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.Enclosed bus ducts are usually used for systems with high power consumption,where multiple components are included,resulting in a strong overall effect.The enclosed busbar trunking linear busbar unit is used to extend power supply and distribution lines.The enclosed busbar with tap changer is used in conjunction with the plug-in box to distribute power loads.The starting busbar unit is matched with the starting incoming box to form the connection component between the busbar and the cable.The starting busbar unit can also be connected to transformers or distribution cabinets.

　　The expansion busbar unit is used to absorb the axial variation of the busbar caused by thermal expansion.When the length of the busbar exceeds 80m,a joint expansion busbar unit should be installed.The variable diameter busbar unit is used to connect different rated current units in the same system,in order to make the power supply of the entire busbar system economical and reasonable.The smaller the rated current of the enclosed bus duct,the lower the requirement for short-circuit strength.Under the same load short-circuit condition,the short-circuit current generated by a closed bus duct with a lower rated current is also smaller.However,the main factor that depends on the magnitude of the short-circuit current is not impedance,but the distance between the short-circuit point and the power supply.

　　The situation of short circuit in the enclosed bus duct at a distance of 50m from the substation and at a distance of 10m from the substation is different.In engineering,the requirements for short circuit strength are different in different places.The required short circuit strength is higher near the power supply end,and the farther away from the power supply end,the lower the required short circuit strength.The short-circuit strength is also related to the distance between the busbars.The larger the distance between the busbars,the smaller the electric force generated during the short-circuit,and therefore the short-circuit strength is also greater.The resin casting with a fixed distance between our busbars has a higher short-circuit strength than the dense type.

　　Enclosed bus ducts are basically maintenance free lines,but if they are located in damp or corrosive gas environments,such as coastal areas,textile enterprises,etc.,they need to undergo comprehensive anti-corrosion coating and maintenance every two years.The enclosed busbar trunking is not suitable for fire and explosion prevention places,mainly because the connection method of the connection parts of this type of trunking cannot meet the explosion prevention requirements.With the development of the times,ordinary power supply equipment can no longer meet people's demand for electricity consumption,and the emergence of bus ducts can solve this problem very well.