MCQ
781. Inverse time current relays are used for the protection of-
Feeders
Transformers
Alternators
Both A and B
782. The operating speed of a relay depends upon the-
Rate of flux built up
Armature core air gap
Spring tension
All of these
783. Factors on which soil resistance depends/RPCI--
depth of the electrode
moisture
Nacl
all the above
784. The main function of a fuse is to-
Protect the line
Open the circuit
Prevent excessive currents
None of the above
785. A thermal protection switch can protect against-
Short-circuit
Overload
Temperature
Over voltage
786. An ideal location for the substation would be at ---the of load.
Centre of gravity
Load centre
Nearer to consumer
None of the above
787. Admittance relay-
Non-directional relay
Directional relay
Differential relay
None of the above
788. The relay used for feeder protection --
Under voltage relay
Translay relay
Thermal relay
Buchholz relay
789. In SF6 circuit breakers, the SF, gas-
has insulating properties
is non-inflammable
is non-poisonous
all of the above
790. Average resistance of human body is-
500 ohms
1000 ohms
1500 ohms
2000 ohms
791. Where severe synchronising swing occur, the relay employed is
Impedance relay
Mho relay
Reactance relay
Induction relay
792. A circuit breaker is essentially-
an automatic switch
a manual switch
a high-lightning arrester
none of the above
793. The most severe fault on the power system is-
there phase short circuit
line to line fault
double line to ground fault
single line to ground fault
794. In aluminium conductors, steel core is provided to-
compensate for skin effect
neutralise proximity effect
reduce line inductance
increases the tensile strength
795. A fuse is a--
protective device
current limiting device
current controling device
none of the above
796. In sheet metal blanking, shear is provided on punches and dies so that--
press load is reduced
good cut edge in obtained
warping of sheet is minimized
cut blanks are straight
797. IDMT relays are used to protect the power transformers against-
External short-circuit
Overloads
Internal short-circuits
Both (a) and (b)
798. For the protection of lines against faults Involving variable fault resistance, the preferred relaying scheme is a-
Plain impedance relay
Directional over-current relay
Mho relay
Reactance relay
799. Outdoor sub-station requires-space.
Less
More
Medium
Any of the above
800. For ground fault we prefer-
Plain impedance relay
Directional over current relay
Mho relay
Reactance relay