A three phase transformer of 400kVA, 10kV/400V, Dy11 isconnected to its nominal load with cosφ = 1.
a) Calculate the nominal primary and secondary linecurrent.
b) Calculate the corresponding currents in the primary andsecondary winding.
At an open circuit test, the primary line current is 0,52A withcosφ = 0,05 at nominal line voltage.
The short circuit test (at nominal current) shows 214V primary linevoltage and P=1,333kW per phase.
c) Calculate the total iron losses and total copper losses ofthis transformer.
d) Calculate the efficiency η of this transformer.
Now the transformer will be loaded with 210kW with cosφ = 0,83(lagging).
e) Give both the iron losses and the copper losses as apercentage of what they are nominally.
Please show process and computations withcomments.
