The bus duct should be metal enclosed and comply with IEC62271-200 standard. The metal casing of the bus duct, like the metal casing of the switchgear, has multiple functions. The following cable tray manufacturer will analyze for you:
It protects personnel from the danger of contact with live conductors.
It provides mechanical support for conductors and their insulation systems.
It protects conductors from mechanical damage and environmental damage.
When discussing metal shells, the first material we think of is steel - ordinary daily cold-rolled carbon steel. However, steel as a shell material has some drawbacks. Importantly, it is magnetic, and the magnetic field around the conductor induces a circulating current in the casing. These currents have several adverse effects. When they flow through the resistance of steel, they represent energy loss. Conversely, this will increase the temperature of the casing, reduce the efficiency of dissipating heat generated in the busbar, and make the entire busbar duct run hotter.
This effectively reduces the continuous current rating of the bus duct, as the continuous current rating is determined by the temperature rise of the conductor and enclosure.
A common method to reduce these magnetic effects is to make at least one side of the busbar duct casing using non-magnetic materials (usually aluminum). The usual practice is to make an aluminum busbar duct cover with a rated current exceeding 1200A. At certain very high ratings, the entire bus duct casing may be made of aluminum.
Another disadvantage of steel is that even if good paint is applied to galvanized steel, it may not be able to withstand certain harsh environments. Galvanized steel is often used for all outdoor bus duct enclosures. To a lesser extent, aluminum may also have environmental issues. If steel is not suitable and aluminum is suitable, then refer to the full aluminum bus duct casing.
However, if both galvanized carbon steel and aluminum are not suitable for this environment, the third option is to make the bus duct casing stainless steel, which can withstand harsh environments well and is also non magnetic. The disadvantage of using stainless steel is its high cost. The basic raw materials are much more expensive than carbon steel or aluminum, and manufacturing them requires greater effort. If the situation requires, stainless steel casing will be provided for the bus duct and an appropriate price will be provided. Due to price increases, stainless steel bus duct enclosures should not be specified unless materials are indeed required.
For the 4000A bus bridge, using a stainless steel shell is necessary because the non magnetic material causes too much heat and huge losses due to eddy currents in the bus, resulting in excessive temperature rise. However, using stainless steel material can reduce the temperature rise and easily pass the temperature rise test. For more related content, come to our website http://0512lc.com consulting service