Switchgear Protections MCQ

Test your knowledge with important Switchgear Protections MCQ and their applications. These MCQs are beneficial for competitive exams too. Explore 30+ more Switchgear Protections MCQs on Bissoy. Bissoy App

• The information to the circuit breaker under fault conditions is provided by
  ক

  relay

  খ

  rewirable fuse

  গ

  H.R.'only

  ঘ

  all of the above
• The main function of a fuse is to
  ক

  protect the line

  খ

  open the circuit

  গ

  protect the appliance

  ঘ

  prevent excessive currents

  ঙ

  none of the above
• For the protection of power station buildings against direct strokes the requirements are
  ক

  interception

  খ

  interception and conduction

  গ

  interception, conduction and dissipation

  ঘ

  interception, conduction, dissipation and reflection

  ঙ

  none of the above
• ________ relay is preferred for phase fault on short transmission line.
  ক

  Induction type

  খ

  Reactance

  গ

  Impedance

  ঘ

  None of the above
• D.C. shunt relays are made of
  ক

  few turns of thin wire

  খ

  few turns of thick wire

  গ

  many turns of thin wire

  ঘ

  many turns of thick wire
• H.R.C. fuses provide best protection against
  ক

  overload

  খ

  reverse current

  গ

  open-circuits

  ঘ

  short-circuits
• To reduce short circuit fault currents are used.
  ক

  reactors

  খ

  resistors

  গ

  capacitors

  ঘ

  none of the above
• Overheating of relay contacts or contact born out is due to
  ক

  slow making and breaking of load circuit contacts

  খ

  foreign matter on the contact surface

  গ

  too low contact pressure

  ঘ

  all of the above
• Circuit breakers usually operate under
  ক

  transient state of short-circuit current

  খ

  sub-transient state of short-circuit current

  গ

  steady state of short-circuit current

  ঘ

  after D. C. component has ceased
• An isolator is installed
  ক

  to operate the relay of circuit breaker

  খ

  as a substitute for circuit breaker

  গ

  always independent of the position of circuit breaker

  ঘ

  generally on both sides of a circuit breaker
• Air blast circuit breakers for 400 kV power system are designed to operate in
  ক

  100 microsecond

  খ

  50 millisecond

  গ

  0.5 sec

  ঘ

  0.1 sec
• SF₆ gas
  ক

  Is yellow in colour

  খ

  Is lighter than air

  গ

  Is nontoxic

  ঘ

  Has pungent small

  ঙ

  None of the above
• Wave trap is used to trap waves of
  ক

  power frequencies

  খ

  higher frequencies entering generator or transformer units

  গ

  either of the above

  ঘ

  none of the above
• A fuse in a motor circuit provides protection against
  ক

  overload

  খ

  short-circuit and overload

  গ

  open circuit, short-circuit and overload

  ঘ

  none of the above
• To protect most of the electrical equipment handling low power, the types of relays used are
  ক

  Thermocouple

  খ

  Electronic and bimetallic

  গ

  Both (A) and (B)

  ঘ

  None of the above
• For which of the following protection from negative sequence currents is provided ?
  ক

  Generators

  খ

  Motors

  গ

  Transmission line

  ঘ

  Transformers
• Distance relays are generally
  ক

  split-phase relays

  খ

  reactance relays

  গ

  impedance relays

  ঘ

  none of the above
• An efficient and a well designed protective relaying should have
  ক

  good selectivity and reliability

  খ

  economy and simplicity

  গ

  high speed and selectivity

  ঘ

  all of the above
• Insulation resistance of high voltage circuit breakers is more than
  ক

  1 mega ohms

  খ

  10 mega ohms

  গ

  100 mega ohms

  ঘ

  500 mega ohms
• Series reactors should have
  ক

  low resistance

  খ

  high resistance

  গ

  low impedance

  ঘ

  high impedance
• A _______ is used to measure the stator % winding temperature of the generator.
  ক

  thermocouple

  খ

  pyrometer

  গ

  resistance thermometer

  ঘ

  thermometer
• With which of the following, a circuit breaker must be equipped for remote operation ?
  ক

  Inverse time trip

  খ

  Time-delay trip

  গ

  Shunt trip

  ঘ

  None of the above

  ঙ

  All of the above
• A switchgear is device used for
  ক

  Interrupting an electrical circuit

  খ

  Switching an electrical circuit

  গ

  Switching and controlling an electrical circuit

  ঘ

  Switching, controlling and protecting the electrical circuit and equipment
• A differential relay measures the vector difference between
  ক

  two currents

  খ

  two voltages

  গ

  two or more similar electrical quantities

  ঘ

  none of the above
• In a single bus-bar system there will be complete shut down when
  ক

  fault occurs on the bus itself

  খ

  fault occurs on neutral line

  গ

  two or more faults occur simultaneously

  ঘ

  fault occurs with respect to earthing
• Series capacitors are used to
  ক

  compensate for line inductive reactance

  খ

  compensate for line capacitive reactance

  গ

  improve line voltage

  ঘ

  none of the above
• To limit short-circuit current in a power system are used
  ক

  earth wires

  খ

  isolators

  গ

  H.R. fuses

  ঘ

  reactors
• The contacts of high voltage switches used in power system are submerged in oil. The main purpose of the oil is to
  ক

  lubricate the contacts

  খ

  insulate the contacts from switch body

  গ

  extinguish the arc

  ঘ

  all of the above

  ঙ

  none of the above
• The single phasing relays are used for the protection of
  ক

  single phase motors only

  খ

  two phase motors only

  গ

  two single phase motors running in parallel

  ঘ

  three phase motors
• The power loss is an important factor for the design of
  ক

  transmission line

  খ

  motor

  গ

  generator

  ঘ

  feeder