Testing And Commissioning Of Electrical Equipment’S Set 2
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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 2
Q1 | When a transmission line is energized, the wave that propagates on it is
- current wave only
- voltage wave only
- both (A) and (B)
- power factor wave only
Q2 | Protective relays are devices that detect abnormal conditions in electrical circuits by measuring
- current during abnormal condition
- voltage during abnormal condition
- constantly the electrical quantities which differ during normal and abnormal conditions
- none of the above
Q3 | The voltage appearing across the contacts after opening of the circuit breaker iscalled______voltage.
- recovery
- surge
- operating
- arc
Q4 | Ionization in circuit breaker is facilitated by
- high temperature
- increase of mean free path
- increasing field strength
- all of the above
Q5 | In a circuit breaker the basic problem is to
- maintain the arc
- extinguish the arc
- transmit large power
- emit the ionizing electrons
Q6 | Overheating of relay contacts or contact born out is due to
- slow making and breaking of load circuit contacts
- foreign matter on the contact surface
- too low contact pressure
- all of the above
Q7 | Interruption of large currents by relay requires
- arc suppressing blow out coils
- wide separation of the opened contacts
- high speed opening of contacts
- all of the above
Q8 | Shunt capacitance is neglected while considering
- short transmission line
- medium transmission line
- long transmission line
- medium and long transmission lines
Q9 | The arc voltage produced in A.C. circuit breaker is always
- in phase with the arc current
- lagging the arc current by 90?
- leading the arc current by 90°
- none of the above
Q10 | The time of closing the cycle, in modern circuit breakers is
- 0.003 sec
- 0.001 sec
- 0.01 sec
- 0.10 sec
Q11 | Insulation resistance of high voltage circuit breakers is more than
- 1 mega ohms
- 10 mega ohms
- 100 mega ohms
- 500 mega ohms
Q12 | H.R.C. fuses provide best protection against
- overload
- reverse current
- open-circuits
- short-circuits
Q13 | The ground wire should not be smaller than No ______ copper.
- 2
- 4
- 6
- 10
Q14 | The delay fuses are used for the protection of ________.
- motors
- power outlet circuits
- fluorescent lamps
- light circuits
Q15 | Which of the following is the least expensive protection for overcurrent is lowvoltage system ?
- Rewireable fuse
- Isolator
- Oil circuit breaker
- Air break circuit breaker
Q16 | Resistance grounding is used for voltage between
- 33kVto66kV
- HkVto33kV
- 3.3kVandllkV
- none of the above
Q17 | The contacts of high voltage switches used in power system are submerged in oil.The main purpose of the oil is to
- lubricate the contacts
- insulate the contacts from switch body
- extinguish the arc
- all of the above
Q18 | In Railway applications ______ circuit breaker is used.
- SFe
- bulk oil
- minimum oil
- air break
Q19 | To protect most of the electrical equipment handling low power, the types of relaysused are
- thermocouple
- electronic and bimetallic
- both (A) and (B)
- none of the above
Q20 | Wave trap is used to trap waves of
- power frequencies
- higher frequencies entering generator or transformer units
- either of the above
- none of the above
Q21 | Ungrounded neutral transmission system is not recommended because of system
- insulation being overstressed due to over voltages
- insulation overstress may lead to failure and subsequent phase to phase faults
- being inadequately protected against ground fault
- all of the above
Q22 | The reflection co-efficient at the open circuited end of a transmission line.
- zero
- infinity
- unity
- none of the above
Q23 | For the protection of power station buildings against direct strokes the requirementsare
- interception
- interception and conduction
- interception, conduction and dissipation
- interception, conduction, dissipation and reflection
Q24 | The interaction between a transmission line and communication line is 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
Q25 | When a wave propagates on a transmission line, it suffers reflection several times at
- tapping
- load end
- sending end
- sending and other end