FA135482
30 September 2021
The nominal current of the transformer and generator is calculated by using the following formula:
However, for the same apparent power Sr, the nominal current of the transformer and the generator have different values as it can be seen on the copies of the screen here below:
This difference is due to the fact that the nominal current of the transformer is calculates by using the voltage at no-load and the nominal current of the generator is calculated by using the rated voltage.
The use of the voltage at no-load is justified by the following paragraphs in the IEC 60076-1 and the NF EN 60076
§ 3.4.2: definition of the rated quantities of the transformer
§ 3.4.7: definition of the rated current
Note: the nominal current of the transformer / generator is used for the cable sizing and the choice of the protection device in the corresponding to the transformer or generator circuit.
