Wires and cables are used to transmit electric (magnetic) energy, information and realizationElectromagnetic energyConverted wire products.In the broad sense, wires and cables are also referred to as cables, while in the narrow sense, cables refer to insulated cables, which can be defined as: aggregates composed of the following parts;One or more insulationWire core, and their respective possibleCladding, total protective layer and outer protective layer. The cable can also have additional uninsulated conductors.
The main features of this product are: pure conductor metal, no insulation andSheath layer, such asSteel cored aluminum strand、Copper aluminum busbar、Electric locomotive lineEtc;The processing technology is mainly pressure processing, such as smeltingCalendering、Drawdown、Stranding/Compact strandingEtc;The products are mainly used in suburban areas, rural areas, user main lines, switchgear, etc.
power cable
power cable
Wire and cable
The main features of this type of product are: extruding (winding) outside the conductorInsulating layer, such asOverhead insulated cable, orSeveral core stranding(corresponding to the phase line, neutral line and ground wire of the power system), such as overhead insulated cable 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, armouring and sheath extrusion. Different process combinations of various products have certain differences.
The product is mainly used for strong electric energy in power generation, distribution, transmission, transformation and power supply linestransmissionThe passing current is large (tens of amperes to thousands of amperes) and the voltage is high (220V to 35kV and above).
The main characteristics of this kind of products are: a wide range of varieties and specifications, a wide range of applications, a large number of use voltages of 1kV and below, and constantly deriving new products in the face of special occasions, such as fire-resistant cables, flame retardant cables, low smoke zero halogen/low smoke low halogen cables, termite resistant, rat resistant cables, oil/cold/temperature/wear resistant cables, medical/agricultural/mining cables, thin wall wires, etc.
Communication cable and optical fiber
With the rapid development of the communication industry, from the simple telephone and telegraph cables in the past to thousands of pairs of voice cables, coaxial cables, optical cables, data cables, and even combination communication cables.The structural dimensions of such products are usually small and uniform, and the manufacturing precision is required to be high.
Winding wire
Winding wire is a kind of conductive metal wire with insulating layer, which is used to wind coils or windings of electrical products.Generated by current when it worksmagnetic field, or cutting magnetic lines of force to generate induced currentelectric energyAnd magnetic energy conversion, so it becomesElectromagnetic wire。
Structural materials
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The vast majority of wire and cable products are cross-section（cross section）The products with identical shape (ignoring the error caused by manufacturing) and long strip shape are determined by the characteristics used to form circuits or coils in the system or equipment.Therefore, to study and analyze the structural composition of cable products, we only need to observe and analyze from its cross section.
The structural elements of wire and cable products can generally be divided into four main structural components: conductor, insulation layer, shield and sheath, as well as filling elements and tension bearing elements.According to the use requirements and application occasions of products, some products are extremely simple in structure.
2. Cable material
In a sense, wire and cable manufacturing industry is a material finishing and assembly industry.First, the amount of materials used is huge, and the cost of materials in cable products accounts for 80-90% of the total manufacturing cost;Second, there are many types and varieties of materials used, and the performance requirements are particularly high. For example, copper used as conductor, the purity of copper is required to be above 99.95%, and some products should use oxygen free high-purity copper;Third, the selection of materials will have a decisive impact on the manufacturing process, product performance and service life.
At the same time, the benefits of wire and cable manufacturing enterprises are also closely related to the scientific material saving in material selection, processing and production management.
Therefore, the design of wire and cable products must be carried out at the same time as the selection of materials. Generally, several materials are selected and determined after the process and performance screening tests.
Materials for cable products can be divided into conductive materialsInsulating material, filling materials, shielding materials, protective layer materials, etc.But some of these materials are common to several structural members.In particular, thermoplastic materials, such as polyvinyl chloride and polyethylene, can be used on insulation or sheath as long as some formula components are changed.
The materials used in the manufacture of cable products cover a wide range of categories, and there are many varieties and specifications (brands).
3. Name and material of product structure
(1) Wire: the most basic and essential main component of the product for current or electromagnetic wave information transmission function.
Main materials: conductor is the abbreviation of conductive core, which is made of copper, aluminum, copper clad steel, copper clad aluminum and other nonferrous metals with excellent conductivitylight-guide fiberAs a wire.
There are bare copper wires and tinned wires;Single branch line and stranded wire;Tin plated wire after twisting.
(2) Insulating layer: It is a component that is wrapped around the periphery of the conductor and plays the role of electrical insulation.That is to say, it can ensure that the transmitted current, electromagnetic wave and light wave only travel along the conductor and do not flow outward, and the potential on the conductor (that is, the potential difference formed on the surrounding objects, that is, the voltage) can be isolated, that is, it is necessary to ensure both the normal transmission function of the conductor and the safety of external objects and people.The conductor and insulation layer are two basic components that must be possessed by cable products (except bare wires).
(3) Filling structure: many wire and cable products are multi-core. After these insulated wire cores or wires are paired into cables (or grouped into cables for several times), the first reason is that the shape is not round, and the second reason is that there is a large gap between insulated wire cores. Therefore, filling structure must be added when cabling. The filling structure is to make the outer diameter of the cabling relatively round to facilitate tape wrapping and sheath extrusion.
