Generic Requirements for Indoor Fiber Optic Cable.