Power System - I (3140914) MCQs

MCQs of Underground Cables

Showing 81 to 90 out of 112 Questions
6 7 8 9 10 11
81.
The source of heat generation in cables is
(a) Copper loss in conductor
(b) Dielectric loss in cable insulation
(c) Losses in metallic sheath and armouring
(d) All of above
Answer:

Option (d)

82.
Cable carrying AC has
(a) Leakage losses only
(b) Hysteresis loss only
(c) Hysteresis and leakage losses
(d) Hysteresis, leakage and friction losses
Answer:

Option (c)

83.
Dielectric hysteresis loss in a cable varies as
(a) Impressed voltage
(b) (Impressed voltage)2
(c) (Impressed voltage)1/2
(d) (Impressed voltage)3/2
Answer:

Option (b)

84.
The current carrying capacity of cables in DC is more than that in AC.  It is mainly due to
(a) Smaller hysteresis losses
(b) Absence of harmonics
(c) Absence of ripples
(d) None of above
Answer:

Option (a)

85.
The fault which are likely to occur in cable is
(a) Breakdown of cable insulation
(b) Cross for short circuit fault
(c) Open circuit fault
(d) All of above
Answer:

Option (d)

86.
Lead sheath of cable may get damaged due to
(a) Mechanical  injury
(b) Crystallization of lead through vibration
(c) Chemical reaction with impurities present in a soil
(d) Any of above
Answer:

Option (d)

87.
The cables should not be operated too hot otherwise
(a) Expansion of oil may cause sheath to bust
(b) The oil may loose its viscosity and it may start drawing off from higher levels
(c) Rapid increase in dielectric losses with the temperature may cause thermal instability
(d) All of above
Answer:

Option (d)

88.
Breakdown voltage of a cable depends upon
(a) Presence of moisture
(b) Operating temperature
(c) Time of application of voltage
(d) All of above
Answer:

Option (d)

89.
Breakdown of cable insulation may occur due to
(a) Thermal instability
(b) Puncture
(c) Tracking
(d) Any of above
Answer:

Option (d)

90.
250 V cable after installation should be checked for about 15 minutes at a voltage not less than
(a) 250 V
(b) 500 V
(c) 1000 V
(d) 200 V
Answer:

Option (b)

Showing 81 to 90 out of 112 Questions
6 7 8 9 10 11