GATE 2021 EE – Question 44

Power Systems · Series and shunt compensation, Electric field distribution and insulators, Distribution systems · 2 marks · Multiple choice

In the figure shown, self-impedances of the two transmission lines are 1.5j p.u each, and $Z_m=0.5j$ p.u is the mutual impedance. Bus voltages shown in the figure are in p.u. Given that $\delta>0$, the maximum steady-state real power that can be transferred in p.u from Bus-1 to Bus-2 is

Diagram for GATE 2021 EE question 44

$|E||V|$
$\dfrac{|E||V|}{2}$
$2|E||V|$
$\dfrac{3|E||V|}{2}$

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Show answer and explanation

Correct answer: (A) $|E||V|$

Explanation

Two coupled parallel lines carry equal currents, so each sees $Z_s+Z_m=1.5j+0.5j=2j$. The equivalent impedance is $\frac{2j}{2}=j$ p.u, and $P_{max}=\frac{|E||V|}{1}=|E||V|$.