Analysis of connection method of aluminum core cable conductor-Henan Sanheng Cable Co.,Ltd

Analysis of connection method of aluminum core cable conductor

Jul 06,2018

Copper is the main conductor material used in wire and cable products, so the copper core code is written in T, except for bare wires and bare conductor products. Bare wire and bare conductor products, power cables, and electromagnetic wire products do not indicate large class codes. Wires and cables for electrical equipment and communication cables are not listed, but subcategories or series codes are listed.

Aluminum and copper cores are commonly used cable conductors, but they cannot be directly connected. The main reasons are:

(1) When the copper and aluminum core conductors are directly connected, the contact surface of the metal is easily formed into an electrolyte under the action of moisture, carbon dioxide and other impurities, thereby forming a primary battery using aluminum as a negative electrode and copper as a positive electrode to electrify the aluminum. Corrosion causes an increase in contact resistance at the junction of the copper and aluminum cores.

Analysis of connection method of aluminum core cable conductor

(2) Since the elastic modulus and thermal expansion coefficient of copper and aluminum differ greatly, after a plurality of thermal cycles (energization and power-off) during operation, a large gap is generated at the contact point to affect the contact. The contact resistance is also increased.

(3) The increase of contact resistance causes the operating temperature to rise, the corrosion oxidation increases at high temperature, the connection quality deteriorates after the vicious cycle, and finally the contact point temperature is too high, smoking, burning and the like.

The "Code for Construction and Acceptance of Bus Installations for Electrical Installations" clearly stipulates that copper-aluminum core conductors should be connected with copper-aluminum transition joints. If copper crimping tubes are used, the inner wall must be tinned. The industry standard stipulates that the DC resistance of the copper-aluminum transitional connection pipe should be no more than 1.2 times the DC resistance of the same length and section aluminum conductor.

Connection of conductors of different cross sections

After using aluminum core cables, the problem is that the connection of copper and aluminum core conductors with different cross sections is more complicated. For the same type of conductor in construction, the method of removing or adding the conductor monofilament can be used to solve the problem. However, firstly, the conductor monofilament is removed or added to cause a large local stress when the conductor is crimped, and the long-term operation may cause the contact resistance to become large. .

Secondly, the conductor monofilament is removed or added, usually forming sharp corners or sharp edges, which may damage the intermediate joint. At this time, the external joint is in tension operation state, thereby causing mechanical damage, and the sharp corner or sharp edge will also cause electric field distortion at the joint portion. , buried hidden dangers for the accident. For the connection of conductors with different cross-sections, only special conductors with different inner diameters can be used to complete the connection. If copper and aluminum are connected, only copper-aluminum transitional joints can be used.

Aluminum core cable conductor connection

The aluminum core cable conductor is generally crimped with an aluminum connector, but in practice it is also crimped with a tinned copper connector. Since the power system has been dominated by copper core cables for the past 20 years, the crimping tools currently installed in the cable installation department are mainly crimped copper core cables. At present, the crimping tool manufacturing enterprises do not manufacture aluminum core cables. Crimp tool.

Analysis of connection method of aluminum core cable conductor

The advantage of the pressure-pressing method of the crimped aluminum core cable is that the pressure is small, and the metal surface is infiltrated at the contact surface of the partial crimping portion, and the oxide film of the aluminum core wire and the surface of the connecting pipe is broken, but the connecting pipe is easily deformed after the crimping.

The advantage of the crimping copper core cable adopting the confining pressure method is that the surface shape of the connecting pipe after crimping is relatively straight and does not deform, and it is easy to solve the problem of electric field concentration at the connecting pipe.

GB/T14315 stipulates that the aluminum pipe is smaller than the copper pipe. The outer diameter of the pipe joint is the same as that of the copper pipe. For example, the outer diameter of the aluminum pipe of 240mm2 and the copper pipe of 300mm2 are the same. Therefore, when the copper-aluminum conductor adopts the same series of crimping tools, the die of the aluminum pipe crimped to the same section is larger than the copper pipe of the same section.

Henan Sanheng Cable Co., Ltd , founded in 2000, It is one of the top wire and cable manufacturers in China's wire and cable industry for nearly 20 years. the company has more than 5 production lines.

The production cable can be divided into more than 50 varieties and subdivided into 1000 specifications.All products have passed national certification, such as China compulsory certification, bv certification, Nigerian SONCAP certificate, China national industrial certification, etc. China national industrial production license, etc.It also has the ability to produce products that meet international standards, such as iec, ce, rohs, etc.
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