A circuit is disconnected by isolators when____________?

Owing to skin effect:

A. current flows through the half cross-section of the conductor
B. portion of the conductor near the surface carries more current and core of the conductor carries less current
C. portion of the conductor near the surface carries less current and core of the conductor carries more cur¬rent
D. any of the above
E. none of the above

Overhead lines generally use__________________?

A. copper conductors
B. all aluminium conductors
C. A.C.S.R. conductors
D. none of these

The phenomenon qf rise in voltage at the receiving end of the open-circuited or lightly loaded line is called the________________?

A. Seeback effect
B. Ferranti effect
C. Raman effect
D. none of the above

The angular displacement between two interconnected stations is mainly due to___________?

A. armature reactance of both alternators
B. reactance of the interconnector
C. synchronous reactance of both the alternators
D. all of the above

jCorona usually occurs when the electrostatic stress in air around the conductor exceeds?

A. 6.6 kV (r.m.s. value)/cm
B. 11 kV (r.m.s. value)/cm
C. 22 kV (maximum value)/cm
D. 30 kV (maximum value)/cm

Besides a method of trial and error, which of the following methods is employed for solution of network problems in interconnected system ?

A. Circulating current method
B. Thevenin’s theorem
C. Superposition of currents
D. Direct application of Kirehhoffs laws
E. All of the above