1
GATE EE 2023
Numerical
+2
-0

The two-bus power system shown in figure (i) has one alternator supplying a synchronous motor load through a Y-$$\Delta$$ transformer. The positive, negative and zero-sequence diagrams of the system are shown in figures (ii), (iii) and (iv), respectively. All reactances in the sequence diagrams are in p.u. For a bolted line-to-line fault (fault impedance = zero) between phases 'b' and 'c' at bus 1, neglecting all pre-fault currents, the magnitude of the fault current (from phase 'b' to 'c') in p.u. is ____________ (Round off to 2 decimal places).

GATE EE 2023 Power System Analysis - Symmetrical Components and Symmetrical and Unsymmetrical Faults Question 2 English 1GATE EE 2023 Power System Analysis - Symmetrical Components and Symmetrical and Unsymmetrical Faults Question 2 English 2GATE EE 2023 Power System Analysis - Symmetrical Components and Symmetrical and Unsymmetrical Faults Question 2 English 3

Your input ____
2
GATE EE 2018
MCQ (Single Correct Answer)
+2
-0.67
The positive, negative and zero sequence impedances of a three phase generator are Z1, Z2 and Z0 respectively. For a line-to-line fault with fault impedance Zf, the fault current is If1 = kIf, where If is the fault current with zero fault impedance. The relation between Zf and k is
A
$${Z_f} = {{\left( {{Z_1} + {Z_2}} \right)\left( {1 - k} \right)} \over k}$$
B
$${Z_f} = {{\left( {{Z_1} + {Z_2}} \right)\left( {1 + k} \right)} \over k}$$
C
$${Z_f} = {{\left( {{Z_1} + {Z_2}} \right)k} \over {1 - k}}$$
D
$${Z_f} = {{\left( {{Z_1} + {Z_2}} \right)k} \over {1 + k}}$$
3
GATE EE 2017 Set 1
Numerical
+2
-0
The positive, negative and zero sequence reactances of a wye-connected synchronous generator are 0.2 pu, 0.2 pu, and 0.1 pu, respectively. The generator is on open circuit with a terminal voltage of 1 pu. The minimum value of the inductive reactance, in pu, required to be connected between neutral and ground so that the fault current does not exceed 3.75 pu if a single line to ground fault occurs at the terminals is _______ (assume fault impedance to be zero). (Give the answer up to one decimal place)
Your input ____
4
GATE EE 2016 Set 1
Numerical
+2
-0
A 30 MVA, 3-phase, 50Hz, 13.8 kV, star-connected synchronous generator has positive, negative and zero sequence reactances, 15%, 15% and 5% respectively. A reactance (Xn) is connected between the neutral of the generator and ground. A double line to ground fault takes place involving phases ‘b’ and ‘c’, with a fault impedance of j0.1 p.u. The value of Xn (in p.u.) that will limit the positive sequence generator current to 4270 A is __________.
Your input ____
GATE EE Subjects
EXAM MAP