CL wadhwa bits solutions (59-65)

Lesson 11 of 21 • 34 upvotes • 11:04mins

Anvesh Sameer

59. Tick out the correct one: (a) The insulators and lightning arresters should have high impulse ratio (b) The insulators and lightning arresters should have low impulse ratio (c) The insulator should have high impulse ratio and lightning arrester low (d) The lightning arrester should have high impulse ratio but insulator low. 60. Phase modifier is normally installed in the case of: (a) Short transmission lines (b) Medium length lines (c) Long length lines (d) For all length lines. 61. Series compensation on EHV lines is resorted to: (a) Improve the stability (b) Reduce the fault level (c) Improve the voltage profile (d) As a substitute for synchronous phase modifier. 62. Ferranti effect on long overhead lines is experienced when it is: (a) Lightly loaded (b) On full load at unity p.f. (c) On full load at 0.8 p.f. lag (d) In all these cases. 63. Stringing chart is useful for: (a) Finding the sag in the conductor (b) In the design of tower (c) In the design of insulator string (d) Finding the distance between the tower.   
 64. The presence of earth in case of overhead lines: (a) Increases the capacitance (b) Increases the inductance (c) Decreases the capacitance (d) Decreases the inductance. 65. For an existing a.c. transmission line the string efficiency is 80%. Now if d.c. voltage is supplied for the same set up, the string efficiency will be: (a) 80% (b) More than 80% (c) Less than 80% (d) 100%.