1. Classification and models of power transformers2. 1. Classification by use3. (1) Step-up transformer: used by the power plant to transmit electricity to the outside.4. (2) Step-down transformer: The substation of the power supply bureau is used for voltage conversion.5. (3) Distribution transformer: used to supply power to users.6. (4) Plant transformer: Provides internal electricity for the power plant.7. (5) Transformer for station: Provide internal electricity for the substation.8. (6) Converter transformer: for DC power transmission, one side is connected to AC power, and one side is connected to the converter valve.9. (7) Rectifier transformer: used in thermal power plants to supply power to electrostatic precipitators.