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    Home > Chemicals Industry > Chemical Technology > Watch out! When connecting aluminum alloy cables, 3 fatal safety hazards need to be noted

    Watch out! When connecting aluminum alloy cables, 3 fatal safety hazards need to be noted

    • Last Update: 2022-11-17
    • Source: Internet
    • Author: User
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    In August, the State Grid Corporation of China made an official reply to the National People's Congress meeting "Suggestions on Expanding the Application of Aluminum Alloy Cables in the Power Industry", clearly stating that wire and cable "aluminum instead of copper" has important strategic significance, in order to further promote the application of aluminum alloy cables in the power system, it has been included in the State Grid Corporation 2014 version of the new technology catalog
    .
    This means that from now on, aluminum alloy cables can get rid of those senseless disputes and enter the power system market fairly, reasonably and
    legally.

    Aluminum alloy power cable refers to power cable
    using the 8000 series aluminum alloy material in the ASTM 800-05 (R2011) standard as the conductor.
    By adding a certain proportion of trace alloying elements, it can not only maintain the excellent electrical properties of pure aluminum, but also greatly improve the mechanical properties, completely solve the problems of low elongation, compressive creep resistance, tensile strength, anti-corrosion performance, poor flexibility and other problems of pure aluminum conductors, and enhance the safety and reliability of the connection of transmission and
    distribution systems.
    It also makes it feasible
    for aluminum alloy cables to replace copper core cables in power transmission and medium and low voltage power distribution applications.
    However, when aluminum alloy cable is promoted and applied in China, due to the wrong cognition of application technology, the aluminum alloy cable has the following three main fatal and difficult to solve safety hazards in terms of connection;

    First, the connection terminals of fatal safety hazards do not match

    The most important thing in power installation and power transmission is the quality of cable products, connection terminals, and terminal connection quality
    .
    In comparison, aluminum alloy cables should pay more attention to the selection of connection terminals and the control of terminal connection quality in the installation and connection
    .

    At present, there are very few special aluminum alloy copper connection terminal products in the domestic market consistent with the performance of the connected aluminum alloy cable, and many constructions mistakenly use the copper aluminum transition terminal or even microalloy copper connection terminal originally used to connect the aluminum cable instead, which is a very unscientific solution
    。 Because the aluminum alloy cable is invented to solve the lack and defects of the physical and mechanical properties of the aluminum cable, especially the poor compressive creep performance and other defects, but when connecting, the copper aluminum transition terminal originally used for the aluminum cable, the aluminum part of the terminal also has all the defects of aluminum, the entire connection scheme because of the existence of aluminum and the so-called high conductivity or other performance microalloys that are inconsistent with the performance of the aluminum alloy cable, so that the advantages and value of the aluminum alloy cable can not be played and reflected, what is the difference between this and the direct use of aluminum cable? This connection scheme is extremely unreasonable, wrong, and has security risks
    .

    Although professional aluminum alloy cable manufacturers provide terminal crimping tools and on-site technical guidance for construction as much as possible, users are provided with 1000 thermal cycle test reports of selected copper and aluminum transition terminals and cable connections (this test is mainly for the connection test
    of the same performance material.
    Aluminum and alloyed conductor aluminum alloy have the same electrical properties, physical and mechanical properties have been completely different, are already two different materials
    .
    After all, this test is an experiment after the laboratory terminal specification crimping, and the test time is short, the test in fact can not really reflect the creep tendency of aluminum materials and other characteristics), in an attempt to prove the reliability of the connection, but after all, the facts have proved that the aluminum connection has the fatal problem
    of unreliability and insecurity.
    This copper-aluminum transition terminal connection scheme is one of
    the most fatal safety hazards in aluminum alloy cable applications.

