With the development of the power industry,people have been using enclosed bus ducts for a long time,playing an important role in power transmission.The general shell is made of aluminum alloy or steel,and the main function of the shell is to protect the busbar inside the shell.The shell undergoes various processes such as acid washing,phosphating,drying,dust removal,and solidification.The shell is sprayed with polyester epoxy powder.Surface adhesion can be maintained for a long time,playing an insulating role.A closed bus duct is a busbar system composed of metal plates or steel plates and aluminum plates to protect the conductive insulation of the enclosure and related accessories.

　　The shell of the busbar is made of aluminum alloy sheet with a thickness of not less than 4 millimeters,and the shell must have sufficient strength to prevent changes in stress caused by installation errors.The top of the shell should not be waterless,and the metal parts and supporting structures of the shell must be reliably grounded.At least a reliable grounding point should be installed on the outer shell of each section of the enclosed busbar,and the outer shells between the busbar sections should be connected by wires.The grounding terminal of the shell should have a grounding terminal that is easy to connect,and the grounding wire and grounding terminal of the enclosed busbar should have sufficient cross-section and the ability to pass short-circuit current.When the busbar passes through a short-circuit current,the induced voltage of the shell should not exceed 24V.

　　The welding between the conductor and the shell should use inert gas shielded arc argon arc welding,and the weld section should not be less than 1.25 times the welding section.The width of the weld seam is 2 millimeters larger than the width of the groove,with a depth not exceeding 5%of the thickness of the metal to be welded,and the length of incomplete penetration shall not exceed 10%of the length.weld line.The weld seam shall not rupture,burn,weld,weld.Tumors and other welds should be inspected by X-ray or ultrasonic testing.The length of the conductor and expansion joint shall not be less than 25%of the weld length,and the shell shall not be less than 10%of the weld length.The fasteners connected to the busbar conductor are made of non-magnetic materials,and the current carrying capacity of all flexible connections should not be less than that of the connecting busbar.

　　The connection end between the busbar and the equipment cabinet should use sealed insulation sleeves or bowl insulators to prevent faults from spreading to the busbar insulators inside the cabinet.In horizontal and vertical bending sections,the distance between insulators should be adjusted according to the electromotive force.Effective measures should be taken to ensure the distance between insulators in horizontal and vertical curved sections.Relatively speaking,the error between the conductor of a regular box type busbar and the outer shell should not exceed 2 millimeters.As a new type of distribution cable,enclosed bus duct and plug-in bus duct have become a new type of cable.Compared with traditional cables,they have the advantage of high current transmission.