Bus is a professional term in the transmission and transformation network or distribution network. It refers to the special conductor used for the connection of transmission lines and transformation equipment in power plants, substations or switchyards, and distribution rooms at a certain voltage level. It is not the trunk line or power line of the transmission line.

       For example, there are four circuits and two transformers in the 110KV part of a substation. How do these transmission lines and transformers connect in the substation? The bus is installed in the station, and all transmission lines and substation equipment are connected to the bus. The bus is called the 110KV bus of the station.

       The main connection form of a certain voltage level in the substation refers to the connection form of the bus of that voltage level. At present, the main connection forms are: single bus, single bus section, double bus, double bus section (all the above connection forms can have side bus), 3/2 connection.

       According to the use of bus material, there are flexible bus (using ordinary steel core aluminum stranded wire as bus), tube bus, bus bridge (using copper bar or aluminum bar to erect bus, mostly used in distribution stations), and enclosed bus in GIS.

       Of course, there are also the concepts of DC small bus, voltage small bus, closing bus and control bus in the secondary circuit of the substation or power plant. But when it comes to bus, it is generally used for the purpose of confluence or aggregation. Bus is an important node in the system (whether primary or secondary system).