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This set of Switch Gear and Protection Multiple Choice Questions & Answers (MCQs) focuses on Switch Gear And Protection Set 3
Q1 | The line insulation is the insulation level of the station equipment.
- less than
- same as
- more than
- not directly related with
Q2 | The interaction between a transmission line and communication lineis minimized by
- transposing transmission as well as communication lines
- increasing the height of the trans-mission line tower
- increasing the distance between the two lines
- all of the above
Q3 | When a wave propagates on a transmission line, it suffers reflection several times at
- tapping
- load end
- sending end
- sending and other end
Q4 | Which of the following statements is incorrect?
- Station batteries are used to operate relay only
- The lightning arresters are basically surge diverters
- An impedance relay has maximum fault current when fault occurs near the relay
- A high speed relay has an operation of 1 to 2 cycles
Q5 | Discrimination between main and back up protection is provided bythe use of relays which are
- fact
- sensitive
- slow
- none of the above
Q6 | Induction cup relay is operated due to changes in
- current
- voltage
- impedance
- all of the above
Q7 | A.C. network analyser is used to solve problems of
- load flow
- load flow and short-circuit
- load flow and stability
- load flow, short-circuit and stability
Q8 | Which of the following statements is incorrect ?
- Lightning arrestors are used before the switchgear
- Shunt reactors are used as compensation reactors
- The peak short current is (1.8 xV2) times the A.C. component
- The MVA at fault is equal to base MVA divided by per unit equivalent fault reactance
Q9 | Short-circuit currents are due to
- single phase to ground faults
- phase to phase faults
- two phase to ground faults
- any of these
Q10 | To reduce short circuit fault currents are used.
- reactors
- resistors
- capacitors
- none of the above
Q11 | Bus coupler is very essential in arrangement
- single bus
- double bus, double breaker
- main and transfer bus
- all of the above
Q12 | For cost and safety, the outdoor substations are installed for voltagesabove
- 11 kV
- 33 kV
- 60kV
- 110kV
Q13 | The short circuit in any winding of the transformer is the result of
- mechanical vibration
- insulation failure
- loose connection
- impulse voltage
Q14 | relays are used for phase faults on long line.
- Impedance
- Reactance
- Either of the above
- None of the above
Q15 | For which of the following protection from negative sequencecurrents is provided?
- Generators
- Motors
- Transmission line
- Tr
Q16 | relay is preferred for phase fault on short transmission line.
- Induction type
- Reactance
- Impedance
- None of the above
Q17 | Distance relays are generally
- split-phase relays
- reactance relays
- impedance relays
- none of the above
Q18 | For which of the following ratings of the transformer differentialprotection is recommended ?
- above 30 kVA.
- equal to and above 5 MVA
- equal to and above 25 MVA
- none of the above
Q19 | A _______ is used to measure the stator % winding temperature ofthe generator.
- thermocouple
- pyrometer
- resistance thermometer
- thermometer
Q20 | The under voltage relay can be used for
- generators
- busbars
- transformers
- all of the above
Q21 | The relay with inverse time characteristic will operate within
- 1.5 sec
- 5 to 10 sec
- 5 to 20 sec
- 20 to 30 sec
Q22 | The single phasing relays are used for the protection of
- single phase motors only
- two phase motors only
- two single phase motors running in parallel
- three phase motors
Q23 | Which of the following devices will receive voltage surge firsttravelling on the transmission line ?
- Lightning arresters
- Relays
- Step-down transformer
- Switchgear
Q24 | Which of the following parameter can be neglected for a short line ?
- Inductance
- Capacitance
- Resistance
- Reactance
Q25 | Series reactors should have
- low resistance
- high resistance
- low impedance
- high impedance