Power Quality And Management Set 4

Electrical Engineering

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This set of Power Quality and Management Multiple Choice Questions & Answers (MCQs) focuses on Power Quality And Management Set 4

Q1 | In a load comprising of resistance and inductance:
  • Load current lags voltage
  • Load voltage lags current
  • Both are in phase
  • Any of above
Answer: Load current lags voltage
Q2 | The power factor of capacitive circuits is:
  • Leading
  • Lagging
  • Both of these
  • Any of these
Answer: Leading
Q3 | A circuit having poor power factor will draw:
  • No current
  • Low current
  • Normal current
  • High current
Answer: High current
Q4 | The power factor of purely inductive circuits is:
  • Leading
  • Lagging
  • Both of these
  • Any of these
Answer: Lagging
Q5 | A 500 kVA circuit drawing 200 kW and an inductive load requires how much capacitance to obtain unity power factor:
  • 100
  • 200
  • 300
  • 400
Answer: 300
Q6 | Which of the following statement refer to IEEE definition on power quality?
  • The concept of powering of any electronic equipment in a manner suitable for the equipment.
  • The concept grounding sensitive electronic equipment in a manner suitable for the equipment.
  • The concept of grounding for whatever equipment in a manner suitable for the equipment.
  • The concept of powering and grounding sensitive electronic equipment in a manner suitable for the equipment.
Answer: The concept of powering and grounding sensitive electronic equipment in a manner suitable for the equipment.
Q7 | Which of the following explains the reasons for concern with power quality?
  • End-user equipment become more sensitive to power quality due to many microprocessor-based controls
  • The adjustable-speed motor drives helps to reduce harmonic levels
  • Modern load & equipment are less sensitive to power quality variations.
  • Power electronics equipment do not affect the power quality at all.
Answer: End-user equipment become more sensitive to power quality due to many microprocessor-based controls
Q8 | The following statement describes the effects of poor power quality, EXCEPT
  • Equipment malfunction
  • Increased costs from downtime
  • Premature failure of equipment
  • Reduced maintenance, repair time and expenses
Answer: Premature failure of equipment
Q9 | Since most of the industrial loads are inductive type, which of the following will help to correct the power factor?
  • Increase lagging reactive current demand of the loads
  • Compensate lagging reactive current by supplying leading reactive current to the power system
  • Compensate leading reactive current by supplying lagging reactive current to the power system
  • Reduce leading reactive current demand of the loads
Answer: Compensate lagging reactive current by supplying leading reactive current to the power system
Q10 | Which of the following is an advantages of power factor correction (PFC)?
  • Electricity bills increased
  • Power consumption reduced
  • Increased heating in equipment
  • Extra kVAr availability from the supply
Answer: Power consumption reduced
Q11 | Which of the following represents short duration voltage variation?
  • Under Voltage
  • Over Voltage
  • Voltage Outage
  • Voltage Interference
Answer: Voltage Outage
Q12 | Which of the following terms describes the transient voltage variation?
  • The duration is within 0.5 s to 30 cycles
  • It can be classify to instantaneous, momentary or temporary
  • It can be solved by using static Var systems
  • It can be caused by lightning, electrostatic discharge or load switching.
Answer: It can be caused by lightning, electrostatic discharge or load switching.
Q13 | Which of the following terms describes the effects of harmonics to industrial power systems?
  • Disturbance to Electric and Electronic Devices
  • Extra Fault Current
  • Lower Losses
  • Increased costs from downtime
Answer: Disturbance to Electric and Electronic Devices
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