Main material: PP rope
(4) Shielding: it is a component that isolates the electromagnetic field in the cable product from the external electromagnetic field;Some cable products also need to be isolated from each other between different wire pairs (or wire groups) inside.It can be said that the shielding layer is an "electromagnetic isolation screen".The purpose of conductor shielding and insulation shielding of high-voltage cables is to homogenize the distribution of electric field.
Main materials: bare copper wire, copper clad steel wire, tinned copper wire
(5) Protective layer: When wire and cable products are installed and operated in various environments, they must have components that protect the overall product, especially the insulation layer, which is called protective layer.
Because insulating materials are required to have excellent electrical insulation properties, they must have very high purity and very low impurity content;It is often impossible to give consideration to its ability to protect the outside world, so the bearing or resistance of various mechanical forces to the outside world (i.e., installation, application and use), resistance to atmospheric environment, chemicals or oils, prevention of biological damage, and reduction of fire hazards must be borne by various protective layer structures.
Main materials: PVC, PE, rubber, aluminum, steel strip
(6) Tensile element: typical structure is steel cored aluminum strand, optical fiber cable, etc.In a word, the tension element plays a major role in the special small and soft products that require multiple bending and twisting.
Main material: steel wire
Model designation
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Basic concepts
The complete naming of wires and cables is usually complicated, so people sometimes use a simple name (usually a category name) in combination with the model and specification to replace the complete name. For example, "low-voltage cable" represents all plastic insulated power cables of 3kV and below.The type spectrum of wires and cables is relatively complete. It can be said that as long as the standard models and specifications of wires and cables are written, specific products can be identified, but what is the complete name of them.
The naming of wire and cable products has the following principles:
1. Contents included in the product name
(1) Name of product application or size category
⑵ Product structural material or type;
⑶ Important or additional features of the product
The names are basically in the above order. Sometimes, in order to emphasize important or additional features, the features are written before or before the corresponding structure description.
2. Sequence of structure description
The product structure description follows the principle of "from inside to outside":conductor--Insulation--Inner sheath--Outer sheath--Armor type。
3. Simplification
In case of no confusion, some structural descriptions are omitted or abbreviated, for example, aluminum conductors are not allowed in automobile wires and flexible wires, so conductor materials are not described.
Case:
8.7/15 (17.5) kV copper core XLPE insulated steel tape armored PVC sheathed flame-retardant class C power cable, 3-core, nominal section 300mmtwo。
"8.7/15 (17.5) kV" - 8.7 phase voltage;15 line voltage;17.5 Maximum system voltage
"Flame retardant class C" - Flame retardant grade
"Copper core" - conductor material
"Cross linked polyethylene insulation" - insulation material
"Steel strip armor" - armor layer material and type (double steel strip gap wrapping, the first 2)
"PVC sheath" - the inner sheath is V, and the second outer sheath is 2.
"Power cable" - name of product category
The corresponding model is ZC-YJV22-8.7/15kV, 3 * 300
See the description below for the model.
4. The first letter of Chinese phonetic alphabet is used to indicate the insulation type, conductor material, inner sheath material and structural characteristics.For example, Z represents paper (zhi);L stands for aluminum (lv);Q stands for lead (qian);F represents phase separation (fen);ZC represents flame retardant Class C (zuran);NH stands for fire resistance (naihoo);D stands for low smoke (diyan).
For example, WDZN-YJV22-0.6/1kV, 4 * 120.The letters in front represent: halogen-free, low smoke, flame retardant and fire-resistant
5. The composition of the outer sheath is represented by two figures.No number means no armor layer and no outer cover layer.The first digit represents the armor, and the second digit represents the outer cover. For example, the outer cover of thick steel wire armored fiber is 41.
6. According to the arrangement of cable structure, the general sequence of cable models is: insulation materials;Conductor material;Inner protective layer;Outer sheath.
7. Cable products are represented by model, rated voltage and specification.The method is to add the rated voltage, number of cores andNominal cross-sectional area。
CEF——EPDMinsulationNeopreneSheath, marine flame-retardant power cable.
CVV - PVC insulated, PVC sheathed marine flame-retardant power cable.
BV, BX, RV, RVV series wires are often used for oxygen cabin wires, among which:
BV - copper core PVC insulated wire, with long-term allowable temperature of 65 ℃, minimum temperature of - 15 ℃, working voltage of 500V AC, 1000V DC, fixed indoor and outdoor, can be exposed or concealed.
BX -- Copper core rubber insulated wire, with maximum service temperature of 65 ℃, applied indoors.
RV - PVC insulated single core flexible wire, with the maximum use temperature of 65 ℃, the minimum use temperature of - 15 ℃, and the working voltage of 250V AC, 500V DC, used as the internal wiring of instruments and equipment.
RVV - copper core PVC insulated and sheathed flexible wire, with allowable long-term working temperature of 105 ℃, working voltage of 500V AC and 1000V DC, is used in wet, high mechanical protection requirements, frequent movement and bending occasions.
