MCQ
801. -relays are preferred for phase fault on short transmission line
Induction type
Reactance
Impedance
None of the above
802. 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
803. DC shunt relays are made of--
Few turns of thin wire
Few turns of thick wire
Many turns of thin wire
Many turns of thick wire
804. -relays are used for phase faults on long line.
Impedance
Reactance
Mho
Either of the above
805. A bus-bar is rated by-
Current only
Voltage only
Current, voltage and frequency
Current, voltage, frequency and short circuit current
806. The relay operating speed depends upon-
The spring tension
The rate of flux built up
Armature core air gap
All of the above
807. The relay with inverse time characteristic will operate within--
1.5 sec
5 to 20 sec
5 to 10 sec
20 to 30 sec
808. Both voltage and current signals are required for-
A plain over-current relay
A differential relay
A directional relay
A biased directional relay
809. The over-voltage surge in power systems may be caused by-
Lightning
Resonance
Switching
All of the above
810. The material used for bus-bar should have-
Low resistivity
Low cost
High-softening temperature
All of the above
811. The relay used for phase fault protection of short transmission lines is-
Reactance relay
Mho relay
Impedance relay
IDMT relay
812. When an alternator connected to the bus-bar is shut down the bus-bar voltage will --
Fall
Rise
Remain unchanged
None of the above
813. Which of the following can be used for bus-bars?
Tubes
Bars
Rods
Any of the above
814. Which of the following bus-bar schemes has the lowest cost?
Ring bus-bar scheme
Single bus-bar scheme
Breaker and a half scheme
Main and transfer scheme
815. Which of the following equipment is used to limit short circuit current level in a sub-station?
Isolator
Lightning switch
Coupling capacitor
Series reactor
816. The voltage of a particular bus is regulated by controlling the --
Active power of the bus
Reactive power of the bus
Phase angle
Phase angle and reactive power
817. In the case of transmission line protection, over current relay is used-
Only up to 110kV
Only up to 220kV
Only up to 50k V
Only up to 1100k V
818. Surge absorbers are used for protection against-
High-voltage low-frequency oscillations
High-voltage high-frequency oscillations
Low-voltage high-frequency oscillations
Low-voltage low-frequency oscillations
819. The bus-bar zone, the purpose of protection includes-and-
Bus-bars, isolating switches, circuit breakers
Transformers, relays, circuit breakers
Transformers, conductors and relays
None of the above
820. The under voltage relay can be used for--
Generators
Bus bars
Transformers
All of the above