Find secondary voltage and primary, secondary currents in a three single-phase step-up transformer.
Three single-phase step-up transformers rated at 10MVA, 4.6kV/13.8kV are connected in Wye-Delta configuration. The three transformers are used to feed a 20MVA load at 0.9 p.f. With an efficiency of 96 percent. Using per unit system, calculate:
a. secondary line voltage.
b. primary and secondary line currents when supplying this load.