A single-phase two-winding transformer is rated 20kVA, 480/120 V, 50 Hz. A source connected to the primary winding supplies an impedance load connected to the secondary winding. The load absorbs 15 kVA at 0.8 p.f. lagging when the load voltage is 118 V. Assume
that the transformer is ideal and calculate the following:
a) Change the power factor to 0.2 lagging and 0.2 leading condition. Calculate the reactive power for the ideal transformer. What kind of effect may take place due to these changes?
b) Plot the complex power during 0.8 lagging, 0.2 lagging and 0.2 leading condition as a function of active power for the ideal transformer.
c) Assume the transformer is not ideal but has the parameters: r1 = 0.1 , x1 = 0.2 , r2 = 0.01 , x2 = 0.02 and calculate the percent voltage regulation.