The output of high-performance fireproof cables reaches 40,000 kilometers

ThePower Cable industry is an industrial basic industry, and its products are widely used in energy, transportation, communications, automobiles, petrochemicals and other fields, occupying an extremely important position in my country’s national economy, and the market demand is huge.
Since the 21st century, China’s economy has continued to grow at a high speed. In particular, large-scale projects such as power grid transformation and UHV have been successively invested in upgrading and construction, providing a huge market space for the development of the wire and cable industry. Among them, the market demand for special cables such as high-temperature superconducting cables, aerospace cables, and high-performance fire-resistant cables is increasing.
Despite the huge market space in the entire industry, high-performance special cables with increasing demand have always been the shortcomings of my country’s wire and cable industry, occupying a relatively low proportion in the entire industry, showing that foreign-funded enterprises are leading the way and domestic enterprises are closely following the situation. In terms of market segments, the high-end market for special cables has the characteristics of high technical content, high entry barriers, strict protection of intellectual property rights, and high added value of products. Therefore, how to upgrade the technical level of domestic cable manufacturers, pry open the high-end market, continuous research and development, strengthen innovation, and build brands is the key.

At present, economic construction is shifting from traditional infrastructure such as “Tie Gongji” to “new infrastructure”, which brings new opportunities and new challenges to the wire and cable industry. The cable industry has entered a reshuffle period, and the industry concentration will further increase; “One Belt One Road” The implementation of the strategy has led to a significant increase in the role of overseas markets in the market structure; industry consensus and restrictions on safety, environmental protection, and energy conservation force cable companies to accelerate their entry into the high-end specialOverhead Cable market.

During the “14th Five-Year Plan”, China’s wire and cable industry will usher in new developments, and the market for high-performance special cables will exceed 100,000 kilometers. Wire and cable companies must firmly seize major development strategic opportunities such as power investment, rail transit construction, high-voltage and ultra-high-voltage transmission and distribution network construction, aerospace industry, and deep-sea mining, relying on technological innovation and focusing on digital and intelligent manufacturing. , Focusing on the fields of ultra-high voltage and ultra-high voltage power cables, high-performance fireproof cables, high-temperature superconducting cables, aerospace cables, special cables for urban rail, special cables for nuclear power, etc., strengthen the research and development of key materials and equipment, and strengthen process research , Accelerate the research and development of various new products, strive to make new breakthroughs in basic technologies and common technologies, strengthen the foundation of industrial technology upgrading, seize the commanding heights of international industrial competition, and seek the initiative for future development to promote the optimization and upgrading of the entire industrial chain of the industry, and accelerate Build an industrial basic capability system for the cable industry in the new era, create a modern industrial chain with stronger innovation, higher added value, safer and more reliable, and better support the construction of a modern industrial system.

Recommendations for BTLY cable cross-section selection

1. Select the cross section according to the temperature rise of the core
When the load current is passed, the core temperature does not exceed the long-term working temperature allowed by the cable insulation. That is to say, select according to the allowable current-carrying capacity.
Suggestion: The cable passes through different heat dissipation conditions. The corresponding core operating temperature will be different, and the section should be selected according to the area with severe heat dissipation conditions (usually no more than 1 meter).

2. Select the cross section according to the allowable range of voltage loss
When the terminal voltage of the electrical equipment actually deviates from the rated value, its performance will be affected, and the extent of the impact will be determined by the magnitude and duration of the voltage deviation.
Suggestion: The voltage loss increases due to the sharp rise of the core temperature during fire. The voltage loss should be calculated according to the fire conditions to ensure the continuous operation of important equipment. Due to the excellent heat insulation and heat dissipation characteristics of BTLY products, it is only necessary to enlarge the cable selected according to the normal situation by one to two. Usually, it can meet the condition that the voltage deviation under fire conditions is not more than -10%.
Three, select the cross section according to the economic current
The total cost during the economic life is small. That is, the initial investment and the cost of line loss during the economic life are small.
The so-called economic current is the working cable (range) corresponding to the applicable cross-section (range) during the life of the cable, the sum of investment and conductor loss costs. For details, please refer to “Low Voltage Cable Economic Current Density Range Table”.

