A 230kVA, 2300/230V, 60 Hz, step-down transformer has the following parameters. RH =1.2-ohm, XH =3-ohm, RL =12m-ohm, XL =30m-ohm, Rh+c=2k-ohm, , Xm =1.8k-ohm. If the transformer operates at half load with unity power factor, what is the voltage regulation and efficiency. Repeat the problem with half load with 0.8 power factor lag load and 0.8 power factor lead. Compare the results for all the three loads.