Aluminum alloy cable safety performance

1, the history is proved

Aluminum alloy cable since 1968, the United States now, 43 years research and development, the use, the product use has been quite common, the market share of 80% in the north American countries. After 43 years of practice has proved that using aluminum alloy cable never happened any fault, to be safe.

2, testing and certification

Aluminum alloy cable through American UL, Canada CUL, Australian SAI GLOBAI international authoritative organization certification testing center and China national cable wire, its Chinese wuhan high voltage research institute, national fireproof construction material quality supervision inspection center testing authority, such as aluminum alloy conductor in accordance with CSA standard C22.2 terms about ACM alloy wires, 38 and GB12706.1-2008 and IEC60502.1 the latest version of the performance requirements, and the related standard UL to AA8000 series.

3, aluminum alloy components

Pieces of aluminum alloy conductor composition after joining the composition such as rare earth and iron, greatly improve the performance of the conductive performance and connection, especially when the conductor annealing adding iron to produce the creep resistant properties of high strength, when the current overload, iron play a role of persistent connection, make the aluminum alloy conductor creep will not occur.

If pieces creep great harm to the cable, cable creep, original pressure tight enough, the contact pressure that contact resistance increases rapidly, after electric current flows through the junction overheating, if no preventive maintenance, will appear safe hidden trouble. Solve the problem of cable creep is very important.

Creep: the metal temperature, under the action of external force and gravity, with the passage of time, will slowly can't recover permanent deformation, the phenomenon of creep.

4, flame retardant performance

Aluminum alloy cable insulation using flame retardant silane crosslinked polyethylene (described.properties), craft adopt self-locking armoured structure, the heat dissipation performance is much better than the sheath of PVC material, can quickly heat, flame disappeared after fire quickly extinguished, but not delay other materials, flame retardant performance is very excellent. Aluminum alloy cable using new materials and new technology, to ensure its use more secure.

Electric properties of aluminum alloy cable

1, cable current carrying capacity

Mixer alloy conductor cross-sectional area was 1.5 times of copper, alloy conductor and copper conductor electrical properties, implements the same traffic load, resistance, and the pressure loss.

Resistivity between aluminum and copper pieces of aluminum alloy, slightly higher than that of aluminum, and lower than copper, under the precondition of the same amount of river closure, the weight of the same length of aluminum alloy conductor is half that of copper. If calculated on the conductivity of copper is 100%, the alloy conductor of electrical conductivity is about 61.2%, the proportion of alloy is 2.7, the proportion of copper is 8.9, the (8.9/2.7) * (0.612/1) = 2, 2 unit weight of the resistance of copper and 1 unit of the resistance of the alloy in the quality of the same, therefore, when the alloy conductor cross-sectional area is 1.5 times that of copper, its electrical properties are the same, namely, achieve the same amount of river closure and copper, resistance, and voltage loss.

Many factors affect the amount of power cable closure, such as; Line characteristics (such as work, current type, frequency, load factor). The structure of wire and cable, such as the structure of the conducting wire core, some conclusions, the types of insulating materials, shielding layer and the structure of the inner and outer sheath and material, the total diameter); Laying conditions (such as laying in the air, pipeline laying, directly buried laying underground channel laying, laying in the bottom). Conducting wire core maximum allowable working temperature and ambient conditions (such as air and soil temperature, soil coefficient of thermal resistance, heat around the proximity effect), etc.

2, reduce cable cross section

In the production of aluminum alloy cable, Germany's most advanced press technology, the filling coefficient of the conductor can reach 93%. And aluminum alloy cable USES is silane crosslinked polyethylene, this only two-thirds of polyvinyl chloride (PVC) the thickness of the insulation can be far more than conventional insulation performance. And the filling coefficient of copper normally only reached 80%, the insulation of the common USES is PVC, so only on the basis of copper aluminum alloy cable diameter increased 11%, copper can have the same electrical performance. Visible, the use of aluminum alloy cable does not need to change the original pipeline design of using copper cable. (general designer of laying pipe size of copper 150%, consider capacity expansion problem recently, size increased to 200% of the copper pipe laying, so wear is not a problem.)

3, reduce the cable line loss

Non-magnetic materials, won't produce eddy current, can reduce the wastage of the line. Aluminum alloy with even armoured lock with nonmagnetic materials, even if there is unbalanced three-phase current, also won't produce eddy current, to reduce line losses.

The mechanical properties of the aluminum alloy cable

1, the extension performance of aluminum alloy cable

Elongation is an important indicator, conductor mechanical properties is an important symbol of product quality and can bear the external force size. Is also an important indicator of test cable conductor mechanical properties. After annealing treatment of aluminum alloy cable and the elongation rate can reach 30%, while copper elongation is 25%, average aluminum pole elongation of 15%, is to replace an important index of aluminium cable with copper.

2, flexible performance of aluminum alloy cable

Twist test: the main test the toughness of the metal wire, the better toughness, can withstand the larger the number of twist. Ordinary aluminum wire high brittleness is one of the most important weakness, as long as several times while installing the torsion Angle, the conductor can produce cracks, cracks will be fever, corrosion, is an important cause of a fire. Using aluminum alloy cable, because of its good toughness and doesn't produce cracks, appear in the installation of safety hidden dangers.

3, aluminum alloy cable bending performance

Bending test: the main test metal bending resistance. Uneven material or brittle materials, poor resistance to bending performance.

