Transformer MVA rating IEEE vs. IEC 2

[cuky2000]

There are difference between IEEE STD and IEC STD associated to power transformer rating as shown on the table below.
For a 100MVA unit with 30 degree C average ambient temperature in 24 hrs. What should be the maximum rating if specified per IEEE or the same maximum rating if designed based on the IEC std.?

 

[7anoter4]

Here is Table 6 also

 

[prc]

1) Transformer overloading standards have changed significantly during the past 30 years. The relevant standards today are IEC 60076-7 ed2.0-2017 & IEEE C57.91-2011 for oil-filled transformers and IEC 60076-12-2008 & C57.96-2013 for dry-type transformers.
2) Manufacturers design transformers for the maximum permissible hot spot, and the average winding temperature rises. These are the same in both standards. IEC refers to the average weighted annual ambient temperature of 20C, while IEEE refers to the average monthly temperature of 30C. Remember, the average monthly temperature is 30C in IEC, as well.
3) IEEE is now under revision and will align exactly as per IEC's latest revision.
4) Conclusion: There is no difference between IEC and IEEE regarding the thermal performance of transformers.