From the widely used cable trays at the beginning to the steel shell bus ducts today,some shortcomings have been exposed in practical applications.The combination aluminum alloy enclosed bus duct has only entered the domestic market in recent years and has attracted great attention from the industry due to its excellent performance.In the power system of the construction base production complex building project,a combination of aluminum alloy enclosed bus ducts has been adopted successively.Through several construction projects and repeated exploration and testing,various technical difficulties encountered in the actual construction and installation of aluminum alloy enclosed bus ducts have been solved,and a relatively mature construction method has been summarized.

　　The composite aluminum alloy enclosed bus duct has corrosion resistance,good heat dissipation,and can be used as a 100%grounding wire.It has the advantages of large conveying capacity,strong overload capacity,flexible line expansion,beautiful appearance,compact structure,and easy installation and maintenance.This structure can effectively balance the impedance of each phase,thereby greatly reducing the voltage loss of the bus duct system and enabling the bus to have a higher effective current carrying capacity.Quick connector can ensure fast installation of busbars;The unique high-strength shear bolts reduce users'requirements for specialized joint assembly;The connector housing is equipped with prominent warning signs and temperature rise warning signs to ensure user safety during use.

　　Enclosed busbars can be divided into air busbars,high-strength busbars,high-strength dense busbars,and fire-resistant combination enclosed busbars.They are mainly used for power transmission and distribution,suitable for three-phase four wire or three-phase five wire power supply and distribution lines with rated working voltage of 660V,rated working current of 250-2500A,and frequency of 50HZ.They have a series of characteristics such as compact structure,high insulation strength,large transmission current,good interchangeability,stable electrical performance,easy installation and maintenance,and long service life.Widely used in power supply and distribution systems in industrial and mining enterprises,high-rise buildings,and public facilities.The application of enclosed busbar trunking is in low-voltage,high current power supply and distribution systems,usually installed in electrical shafts,using a single central busbar system to supply and distribute power to each floor.

　　The modular aluminum alloy enclosed busbar trunking system consists of an aluminum alloy shell and multiple busbar units;The aluminum alloy shell of the composite aluminum alloy enclosed bus duct compensates for the shortcomings of ordinary steel shell bus ducts in terms of corrosion resistance and heat dissipation to a large extent.The larger the cross-section of the enclosed busbar conductive copper bar,the smaller the energy loss,but the investment,maintenance and management of the line,as well as the consumption of non-ferrous metals,will correspondingly increase.Therefore,when designing and selecting enclosed busbars,we should start from an economic perspective and choose enclosed busbars of reasonable specifications,which not only ensure low power loss of the line,but also do not increase line investment,maintenance management,and consumption of non-ferrous metals.