MCQ
1421. Which of the following rotor is used in thermal power plants?
cylindrical rotor
salient pole rotor
squirrel cage rotor
either of these
1422. When power is to be transmitted over a distance of 250km, the transmission voltage should be-
66kV
132kV
33kV
11kV
1423. ACSR means-
Aluminium core steel reinforced
Aluminium conductor steel reinforced
Aluminium copper steel reinforced
reinforced all conductor steel
1424. Four identical alternators each are rated for 20 MVA, 11KV having a subtransient reactance of 16% are working in parallel. The short circuit level at the busbar is-
500 MVA
400 MVA
125 MVA
100 MVA
1425. If the frequency is increased, then skin effect will—
increases
decreases
remains unaffected
any of the above
1426. Find the number of strands of ACSR conductor for 4 layer transmission line.
1
67
37
2
1427. Suspension insulators are used when transmission voltage is-
high
low
fluctuating
steady
1428. Surge impedance loading of a 3-phase, 400k Y transmission line is 4002. The surge impedance loading is-
400MW
1600MW
800MW
200MW
1429. Plog setting of a relay can be altered by varying-
air gap of magnetic path
adjustable back up stop
no. of ampere-turns
none of these
1430. The presence of earth in case of overhead lines-
increase inductance
increase capacitance
decrease inducatance
decrease capacitance
1431. Proximity effect is more in case of-
power cables
same in both cases
overhead lines
none of the above
1432. Length of the cable is doubled, its capacitance C will be-
one-fourth
doubled
one-half
unchanged
1433. If the fault current is 2000A, the relay setting is 50% and CT ratio is 400: 5, then plug setting multiplier will be-
10
25
15
50
1434. The skin effect shows that-
the distribution of AC current is uniform through the cross section of the conductor
current density is more at the centre of the condutor
current density is lower at the surface of the condutor
current density is more at the surface of the condutor
1435. India's largest thermal power station is located at--
Madhya Pradesh
Neyveli
Kota
Chandrapur
1436. Interference between a power line and a communication line is due to-
electromagnetic induction
electrostatic induction
electromagnetic and electrostatic induction.
none of the above
1437. The charging reactance of 50km transmission line is 1500Ω. What is the charging reactance for 100km length of line?
1500 Ω
750 Ω
300 Ω
1000 Ω
1438. Objectives of power system is/are-
Cost of electrical energy per kWh is to be minimum
Rated voltage and frequency has to be supplied to the consumers
both 1 and 2
nether 1 nor 2
1439. The skin effect of conductor will increase when-
diameter decrease
resistivity decrease
frequency decrease
all of the above
1440. The volume of copper required for an ac transmission line is inversely proportional to-
current
voltage
power factor
both b & c