Common models
VV means: PVC insulation (the first V), PVC sheath (the second V)
YJV22 indicates: cross-linked polyethylene insulation (YJ), PVC sheath (V), double steel tape armouring (the first 2), PVC outer sheath (the second 2)
The model with "ZR" or "FR" is flame retardant cable (wire).Add "L" for aluminum wire, and "TR" for flexible copper wire
The model of wire is simple:
BVV -- PVC insulated and sheathed copper core wire,
Square X 1.83=weight of copper X current copper price+price of rubber (weight X 0.4 yuan/jin)=cost price+10% processing fee
Cable price=manufacturing material cost+fixed expense+tax+business expense+profit
Manufacturing material cost=material cost * (1+material consumption) (material cost is the value calculated theoretically)
Fixed expenses vary from company to company, generally including production wages, management wages, utilities, repair costs, depreciation costs, rent, transportation costs
Calculation formula of carrying capacity
Pithy formula for estimating
Multiply two five times nine, and go up minus one.
Thirty five times three and a half.
Conditions are subject to change, conversion, and upgrading of 10% copper at high temperature.
The number of pipe penetrations is two, three, four, and eight, seven, six fold full load flow.
Note: The pithy formula in this section does not directly point out the current carrying capacity (safety current) of various insulated wires (rubber and plastic insulated wires), but is expressed by "multiplying the section by a certain multiple", which is obtained by mental calculation.It can be seen from Table 53 that the multiple decreases with the increase of the section.
Multiply 2:5 by 9, and subtract one from the top. Go ahead
At 2:5, multiply by 9, and then subtract one from the top. "It says that the current carrying capacity of aluminum core insulated wires with various cross-sections of 2.5mm and below is about 9 times the number of cross-sections.For example, the current carrying capacity of 2.5mm 'conductor is 2.5 × 9=22.5A.The multiple relationship between the current carrying capacity and the number of cross sections of conductors from 4mm 'and above is to go up along the line number, and the multiple is gradually reduced by 1, that is, 4 × 8, 6 × 7, 10 × 6, 16 × 5, 25 × 4.
Thirty five times three and a half.
Thirty five times three and a half, double double group minus five ", say 35mm"Current carrying capacity of conductorIs 3.5 times the number of sections, i.e. 35 × 3.5=122 5A.From the multiple relationship between the current carrying capacity and the number of cross sections of 50 mm 'and above conductors, two wire numbers form a group, and the multiple is reduced by 0.5 in turn.That is, the current carrying capacity of 50 and 70mm 'conductors is 3 times of the number of sections;The current carrying capacity of 95 mm and 120 mm conductor is 2.5 times of its sectional area, and so on.
Conditions are subject to change, conversion, and upgrading of 10% copper at high temperature.
"Conditions are subject to change and conversion, and 10% copper is upgraded at high temperature".The above pithy formula is determined by the aluminum core insulated wire and exposed laying at the ambient temperature of 25 ℃.If the aluminum core insulated wire is exposed laid in an area where the ambient temperature is higher than 25 ℃ for a long time, the current carrying capacity of the wire can be calculated according to the above formula, and then it can be reduced by 10%;When copper core insulated wire is used instead of aluminum wire, its current carrying capacity is slightly larger than that of aluminum wire of the same specification. The current carrying capacity of one wire larger than that of aluminum wire can be calculated according to the above formula method.For example, the current carrying capacity of 16mm 'copper wire can be calculated as 25mm2 aluminum wire.
The number of pipe penetrations is two, three, four, and eight, seven, six fold full load flow.
When two, three and four wires are laid through pipes, the ampacity is 80%, 70% and 60% of the ampacity calculated by the electrician (single laying).
Relevant standards
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1. Appearance standard, the wire must have the certification mark, manufacturer, wire diameter, etc., and the ground wire must have a yellow green insulation layer
2. Mechanical strength
3. Sheath insulation (generally more than 100M Ω) and withstand voltage strength (above 500V and below 1500V)
4. The line resistance shall not be greater than a certain resistance under a certain wire diameter, conductivity and length
5. The wire shall not crack under the impact of 140 ℃ at high temperature and - 30 ℃ at low temperature
Shopping points
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As the main carrier of power transmission, wires and cables are widely used in electrical equipment, lighting lines, household appliances and other aspects. Their quality directly affects the project quality and the safety of consumers' lives and property.There are many kinds of wires in the market, so you should use appropriate wires according to your own power load.
Some wires sold in the market are cheap and some are expensive, and some people tend to compare them first. However, many cheap wires fail to meet the performance he explained, which may bring many potential safety hazards to themselves.The production technology of wires is not too high, and the raw materials are not too different. If the price is too much, it is either jerry building or the quantity is not enough.How to identify it.Let me tell you some easy identification methods:
1. Look at the package. The national standard wires are usually well made, neat, and have a sense of quality.
2. It is necessary to open the package and check the wires inside. The national standard wires of 1.5 to 6 square meters require a thickness of 0.7mm (insulation thickness). If the wires are too thick, they are non-standard. The corresponding inner core is definitely not enough. You can pull the wire cover hard. The wires that are not easy to tear are generally national standard
3. Burn it with fire and extinguish it within 5s after leaving. The line with certain flame retardant function is the national standard line.
4. 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 has no sense of hierarchy.The national standard requires that the inner core must be made of oxygen free copper.Non standard products such as black rod copper may have potential accidents.