Suggestion: BTLY products should have good heat dissipation characteristics. If the cross section is selected according to the temperature rise of the core, the selection can be reduced by one level. But taking into account the economic current factor. Therefore, it is not recommended. If selected in accordance with the routine, the line loss will be reduced by 4-7%, which is of great economic significance.
Fourth, the selection of the cross section of the neutral power cable and the ground wire
(1) In a single-phase two-wire circuit, regardless of the size of the phase wire cross section, the neutral wire and ground wire should be the same cross section as the phase wire.
(2) In the three-phase five-wire power distribution system, the allowable current carrying capacity of the neutral wire and ground wire should not be less than the sum of the large unbalanced load current and harmonic current in the line. When the phase wire core is not larger than 16mm2, the neutral wire and ground wire should have the same cross-section as the phase wire. When the phase wire core is larger than 16mm2, if the neutral wire current is small, the cross section of the phase wire can be selected, but it should not be less than 50% of the phase wire cross section and not less than 16mm2.
Suggestion: Use the aluminum metal sheath in the BTLY cable as the grounding core. The aluminum pipe grounding wire is connected by a dedicated connector, and the connection is firm and reliable. The equivalent resistance of the aluminum tube section of the BTLY cable meets the grounding needs of the corresponding copper core

The basic structure of the wire

1. Single round wire The main varieties are copper single wire, aluminum single wire and copper-aluminum alloy wire. The diameter of the wire is used as the structural parameter, ranging from 0.01mm to 3.00mm. Except for some of the round single wires used directly as products, most of them are semi-finished products used by twisting single wires into multiple twisted wires.
In addition to the round single wire of a single material, there are also compound round single wires. Commonly used are bimetal round single wires, such as aluminum clad steel wire (high conductivity of aluminum, strong tensile strength of steel wire), copper clad aluminum wire (high conductivity of copper, light aluminum) and coated single wire, such as tinned copper wire, Nickel-plated copper wire.
2. The round stranded wire and cable are products of large length, which have to withstand many times of winding and unwinding during production, installation and use. If the wires with larger cross-sections are not used to twist small-diameter single wires into a certain cross-section Twisted wire, the product cannot be manufactured and used. Different use conditions and conditions require wires and cables to have different flexibility-that is, bendable or twistable. Therefore, the stranded wires used in various products have different requirements in terms of flexibility, etc. Therefore, 7 kinds of wire structures are specified in the wire standard. Table 1 is the wire structure specified by the standard.

Wires with the same material and the same cross-section can be composed of several structures, that is, the number and diameter of single wires are different. The more single wires in the same cross-section (the thinner the single wire diameter), the higher the flexibility of the wire.
The structural parameters of  round stranded wire are the cross-sectional area of ​​the wire (in mm2), the number of single wires and the diameter (mm), the stranded pitch diameter ratio, etc.
3. Derivative structure of round stranded wire
(1) Compact round stranded wire In the wire stranding process, the stranded wire is pressed tightly by means of a pressing wheel, etc., so that the conductor occupancy rate in the cross-section reaches about 90%. One is to flatten the protruding shape of the wire surface, which is beneficial to squeeze the thin (0.5-1mm), inner semiconductor layer (for uniform electric field) of the medium and high voltage XLPE cable, which is not easy to puncture. The second is to reduce the gap between the single lines.

(2) The diameter of the inner groove of the round stranded wire with inner hollow groove is generally 14-18mm. There are two kinds of product requirements, namely, oil-filled cables are used as oil grooves for oil flow, and high-current cables are used as channels for internal cooling through gas or liquid. (Can increase the energizing capacity). The conductor of the oil-filled cable is generally formed by twisting a Z-line or arc-shaped single wire to form a ring-shaped cross-section, and it can also be formed by twisting a round single wire into a spiral tube. As the internal cooling type forced cooling, the internal hole groove adopts a sealed metal tube.
(3) The sector conductor is the conductor structure used in the medium and low voltage 3-4 core oil-paper insulated power cable (1-10kv). It is used to make the insulated cores of the paper wrap insulation into three 120 shapes, which are twisted into a circle when the cable is formed. Shape (four-core cable is three 100, and the neutral wire 60 is sector-shaped), in order to save a lot of outer material. The line is rarely used.

The Advantages of Copper Cable and Aluminum Cable

We all know that copper and aluminum are the main materials of wire and cable, so who knows what advantages copper cable and aluminum cable have?

1.Low resistivity: the resistivity of copper-core cable is 1.68 times lower than that of aluminum-core cable, with less energy consumption.

2.Good ductility: the extension rate of copper for electrical use is more than 30%, while that of aluminum alloy is only 18%.

3.High Strength: The promising strength of copper is much higher than that of aluminum.At room temperature, the promising force of copper is 7~28% higher than that of aluminum.And the stress at high temperature, the difference between the two is greater.

4.Fatigue resistance: copper repeated bending is not easy to break, aluminum repeated bending is easy to break.In terms of elasticity index, copper is also about 1.7~1.8 times higher than aluminum.

5.Good stability, corrosion resistance: aluminum core is easy to oxidize and be corroded, copper core is relatively stable, strong oxidation resistance.

