Inron Loss and Full Load Copper Loss for Transformers

My ancient textbook gives examples of (50Hz) :-

1. 1000 kVA 3 phase 6.6/0.44 kV Copper loss 6.6 kW a 75 Celsius copper temperature, Iron loss 3.7 kW Full LOad. Hence Efficiency ~99%.
2. 15000 kVA, 3 phase 33/6.6 kV Copper loss 99 kW a 75 Celsius copper temperature, Iron loss 26 kW Full Load. Hence Efficiency ~99.2%.

But single phase will be worse and low voltage/high current worse efficiency. In practice, copper temperature will depend on ambient and previous loading. Application where load % is typically low will emphasize low core loss over low copper loss because core loss is 24 hour/day cost for supplier.

THIS IS AVAILABLE IN THE MANUFACTURERS DATASHEET.

HOWEVER IF YOU WANT TO KNOW THE TREND FOR THE BEST MANUFACTURERS THE NO LOAD LOSSES SHALL BE LESS THAN 1%,AND THE TOTAL LOSSES ARE A TRADE OF BETWEEN THE PRICES BETWEEN THE GOOD AND BAD MANUFACTURER.THE END USER HAS TO COMPARE THE COST REDUCTION VERSES LOSSES IN ENERGY FOR THE ENTIRE LIFESPAN OF THE TRANSFORMER .

Please refer AC machines by MG SAY. It gives the complete procedure

There is no such thing as RATED, . . or STANDARD loss for power transformers.

Each manufacturer will provide numbers on losses for his transformers, . . . and even these will vary according to application.

Losses will also depend on the transformer cooling - "dry type" or "liquid immersed" . .

HOWEVER, the US DOE Rule suggests efficiencies:

1,500 kVA - 99.14% - dry type, 99.42% - oil immersed.

2,500 kVA - 99.31% - dry type, 99.49% - oil immersed.

No numbers provided for transformers above 2,500 kVA.

Oleh

Go to the Data Sheet of the items