61
Insulation resistance of a cable decreases with
Answer: Increases in the length of the insulation of cable
Questions
62
Size of the earth wire is determined by
Answer: The ampere capacity of the service
63
As per Indian Standards, the cross-sectional area of the neutral wire in a 3-phase 4 wire system is
Answer: One-fourth that of a phase conductor
64
The characteristic impedance of a lossless cable is typically
Answer: 40 to 60 Ω
65
Visual corona takes place in parallel wires at a voltage
Answer: Higher than disruptive critical voltage
67
If fault occurs near an impedance relay, the V I ratio is
Answer: Lower than the value if fault occurs away from the relay
69
During rains, the direct capacitance of suspension type insulator
Answer: Decreases
71
To increases the power transmitting capacity of a transmission line we
Answer: Increases its line capacitance
72
For a power system, to be stable, the phase constant β of its transmission line should be
Answer: (RL -RO)/(RL +RO )
73
In a transmission line, the shunt conductance results due to
Answer: Leakage over the insulator
74
Any voltage surge travelling on the transmission line first enters
Answer: Lightning arrestor
75
The sag of a transmission line is affected by
Answer: Both (a) and (b) above
76
Which of the following system is preferred for good efficiency and high economy in distribution system?
Answer: 3 phase 3 wire system
77
Breakdown of insulation of a cable can be avoided economically by the use of
Answer: Both (a) and (b) above
78
For most reliable distribution supply, the configuration used is
Answer: Ring main
79
ACSR is used for transmission of power in preference to copper conductors because
Answer: It is more economical
