A closed busbar duct is a busbar system composed of metal plates(steel plates or aluminum plates)as protective shells,conductive bars,insulation materials,and related accessories.It can be made into a plug-in enclosed busbar slot with plug-in junction boxes at regular intervals,or a feeding enclosed busbar without a junction box in the middle.In the power supply system of high-rise buildings,power and lighting lines are often set separately,and enclosed bus ducts are installed vertically along the wall in the electrical shaft as the main power supply line.

　　Enclosed bus ducts generally consist of high-strength enclosed bus ducts at the starting end,straight through enclosed bus ducts(with and without sockets),L-shaped vertical(horizontal)curved enclosed bus ducts,Z-shaped vertical(horizontal)offset enclosed bus ducts,T-shaped vertical(horizontal)three-way enclosed bus ducts,X-shaped vertical(horizontal)four-way enclosed bus ducts,variable capacity enclosed bus ducts,expansion enclosed bus ducts,terminal heads,terminal junction boxes,plug-in boxes,accessories and fastening devices related to enclosed bus ducts.High strength enclosed bus ducts can be divided into three types according to insulation methods:air type plug-in enclosed bus ducts,dense insulation plug-in enclosed bus ducts,and high-strength plug-in enclosed bus ducts.

　　The application limitations of substation engineering and construction are due to the fact that transformers and low-voltage distribution boxes are forced to be at different levels,and large capacity transformers and cables cannot meet the needs of low-voltage and high current transmission.Using enclosed busbars is a more reasonable choice.When designing the substation,a 3000t polyester polymerization device was used to enclose the busbar.The incoming line of the 6kV substation has a transformer capacity of 2000kva.Due to engineering and architectural limitations,the high voltage distribution room and the distribution room are located on different floors,with two transformers and low voltage distribution box air low voltage side busbar connection types.Closed bus duct pipelines are used in large-scale production and processing factories for small single loads and evenly distributed large plants,such as textile weaving workshops,knitting workshops,mechanical processing enterprises,and other small processing workshops.You can use a closed bus duct and plug combination frame.

　　In this case,the advantage of enclosed bus ducts compared to conventional power sources(cables)is that they do not require balanced distribution of power loads,making them adaptable to situations of unbalanced loads.Even if the circuit bus design is completed or installed when turned off,it can still be a simple adjustment of the load according to changes in the new program,which cannot be compared to traditional power sources(cables).In addition,cheap plug boxes have replaced expensive low-voltage distribution cabinets and power boxes,which can reduce investment.Stopping transmission operation is very simple when the power switch is close to the electrical equipment plug.