Which of the following D.C. distribution system is the simplest and lowest in first cost ?
(A) Radial system
(B) Ring system
(C) Inter-connected system
(D) None of the above
Due to which of the following reasons the cables should not be operated too hot ?
(A) The oil may loose its viscosity and it may start drawing off from higher levels
(B) Expansion of the oil may cause the sheath to burst
(C) Unequal expansion may create voids in the insulation which will lead to ionization
(D) The thermal instability may rise due to the rapid increase of dielectric losses with temperature
(D) All of the above
Which of the following methods is used for laying of underground cables ?
(A) Direct laying
(B) Draw-in-system
(C) Solid system
(D) All of the above
The operating voltage of extra high tension cables is upto_______________?
(A) 6.6 kV
(B) 11 kV
(C) 33 kV
(D) 66 kV
(D) 132 kV
The operating voltage of supertension cables is up to_________________?
(A) 3.3 kV
(B) 6.6 kV
(C) 11 kV
(D) 33 kV
The minimum clearance between the ground and a 220 kV line is about_________________?
(A) 4.3 m
(B) 5.5 m
(C) 7.0 m
(D) 10.5 m
The material commonly used for sheaths of underground cables is______________?
(A) lead
(B) rubber
(C) copper
(D) iron
The material generally used for armour of high voltage cables is_____________?
(A) aluminium
(B) steel
(C) brass
(D) copper
In transmission lines the cross-arms are made of________________?
(A) copper
(B) wood
(C) R.C.C.
(D) steel
The power factor of industrial loads is generally______________?
(A) unity
(B) lagging
(C) leading
(D) zero