GATE EE 2022 | Symmetrical Components and Symmetrical and Unsymmetrical Faults Question 1 | Power System Analysis

The valid positive, negative and zero sequence impedances (in p.u.), respectively, for a 220 kV, fully transported three-phase transmission line, from the given choices are

1.1, 0.15 and 0.08

0.15, 0.15 and 0.35

0.2, 0.2 and 0.2

0.1, 0.3 and 0.1

GATE EE 2018

Numerical

-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 Z_m (in $$\Omega $$) is ______(up to 2 decimal places).

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GATE EE 2018

Numerical

-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).

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GATE EE 2014 Set 1

MCQ (Single Correct Answer)

-0.3

Three phase to ground fault takes place at locations $${F_1}$$ and $${F_2}$$ in the system shown in the figure. GATE EE 2014 Set 1 Power System Analysis - Symmetrical Components and Symmetrical and Unsymmetrical Faults Question 36 English

GATE EE 2014 Set 1 Power System Analysis - Symmetrical Components and Symmetrical and Unsymmetrical Faults Question 36 English

If the fault takes place at location $${F_1}$$, then the voltage and the current at bus A are $${V_F1}$$ and $${{\rm I}_{F1}}$$ respectively. If the fault takes place at location $${F_2}$$, then the voltage and the current at bus A are $${V_{F2}}$$ and $${{\rm I}_{F2}}$$ respectively.

The correct statement about voltages and currents during faults at $${F_1}$$ and $${F_2}$$ is

$${V_{F1}}$$ leads $${{\rm I}_{F1}}$$ and $${V_{F2}}$$ leads $${{\rm I}_{F2}}$$

$${V_{F1}}$$ leads $${{\rm I}_{F1}}$$ and $${V_{F2}}$$ lags $${{\rm I}_{F2}}$$

$${V_{F1}}$$ lags $${{\rm I}_{F1}}$$ and $${V_{F2}}$$ leads $${{\rm I}_{F2}}$$

$${V_{F1}}$$ $${{\rm I}_{F1}}$$ and $${V_{F2}}$$ lags $${{\rm I}_{F2}}$$