,en намінальны value of the transformer is the regulation made by the transformer manufacturer for the normal use of the transformer. The operation of the transformer at the specified намінальны value can ensure the long-term reliable operation of the transformer and have good performance. Its rating includes the following aspects:

1. Rated capacity: it is the guaranteed value of the output capacity of the transformer under the rated state, expressed in volt amperes (VA), kilovolt amperes (kVA) or megavolt amperes (MVA). Because the transformer has high operating efficiency, the rated capacity design values of the primary and secondary windings are usually the same.

2. Rated voltage: refers to the guaranteed value of the terminal voltage of the transformer at no-load, expressed in volts (V) and kilovolts (kV). Unless otherwise specified, rated voltage refers to line voltage.

3. Rated current: line current calculated from rated capacity and rated voltage, expressed in amperes (A).

4. No load current: the percentage of excitation current to the rated current when the transformer operates under no load.

5. Short circuit loss: the active loss when one side of the winding is short circuited and the other side of the winding applies voltage to make both sides of the winding reach the rated current, expressed in watts (W) or kilowatts (kW).

6. No load loss: refers to the active power loss of the transformer during no-load operation, expressed in watts (W) or kilowatts (kW).

7. Short circuit voltage: also known as impedance voltage, it refers to the percentage of the voltage applied when one side of the winding is short circuited and the other side of the winding reaches the rated current and the rated voltage.

8. Connection group: it refers to the connection mode of the primary and secondary windings of the transformer and the phase difference between line voltages, expressed in clock.