$${v_1}\left( t \right) = 100\cos \left( {\omega t} \right)$$
$${v_2}\left( t \right) = 100\cos \left( {\omega t + {\pi \over {18}}} \right)$$
and $${v_3}\left( t \right) = 100\cos \left( {\omega t + {\pi \over {36}}} \right)$$.
The circuit is in sinusoidal steady state, and R << $${\omega L}$$.
P1, P2 and P3 are the average power outputs. Which one of the following statements is true?
A
P1 = P2 = P3 = 0
B
P1 < 0, P2 > 0, P3 > 0
C
P1 < 0, P2 > 0, P3 < 0
D
P1 > 0, P2 < 0, P3 > 0
2
GATE EE 2018
MCQ (Single Correct Answer)
+2
-0.67
Consider the two bus power system network with given loads as shown in the figure. All
the values shown in the figure are in per unit. The reactive power supplied by generator G1
and G2 are QG1 and QG2 respectively. The per unit values of QG1, QG2, and line reactive
power loss (Qloss) respectively are
A
5. 00, 12.68, 2.68
B
6.34, 10.00, 1.34
C
6.34, 11.34, 2.68
D
5.00, 11.34, 1.34
3
GATE EE 2018
Numerical
+1
-0.33
The series impedance matrix of a short three-phase transmission line in phase coordinates is
$$\left[ {\matrix{
{{Z_s}} & {{Z_m}} & {{Z_m}} \cr
{{Z_m}} & {{Z_s}} & {{Z_m}} \cr
{{Z_m}} & {{Z_m}} & {{Z_s}} \cr
} } \right]$$.
If the positive sequence impedance is (1 + 𝑗 10) $$\Omega $$, and the zero
sequence is (4 + 𝑗 31) $$\Omega $$, then the imaginary part of Zm (in $$\Omega $$) is ______(up to 2 decimal
places).
Your input ____
4
GATE EE 2018
Numerical
+1
-0.33
The positive, negative and zero sequence impedances of a 125 MVA, three-phase, 15.5 kV,
star-grounded, 50 Hz generator are 𝑗0.1 pu, j0.05 pu and j0.01 pu respectively on the
machine rating base. The machine is unloaded and working at the rated terminal voltage. If
the grounding impedance of the generator is j0.01 pu, then the magnitude of fault current
for a b-phase to ground fault (in kA) is __________ (up to 2 decimal places).
