91. Gauss-Seidel iterative method can be used for solving a set of
(a) linear differential equations only
(b) linear algebraic equation only
(c) both linear and nonlinear algebraic equations
(d) both linear and nonlinear differential equations
Ans: b
92. Pure inductive circuit takes power (reactive) from the a.c. line when
(a) both applied voltage and current rise
(b) both applied voltage anti current decrease
(c) applied voltage decreases but current Increases
(d) none of these
Ans: b
93. An alternator has a phase sequence of RYB for itB phase voltage. In case offield current is reversed, the phase sequence will become
(a) RBY
(b) RYB
(c) YRB
(d) none of these
Ans: b
94. An alternator has a phase sequence of RYB for its phase voltage. In case the direetior of rotation of alternator is reversed, the phase sequence will become
(a) RBY
(b) RYB
(c) YRB
(d) none of these
Ans: a
95. A synchronous generator connected to an infinite bUB delivers power at a lag p.r. If its excitation is increased
(a) the terminal voltage increases
(b) voltage angle 8 increases
(c) current delivered increases
(d) all of the above
Ans: c
96. A synchronous motor connected to an infinite bUB takes power at a lag p.f. If its excitation is increased
(a) the terminal voltage increases
(b) the load angle increases
(c) the p.f. of motor increases
(d) all of the above
Ans: c
97. A star-conneted 440 V, 50 Hz alternator has per phase synchronous reactance of 10 n. It supplies a bal anced capacitive load current of 20 A, as shown in per phase equivalent circuit of the given figure. It is desirable to have zero voltage regulation. The load power factor should be
(a) 0.82
(b) 0.47
(c) 0.39
(d) 0.92
Ans: a
98. A 10k VA, 400 V/200 V single phase transformer with 10 % impedance draws a steady short circuit line current of
(a) 50 A
(b) 150 A
(c) 250 A
(d) 350 A
Ans: b
99. The percentage resistance and percentage reactance of a 10 kVA, 400 V/200 V, 3-phase transformer are 2% and 10% respectively. If the constant losses in the machine are 1 %, the maximum possible percentage efficiency of the transformer is
(a) 98.32
(b) 97.25
(c) 96.85
(d) 96.12
Ans: c
100. The voltage of CI generator and an infinite bus are given as O.92LIO 0 and 1.0L'O 0 respectively. The active power will flow from
(a) generator to infinite bus
(b) infinite bus to generator
(c) the data is insufficient to judge
(d) none of the above
Ans: a
101. In case ora 3 phase short circuit in a system the power fed into the system is
(a) mostly reactive
(b) mostly active
(c) active and reactive both equal
(d) reactive only
Ans: a
102. With the help of a reactive compensator it is possible to have
(u) constant voltage opei ation only
(b) unity p.f. operation only
(c) both constant voltage and unity p.f.
(d) either constant voltage or unity p.f.
Ans: d
103. For a long uncompensated line the limit to the line loading is governed by
(a) thermal limit
(b) voltage drop
(c) stability limit
(d) corona loss
Ans: c
104. A shunt reactor at 100 MVAr is operated at 98% of its rated voltage and at 96% of its rated frequency. The reactive power absorbed by the reactor is
(a) 98 MVAr
(b) 104.02 MVAr
(c) 96.04 MVAr
(d) 100.04 MVAr
Ans: d
105. A 100 kVA transformer has 4% impedance and 50 k VA transformer has 3% impedance when they are operated in parallel, which 6 transformer will reacb full load first
(a) 3%
(b) 4%
(c) data is insufficient
(d) none of the above
Ans: a
Read More Questions:
Power Systems MCQs Part1
Power Systems MCQs Part2
(a) linear differential equations only
(b) linear algebraic equation only
(c) both linear and nonlinear algebraic equations
(d) both linear and nonlinear differential equations
Ans: b
92. Pure inductive circuit takes power (reactive) from the a.c. line when
(a) both applied voltage and current rise
(b) both applied voltage anti current decrease
(c) applied voltage decreases but current Increases
(d) none of these
Ans: b
93. An alternator has a phase sequence of RYB for itB phase voltage. In case offield current is reversed, the phase sequence will become
(a) RBY
(b) RYB
(c) YRB
(d) none of these
Ans: b
94. An alternator has a phase sequence of RYB for its phase voltage. In case the direetior of rotation of alternator is reversed, the phase sequence will become
(a) RBY
(b) RYB
(c) YRB
(d) none of these
Ans: a
95. A synchronous generator connected to an infinite bUB delivers power at a lag p.r. If its excitation is increased
(a) the terminal voltage increases
(b) voltage angle 8 increases
(c) current delivered increases
(d) all of the above
Ans: c
96. A synchronous motor connected to an infinite bUB takes power at a lag p.f. If its excitation is increased
(a) the terminal voltage increases
(b) the load angle increases
(c) the p.f. of motor increases
(d) all of the above
Ans: c
97. A star-conneted 440 V, 50 Hz alternator has per phase synchronous reactance of 10 n. It supplies a bal anced capacitive load current of 20 A, as shown in per phase equivalent circuit of the given figure. It is desirable to have zero voltage regulation. The load power factor should be
(a) 0.82
(b) 0.47
(c) 0.39
(d) 0.92
Ans: a
98. A 10k VA, 400 V/200 V single phase transformer with 10 % impedance draws a steady short circuit line current of
(a) 50 A
(b) 150 A
(c) 250 A
(d) 350 A
Ans: b
99. The percentage resistance and percentage reactance of a 10 kVA, 400 V/200 V, 3-phase transformer are 2% and 10% respectively. If the constant losses in the machine are 1 %, the maximum possible percentage efficiency of the transformer is
(a) 98.32
(b) 97.25
(c) 96.85
(d) 96.12
Ans: c
100. The voltage of CI generator and an infinite bus are given as O.92LIO 0 and 1.0L'O 0 respectively. The active power will flow from
(a) generator to infinite bus
(b) infinite bus to generator
(c) the data is insufficient to judge
(d) none of the above
Ans: a
101. In case ora 3 phase short circuit in a system the power fed into the system is
(a) mostly reactive
(b) mostly active
(c) active and reactive both equal
(d) reactive only
Ans: a
102. With the help of a reactive compensator it is possible to have
(u) constant voltage opei ation only
(b) unity p.f. operation only
(c) both constant voltage and unity p.f.
(d) either constant voltage or unity p.f.
Ans: d
103. For a long uncompensated line the limit to the line loading is governed by
(a) thermal limit
(b) voltage drop
(c) stability limit
(d) corona loss
Ans: c
104. A shunt reactor at 100 MVAr is operated at 98% of its rated voltage and at 96% of its rated frequency. The reactive power absorbed by the reactor is
(a) 98 MVAr
(b) 104.02 MVAr
(c) 96.04 MVAr
(d) 100.04 MVAr
Ans: d
105. A 100 kVA transformer has 4% impedance and 50 k VA transformer has 3% impedance when they are operated in parallel, which 6 transformer will reacb full load first
(a) 3%
(b) 4%
(c) data is insufficient
(d) none of the above
Ans: a
Read More Questions:
Power Systems MCQs Part1
Power Systems MCQs Part2
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