6.Large carrying capacity: copper core resistivity is low, so the copper core cable can pass the maximum current carrying capacity is 30% higher than the aluminum core.

7.Low heating temperature: under the same current, the calorific value of the copper core cable with the same cross section is much smaller than that of the aluminum core cable, making the operation safer.

8.Low power consumption: Due to the low resistivity of copper, it is obvious that the copper cable has a lower power loss than the aluminum cable.This is conducive to improving the efficiency of power generation and protecting the environment.

9.Oxidation resistance, corrosion resistance: copper core cable connector performance is stable, no accident due to oxidation.The unstable joint of aluminum core cable often causes accidents due to the increase of contact resistance and heating caused by oxidation.As a result, the accident rate is much greater than the copper core cable.

10.Convenient construction: the copper core is flexible and the allowable bending radius is small, so it is convenient to turn and easy to pipe;Copper core fatigue resistance, repeated bending is not easy to break, so convenient wiring;The copper core has high mechanical strength and can bear large mechanical tension, which brings great convenience to the construction laying and also creates conditions for mechanized construction.

The discrimination of flame-retardant cables

Nowadays, electricity is used more and more frequently, and life is inseparable from electricity. Today, the editor brings you a mine-used flame-retardant cable worthy of trust in mines.
Advantages and disadvantages of mine flame retardant cables
The characteristic of flame-retardant cable is to delay the spread of flame along the cable so that the fire will not expand. Because of its low cost, it is a large number of cable varieties used in fire-resistant cables. Regardless of whether it is a single cable or a bundle laying, the cable knows that the flame spread can be controlled within a certain range when burning, so it can avoid major disasters caused by fire and prolonged combustion, thereby improving the fire protection level of the cable line.
The difference between mine flame-retardant cable and fire-resistant cable

1 The difference in principle
The principle of fire-resistant cables is different from that of flame-retardant cables. The flame-retardant principle of halogen-containing cables is based on the flame-retardant effect of halogen, and the flame-retardant principle of halogen-free cables is to extinguish the fire by reducing the temperature of the precipitated water. Fire-resistant cables rely on the fire-resistant and heat-resistant characteristics of the mica material in the refractory layer to ensure the cable It also works fine during a fire.
2 The difference between structure and material

The structure and materials of fire-resistant cables are different from those of flame-retardant cables.

Carbon fiber composite coreconductor

Carbon fiber composite wire is a high-strength carbon fiber composite power transmission wire. It has a core and a ring-shaped conductive layer wrapped around the core. The core is a conductive core composed of carbon fiber, and there is a composite conductive core composed of carbon fiber. It is composed of carbon fiber and aluminum or copper wire twisted.
This kind of carbon fiber composite core wire has many advantages and is the strength of contemporary scientific and technological development. It uses the high strength and corrosion resistance of carbon fiber to produce a new type of wire. Compared with the conventional steel core aluminum stranded wire, the carbon fiber The fiber composite core conductor has obvious advantages. It has many characteristics such as light weight, high tensile strength, high temperature resistance, radiation resistance, and large current carrying capacity. It can be said that all aspects of performance are upgraded.

The carbon fiber composite core wire has a very strong transmission capacity. It can effectively reduce power loss during the process of transporting electrical energy. It has high heat resistance and can continue to work under a high temperature environment of 160 degrees, even in a peak environment. Can fully meet the demand.

The tensile strength of general steel wire is 1240MPa, while the strength of carbon fiber composite core can reach more than 2400MPa, and the strength safety factor of carbon fiber composite core wire is increased by nearly 2 times. Not only the strength is enhanced, the expansion coefficient of the carbon fiber composite core wire is also very small, which avoids the thermal expansion sag of the traditional steel core cable. The height of the poles and towers can be reduced, and the distance between the poles can be increased, thereby reducing the transmission line corridors and saving land resources. This makes it not only have a strong comprehensive benefit advantage in the transformation of the old line; even in the construction of the new line, it also has a competitive advantage.

Classification of home improvement wires

BV wire, full name copper core PVC insulated wire, referred to as plastic copper wire. That is, a general-purpose single-core hard conductor non-sheathed cable with a diameter of 1mm or more.
It is suitable for wires used in power installations, household appliances, meters and telecommunication equipment with AC voltage of 450/750 and below. It has the characteristics of acid and alkali resistance, oil resistance, moisture resistance, mildew resistance, and long service life. Because it has a certain degree of hardness, it is more convenient in straightening and folding corners.