5. The country has certain requirements on the thickness of the core, but they are not very strict.But it can't make many mistakes, just a little bit, which is usually invisible to the eye.
6. In terms of length, the state does not force rice, but many manufacturers have also beaten rice. The rice that has been beaten may not be the national standard, but the general national standard does not beat rice.The non-standard rice beating is just a means.
7. According to the national regulations, certain marks must be printed on the wires, and the next same mark will be printed if the maximum size is no more than 500mm. Generally, there are product trademarks, manufacturer names, executive standards, etc
Scope of application
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Power system
The wire and cable products used in the power system mainly include overhead bare wires, bus bars (buses), power cables (plastic cables, oil paper cables, which are basically replaced by plastic power cables), rubber sheathed cables, overhead insulated cables, branch cables (which replace some buses), electromagnetic wires, and electrical equipment wires and cables for power equipment.
Information transmission system
The wires and cables used for information transmission system mainly includeTelephone cable、TV cable、Electronic cable、RF cable、Fiber optic cable、Data cable、Electromagnetic wire, power communication orOther composite cablesEtc.
Mechanical instrument system
This part applies to almost all products except overhead bare wires, but mainly power cables, electromagnetic wires, data cables, instrument cables, etc
matters needing attention
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Common cable faults
Wire surface marks - according to the national standards, the wire surface shall have continuous marks of manufacturer name, product model and rated voltage.This is conducive to finding the manufacturer in time when problems occur during the use of wires. Consumers must pay attention to this when selecting wires.At the same time, when purchasing wires, consumers should pay attention to whether the manufacturer name, product model, rated voltage indicated on the certificate are consistent with the printed marks on the wire surface to prevent counterfeit products.
Wire appearance - When purchasing wires, consumers should pay attention to the smoothness of the wire appearance, no damage to the insulation and sheath layers, clear signs, and no greasy feeling when modeling wires.From the cross section of the wire, the thickness of the insulation or sheath on the whole circumference of the wire should be uniform, without core deflection, and the insulation or sheath should have a certain thickness.
Conductor diameter - When purchasing wires, consumers should pay attention to whether the conductor diameter is consistent with the section indicated on the certificate. If the conductor section is too small, it is easy to heat the wires and cause short circuits.It is recommended that wires for household lighting lines should be 1.5mm2 and above;For household appliances with large power such as air conditioners and microwave ovens, 2.5 mm2 and above wires shall be used.
Standardized use - wiring should be standardized, and BV single core wire should preferably be used for fixed wiring to pass through the pipe. Pay attention not to damage the wire when wiring, and not to damage the wire when decorating the room;Do not connect in the middle of a route;Do not touch the wire when the wire is connected to the electrical box (box);In addition, household appliances with large power consumption, such as air conditioners, should be powered by a separate wire;The wires for weak and strong electricity should be kept at a certain distance.
Common faults of cable lines include mechanical damage, insulation damage, insulation damp, insulation aging and deterioration, overvoltage, cable overheating, etc.When the above fault occurs to the line, the power supply of the faulty cable shall be cut off, the fault point shall be found, the fault shall be checked and analyzed, and then the repair and test shall be carried out. The power supply can be restored only after the fault is eliminated.
Safety requirements for buried cables
1. When cables cross each other,High voltage cableIt shall be under the low-voltage cable.If one of the cables passes through a pipe for protection or is separated by a partition within 1m around the intersection, the minimum allowable distance is 0.15 m.
2. When the cable is close to or crossed with the thermal pipeline, if there are thermal insulation measures, the minimum distance between the parallel and cross is 0.5m and 0.15m respectively.
3. When the cable crosses the railway or road, it shall be protected through a pipe, which shall extend 2m beyond the track or road surface.
4. The distance between the cable and the building foundation shall ensure that the cable is buried outside the building apron;When the cable is led into the building, it should be protected through the pipe, and the protective pipe should also be beyond the building apron.
5. The distance between the cable directly buried underground and the grounding of general grounding device shall be 0.15~0.5m;The buried depth of cables directly buried underground should generally not be less than 0.7m, and should be buried under the frozen soil layer.
Fire measures
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1. Ensure the construction quality, especially the production quality of the cable head must strictly meet the requirements.
2. Strengthen cable operation monitoring to avoid cable overload operation.
3. Cable test shall be carried out on schedule, and any abnormality found shall be handled in time.
4. The cable trench shall be kept dry to prevent the cable from being damped, which may cause insulation decline and short circuit.
5. Regularly clean the dust accumulated on the cable to prevent the self ignition of the accumulated dust from causing the cable to catch fire.
6. Strengthen the regular calibration and maintenance of cable circuit switch and protection to ensure its reliable action.
7. When laying the cable, keep enough distance from the hot pipe, and the control cable shall not be less than 0.5m;Power cable shall not be less than 1m.The control cable and power cable shall be arranged in separate trenches, layers and layers, and shall not be overlapped.Flame retardant and heat insulation measures shall be taken for cables that do not meet the requirements.
