Testing And Commissioning Of Electrical Equipment’S Set 3
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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 3
Q1 | 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
Q2 | Discrimination between main and back up protection is provided by the use ofrelays which are
- fact
- sensitive
- slow
- none of the above
Q3 | Induction cup relay is operated due to changes in
- current
- voltage
- impedance
- all of the above
Q4 | 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
Q5 | 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
Q6 | To reduce short circuit fault currents are used.
- reactors
- resistors
- capacitors
- none of the above
Q7 | Bus coupler is very essential in arrangement
- single bus
- double bus, double breaker
- main and transfer bus
- all of the above
Q8 | For cost and safety, the outdoor substations are installed for voltages above
- 11 kV
- 33 kV
- 60kV
- 110kV
Q9 | The short circuit in any winding of the transformer is the result of
- mechanical vibration
- insulation failure
- loose connection
- impulse voltage
Q10 | relays are used for phase faults on long line.
- Impedance
- Reactance
- Either of the above
- None of the above
Q11 | For which of the following protection from negative sequence currents is provided ?
- Generators
- Motors
- Transmission line
- Transformers
Q12 | relay is preferred for phase fault on short transmission line.
- Induction type
- Reactance
- Impedance
- None of the above
Q13 | Distance relays are generally
- split-phase relays
- reactance relays
- impedance relays
- none of the above
Q14 | For which of the following ratings of the transformer differential protection is recommended ?
- above 30 kVA.
- equal to and above 5 MVA
- equal to and above 25 MVA
- none of the above
Q15 | A _______ is used to measure the stator % winding temperature of the generator.
- thermocouple
- pyrometer
- resistance thermometer
- thermometer
Q16 | The relay with inverse time characteristic will operate within
- 1.5 sec
- 5 to 10 sec
- 5 to 20 sec
- 20 to 30 sec
Q17 | 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
Q18 | Which of the following devices will receive voltage surge first travelling on thetransmission line ?
- Lightning arresters
- Relays
- Step-down transformer
- Switchgear
Q19 | Which of the following parameter can be neglected for a short line ?
- Inductance
- Capacitance
- Resistance
- Reactance
Q20 | Series reactors should have
- low resistance
- high resistance
- low impedance
- high impedance
Q21 | Which of the following circuit breakers has high reliability and minimummaintenance ?
- Air blast circuit breakers
- Circuit breaker with SF6 gas
- Vacuum circuit breakers
- Oil circuit breakers
Q22 | Arc in a circuit breaker is interrupted at
- zero current
- maximum current
- minimum voltage
- maximum voltage
Q23 | transmission line has reflection coefficient as one.
- Open circuit
- Short-circuit
- Long
- None of the above
Q24 | What will be the reflection co-efficient of the wave of load connected to transmission line if surge impedance of the line is equal to load ?
- Zero
- Unity
- Infinity
- None of the above
Q25 | The inverse definite mean time relays are used for over current and earth fault protection of transformer against
- heavy loads
- internal short-circuits
- external short-circuits
- all of the above