The enclosed busbar trunking has excellent short-circuit resistance performance.Due to the protection of the aluminum(or weak magnetic steel plate)shell,it can effectively reduce the structural heating caused by eddy currents or circulating currents,lower the temperature of the enclosed busbar shell,reduce electrical energy loss,increase current carrying capacity,and reduce electric power.The enclosed busbar duct structure allows for installation and maintenance holes to be freely set at the upper or lower part of the enclosed busbar.For high current indoor enclosed busbars,ventilation louvers are installed on both sides and the lower part of the housing to enhance heat dissipation and reduce temperature rise.

　　The enclosed bus duct adopts double insulation and multi-point connection grounding of the shell,which significantly reduces maintenance workload and improves safety performance.The enclosed bus duct adopts corrugated tube expansion joints,which are easy to install and can adjust two degrees of freedom in the horizontal and vertical directions.It can not only meet the expansion and contraction requirements caused by different temperature drops and thermal expansion and contraction,but also compensate for errors caused by foundation settlement,solving the disadvantages of poor protection level,inconvenient installation,and unreliable operation of traditional sliding plate expansion devices.In order to address the negative impact of vibration generated during the operation of transformers,generators,and distribution cabinets on enclosed busbars,soft connections or copper braided tapes are used outside their connection to the enclosed busbars,and rubber pads are added between the shells to reduce vibration;For the enclosed busbar trunking body,shock absorbers are installed in the system to provide elastic support for the ceramic flat and conductive bars,effectively avoiding mechanical vibrations and seismic waves caused by the shell from damaging the enclosed busbar.

　　The heat transfer of enclosed bus ducts mainly relies on thermal radiation.In order to make good use of thermal radiation,light gray paint is sprayed on the outer surface of the enclosed bus to reduce the absorption of visible light;Spray black paint on the inner surface of the enclosed busbar to enhance the radiation of internal heat to the shell and prevent corona.In order to avoid accidental condensation caused by temperature changes outdoors and indoors in winter,wall sleeves are installed at the through wall locations to completely isolate the outdoor and indoor enclosed busbars;When installed vertically,the flange is inside,and when installed horizontally,the flange is outside.In order to improve the allowable operating temperature rise of the enclosed busbar trunking,prevent electrolytic corrosion of the joints in coastal open air and severe electrochemical corrosion atmosphere,and reduce contact resistance,all joints with a current greater than or equal to 3000A of the enclosed busbar are treated with silver plating,so that the allowable temperature rise of the joints can be increased to 65K,which is much higher than the temperature rise during normal operation.

　　The natural frequency of the enclosed bus duct should avoid the frequency range where resonance occurs(for a single bus,the resonance frequency range is 35-135Hz),and reduce the electric force acting on the bus.Reasonably determine the span between insulators,and select the type,specification,and strength level of insulators.In order to monitor the temperature of detachable joints,sealed observation windows are installed at the connection outlets between transformers,generators,and distribution cabinets and enclosed busbars.Temperature is directly measured through temperature sensors or far-infrared temperature measuring devices to monitor the operation of the busbar system.Install current transformers at the generator outlet and on the primary side of the excitation transformer to facilitate user detection of current.