Don’t confuse a high-voltage switchgear with a transformer.
"Box transformer" is the abbreviation of box-type substation, also known as pre-installed substation or pre-installed substation. It is a kind of high-voltage switchgear, distribution transformer and low-voltage distribution device, which are prefabricated indoor and outdoor compact distribution equipment according to a certain wiring scheme, that is, the functions of transformer step-down and low-voltage distribution are organically combined.
It is installed in a moisture-proof, rust-proof, dust-proof, rat-proof, fire-proof, anti-theft, heat insulation, fully enclosed and movable steel structure box, which is especially suitable for the construction and transformation of urban network. It is a brand-new substation that rises after the civil substation. Box substation is suitable for mines, factories, enterprises, oil and gas fields and wind power stations. It replaces the original civil power distribution room and power distribution station and becomes a new complete set of power transformation and distribution equipment.
The box transformer is a "combined" equipment including high-voltage incoming and outgoing lines, metering devices, transformers, low-voltage incoming lines and low-voltage distribution outgoing lines, which is equivalent to a complete substation. However, box-type substations are usually installed outside buildings, so there is no special requirement for the selection of transformers, and oil-immersed transformers are generally used.
So what is a transformer? Dry-type transformer: It is only a kind of transformer, because the winding heat dissipation of dry-type transformer is natural heat dissipation or forced air cooling (forced air convection by fan), and there are no flammable and explosive substances, so it is widely used in places with high requirements, such as underground rooms in buildings. In contrast, there is an oil-immersed transformer, which uses the convection of transformer oil to dissipate heat. However, in case of accident or leakage of transformer oil, it is dangerous to burn, so it cannot be directly installed in the above places.