Basic knowledge of busbars

Busbar, as an indispensable component of the power system, its material selection is crucial. Common busbar materials include copper, aluminum, aluminum alloys, and steel. Soft busbars often use multi strand steel core aluminum stranded wires (i.e. overhead wires), while hard busbars are mainly made of aluminum and copper bars, and tubular busbars are mostly made of aluminum alloy materials. Bus duct is a high current trunk type tapping power supply system composed of a metal shell, conductive material, and insulation material, used for high current transmission in industrial plants, high-rise buildings, and other places.

Specifically, copper busbars are known for their low electrical resistivity, high mechanical strength, and strong corrosion resistance, but they are relatively expensive. It is often used in situations where the continuous working current is high, the space is small, and it is corrosive to aluminum but less corrosive to copper. Although aluminum busbar has a relatively high resistivity, about 1.7-2 times that of copper, it is lightweight and affordable, making it a widely used busbar material.

In addition, aluminum alloy busbars have also attracted much attention. It is divided into two types: aluminum manganese alloy and aluminum magnesium alloy, and mostly in the form of pipes. Aluminum manganese alloy busbar has a high current carrying capacity, but its mechanical strength is slightly inferior. After taking appropriate compensation measures, it can be widely used; Aluminum magnesium alloy busbars, on the other hand, have a relatively narrow range of applications due to their high mechanical strength, difficult welding, and low current carrying capacity.

On the other hand, steel busbars are favored for their high mechanical strength and low price. But its resistivity is high, and there are significant hysteresis and eddy current losses in AC environments, making it more suitable for small capacity circuits with operating currents greater than 300-400A.