POWER SYSTEMS MCQS SET 01

POWER SYSTEMS MCQS SET 01

1. Single core cables for AC systems are not provided with armouring.
a) True             b) False
Answer: a

2. Single core cables for ac systems are provided with armouring.
a) True           b) False
Answer: a
3. For a transmission system of voltage ‘765 kV’ volts having the core radius of ‘5’ cm and outer radius of ‘0.40’ m. The maximum dielectric stress on single core cable is _________
a) 7357.7 kV         b) 919.7 kV      c) 4247 kV    d) 530 kV
Answer: a
 

4. The ratio of dielectric stress of the on the cable corresponding to the maximum and minimum is ____
a) R/r         b) r/R            c) rR           d) (R/r)2
Answer: a
5. The condition at which the minimized dielectric stress condition (R/r) will take place is ______
a) 2.7188     b) 0.7188    c) 1/2.7188       d) 2.71882
Answer: a
6. Grading of the cables is performed in order to achieve ____________
(i) uniform stress
(ii) reduction in quantity of insulation
(iii) reduction in quality of insulation
a) (i), (ii)       b) (ii)         c) (i),(iii)          d) (ii), (iii)
Answer: a

7. The resistance of the insulation used for the cables is 40 ohms for a length of ‘x’ km. If the proposed plan needs to extend the transmission line cable to extra ‘2x’ m then the resistance of the cable offered will be _____________ (in ohms).
a) 13.33     b) 20          c) 120      d) 40
Answer: a
 

8. Dielectric power loss of a transmission line cable operating for ‘V’ volts, ‘f’ Hz having a capacitance of ‘C’ Farads with the tangent loss angle of δis ____________
a) ωCV2 tanδ        b) ωCV2/tanδ      c) (tanδ/ωCV)2      d) ωCV2 tanδ2
Answer: a