Before the maintenance of the bus duct,it is necessary to conduct a power outage inspection of the bus duct system,completely cut off all power sources of the bus duct,and use a multimeter to measure whether there is voltage in the conductive body.Only after confirming that the bus duct system is not energized can routine maintenance be carried out.Prevent serious accidents caused by high voltage that may cause physical injury or even death to operators.During long-term operation of the bus duct,the temperature rise of the joints should be regularly checked once a year.The temperature rise of the joints should not exceed 70K according to the standard to be qualified.Check whether there is any looseness in the connecting bolts and contact parts of the conductors of all bus duct joints.

　　We need to prevent the joint from heating up due to increased resistance caused by looseness,check whether the insulation material has aged,and whether the conductive part of the continuous mixer has melted and deformed.If there is a phenomenon of phase to phase grounding or insulation breakdown,it should be dismantled in sections and checked in sections with a voltage tester to identify the fault,or the bus duct should be replaced or insulated again.Check if the plug box pins of the bus duct system are in good contact with the busbar.During the operation of the bus duct,it is necessary to continuously check whether there are leaks,water sprays,potential sources of moisture around the entire system,and whether there are any organisms that pose a threat to the system.

　　The heat source affected by the temperature rise of the bus duct system is the cone screw strip mixer.The cone screw strip mixer is checked for foreign objects entering the interior of the bus duct,and the components of the bus duct system are checked for defects,rust,and whether the bracket springs have appropriate elasticity.If any problems are found,they should be replaced immediately.Bus duct is divided into main unit,feeding unit,tap unit,variable diameter unit,expansion unit,various bending units,etc.The mainline unit is divided into mainline units without tapping devices and mainline units with tapping devices.Two types of mainline units with the same current level have the same basic structure and external dimensions,making it very convenient to connect and install them together.The feeding unit includes incoming units,incoming boxes,intermediate incoming boxes,and other units.

　　The incoming unit is matched with the incoming box to form the connection component between the bus duct and the cable.The incoming unit can be directly connected to the distribution cabinet or transformer as the power input or output terminal of the bus duct.The tapping unit adopts a plug-in junction box,which leads out the power branch from the main line.The tapping current of the junction box is determined by the circuit breaker.The variable diameter unit is used to connect the transition section of two different rated current busbar main units,and the standard length of the variable diameter unit is 1 meter.It can change from any current level between 60~5000A to another current level.There are four types of bending units:L-shaped,T-shaped,Z-shaped,and cross shaped,which are used for connecting horizontal and vertical distribution bus ducts and changing the direction of the bus.