Explore topic-wise MCQs in Electrical Engineering Questions.

This section includes 180 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering Questions knowledge and support exam preparation. Choose a topic below to get started.

1.

Which among the following phenomenon is generally associated with voltage stability?
A. Temporary load reduction
B. Voltage is reduced
C. Voltage collapses
D. All of these
E. None of these
Answer» E. None of these
Discussion
2.

Which among the following assumptions are made in the reactance diagram?
A. The neutral reactance are neglected
B. Static loads are neglected.
C. The capacitance of the transmission lines are neglected
D. Only a and c
E. All of these
Answer» F.
Discussion
3.

What is the simplified diagram called, after omitting all resistances, static loads, capacitance of the transmission lines and magnetising circuit of the transformer?
A. Single line diagram
B. Resistance diagram
C. Reactance diagram
D. Both (a) and (b)
E. None of these
Answer» D. Both (a) and (b)
Discussion
4.

What is the value of the letter ‘a’ or ‘α’ which is commonly used in symmetrical components?
A. 1 ∠ 90°
B. 1 ∠ 30°
C. 1 ∠ 120°
D. 1 ∠ -120°
Answer» D. 1 ∠ -120°
Discussion
5.

Which among these is the major advantage of per unit computations?
A. Per unit impedance of transformers is the same referred to either side of it.
B. For simulating steady state and transient models in the computer this method is very useful.
C. Manufactures usually specify the impedance of an apparatus in per unit system.
D. All of these
Answer» E.
Discussion
6.

Which among these is the most commonly occurring fault?
A. Single line to ground fault.
B. Double line to ground fault
C. Line to line fault
D. Fault due to all the three phases to earth.
Answer» B. Double line to ground fault
Discussion
7.

What is the per unit system (PU)?
A. A ratio of actual value in any units to the base or reference value in the same units
B. A ratio of the base or reference value in any units to the actual value in the same units.
C. Ratio of the square of the actual value in any units to the square of base or the reference value in the same units
D. All of these
Answer» B. A ratio of the base or reference value in any units to the actual value in the same units.
Discussion
8.

Which among theses quantities are to be determined in slack bus?
A. P and Q
B. Q and |V|
C. |V| and δ
D. Q and δ
Answer» B. Q and |V|
Discussion
9.

Which among the following buses constitute the maximum number in a power system?
A. Slack bus
B. P Q bus
C. P V bus
D. All of these
E. None of these
Answer» C. P V bus
Discussion
10.

What are cross country faults?
A. A fault occurring at any point of the power system
B. Two or more faults occurring simultaneously on the power system
C. Line to line fault
D. All of these
E. None of these
Answer» C. Line to line fault
Discussion
11.

What is infinite bus in power system?
A. A large system with infinite voltage
B. A large system in which the voltage and frequency varies
C. A large system whose voltage and frequency remains constant throughout.
D. Both (a) and (b)
E. None of these
Answer» D. Both (a) and (b)
Discussion
12.

Which of the following fault results into a three phase faults?
A. Single line to ground fault.
B. Double line to ground fault
C. Line to line fault
D. Fault due to all the three phases to earth.
Answer» E.
Discussion
13.

What percentage of faults occurring is single line to ground fault?
A. 50 %
B. 60 %
C. 35 %
D. 70 %
Answer» E.
Discussion
14.

In which portion of the transmission system is the occurrence of the fault more common?
A. Alternators
B. Transformers
C. Transmission lines
D. Underground cables
Answer» D. Underground cables
Discussion
15.

What happens if the neutral is not grounded in case of the single line to ground fault?
A. Only the zero sequence impedance will be zero
B. The zero sequence impedance will be infinite
C. Fault current will be zero
D. Both (b) and (c)
E. All of these
Answer» E. All of these
Discussion
16.

What is an oriented graph?
A. A connection of network topology, represented by replacing all physical elements by lines.
B. A graph in which the direction is assigned to each branch.
C. A graph where at least one path exists between any two nodes of the graph.
D. None of these
Answer» C. A graph where at least one path exists between any two nodes of the graph.
Discussion
17.

