Power System Analysis MCQs

 

Power System Analysis MCQs (51–100)

Q51. The impedance diagram of a power system is usually drawn on:
A) kV base only
B) MVA base only
C) Common MVA and kV base
D) None
Ans: C

Q52. If base MVA is changed, per unit reactance will:
A) Remain same
B) Change
C) Be zero
D) Be infinite
Ans: B

Q53. Load flow solution gives:
A) Only real power flow
B) Only reactive power flow
C) Both bus voltages and line flows
D) Only losses
Ans: C

Q54. The main drawback of Gauss-Seidel method is:
A) Slow convergence
B) Large memory requirement
C) Complex programming
D) None
Ans: A

Q55. Newton-Raphson method requires:
A) Less memory
B) Faster convergence
C) Both faster convergence and more memory
D) None
Ans: C

Q56. In load flow studies, flat start means:
A) Voltage magnitude = 1.0 p.u., angle = 0°
B) Voltage magnitude = 0 p.u.
C) Angle = 90°
D) Random initialization
Ans: A

Q57. The slack bus provides:
A) Active power only
B) Reactive power only
C) Both P and Q balance
D) None
Ans: C

Q58. In economic dispatch, the cost function is usually:
A) Linear
B) Quadratic
C) Exponential
D) Cubic
Ans: B

Q59. Transmission loss formula involves:
A) B-coefficients
B) Z-bus
C) Y-bus
D) Jacobian
Ans: A

Q60. Voltage stability problem is related to:
A) Reactive power support
B) Real power flow
C) Frequency control
D) Economic dispatch
Ans: A

Q61. A bus with specified P and V is:
A) PQ bus
B) PV bus
C) Slack bus
D) None
Ans: B

Q62. Short circuit MVA is used to:
A) Design transformers
B) Design generators
C) Rate circuit breakers
D) Improve stability
Ans: C

Q63. The most common fault in power systems is:
A) Single line-to-ground fault
B) Three-phase fault
C) Line-to-line fault
D) Double line-to-ground fault
Ans: A

Q64. Sequence networks are connected in series for:
A) L-G fault
B) L-L fault
C) L-L-G fault
D) 3-phase fault
Ans: A

Q65. Sequence networks are connected in parallel for:
A) L-L fault
B) L-L-G fault
C) L-G fault
D) None
Ans: A

Q66. The Z-bus matrix is:
A) Inverse of Y-bus
B) Equal to Y-bus
C) Square of Y-bus
D) None
Ans: A

Q67. In symmetrical components, zero sequence current has:
A) Equal magnitude, 0° phase displacement
B) Equal magnitude, 120° displacement
C) Different magnitudes
D) None
Ans: A

Q68. Negative sequence current causes:
A) Rotor heating in synchronous machines
B) Overvoltage
C) Corona
D) Stability improvement
Ans: A

Q69. The inertia constant (H) is expressed in:
A) kWh
B) MJ/MVA
C) kVA
D) Hz
Ans: B

Q70. The swing equation is a:
A) First order differential equation
B) Second order differential equation
C) Algebraic equation
D) None
Ans: B

Q71. The equal area criterion is valid for:
A) First swing stability
B) Multi-swing stability
C) Steady state stability
D) None
Ans: A

Q72. Critical clearing angle depends on:
A) System inertia
B) System reactance
C) System voltage
D) All of these
Ans: D

Q73. Real power transfer capability of a line increases with:
A) Decrease in line reactance
B) Increase in reactance
C) Increase in resistance
D) None
Ans: A

Q74. Reactive power flow in a line depends on:
A) Voltage magnitude difference
B) Phase angle difference
C) Line resistance
D) None
Ans: A

Q75. In steady state, synchronous generator rotor speed is:
A) Equal to synchronous speed
B) Greater than synchronous speed
C) Less than synchronous speed
D) Random
Ans: A

Q76. Infinite bus has:
A) Constant voltage and frequency
B) Constant load
C) Constant current
D) None
Ans: A

Q77. In transmission line modeling, shunt capacitance is neglected in:
A) Short line
B) Medium line
C) Long line
D) None
Ans: A

Q78. Surge impedance loading (SIL) is proportional to:
A) (V²/Zc)
B) (V/Zc²)
C) (V²/2Zc)
D) (V/Zc)
Ans: A

Q79. Bundled conductors are used to:
A) Increase corona inception voltage
B) Reduce reactance
C) Increase current capacity
D) All of these
Ans: D

Q80. Stability of power system can be improved by:
A) Fast excitation system
B) High speed breakers
C) Series compensation
D) All of these
Ans: D

Q81. FACTS controllers include:
A) STATCOM
B) TCSC
C) SSSC
D) All of these
Ans: D

Q82. SVC (Static Var Compensator) provides:
A) Active power support
B) Reactive power support
C) Frequency control
D) None
Ans: B

Q83. In HVDC, rectifier end operates at:
A) Lagging power factor
B) Leading power factor
C) Unity power factor
D) None
Ans: A

Q84. In HVDC, inverter end operates at:
A) Lagging power factor
B) Leading power factor
C) Unity power factor
D) None
Ans: B

Q85. HVDC link control is achieved by:
A) Controlling firing angle of converters
B) Changing transmission line parameters
C) Changing frequency
D) None
Ans: A

Q86. Corona discharge is reduced by:
A) Increasing conductor size
B) Increasing spacing
C) Bundling conductors
D) All of these
Ans: D

Q87. Power factor of a transmission line is improved by:
A) Series capacitor
B) Shunt capacitor
C) Reactor
D) Resistor
Ans: B

Q88. Series capacitor in a line reduces:
A) Effective reactance
B) Effective resistance
C) Line charging
D) Surge impedance
Ans: A

Q89. The primary purpose of load frequency control is to:
A) Maintain scheduled frequency
B) Control reactive power
C) Minimize fuel cost
D) Improve transient stability
Ans: A

Q90. Automatic Generation Control (AGC) maintains:
A) Tie-line power and frequency
B) Voltage profile
C) Reactive power
D) Transmission loss
Ans: A

Q91. In two-area load frequency control, the tie-line power depends on:
A) Frequency difference
B) Voltage difference
C) Impedance
D) None
Ans: A

Q92. Reactive power compensation using shunt capacitors results in:
A) Increased voltage
B) Decreased losses
C) Improved stability
D) All of these
Ans: D

Q93. In per unit system, base kV on each side of a transformer is chosen in proportion to:
A) Turns ratio
B) Current ratio
C) Impedance
D) Resistance
Ans: A

Q94. Load curve gives information about:
A) Maximum demand
B) Energy consumed
C) Load factor
D) All of these
Ans: D

Q95. Diversity factor is:
A) Sum of individual maximum demands ÷ Maximum demand of system
B) Maximum demand ÷ Connected load
C) Average load ÷ Maximum demand
D) None
Ans: A

Q96. Load factor is:
A) Average load ÷ Maximum demand
B) Maximum load ÷ Average load
C) Load ÷ Connected load
D) None
Ans: A

Q97. Plant capacity factor is:
A) Average demand ÷ Plant capacity
B) Maximum demand ÷ Plant capacity
C) Connected load ÷ Plant capacity
D) None
Ans: A

Q98. Power system frequency is controlled by:
A) Active power balance
B) Reactive power balance
C) Voltage
D) None
Ans: A

Q99. Power system voltage profile is mainly controlled by:
A) Reactive power
B) Real power
C) Frequency
D) Load factor
Ans: A

Q100. The overall objective of power system analysis and operation is:
A) Reliability and economy
B) Voltage reduction
C) Minimum load
D) Frequency rise
Ans: A