Question

A 400 kV transmission line has a maximum power transfer capacity of P. If the same transmission line is used for 100 kV transmission with series reactance unchanged, the new maximum power transfer capacity will be

• A. $\frac{P}{32}$
• B. $\frac{P}{16}$
• C. $\frac{P}{4}$
• D. $\frac{P}{8}$

Answer 1

The correct option is B $\frac{P}{16}$

Power transfer capacity $\propto V^2$

$\frac{P_1}{P_2}=\frac{V_1^2}{V_2^2}$

$P_2=P_1\frac{V_2^2}{V_1^2}=P{\left(\frac{100}{400}\right)}^2=\frac{P}{16}$