According to GB/T12706 on copper cable installation in the regulation of bending radius, bending radius of copper is 10-20 times the cable diameter, aluminum alloy the minimum bending radius of the cable for 7 times the cable diameter, using aluminum alloy cable can be reduced space layout, more easy to installation, reduce installation costs.

4, aluminum alloy cable rebound performance

The practice proved: at room temperature under the condition of copper and aluminum alloy cable bent 90 degrees, stress release, 60% of copper aluminum alloy cable rebound Angle. For aluminum alloy cable has no memory, so a rebound performance is better than that of copper core cable, terminal connector in the installation process is easy to compress, increase its close degree, improve the stability of the connection.

The service life of aluminum alloy cable

1 there are two main types of corrosion, the conductor parts: chemical corrosion and electrochemical corrosion;

Chemical etching: refers to the metal in the atmosphere with oxygen, chlorine, sulfur dioxide, hydrogen sulfide and other gases do happen with corrosion.

After the metal surface with oxygen, produce different metal oxide.

Aluminum oxide can form dense have a certain hardness of surface protective film.

Iron oxide structure is loose, easy to fall off, and continue to the inside metal infiltration, diffusion, and destroy the material.

Copper oxide, commonly known as green, between the above two, is a kind of toxic substances.

Electrochemical corrosion: refers to the consists of metal and medium after primary element, formed the corrosion of metal process, when connected to the metal of the two different electrode potential, and there is water or other electrolytes, creates an electric current between two metal form a galvanic cell, one of the metal in the positive potential, another is in the negative potential, in the negative potential of the metal is constantly to ion state via the electrolyte to metal accumulation in a positive potential. Making the metal loss gradually in the negative potential, form the electrochemical corrosion. The difference between the two metal electrode potential is larger, the electrochemical corrosion is strong. The higher the temperature, the corrosion of metals is also more serious.

Different metals have different electrode potential. The commonly used several kinds of metal electrode potential order; Metal Ag (silver) Cu (copper) Pb (lead), Sn (tin) Fe (iron), zinc (Zn) A1 (aluminum). Potential + 0.8 + 0.334-0.122-0.122-0.44-0.76-0.76 electrode potential, the greater the negative value of the metal into the electrolyte become ions in the stronger the trend, namely the more susceptible to corrosion. Aluminum electrode potential negative value is bigger, but because of its surface often have a layer of oxide film covering layer, can improve its corrosion resistance.

Rare earth aluminum alloy material is adding rare earth elements in aluminum, it can purify the, improve purity, fill the surface defects, refine the grain size. Reduce segregation, eliminate uneven microstructure caused by the role of local corrosion, also bring aluminum electrode potential negative move at the same time, with the sacrifice anode effect and excellent electric conductivity, thus greatly improving the corrosion resistance of aluminum. For C1 - and oil in the Marine environment, S in chemical industry environment, corrosion problems such as H2S + our fleet, this material has a unique anti-corrosion mechanism. Strong reducibility of rare earth metal can with S, H2S, C1 - strong oxidizing effective union, interaction, generate stable compounds (C1 - and rare earth alloy generating stable coordination compounds), the chemical reactions of oxidation and reduction process of organic unity, interaction, fundamentally as the S, H2S, C1 - corrosion damage caused by the corrosive medium, such as oxidation activity, thus completely solve the around the world, including the United States has a good developed countries failed to solve the problem, by the Beijing nonferrous metal research institute and the national testing department of testing and data analysis of engineering examples show that in the chloride ion, seawater and sea atmosphere, salt fog environment (dry and wet alternate), saturation HzS, sulfur and high temperature, high pressure conditions, the annual corrosion rate of rare earth alloy is zero or almost zero.

Part 2, insulation

Pieces of power cable current carrying capacity refers to the maximum allowable temperature, cable conductor allows maximum current. When designing selection of cable, cable should be the part of the heat dissipation can't more than cable allows the highest temperature, in most cases, the transmission capacity of the cable is the highest limit as determined by the temperature of the cable, the maximum allowable temperature of the cable, mainly depends on the thermal aging properties of insulating materials used, because the cable working temperature is exorbitant, insulation aging accelerates, cable life who were reduced. If the cable run over the allowed temperature, cable will be 30 years safety work.

Described.properties mixer is the abbreviation of crosslinked polyethylene (English name, polyethylene is a kind of linear molecular structure, easy to deformation at high temperature. Crosslinked polyethylene process make it into a mesh structure. This structure even at high temperature also has a strong ability to resist deformation.

Pieces of crosslinking polyethylene excellent anti-aging properties and super heat deformation determines in the normal operating temperature (90 c) short fault (130 c) and under the condition of short circuit (250 c) allow large current to pass. Because of its operating temperature is higher than PVC 20 c, excellent thermal performance, and increase the anti-aging properties of the insulation, life is greatly increased.

The economic performance of aluminum alloy cable

1, direct purchasing cost

Aluminum alloy cable compared with the price of copper core cable: aluminum alloy cable with excellent safety performance, electrical properties, mechanical properties and longer service life of the premise, the price of aluminum alloy cable is only about 75% of the copper cable.

2, installation cost reduction

Saving the cost of installation: due to the bending of aluminum alloy cable performance is good and light weight, easy to install.

Aluminum alloy cable does not need to install bridge, don't wear tube, can save a lot of installation materials and installation costs can be reduced by 20% - 50%.