A 25-kVA, 2200:220-V, 60-Hz, single-phase transformer has an equivalent series impedance of 3.5 + j4.0 referred to the primary high voltage side.
(a) Determine the highest value of voltage regulation for full-load output at rated secondary terminal voltage.
(b) At what power factor does it occur?
(c) Sketch the corresponding phasor diagram.