Identify the base impedance relationship

Per unit impedance is defined as $Z_{pu} = \frac{Z_{actual}}{Z_{base}}$, where $Z_{base} = \frac{V_b²}{S_b}$. Substituting this, we get $Z_{pu} = \frac{Z_{actual} \times S_b}{V_b²}$.

$Z_{pu} \propto \frac{1}{V_b²}$

Apply the scaling factor

Given $V_{new} = 1.1 V_{old}$ and keeping the actual impedance $Z_{actual}$ and base MVA $S_b$ constant, the new per unit impedance relates to the old one as $Z_{pu(new)} = Z_{pu(old)} \times (V_{old} / V_{new})^2$.

$Z_{pu(new)} = 0.242 \times \left( \frac{1}{1.1} \right)^2$

Calculate the result

Calculating the square of the ratio: $1.1°2 = 1.21$. Then, $Z_{pu(new)} = 0.242 / 1.21 = 0.2$.

$Z_{pu(new)} = 0.2$