Performance comparison of bus duct

Posted by bruce zhu on October 15th, 2022

Performance comparison of bus duct

The bus duct has good heat dissipation performance The insulation materials of cables (core wire insulation and sheath insulation) are both insulation materials and thermal insulation materials. Therefore, when laying power cables in the bridge, busbar bending machine it is allowed to lay up to two layers, because heat dissipation is considered. The bus duct uses air conduction to dissipate heat, and emits heat through the closely contacted steel shell. Therefore, compared with the cable, its heat dissipation performance is obvious.

The bus duct hardly needs maintenance. The routine maintenance is usually to measure the temperature rise of the shell and core bolts, the temperature rise of the joints of the incoming box, etc. If the core bolts are 4.8, they need to be fastened regularly. If the high-strength bolts of 8.8 are used, they need not be fixed regularly. However, busbar bender due to the limitation of such factors as easy wear, aging and short service life, cables need to be inspected, maintained and even replaced regularly

Current carrying range At present, the cable can only achieve a maximum sectional area of 1000mm and rated current of 1600A. However, this kind of large size cable is rarely used in practical projects due to its large volume and weight In the project, 400 mm and below cables are generally used for power distribution, which requires many cables to supply power at the same time. The maximum rated current of the busbar machine can reach 6300A, and its strong current carrying capacity is incomparable to cables

The bus duct has strong overload capacity Depending on the high working temperature of the insulation materials used, the insulation materials used for bus duct are made of materials with working temperature of 105 ℃. Radiation cross-linked flame retardant winding tape (PER) and radiation cross-linked polyolefin heat shrinkable pipe with working temperature of more than 140 ℃ have been developed. However, the insulation materials used for cables usually work at 95 ℃ and 105 ℃, so the overload capacity of bus duct is far greater than that of cables.

The bus duct is easy to tap The so-called plug-in bus duct is that it uses the plug-in method to connect the power supply of the trunk line to the branch line, and there is a plug-in box opening every few meters, so the tapping is very convenient. However, the cables need to be tapped on site, which is of poor reliability. Even prefabricated branch cables also have a particularly obvious disadvantage, mainly because they need to be customized to the factory. The branch connection mode uses an open "C" type hoop. Can the hoop force be guaranteed after a long time? In addition, the price of each branch head is expensive, so prefabricated branch cables are still not widely used. If any floor needs to cut off the power supply, the bus duct does not need to be cut off, as long as the plug box of the bus duct is removed under no-load condition. However, it is very dangerous to cut off the branch power supply of the prefabricated branch cable when it is live

Bus duct can prevent overload and fire On August 27, 2000, the Ostankino TV Tower in Moscow, the second tallest building in the world and the first tallest building in Europe, was set ablaze in Russia. The reason is caused by cable overload; The shutdown of three converters at Baosteel was also caused by cable fire. The insulating layer and sheath of ordinary cables will burn, and flame retardant cables will also burn under the flame. They will not burn until the flame leaves. Fire resistant cables will not burn, but they are expensive. Fire resistant cables are only used for power supplies that are not allowed to cut off power, such as fire protection. The bus duct shell is metal and will not burn. Even if the insulating material of the copper bar burns, the flame will not escape to the outside of the bus duct