8. InstallationFire alarm deviceFind out the fire in time to prevent the cable from catching fire.
9. Take fire and flame retardant measures.
Industry development
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Development status
Although the wire and cable industry is only a supporting industry, it occupies ChinaElectrical industry1/4 of the output value.It has a wide range of products and applications, involving power, construction, communication, manufacturing and other industries, and is closely related to all sectors of the national economy.Wires and cables are also known as the "artery" and "nerve" of the national economy. They are essential basic equipment for transmitting electric energy, transmitting information, manufacturing various motors, instruments, meters, and realizing electromagnetic energy conversion. They are also essential basic products in the future electrification and information society.
The wire and cable industry is the second largest industry in China after the automobile industry, with the product variety satisfaction rate and domestic market share exceeding 90%.Worldwide, China's total output value of wires and cables has exceeded that of the United States, becoming the world's largest wire and cable producer.With the rapid development of China's wire and cable industry, the number of new enterprises is rising, and the overall technical level of the industry has been greatly improved.
From January to November 2007, China's wire and cable manufacturing industry achieved a total industrial output value of 47674252600 yuan, an increase of 34.64% over the same period of the previous year;The accumulated product sales revenue was 457503436 thousand yuan, up 33.70% over the same period of the previous year;The total accumulated profits reached 18808301000 yuan, up 32.31% over the same period of the previous year.
From January to May 2008, China's wire and cable manufacturing industry realized a total industrial output value of 241435450000 yuan, an increase of 26.47% over the same period of the previous year;The accumulated product sales revenue was 227131384000 yuan, an increase of 26.26% over the same period of the previous year;The total accumulated profit was 8519637000 yuan, an increase of 26.55% over the same period of the previous year.In November 2008, China responded to theWorld financial crisisThe government decided to invest 4 trillion yuan to stimulate domestic demand, of which more than 40% was used for the construction and transformation of urban and rural power grids.The national wire and cable industry has a good market opportunity again. Wire and cable enterprises around the country seize the opportunity to welcome a new round of urban and rural areaspower gridConstruction and transformation.
The past 2012 was a threshold for China's wire and cable industry. Due to the slowdown of GDP growth, the global economic crisis, the adjustment of domestic economic structure and other reasons, domestic cable enterprises generally ran short of operating rate and overcapacity, and even caused the industry to worry about bankruptcy.With the arrival of 2013, China's wire and cable industry will usher in new business opportunities and markets.
As of 2012, the global wire and cable market has exceeded 100 billion euros. Within the global wire and cable industry, the market size of Asia accounts for 37%, the European market accounts for nearly 30%, the American market accounts for 24%, and other markets account for 9%.Among them, although China's wire and cable industry plays an irreplaceable role in the global wire and cable industry, and as early as 2011, the output value of China's wire and cable enterprises has exceeded that of the United States, ranking first in the world.However, objectively speaking, compared with the wire and cable industry in Europe and the United States, China is still in a big but not strong situation, and there is still a big gap between China and foreign well-known wire and cable brands.
In 2011, the sales value of China's wire and cable industry reached 1143.8 billion yuan, breaking through trillion yuan for the first time, with a growth rate of 28.3% and a total profit of 68 billion yuan.In 2012, from January to July, the sales value of the national wire and cable industry was 671.5 billion yuan, the total profit was 28.1 billion yuan, and the average profit was only 4.11%. The industry profit was 4.88% lower than the average profit of China's electrical industry, which was significantly lower than that of 2011.
In addition, judging from the asset scale of China's cable industry, the assets of China's wire and cable industry reached 790499 million yuan in 2012, an increase of 12.20% year on year.East China accounts for more than 60% of the country, and still maintains strong competitiveness in the entire wire and cable manufacturing industry.[1]
The sustained and rapid growth of China's economy has provided a huge market space for cable products. The strong allure of the Chinese market has made the world focus on the Chinese market. In the short decades of reform and opening up, the huge production capacity of China's cable manufacturing industry has made the world look up to it.along withChina's electric power industry, data communication industryUrban rail transitWith the continuous expansion of transportation, automobile, shipbuilding and other industries, the demand for wires and cables will also grow rapidly. In the future, the wire and cable industry has huge development potential. For details, please refer to the Analysis Report on Market Demand Forecast and Investment Strategic Planning of China's Wire and Cable Industry.
In the process of promoting the transnational business strategy of wire and cable enterprises and implementing strategic management and control, the following principles should be followed: giving consideration to both domestic and international business, seeking the connection between resources and industrial layout, matching scale and efficiency, matching ownership and control, and coordinating the business of parent company and subsidiary company,The organizational form of production is compatible with the organizational structure and management system of operation and management.To follow these principles, wire and cable enterprises should handle the following relationships:
1. Correctly handle the relationship between domestic business and international business
It should be pointed out that the transnational operation of wire and cable enterprises is the requirement and objective result of the expansion of enterprise productivity, rather than the subjective and artificial intention.Not all wire and cable enterprises must be engaged in transnational operations. Due to different enterprise scale and business nature, a considerable number of wire and cable enterprises are only suitable for carrying out business in the domestic market.Wire and cable enterprises with transnational business conditions still need to correctly handle the relationship between domestic business and international business.The domestic market is the base for the survival and development of enterprises. Wire and cable enterprises can take advantage of the favorable conditions of time, place and people when conducting business in China, while they must bear certain risks in these aspects when developing international markets;However, the development of Chinese wire and cable enterprises should also focus on the long-term and expand the regional scope of business from the perspective of optimal allocation of production factors to improve market share and competitiveness.
