Types and characteristics of commonly used transformers

The classification of commonly used transformers can be summarized as follows:

1. According to the number of phases:

(1) Single-phase transformer: used for single-phase load and three-phase transformer group.

(2) Three-phase transformer: used for raising and lowering voltage of three-phase system.

Second, according to the cooling method:

(1) Dry-type transformers: rely on air convection for cooling, generally used for small-capacity transformers such as local lighting and electronic circuits.

(2) Oil-immersed transformer: rely on oil as cooling medium, such as oil-immersed self-cooling, oil-immersed air cooling, oil-immersed water cooling, forced oil circulation, etc.

3. According to usage:

(1) Power transformer: used to raise and lower the voltage of the transmission and distribution system.

(2) Instrument transformers: such as voltage transformers, current transformers, measuring instruments and relay protection devices.

(3) Test transformer: It can generate high voltage and conduct high voltage test on electrical equipment.

(4) Special transformers: such as electric furnace transformers, rectifier transformers, regulating transformers, etc.

4. According to the winding form:

(1) Double winding transformer: used to connect two voltage levels in the power system.

(2) Three-winding transformer: generally used in power system area substations, connecting three voltage levels.

(3) Autotransformer: used to connect power systems with different voltages. It can also be used as an ordinary step-up or step-down transformer.

5. According to the form of iron core:

(1) Core transformer: used for high-voltage power transformers.

(2) Shell transformers: special transformers for large currents, such as electric furnace transformers, welding transformers; or power transformers for electronic instruments, televisions, radios, etc.