Testing And Commissioning Of Electrical Equipment’S Set 12

Electrical Engineering

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This set of Testing and Commissioning of Electrical Equipment’s Multiple Choice Questions & Answers (MCQs) focuses on Testing And Commissioning Of Electrical Equipment’S Set 12

Q1 | The domains of power system where directional over current relay is indispensableare
  • In case of parallel feeder protection
  • In case of ring main feeder protection
  • Both A and B
  • None of the above
Answer: Both A and B
Q2 | In an inverse definite minimum time, electromagnetic type over current relay, theminimum time feature is achieved because of
  • Saturation of the magnetic circuit
  • Proper mechanical design
  • Appropriate time delay element
  • Electromagnetic damping
Answer: Saturation of the magnetic circuit
Q3 | Impedance relay can be used for
  • Phase faults only
  • Earth faults only
  • Both earth and phase faults
  • None of the above
Answer: Phase faults only
Q4 | Impedance relay may use
  • Balance beam structure
  • Induction cup structure
  • Shaded pole structure
  • Either A or B
Answer: Either A or B
Q5 | An impedance is relay is a
  • Voltage restrained over current relay
  • Voltage restrained directional relay
  • Directional restrained over current relay
  • Directional restrained over voltage relay
Answer: Voltage restrained over current relay
Q6 | On transient fault OC and impedance relay
  • Under reaches
  • Over reaches
  • Reach unaffected
  • None of the above
Answer: Under reaches
Q7 | Threshold characteristics of a plain impedance relay in a complex Z plane is a
  • Circle passing through origin
  • Circle with the centre at the origin
  • Straight line passing through origin
  • Straight line offset from the origin
Answer: Circle with the centre at the origin
Q8 | The structure used in reactance relay is
  • Induction cup
  • Double induction loop
  • Single induction loop
  • Either A or B
Answer: Either A or B
Q9 | Reactance relay is normally used for protection against
  • Earth fault only
  • Phase fault only
  • Both earth and phase faults
  • None of the above
Answer: Earth fault only
Q10 | The operating characteristics of the reactance relay in the complex impedanceplane is a
  • Circle with its origin at the centre of the R-X plane
  • Circle passing through the origin
  • Straight line passing through the origin
  • Straight line parallel to the X axis
Answer: Straight line parallel to the X axis
Q11 | A reactance relay is
  • Voltage restrained overcurrent relay
  • Voltage restrained directional relay
  • Directional restrained overcurrent relay
  • Directional restrained over voltage relay
Answer: Directional restrained overcurrent relay
Q12 | Reactance relays are used for phase fault in.......line
  • Short
  • Medium
  • Long
  • All of the above
Answer: Short
Q13 | A differential relay response to
  • Algebraic difference of two or more similar electrical quantities
  • Phasor difference of two or more similar electrical quantities
  • Algebraic difference between two currents
  • Algebraic difference between two voltages
Answer: Phasor difference of two or more similar electrical quantities
Q14 | Differential relays are used for protection of
  • Feeders
  • Alternators
  • Transformers
  • All of the above
Answer: All of the above
Q15 | Differential relays are used for protection of equipments against
  • Internal faults
  • Over current
  • Reverse current
  • Reverse power
Answer: Internal faults
Q16 | In a biased differential relay the bias is defined as a ratio of
  • Number of turns of restraining and operating coil
  • Operating coil current and restraining coil current
  • Fault current and operating coil current
  • Fault current and restraining coil current
Answer: Operating coil current and restraining coil current
Q17 | Both voltage and current signals are required for
  • A plain over current relay
  • A differential relay
  • A directional relay
  • A biased directional relay
Answer: A directional relay
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