2. Give reasonable consideration to the relationship between industrial layout and resource allocation
Therefore, wire and cable enterprises should not only develop resources overseas, but also use local materials overseas as much as possible to reduce the cost of raw materials and some transportation costs.At the same time, wire and cable enterprises belong to manufacturing enterprises, so the impact of natural resources and energy shortage on industrial layout should be reasonably considered, and resource intensive production links should be distributed in overseas countries and regions with rich resources and low costs.
3. Correctly handle the relationship between scale expansion and efficiency improvement
For many years, the scale of transnational operation of Chinese wire and cable enterprises has been concerned. It is generally believed that many enterprises have not produced the expected economic benefits due to their small scale.Therefore, for a period of time, some wire and cable enterprises in China have gone to another extreme in their transnational operations, pursuing expansion of scale unilaterally and ignoring economic benefits, which is contrary to the original purpose of transnational operations.Therefore, wire and cable enterprises should correctly handle the relationship between scale and efficiency in the process of transnational strategic planning and implementation, and expand scale in order to obtain higher efficiency.
4. Correctly handle the relationship between ownership and control
Wire and cable enterprises passedForeign direct investmentThe purpose of obtaining partial or full ownership of overseas enterprises is to obtain control over overseas enterprises through ownership, so as to serve the overall development strategy of the parent company to obtain maximum economic benefits.On the contrary, if a wire and cable enterprise obtains partial or full ownership of an overseas enterprise, but does not exercise control over the enterprise, and does not make ownership serve the overall strategy of the head office, then transnational operation will lose its true meaning, and the enterprise will not be a truly transnational enterprise.Therefore, a wire and cable enterprise with global market as its strategic goal must obtain corresponding control power no matter how much ownership it obtains in transnational operation.
5. Correctly handle the relationship between parent subsidiary companies and overseas enterprises
The headquarters of wire and cable enterprises is the decision-making center of transnational operations, and the subsidiary is the profit production center of the parent company.The business of overseas enterprises should echo each other rather than internal competition.In the parent companySystem controlThe overseas enterprises shall carry out production and operation activities in order to fulfill the instructions of the headquarters.
6. The organizational form of production is compatible with the organizational structure and management system of operation and management
In different stages of transnational operation, wire and cable enterprises adopt different production organization forms, orHorizontal integration, or vertical integration.Therefore, the organizational structure and management system of the operation and management of wire and cable enterprises should correspond to the organizational form of production, so as to form a consistent, reasonable and efficient management and control system inside and outside.
Industry concentration analysis
Product concentration
The output value of the five major categories of products in China's wire and cable industry bare wires, winding wires, electrical equipment wires and cables, power cables and communication cables and optical cables accounted for 18%, 19%, 22%, 31% and 10% of the industry's total output value respectively.
Bare wire products are mainly used as semi-finished products of overhead conductors and other cable products, and their share is relatively stable.With the shortage of national energy and power supply, the construction of new energy projects such as nuclear energy and wind energy keeps pace with the growth of winding line products.Driven by the construction of the national smart grid, power cable products will continue to grow at a high speed.
Since the second half of 2010, the country has successively issued relevant policies to further expand the investment scale of 3G and optical fiber broadband, promote the pilot of three networks integration, and cultivate strategic emerging industries. Therefore, the market share of communication cables and optical cables will be significantly expanded in the next few years.In addition, electrical equipment cables will also maintain rapid growth with the rapid development of energy industry, automobile industry, construction, household appliances and other industries.
Regional concentration
According to statistics, Chinese wire and cable enterprises are mainly concentrated in East China, with more than half of the total number of enterprises in the whole industry, mostly in Jiangsu Province and Zhejiang Province;The number of wire and cable enterprises in central and southern China accounted for 27%, mainly in Guangdong Province;The number of enterprises in North China, Northeast China, Southwest China and Northwest China accounted for 10%, 6%, 4% and 2% respectively.
East China and south central China account for 80% of China's wire and cable market. With the adjustment of industrial structure and the increase of market concentration, the market will be more concentrated in Jiangsu, Guangdong, Zhejiang, Shandong and other major cable production provinces.
Guangdong Province is the province with the largest output value of power cables in China, and there are many cable manufacturers;Jiangsu Province occupies about 40% of the market of communication cables and optical cables in China, and also ranks second in power cables;Famous cable manufacturers such as Far East Group and Baosheng Group are all located in Jiangsu Province;Zhejiang Province and Shandong Province are in the forefront of the domestic in terms of winding wires and power cable products.
Future market forecast
In 2010Macroeconomic situationOn the whole, it is still conducive to the development of the electrical industry.But at the same time, due to the weak foundation of China's economic recovery and the existence of various uncertainties at home and abroad, the development path in 2010 is doomed to be uneven.
