Chapter 3, Problem 3.53P

The ratings of a three-phase, three-winding transformer are

Primary: Y connected, $\text{66 kV},\text{ 15 MVA}$

Secondary: Y connected, $\text{13}.\text{2 kV},\text{ 1}0\text{ MVA}$

Tertiary: $\Delta$ connected, $\text{2}.\text{3 kV},5\text{MVA}$

Neglecting resistances and exciting current, the leakage reactances are:

${\text{X}}_{\text{PS}}\text{=0}\text{.09}$ per unit on a $\text{15-MVA, 66-kV}$ base

${\text{X}}_{\text{PT}}\text{=0}\text{.08}$ per unit on a $\text{15-MVA, 66-kV}$ base

${\text{X}}_{\text{ST}}\text{=0}\text{.05}$ per unit on a $\text{10-MVA, 13}\text{.2-kV}$ base

Determine the per-unit reactances of the per-phase equivalent circuit using a base of 15 MVA and 66 kV for the primary.