Power System, Transmission & Distribution Test Questions Start Creating PDF

MCQ: What is the safe working temperature for a conductor in case of armoured cables?

1. 50° C
2. 75° C
3. 65° C
4. 40° C

MCQ: The capacitances of a 3 phase belted cable are 12.6 μ F between the three cores bunched together and the lead sheath and 7.4 μ F between one core and the other two connected to sheath. What will be the charging current drawn by the cable when connected to a 66 kV supply?

1. 100 A
2. 99.3648 A
3. 105.236 A
4. 107.74 A

MCQ: What is the source of heat generation in cables?

1. Copper loss in conductor
2. Dielectric losses in cable insulation
3. Losses in metallic sheathings and armouring
4. All of these

MCQ: In a 3 core cable, the capacitance between two conductors is 3 μF. What will be the capacitance per phase?

1. 1.5 μ F
2. 3 μ F
3. 6 μ F
4. 12 μ F

MCQ: What does capacitance grading of cables mean?

1. Use of dielectrics in different concentrations
2. Introduction of capacitance at various lengths of cable to counter the effect of inductance
3. Use of dielectrics of different permittivities
4. Grading according to capacitance per km length of the cable

MCQ: What will be the most economical value of diameter of a single core cable to be used on 50 kV, single phase system, when the maximum permissible stress is not exceeding 50 kV / cm?

1. 2.52 cm
2. 2.828 cm
3. 3.52 cm
4. 3.82 cm

MCQ: What will be the insulation thickness for a conductor of diameter 2 cm, with maximum and minimum stress 40 kV / cm rms and 10 kV / cm rms respectively?

1. 5 cm
2. 3 cm
3. 2 cm
4. 4 cm

MCQ: What is the maximum stress in the insulation for a 33 kV single core cable with a diameter of 1 cm and a sheath of inside diameter 4 cm?

1. 50.61 kV / cm rms
2. 45.231 kV / cm rms
3. 47.61 kV / cm rms
4. 49.231 kV /cm rms

MCQ: What is the total charging current per phase for a 33 kV, 50 Hz, 3 phase underground cable of 4 km length using 3 single core cables? Each conductor has a diameter of 2.5 cm and the radial thickness of insulation is 0.5 cm.

1. 15.28 A
2. 11.87 A
3. 13.85 A
4. 8.25 A

MCQ: A single core cable has a conductor diameter of 1 cm and the internal sheath diameter of 1.8 cm. If impregnated paper of relative permittivity 4 is used as the insulation, calculate the capacitance for 1 km length of cable?

1. 0.378 μ F
2. 0.257 μ F
3. 0.549 μ F
4. 0.78 μ F