Per unit system for a transformer

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mathilder7

Joined Oct 30, 2018
4
A 50 Hz, three-phase star-star transformer is rated at 1300 MVA, 24.5 kV/345 kV. It has a per unit equivalent reactance of 0.115 pu. If the high-voltage side of the transformer is delivering 810 MVA at 370 kV, 0.9 power factor lagging, calculate:

  1. The per unit phase current at the high voltage side 2. The line voltage across the low voltage side
I want to remove the transformer and only consider impedances to figure out these two questions. My professor did it another way but I am confused. Can I use a S_base = 1300 MVA and a voltage ratio of 0.071 to find out the other basevalues? In that case I got this:
V_base LV side = 24.5 kV. Z_base LV side = 0.462 ohms
V_base HV side = 345 kV. Z_base HV = 91.56 ohms.
How do I move forward after this?
 
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