Wuhan Air-insulated Busway

What are the differences between air-type bus ducts and密集型 (closed) bus ducts in Wuhan? To explain this issue in detail, we have compared the two from the inside out for better understanding.

1. Different insulation medium: There is a certain gap between the copper bars of the air bus duct, meaning the insulation between the copper bars mainly relies on air. In contrast, the insulation medium between the copper bars of the密集型 bus duct (also known as closed bus duct in many regions) is organic insulating material.

2. Different arrangement of copper bars: The copper bars of the air-type bus duct are separated, while those of the密集型 bus duct are closely packed together. Of course, short circuits do not occur because the copper bars are insulated.

Wuhan Air-Type Bus Duct 

3. Different appearance: The air bus duct has a uniform thickness from top to bottom, while the密集型 bus duct expands at the joints, giving it a somewhat bulky appearance.

4. Different applications: The air-type bus duct has better moisture resistance and is used in humid environments such as vertical shafts. The密集型 bus duct carries higher currents and is used for main lines like connecting busbars.

5. Different heat dissipation: The air-type bus duct dissipates heat mainly through convection between the air inside the duct and the external air, resulting in relatively low efficiency. In contrast, the closed bus duct has its heat sink (outer shell) directly connected to the busbar, making its heat dissipation more effective than the air-type.

6. Different prices: Due to cost factors, the密集型 bus duct is slightly more expensive.

7. Different protection levels: The closed bus duct has a higher protection level, generally reaching IP68.

8. Different installation environments: The air-type bus duct requires more installation space due to its larger overall volume. In contrast, the密集型 bus duct is much slimmer.

9. Different installation efficiency: For bus ducts of the same capacity, the closed bus duct is compact and easier to install quickly.

10. Different safety concerns: Foreign objects may accidentally fall into the air-type bus duct, affecting normal operation, while the密集型 bus duct has no such concern as it is fully enclosed.

11. Chimney effect: The air bus duct may produce a chimney effect in case of fire; the密集型 bus duct does not.

12. Lineup coefficient: The air bus duct requires consideration of the lineup coefficient during vertical or inclined installation, as incorrect positioning can affect air circulation and heat dissipation. The密集型 bus duct is not affected by this.

13. Different losses: The air bus duct experiences thermal losses due to temperature changes (higher temperature increases resistance), while the closed bus duct has lower losses due to its lower temperature.