Why are series reactors used?
A. Improve the transmission efficiency
B. Improve the power factor of the power system
C. To bring down the fault level with in the capacity of the switchgear instrument
D. All of these
Answer» D. All of these
Discussion
18.

What happens to the value of the fault current in case of SLG fault, if fault impedance is introduced?
A. The fault current increase
B. The fault current remains same as in case of SLG fault.
C. The fault current becomes zero
D. The fault current is reduced
Answer» E.
Discussion
19.

Which among the following is the main assumption to solve a load flow problem by GS method?
A. All the buses are to be considered as PQ bus including the slack bus.
B. All the buses are to be considered as PV bus including the slack bus.
C. All the buses are to be considered as PQ bus excluding the slack bus.
D. All the buses are to be considered as PV bus excluding the slack bus.
Answer» D. All the buses are to be considered as PV bus excluding the slack bus.
Discussion
20.

Which among the following quantities are specified at the generator bus?
A. P and Q
B. P and |V|
C. Q and |V|
D. P and δ
Answer» C. Q and |V|
Discussion
21.

What is the element of the graph that is not included in the tree called?
A. Links
B. Branches
C. Oriented graph
D. All of these
Answer» B. Branches
Discussion
22.

Why are load flow studies carried out?
A. To study of stability of the system
B. For fault calculations
C. For planning the power system
D. All of these
Answer» D. All of these
Discussion
23.

Which among the following quantities are specified at the load bus?
A. P and Q
B. P and |V|
C. Q and |V|
D. P and δ
Answer» B. P and |V|
Discussion
24.

What is the value of negative sequence impedance?
A. 1
B. Z
C. Same as positive sequence
D. ∞
Answer» D. ∞
Discussion
25.

The positive sequence current is always equal to ______________.
A. Always zero
B. 1/3 of the negative sequence current
C. Negative sequence current
D. 3 times the negative sequence current
Answer» D. 3 times the negative sequence current
Discussion
26.

Which among the following quantities are to be determined in voltage controlled bus?
A. P and Q
B. Q and |V|
C. |V| and δ
D. Q and δ
Answer» E.
Discussion
27.

A balanced three phase system consists of _________.
A. Zero sequence currents only
B. Positive sequence currents only
C. Positive, negative and zero sequence currents
D. Only negative sequence currents
Answer» C. Positive, negative and zero sequence currents
Discussion
28.

In the manufacture of transformers, ANSI prescribes certain standards. What is this standard?
A. High voltage side should lead the low voltage side by 30° with Y - Δ or Y - Δ connections.
B. High voltage side should lead the low voltage side by 60° with Y - Δ or Y - Δ connections.
C. High voltage side should lag the low voltage side by 30° with Y - Δ or Y - Δ connections.
D. High voltage side should lag the low voltage side by 60° with Y - Δ or Y - Δ connections.
Answer» B. High voltage side should lead the low voltage side by 60° with Y - Δ or Y - Δ connections.
Discussion
29.

What percentage of buses in the power system are generator buses?
A. 5 %
B. 25 %
C. 70 %
D. 10 %
Answer» E.
Discussion
30.

What is the value of the zero sequence current?
A. 3 times the current in the neutral wire
B. 1 / 3 times the current in the neutral wire
C. √3 times the current in the neutral wire
D. Equal to the current in the neutral wire
Answer» C. √3 times the current in the neutral wire
Discussion
31.

Phase shift of symmetrical components happens in which among the following?
A. Delta - delta
B. Star – delta
C. Delta – star
D. Both (b) and (c)
E. All of these
Answer» E. All of these
Discussion
32.

In what direction does the phasor get rotated if it is multiplied by the operator ‘a’?
A. Anti clockwise
B. Clockwise
C. Gets rotated by 90° in the clockwise direction
D. Gets rotated by 90° in the anticlockwise direction
Answer» B. Clockwise
Discussion
33.

