The classification of commonly used power transformers can be summarized as follows:
1. According to the number of phases:
(1) Single phase power transformer: used for single-phase loads and three-phase power transformer groups.
(2) Three phase power transformer: used for raising and lowering voltage in three-phase systems.
2. Divided by cooling method:
(1) Dry type power transformer: relying on air convection for cooling, generally used for small capacity power transformers such as local lighting and electronic circuits.
(2) Oil immersed power transformer: relying on oil as the cooling medium, such as oil immersed self cooling, oil immersed air cooling, oil immersed water cooling, forced oil circulation, etc.
3. Classified by purpose:
(1) Power transformer: used for raising and lowering voltage in power transmission and distribution systems.
(2) Instrument transformers: such as voltage transformers, current transformers, used for measuring instruments and relay protection devices.
(3) Test transformer: capable of generating high voltage and conducting high voltage tests on electrical equipment.
(4) Special transformers: such as electric furnace transformers, rectifier transformers, adjustment transformers, etc.
4. Divided by winding form:
(1) Double winding transformer: used to connect two voltage levels in the power system.
(2) Three winding transformer: generally used in regional substations of power systems to connect three voltage levels.
(3) Autotransformer: used to connect power systems of different voltages. It can also be used as a regular step-up or step-down transformer.
5. Divided by iron core form:
(1) Core transformer: used for high-voltage power transformers.
(2) Amorphous alloy transformer: Amorphous alloy iron core transformer is a new type of magnetic material used, which reduces the no-load current by about 80%. It is an ideal energy-saving distribution transformer, especially suitable for low load areas such as rural power grids and developing regions.
(3) Shell type transformer: a special transformer used for high currents, such as electric furnace transformers and welding transformers; Or used as power transformers for electronic instruments, televisions, radios, etc.