    Second, the terminal size of fatal safety hazards is not suitable

    Connection of terminals to electrical end equipment (circuit breakers, micro-breaks, molded case switches, etc
    .
    ).
    At present, aluminum cables are basically not used as power distribution transmission in China, and copper core cables are commonly used, so the design and manufacture of power terminal equipment are adapted to the specifications and sizes of copper
    cables.
    Aluminum alloy cable replaces copper cable to increase the cross-section, specifications to achieve the same electrical performance
    as copper cable.
    When the same electrical performance, the connection size of the connection terminal of the aluminum alloy cable increases accordingly due to the increase in specifications, resulting in the connection terminal of the aluminum alloy cable basically cannot be directly matched with the electrical terminal equipment, and usually only the connection scheme
    of increasing the adapter copper plate can only be adopted.
    However, multi-channel transfer not only brings unreliable connection, but also because of the increased transfer bronze medal, who will bear the cost? It often becomes a contradiction that is difficult for cable manufacturers, distributors, constructors and owners to coordinate, and if it cannot be solved, it often occurs that the terminal contact surface is directly sharpened during construction, and the size of the terminal contact surface is reduced to adapt to the harsh situation
    of connection needs.
    Sharpening the terminal contact surface and reducing the size of the terminal contact surface will directly destroy the mechanical properties of the terminal, and cause the electrical performance and current carrying capacity of the terminal contact surface to be insufficient, overload and heat generation of the connection part, which directly causes fatal safety hazards
    .

    Third, the crimping operation of fatal safety hazards is not standardized

    Specification crimping construction
    of connection terminals.
    The copper aluminum transition terminal originally purchased in China for connecting aluminum cables is to be able to adapt to the products of most aluminum cable manufacturers, because aluminum cables can not use conductor pressing technology, so the margin between the inner diameter of the terminal and the aluminum alloy cable conductor using conductor pressing technology is too large, in order to connect reliably, professional aluminum alloy cable manufacturers or responsible dealers usually provide the construction party with copper aluminum terminal special crimping tools with greater pressure than copper cable crimping tools to solve the terminal crimping, but most non-professional aluminum alloy cable manufacturers can not do this , can not provide professional tools, allow the construction of irregular terminal crimping, resulting in cable connection quality hidden dangers
    .
    Therefore, the quality of the aluminum alloy cable and the terminal connection is very
    dangerous.
    The hidden danger of connection quality caused by the connection construction of aluminum alloy cable and terminal makes the connection scheme of aluminum alloy cable application using the copper aluminum transition terminal originally used for aluminum cable and the so-called microalloy terminal only used to improve the so-called conductivity of the terminal and other properties
    .

    We know that aluminum alloy cables reflect the advantages and value
    of aluminum alloy cables because they solve the fatal safety hazards of aluminum cables.
    However, at present, due to the above three hidden dangers of the connection scheme, the advantages and value of aluminum alloy cables are difficult to reflect
    .
    In the application of cables, the safety problem is usually mainly in the connection, and the connection terminal problem directly affects the safety and reliability of the entire power transmission, and has to be paid great attention to
    .

    In August, the State Grid Corporation of China made an official reply to the National People's Congress meeting "Suggestions on Expanding the Application of Aluminum Alloy Cables in the Power Industry", clearly stating that wire and cable "aluminum instead of copper" has important strategic significance, in order to further promote the application of aluminum alloy cables in the power system, it has been included in the State Grid Corporation 2014 version of the new technology catalog
    .
    This means that from now on, aluminum alloy cables can get rid of those senseless disputes and enter the power system market fairly, reasonably and
    legally.

    Aluminum alloy cable

    Aluminum alloy power cable refers to power cable
    using the 8000 series aluminum alloy material in the ASTM 800-05 (R2011) standard as the conductor.
    By adding a certain proportion of trace alloying elements, it can not only maintain the excellent electrical properties of pure aluminum, but also greatly improve the mechanical properties, completely solve the problems of low elongation, compressive creep resistance, tensile strength, anti-corrosion performance, poor flexibility and other problems of pure aluminum conductors, and enhance the safety and reliability of the connection of transmission and
    distribution systems.
    It also makes it feasible
    for aluminum alloy cables to replace copper core cables in power transmission and medium and low voltage power distribution applications.
    However, when aluminum alloy cable is promoted and applied in China, due to the wrong cognition of application technology, the aluminum alloy cable has the following three main fatal and difficult to solve safety hazards in terms of connection;

    First, the connection terminals of fatal safety hazards do not match

    The most important thing in power installation and power transmission is the quality of cable products, connection terminals, and terminal connection quality
    .
    In comparison, aluminum alloy cables should pay more attention to the selection of connection terminals and the control of terminal connection quality in the installation and connection
    .

