Question $1$

Design a $15$ kVA core type, oil$-$cooled, $3-$phase $-Y$ transformer with a voltage rating of $\frac{11000}{400}V.$ The recommended flux density $1\mathrm{.}7T.$ It is advised that per turn voltage should be $24$ Volt. Calculate:

$($a$)$ The cross$-$section area of the core.

$($b$)$ Number of turns in each winding.

$($c$)$ The full load current of both $LV$ and $HV$ windings.

$($d$)$ Cross$-$sectional area of the copper conductor $($use max current density of $($:$2\mathrm{.}5m\frac{m^2}{A}$