A. Radiation
B. Convection
C. Conduction
D. All of the above
A. zero sequence currents only
B. positive sequence currents only
C. negative and zero sequence currents
D. zero, negative and positive sequence currents
A balanced 3-phase system consists of_______________? Read More »
Switchgear and Protection A. no current flow
B. heavy current flow
C. voltage drop
D. voltage rise
A short-circuit is identified by_____________? Read More »
Switchgear and Protection A. earth wires
B. isolators
C. H.R.C. fuses
D. reactors
To limit short-circuit current in a power system are used______________? Read More »
Switchgear and Protection A. fault occurs on the bus itself
B. fault occurs on neutral line
C. two or more faults occur simultaneously
D. fault occurs with respect to earthing
In a single bus-bar system there will be complete shut down when____________? Read More »
Switchgear and Protection A. distribution transformer
B. generator transformer of the power plant
C. auto-transformer of the power plant
D. station transformer of the power plant
Overfluxing protection is recommended for_____________? Read More »
Switchgear and Protection A. constant for all distances
B. lower than that of if fault occurs away from the relay
C. higher than that of if fault occurs away from the relay
D. none of the above
If the fault occurs near the impedance relay, the VII ratio will be____________? Read More »
Switchgear and Protection A. transposition of the power line
B. transposition of the communication line
C. both (A) and (B)
D. increasing the distance between the conductors
A. Open circuit
B. Short-circuit
E. Long
D. None of the above
transmission line has reflection coefficient as one? Read More »
Switchgear and Protection A. 1.5 sec
B. 5 to 10 sec
C. 5 to 20 sec
D. 20 to 30 sec
E. none of the above
The relay with inverse time characteristic will operate within____________? Read More »
Switchgear and Protection