BVR wire is generally a wire twisted together by 19 copper wires with a diameter of less than 1mm. It is a copper core PVC insulated flexible wire.
The letter B stands for wiring (for example: make an indoor power line and tack it on the wall);
The letter V-polyvinyl chloride plastic sheath (a V stands for one layer of insulation and two V stands for double insulation), which is a plastic insulation layer.

L stands for aluminum wire, without L stands for copper wire.
The letter R stands for soft wire. To be soft, it means to increase the number of conductors and reduce the diameter of each wire.
It is suitable for the occasions where flexibility is required for wiring and the rated voltage is lower than 450/750 with slight movement. When multiple pipes are pierced at the same time, due to the low hardness, it is easy to turn and convenient for construction. Compared with the hard wire, the production is more complicated, and the high-frequency circuit has a larger carrying capacity than the hard wire.
Classification of common specifications and models of wires
Common specifications of wires are 1.5 square, 2.5 square, 4 square, 6 square, and 10 square. The square of the wire is square millimeters, which is the size of the cross-sectional area of ​​the wire.

Points to note for cable operation and maintenance

The operation of power cable lines is extremely important in the entire power production process. Because the safety of cable lines is directly related to the production safety of enterprises and the safety of people’s lives and properties, it is extremely important to understand the operation and maintenance of power cables and lines. Things.

In the power industry, the so-called cable line actually refers to the line for the transmission of electric energy by the cable. Generally, it is composed of cables, cable intermediate joints, and electrical line ends. It also includes laying related projects, such as cable trenches, pipes, and shafts. , Tunnels, etc., according to the different construction requirements of different geographical environments, the cable lines will be adjusted according to local conditions.

Compared with overhead  conductor lines, cable lines have many advantages. One is that they are not affected by natural disasters, such as heavy rain and snow. Cable lines can better isolate these factors. The second is to make the city look neater, and the construction of cable lines will not be disturbed by the trees along the city, beautify the city, and avoid the risk of electric shock for urban people.

Sino-European submarine cable put into use this year

Submarine cables are cables wrapped with insulating materials and laid on the seabed for telecommunications transmission. Submarine cables are divided into submarine communication cables and submarine power cables. Modern submarine cables use optical fibers as materials to transmit telephone and Internet signals. In 1850, people laid the world’s first submarine cable between Calais (France) and Dover (UK). In August 1858, a British private company founded by Sellers Westfield was established in Ireland. (Europe) and Newfoundland (North America) completed the laying of the first intercontinental submarine communication cable. China’s first submarine cable was completed in 1888.

In ancient times, the rulers of the land of China were eager to get in touch with the countries of the Western Regions, so in the period of Emperor Wu of the Han Dynasty, Zhang Qian was sent to the Western Regions to make the Western Regions understand that there was a powerful Han Dynasty on the eastern continent.

Today is the era of the information Internet. The connection of cables can enable the exchange of information between various regions. According to relevant descriptions, this cable will connect China and Pakistan on land, and after that, it will pass through the seabed to the Horn of Africa. , And the focus of its final connection is Marseille in France.

Factors restricting the development of the cable industry

The cable industry has developed to now, and the overall size is very large, with a large number of companies. China has surpassed the United States to become the world’s largest cable manufacturer. However, in this rapid development process, many problems have gradually been exposed.
The first problem is that there are few large domestic cable companies, and they lack competitiveness with foreign cable companies in high-end products. Even in 2018 or so, the annual output value of the top ten companies in  ACSR cable production scale is not as good as the total output value of the industry. 20% of the total, which is in sharp contrast with developed countries. However, it is roughly the same as my country’s current economic structure, and it is basically the same as that of other industries.

The second problem is that the homogeneity of products is serious and the market competition is fierce. There are a large number of cable companies in China, most of which are small and medium-sized enterprises. The operation mode, management and technical level of these companies present serious homogeneity problems. The problem of homogenization has aggravated overcapacity. In a homogeneous product market, users are mainly concerned with price, and competition is almost entirely concentrated on price. The greater the surplus of homogenized production capacity, the fiercer the price competition, the thinner the profit, and the more difficult it is for a company to survive.

The third problem is that the pressure of funds is huge. The xlpe cable industry is a typical heavy-material and light-industry industry and a capital-intensive industry. Therefore, the cable industry is always facing the pressure of the capital chain. The most significant phenomenon is the application of many companies. The total amount of money collected accounts for a high percentage of annual revenue, many of which are 30%. This also leads to financial difficulties for companies, and China’s cable industry is mostly small and medium-sized enterprises, so these companies are generally facing financial pressures. The problems of difficult financing, expensive financing, and high financing costs have sharply increased the risks in the capital chain of enterprises. In the past two years, due to the tightening of the entire financial system, many companies have found it difficult to cope and shut down and revert.