The major difference in busbar trunking accessories refers to the differential circuit composed of all branch currents except for the bus tie switch and section switch.The small difference of a certain section of busbar refers to the differential circuit composed of all the branches connected to the busbar,including the busbar and section switches,and the current.The dense bus duct connector includes upper and lower cover plates,heat dissipation pressure plates,insulation partitions,insulation bushings,and conductor connecting copper plates.The upper and lower cover plates,heat dissipation pressure plates,insulation partitions,insulation bushings,and conductor connecting copper plates are fixed together by fasteners.The insulation bushing is fixed on top of the insulation partition,and the conductor connecting copper plate is fixed between the insulation partition and the insulation bushing.At least one pressure plate device is fixed on the lower surface of the upper cover plate and the lower cover plate respectively.This utility model transmits the fastening pressure to the heat dissipation pressure plate and the side plate through the pressure plate device,and then transmits it to the insulation partition and the connecting copper plate through the heat dissipation pressure plate and the side plate,so that the conductor connecting copper plate is uniformly stressed,preventing the conductor connecting copper plate from being damaged due to uneven stress and ensuring the electrical safety of the bus duct.

　　The large difference ratio differential of the busbar is used to distinguish between faults within and outside the busbar area,while the small difference ratio differential is used for the selection of fault busbars.Due to the convex connection between the insulation protection plates,the conductive bars between the two insulation protection plates are tightly adhered to the insulation protection plates,and the insulation protection plates are in close contact with the conductive bars on the busbar through the copper sheets on them.Effectively ensuring more reliable contact between the conductor of the bus duct and the conductor of the connector,avoiding the occurrence of short circuits.Usually used in dual mother protection,the large difference is used as the initiating component to distinguish the shortcomings within the area;As a component for selection,distinguish the shortcomings on which bus.The difference between the large and small differential actions in the differential protection of the busbar is that in the small differential action,the busbar switch will be tripped at the first limit,and then all switches connected to the same busbar as the defective equipment will be tripped.The major action is to trip all switches within the same time limit,regardless of which bus the equipment is attached to.

　　Bus duct joint heat dissipation device,including joint protective cover,fan,connection base,and control switch for controlling the fan installed on the side of the connection base;The fan is fixed in the middle of the connecting seat,and the joint protective cover is fixedly connected to the connecting seat.The fan is located inside the joint protective cover;The upper surface of the joint protective cover and the upper surface of the connecting seat are respectively provided with heat dissipation holes,which are located above and below the fan;The two ends of the connection seat are respectively provided with connection holes for connecting with the bus duct;The power cord of the fan is connected to the main busbar.The effect is that the normal temperature of the bus duct connector can be ignored,eliminating the problem of rapid heating of the connector caused by high ambient temperature and short cycle overload operation of the bus duct;The bus duct connector has been realized to connect the busbar without increasing the size of the main busbar,saving materials and improving product performance.

　　Under normal dual mother operation,the input is small and selective.During the process of reversing the busbar,the busbar difference is set to a large difference to avoid the protection misoperation caused by the circulating current during the operation of the parallel knife switch.The major difference is more of a starting component,and the key is to choose the faulty busbar based on the minor difference,and then take action.As for the protection plan,the major difference is non selective.The protection plan consists of two busbars,while the minor difference is selective,which can distinguish which busbar has a disadvantage.The protective action will trip all switches and bus tie switches on the defective busbar.