Q.1
Arc in a circuit behaves as
Q.2
Overload relays are of type.
Q.3
Ionization in circuit breaker is facilitated by
Q.4
Arc in a circuit breaker is interrupted at
Q.5
Admittance relay is _______ relay.
Q.6
The voltage appearing across the contacts after opening of the circuit breaker is called______voltage.
Q.7
The material used for fuse must have
Q.8
A fuse is connected
Q.9
The reflection co-efficient at the open circuited end of a transmission line.
Q.10
Protection by fuses is generally not used beyond
Q.11
H.R.C. fuse, as compared to a rewirable fuse, has
Q.12
The inverse definite mean time relays are used for over current and earth fault protection of transformer against
Q.13
Which of the following devices will receive voltage surge first travelling on the transmission line ?
Q.14
For cost and safety, the outdoor substations are installed for voltages above
Q.15
The ground wire should not be smaller than No ______ copper.
Q.16
The relay with inverse time characteristic will operate within
Q.17
H.R.C. fuse, as compared to a rewirable fuse, has
  • no ageing effect
  • high speed of operation
  • high rupturing capacity
  • all of the above
Q.18
Overfluxing protection is recommended for
  • distribution transformer
  • generator transformer of the power plant
  • auto-transformer of the power plant
  • station transformer of the power plant
Q.19
Over voltage protection is recommended for
  • hydro-electric generators
  • steam turbine generators
  • gas turbine generators
  • all of the above
  • E. none of the above
Q.20
The short circuit in any winding of the transformer is the result of
  • mechanical vibration
  • insulation failure
  • loose connection
  • impulse voltage
Q.21
Which of the following is the least expensive protection for overcurrent is low voltage system ?
  • Rewireable fuse
  • Isolator
  • Oil circuit breaker
  • Air break circuit breaker
  • E. None of the above
Q.22
Circuit breakers are essentially
  • current carrying contacts called electrodes
  • arc extinguishers
  • circuits to break the system
  • transformers to isolate the two systems
  • E. any of the above
Q.23
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
Q.24
A fuse is never inserted in
  • neutral wire
  • negative of circuit
  • positive of circuit
  • phase dine
Q.25
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
Q.26
Which of the following medium is employed for extinction of arc in air circuit breaker ?
  • Water
  • Oil
  • Air
  • SF6
Q.27
When a wave propagates on a transmission line, it suffers reflection several times at
  • tapping
  • load end
  • sending end
  • sending and other end
  • E. all of the above
Q.28
The fuse blows off by
  • burning
  • arcing
  • melting
  • none of the above
Q.29
The relay operating speed depends upon
  • the spring tension
  • the rate of flux built up
  • armature core air gap
  • all of the above
Q.30
If the fault occurs near the impedance relay, the VII ratio will be
  • constant for all distances
  • lower than that of if fault occurs away from the relay
  • higher than that of if fault occurs away from the relay
  • none of the above
0 h : 0 m : 1 s