The application of enclosed busbar trunking is in low-voltage,high current power supply and distribution systems,generally installed in electrical shafts,using a single central busbar system to supply and distribute power to each floor.The enclosed busbar trunking system can be composed of multiple busbar units.Linear busbar unit is used to extend power supply and distribution lines.It is a closed busbar with a tap changer and a plug-in box used 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 section of expansion busbar unit should be installed.Variable diameter busbar units are used to connect different rated current units in the same system,in order to make the power supply of the entire busbar system more economical and reasonable.There are four types of busbar bending connection units:L-shaped,T-shaped,Z-shaped,and+-shaped.They are used for connecting and changing the direction of horizontal and vertical power supply and distribution,and can flexibly connect busbar systems.The busbar terminal box is used for the termination end of enclosed busbars to ensure the power supply safety of the busbar system.The plug-in box is used to lead out power outlets on enclosed busbars.The plug-in box is equipped with an automatic air switch for cutting off and connecting power.

　　The busbars used in enclosed bus ducts are produced in complete sets by the factory,with guaranteed quality,low operation and maintenance workload,and easy construction and installation.Eliminating heat induced in steel structures through isolated phase blocking busbars using shell shielding can fundamentally solve the problem of induced heat in steel structures.Reducing the short-circuit electromotive force between phases is due to the dual shielding effect of eddy currents and circulating currents on the outer shell,which greatly reduces the short-circuit electromotive force acting on the phase conductors.Reducing grounding faults and avoiding phase to phase short circuits,the isolated phase enclosed busbar has an outer shell protection that can eliminate grounding faults caused by external moisture,dust,and foreign objects.The use of phase to phase blocking on the busbar also effectively prevents the occurrence of phase to phase short circuits.

　　In terms of operational safety and reliability,the pot type insulator is made of SMC compression,and the busbar is sealed to prevent insulator condensation.At the same time,hydrogen and temperature measuring devices can be used to display or transmit to the DCS system on-site to improve operational safety and reliability.The busbar sealing also creates a prerequisite for the use of ventilated cooling.The enclosure of the enclosed bus duct includes branch circuits within the same phase,and adopts an electrical full connection type.Multiple grounding points are used to keep the enclosure as equipotential as possible,which can effectively prevent accidents from occurring.