According to relevant planning, the total industrial output value, sales output value and other economic indicators of the electrical industry in 2010 are expected to exceed 3 trillion yuan, with a year-on-year growth of about 12%;The total profit will reach 170 billion yuan, up about 10% year on year.Among them, the output of power generation equipment is still expected to reach more than 100 million kilowatts;The output of transformers in power transmission and transformation equipment will exceed 1.4 billion KVA, which is expected to increase by 10%.In order to promote the sound and rapid development of the electrical industry, several major problems affecting the economic operation of the whole industry need to be paid attention to and solved as soon as possible.
IOvercapacity industryThe disorderly development of the wire and cable industry has long been over developed. However, since 2009, driven by the policy of "expanding domestic demand, maintaining growth and stability", and in the name of developing new products or high-end technology products, some local governments have still invested heavily in building new plants, purchasing production lines and equipment from abroad, and expanding production capacity, often costing hundreds of millions or billions of yuan,Even more than 2 billion yuan, forming a new round of repeated investment boom.Regardless of whether the enterprise is state-owned or private, most of the funds invested are fromnational bankLoan.These investment behaviors make the cable industry, which has been over developed and has serious overcapacity, even worse.Taking the vertical production line (VCV) of high-voltage cross-linked cables as an example, there are 32 domestic VCV lines that have been put into production before the end of 2008 (only one of them is domestic), and 28 VCV lines that have purchased equipment and are planned to be put into production in 2009 and later, a total of 60 VCV lines.Such blind investment, regardless of the actual situation, not only wastes a lot of resources, but also greatly endangers the healthy and orderly development of the industry.The completion of these production lines will further idle the domestic VCV production line, which has only 40% equipment utilization rate.At the same time, because of overcapacity, it will also make the vicious competition phenomenon such as jerry building, shoddy goods, low price competition and even fake and shoddy goods more serious.
2、 There are still restrictions on domestic equipment. In some regions and fields of China, there are restrictions on domestic equipment, which seriously hinder the process of major equipment localization.In order to reduce the impact of the financial crisis on China's economy, the country has introduced a series of policies to expand domestic demand and promote steady and rapid economic growth. The National Development and Reform Commission and other nine ministries and commissions jointly issued the Opinions on Implementing the Decision and Deployment of Expanding Domestic Demand and Promoting Economic Growth and Further Strengthening the Supervision of Bidding for Engineering Construction (FGS [2009] No. 1361).The document clearly stipulates that it is prohibited to restrict the use of domestic equipment by setting discriminatory clauses, further strengthen the supervision and management of project construction bidding, standardize the bidding market order, and improve investment efficiency.The phenomenon of restricting domestic equipment and adopting discriminatory clauses in domestic engineering construction bidding has been largely curbed, which has played a positive role in the development of national industry, industrial structure adjustment and product upgrading.However, some places and some fields ignored the central government's policies, even went against the wind, and still used discriminatory clauses in major project construction bidding to restrict domestic equipment.For example, in the bidding document of a city's rail transit line 1 project (400V switchgear procurement project), it unexpectedly appeared that "the circuit breaker, contactor and other components in the bidding product must have two or more metro service performances, of which the main components (circuit breaker, contactor) must be discriminatory clauses of international well-known brands, restricting domestic equipment from participating in bidding activities.The "main components (circuit breakers, contactors)" mentioned in the bidding documents have been produced by many domestic enterprises, and are widely used in many industries and national key projects such as aerospace, airport, subway, power, machinery, petrochemical, metallurgy, textile, etc., such as Qinshan Nuclear Power Station, Zhongnanhai Substation, Oriental Pearl TV Tower, etc., with good operation.The product has the characteristics of good quality, high stability and high cost performance.It can be said that the domestic circuit breakers and contactors for 400V switchgear can fully meet the technical requirements of a city's rail transit project.
Since the 1990s, the cable industry has been known as the "nerve" and "blood vessel" of the city, shouldering the function of supporting the pillar industries of the national economy in all walks of life, and has grown into the second largest industry in China's machinery industry after automobiles.However, the output value of China's cable industry still accounts for only about 15% of the world's cable industry. This huge market still has a lot of development space and gaps to be developed.During the "Eleventh Five Year Plan" period, if the annual growth rate of the national economy is 7%~8%, the development rate of the wire and cable industry will be the same as that of the national economy, which is expected to be about 8.5%.From a macro perspective, the entire Chinese wire and cable industry is in a period of rapid development and growth.
The development is rapid, and the problems also follow.Especially in the middle and low end wire and cable product market with relatively low added value of technology, the situation of underpricing is quite common.Industry insiders believe that blind investment, overcapacity and oversupply are the root causes of low price competition.On the one hand, due to the low investment threshold, a large number of enterprises have poured in, resulting in "too many and too many" enterprises in the industry.The production capacity of these industries exceeded the market demand, and there was a serious surplus.On the other hand, due to the low "threshold", not only is the concentration of the industry getting lower and lower, but also a part of "workshop enterprises" that do not have the necessary means of production capacity, quality control and detection can be mixed in the industry, becoming the source of fake and shoddy, shoddy, steal work and reduce materials, and shoddy cable products,And by means of lowering the sales price and other means, it disturbs the market competition order and intensifies the disordered competition in the industry.