For Y - Δ and Δ - Y transformers, the phase shift between the transformer windings is equal to “ n * 30° “. What does ‘n’ represent in the equation?
A. Number of windings
B. Number of turns
C. Turns ratio
D. Hour number
Answer» E.
Discussion
34.

What is the multiplication factor to be multiplied with symmetrical momentary current to account for the presence of DC off set current?
A. 1.2
B. 1.5
C. 1.6
D. 2.5
Answer» D. 2.5
Discussion
35.

Which among the following reactance have a greater value?
A. Sub transient reactance
B. Transient reactance
C. Synchronous reactance
D. All of these
E. None of these
Answer» D. All of these
Discussion
36.

Which among the following methods are generally used for the calculation of symmetrical faults?
A. Norton theorem
B. Thevnin’s theorem
C. Kirchhoff’s laws
D. Only (b) and (c)
E. All of these
Answer» E. All of these
Discussion
37.

On which among the following factors does the magnitude of the fault current depend?
A. Total impedance upto the fault.
B. Voltage at the fault point
C. Both (a) and (b)
D. None of these
Answer» D. None of these
Discussion
38.

What does the positive sequence component consist of?
A. Three balanced phasors of equal magnitude and displaced by 120°
B. Three unbalanced phasors displaced by 120°
C. Three phasors with equal magnitude and zero displacement.
D. None of these
Answer» B. Three unbalanced phasors displaced by 120°
Discussion
39.

What is the percentage of occurrence of symmetrical faults?
A. 10 %
B. 15 %
C. 5 %
D. None of these
Answer» D. None of these
Discussion
40.

What is the rated breaking capacity of the circuit breaker?
A. The product of rated voltage and rated breaking current
B. The product of rated voltage and rated symmetrical breaking current
C. The product of fault voltage and breaking current
D. None of these
Answer» C. The product of fault voltage and breaking current
Discussion
41.

What will be the multiplying factor if the speed of the circuit breaker is 2 cycles?
A. 2.2
B. 1.2
C. 2.8
D. 1.4
Answer» E.
Discussion
42.

What happens to the zero sequence currents, if the neutral in the Y connection is absent?
A. Minimum
B. Zero
C. Maximum
D. ∞
Answer» C. Maximum
Discussion
43.

If the speed of the circuit breaker is 8 cycles or slower than that what will be the multiplying factor?
A. 2.3
B. 1.0
C. 1.5
D. 1.7
Answer» C. 1.5
Discussion
44.

What is the value of acceleration factor used in the GS method?
A. 2.3 – 2.7
B. 1.6 – 2.0
C. 1.2 – 1.5
D. 2.4 – 2.9
Answer» C. 1.2 – 1.5
Discussion
45.

Which types of equations are solved using Newton Raphson method?
A. Non linear differential equations
B. Linear differential equations
C. Non linear algebraic equations
D. Both (a) and (b)
E. All of these
Answer» D. Both (a) and (b)
Discussion
46.

What are the types of unsymmetrical faults?
A. Single line to ground fault
B. Double line to ground fault
C. Line to line fault
D. All of these
E. None of these
Answer» E. None of these
Discussion
47.

What are zero sequence components?
A. Three balanced phasors of equal magnitude and displaced by 120°
B. Three balanced phasors displaced by 120° and having phase sequence opposite to that of the original phasors.
C. Three phasors with equal magnitude and zero displacement.
D. None of these
Answer» D. None of these
Discussion
48.

Zero sequence currents cannot flow in which of the following connections?
A. Delta
B. Star
C. Star – star
D. Both (b) and (c)
E. All of these
Answer» B. Star
Discussion
49.

To control which among the following is the regulating transformer used in a power system?
A. Power flows
B. Frequency
C. Voltage
D. Power factor
Answer» B. Frequency
Discussion
50.

Which among these is the most severe fault?
A. Single line to ground fault.
B. Double line to ground fault
C. Line to line fault
D. Symmetrical fault.
Answer» E.
Discussion