An electric bus bar is defined as a conductor or group of conductors used to pick up electrical power from the incoming feeders and distributes them to the outgoing feeders. In other words, it is a type of electrical connection in which all incoming and outgoing electric current is gathered. Therefore, the electric bus bar collects the electrical energy in one place. When failure occurs in any section of the bus bar, all circuit equipment connected to that section must be fired to provide complete isolation in the shortest possible time.
The rods used in electrical substations usually have rectangular cross-section bars, but they may also be in another form, such as round tubes, solid round bars or shape tubes. The bus bar is usually made up of aluminum. Aluminum has several advantages over copper, such as higher conductivity, lower cost, excellent resistance to corrosion, etc.
The most common bus bars are 40 × 4 mm ; 40 x 5 mm ; 50 x 6 mm ; 60 x 8 mm ; 80 × 8 and 100 × 10 mm .
There are several types of bus bar arrangements, and the choice of a particular arrangement depends on different factors such as system voltage, the position of a substation in the system, reliability of supply, flexibility and cost. The following are the electrical considerations governing the selection of any particular arrangement.
The arrangement of the busbar is simple and easy in maintenance.
Must have the provision of extension with the growth of the load.
The installation should be as economical as possible, taking into account the needs and continuity of supply.
Alternative arrangements are available in case of interruption of any of the devices.
In a small and medium size station, where shutdown can sometimes be allowed, individual busbars can be used. However, in an important plant, an elaborate busbar arrangement is essential so that the duplicate supply is always available in case of failure, which could lead to interruption of supply to a large area.