Although China's cable industry has experienced more than 20 years and achieved considerable development, it still has not gone out of the strange circle of large but not strong, and there is still a big gap compared with relevant enterprises in the world.There are many problems, such as low industrial concentration, large number and small scale of enterprises, insufficient economies of scale, insufficient independent innovation capacity, and prominent structural contradictions of products.Despite these problems, China's cable industry is facing a new opportunity to take off, that is, to rapidly improve its core competitiveness in development.With the continuous change of the world economic pattern, China's cable industry is also bound to face restructuring and reshuffle.In particular, China's economic development is faced with the bottleneck problem of energy and power shortage. The country has continuously increased its investment in power, making the industry enter a period of rapid development.In order to implement the decision of the central government to increase infrastructure construction and stimulate domestic demand, the State Grid Corporation of China plans to increase investment and accelerate the pace of power grid construction. It is estimated that the investment scale will exceed 1 trillion yuan in the next two to three years, including 790 billion yuan for the construction and transformation of urban and rural power grids and main power grids.The construction scale is 260000 km of 110 (66) kV and above transmission lines, and the transformation capacity is 1.35 billion KVA.
The power transmission and transformation primary equipment industry, which belongs to the power cable manufacturing industry, has relatively low technical content and low entry threshold. The users are mainly State Grid Corporation of China. This market pattern has led to the partial loss of pricing ability of many equipment suppliers. After rapid expansion, the whole industry is faced with the problem of high prices of raw materials, and the competition in the industry is becoming increasingly fierce,The profit shows a downward trend;The secondary power transmission and transformation equipment industry is an industry with relatively small cyclical fluctuations. It involves high-tech fields, has high technical barriers, and is monopolized by several large companies.In view of the development prospect of China's power industry, the wire and cable manufacturing industry, as its sub industry, still has a good expansion space under the promotion of the general environment.
Industry prospect
With the continuous intensification of competition in the wire and cable industry, mergers and acquisitions and capital operations among large wire and cable enterprises are becoming increasingly frequent. The domestic outstanding wire and cable manufacturers are increasingly paying attention to the research of the industry market, especially the in-depth research on the development environment of enterprises and changes in customer demand trends.Because of this, a large number of domestic excellent wire and cable brands have risen rapidly, and gradually become the leaders in the wire and cable industry!
The report of wire and cable industry mainly analyzes the operation and prospect of wire and cable industry;Market demand forecast and procurement of power cable products;Market demand forecast and procurement of communication cable products;Market situation of cables for electrical equipment;Market conditions of bare wires and winding wires;The competitive pattern of wire and cable enterprises and the operation of competitors;Development status and planning of wire and cable industry base;Construction trend of wire and cable industrial base project;Analysis of existing problems in wire and cable industry and suggestions for solutions.At the same time, with comprehensive and detailed first-hand continuous market data of the whole industry in the past five years, you can comprehensively and accurately grasp the market trend and development trend of the entire wire and cable industry
Prospect forecast
No matter in the present or in the future, China's cable industry hardly needs to worry about the problem of market space. China's various industries have ushered in great development. As an important supporting industry of the national economy, the wire and cable industry "needs to use wires and cables wherever there is construction", so the market is huge.In recent years, due to the increase of infrastructure construction in China, the rapid development of the power industry, and the favorable policies, the demand for power cables in China has increased year by year, and the increase in demand has led to the increase in output. Without major fluctuations in the national macroeconomic environment, the output of power cables in China will maintain a stable growth rate in the next few years. It is expected that by 2020,China's output will reach 110 billion meters.In the next few years, China's power, railway, rail transit, energy, construction, ships, automobiles and other industries will still maintain a large scale of investment, which will provide many rare opportunities for the wire and cable industry.[2]
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The cable gland is a suitable power source for connecting the cable and can also protect the cable, so it will not escape.Cable sealing devices are placed in different categories, depending on whether glands are used in general processing industries or need to be protected from excessive temperature or explosion hazards.Incorporating glands in the cable armored or unarmored layer and a different type of gland will be required for each variety.The gland itself can be made of metal, such as copper or aluminum, or plastic. Each material is useful in different environments.
When the electrical work is completed, it may not have cable sealing to ensure the wires of electrical equipment, but for the following reasons, this is a bad idea.The glands provide sealing power to ensure that the cable does not slip during operation.Safety is also provided because the gland ensures that electrical energy can not be attached to the cable near anyone, causing personal injury.Glands usually provide other safety functions, such as grounding wires or insulated cables
There are two main categories for cable sealing: industrial and hazardous.Industrial cable sealing joint is a gland for general use to meet the requirements of general hazards, so it is useful for use in high temperature environment or explosion hazard.If the environment is hazardous, use dangerous glands because these glands meet the necessary additional requirements.They are extra strengthened, so that they can resist the temperature and external forces that ordinary glands cannot withstand.
Two types of cables can be put into the cable gland and classified as armored or non armored layer, which will play a role in the work of glands will rise.Armored cables will require a gland that can be clipped to the wire and have the ability to terminate the energy from the armored part.The non armored type wire does not require termination, but the gland needs to be highly protected and reserved to keep the wire safe.
Most cable gland units are made of brass, which is considered as a general material that is corrosion resistant and conductive.In the presence of aluminum and moisture, brass can start to corrode at the same time.Brass is often plated with other metals to achieve stronger and better corrosion resistance.Plastic is often used as an alternative to metal glands.
