### Testing And Commissioning Of Electrical Equipment’S Set 12

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
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
Q3 | Impedance relay can be used for
• Phase faults only
• Earth faults only
• Both earth and phase faults
• None of the above
Q4 | Impedance relay may use
• Balance beam structure
• Induction cup structure
• 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
Q6 | On transient fault OC and impedance relay
• Under reaches
• Over reaches
• Reach unaffected
• None of the above
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
Q8 | The structure used in reactance relay is
• Induction cup
• Double induction loop
• Single induction loop
• 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
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
Q11 | A reactance relay is
• Voltage restrained overcurrent relay
• Voltage restrained directional relay
• Directional restrained overcurrent relay
• Directional restrained over voltage relay
Q12 | Reactance relays are used for phase fault in.......line
• Short
• Medium
• Long
• All of the above
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
Q14 | Differential relays are used for protection of
• Feeders
• Alternators
• Transformers
• All of the above
Q15 | Differential relays are used for protection of equipments against
• Internal faults
• Over current
• Reverse current
• Reverse power
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
Q17 | Both voltage and current signals are required for
• A plain over current relay
• A differential relay
• A directional relay
• A biased directional relay