A 100-MVA, 13 $13.2 \Delta / 115 \mathrm{Y}-\mathrm{kV}$ Step-Up Transformer with a Series Impedance Of

Essay

A 100-MVA, 13.2-kV three-phase generator, which has a positive-sequence reactance of 1.2 per unit on the generator base, is connected to a 110 -MVA, $13.2 \Delta / 115 \mathrm{Y}-\mathrm{kV}$ step-up transformer with a series impedance of $(0.005+j 0.1)$ per unit on its own base. (a) Calculate the per-unit generator reactance on the transformer base. (b) The load at the transformer terminals is $80 \mathrm{MW}$ at unity power factor and at $115 \mathrm{kV}$ . Choosing the transformer high-side voltage as the reference phasor, draw a phasor diagram for this condition. (c) For the condition of part (b), find the transformer low-side voltage and the generator internal voltage behind its reactance. Also compute the generator output power and power factor.