    At present, there are very few special aluminum alloy copper connection terminal products in the domestic market consistent with the performance of the connected aluminum alloy cable, and many constructions mistakenly use the copper aluminum transition terminal or even microalloy copper connection terminal originally used to connect the aluminum cable instead, which is a very unscientific solution
    。 Because the aluminum alloy cable is invented to solve the lack and defects of the physical and mechanical properties of the aluminum cable, especially the poor compressive creep performance and other defects, but when connecting, the copper aluminum transition terminal originally used for the aluminum cable, the aluminum part of the terminal also has all the defects of aluminum, the entire connection scheme because of the existence of aluminum and the so-called high conductivity or other performance microalloys that are inconsistent with the performance of the aluminum alloy cable, so that the advantages and value of the aluminum alloy cable can not be played and reflected, what is the difference between this and the direct use of aluminum cable? This connection scheme is extremely unreasonable, wrong, and has security risks
    .

    Although professional aluminum alloy cable manufacturers provide terminal crimping tools and on-site technical guidance for construction as much as possible, users are provided with 1000 thermal cycle test reports of selected copper and aluminum transition terminals and cable connections (this test is mainly for the connection test
    of the same performance material.
    Aluminum and alloyed conductor aluminum alloy have the same electrical properties, physical and mechanical properties have been completely different, are already two different materials
    .
    After all, this test is an experiment after the laboratory terminal specification crimping, and the test time is short, the test in fact can not really reflect the creep tendency of aluminum materials and other characteristics), in an attempt to prove the reliability of the connection, but after all, the facts have proved that the aluminum connection has the fatal problem
    of unreliability and insecurity.
    This copper-aluminum transition terminal connection scheme is one of
    the most fatal safety hazards in aluminum alloy cable applications.

    Second, the terminal size of fatal safety hazards is not suitable

    Connection of terminals to electrical end equipment (circuit breakers, micro-breaks, molded case switches, etc
    .
    ).
    At present, aluminum cables are basically not used as power distribution transmission in China, and copper core cables are commonly used, so the design and manufacture of power terminal equipment are adapted to the specifications and sizes of copper
    cables.
    Aluminum alloy cable replaces copper cable to increase the cross-section, specifications to achieve the same electrical performance
    as copper cable.
    When the same electrical performance, the connection size of the connection terminal of the aluminum alloy cable increases accordingly due to the increase in specifications, resulting in the connection terminal of the aluminum alloy cable basically cannot be directly matched with the electrical terminal equipment, and usually only the connection scheme
    of increasing the adapter copper plate can only be adopted.
    However, multi-channel transfer not only brings unreliable connection, but also because of the increased transfer bronze medal, who will bear the cost? It often becomes a contradiction that is difficult for cable manufacturers, distributors, constructors and owners to coordinate, and if it cannot be solved, it often occurs that the terminal contact surface is directly sharpened during construction, and the size of the terminal contact surface is reduced to adapt to the harsh situation
    of connection needs.
    Sharpening the terminal contact surface and reducing the size of the terminal contact surface will directly destroy the mechanical properties of the terminal, and cause the electrical performance and current carrying capacity of the terminal contact surface to be insufficient, overload and heat generation of the connection part, which directly causes fatal safety hazards
    .

    Third, the crimping operation of fatal safety hazards is not standardized

    Specification crimping construction
    of connection terminals.
    The copper aluminum transition terminal originally purchased in China for connecting aluminum cables is to be able to adapt to the products of most aluminum cable manufacturers, because aluminum cables can not use conductor pressing technology, so the margin between the inner diameter of the terminal and the aluminum alloy cable conductor using conductor pressing technology is too large, in order to connect reliably, professional aluminum alloy cable manufacturers or responsible dealers usually provide the construction party with copper aluminum terminal special crimping tools with greater pressure than copper cable crimping tools to solve the terminal crimping, but most non-professional aluminum alloy cable manufacturers can not do this , can not provide professional tools, allow the construction of irregular terminal crimping, resulting in cable connection quality hidden dangers
    .
    Therefore, the quality of the aluminum alloy cable and the terminal connection is very
    dangerous.
    The hidden danger of connection quality caused by the connection construction of aluminum alloy cable and terminal makes the connection scheme of aluminum alloy cable application using the copper aluminum transition terminal originally used for aluminum cable and the so-called microalloy terminal only used to improve the so-called conductivity of the terminal and other properties
    .

    We know that aluminum alloy cables reflect the advantages and value
    of aluminum alloy cables because they solve the fatal safety hazards of aluminum cables.
    However, at present, due to the above three hidden dangers of the connection scheme, the advantages and value of aluminum alloy cables are difficult to reflect
    .
    In the application of cables, the safety problem is usually mainly in the connection, and the connection terminal problem directly affects the safety and reliability of the entire power transmission, and has to be paid great attention to
    .

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