CL Wadhwa bits Solutions (1-7)

Lesson 2 of 21 • 119 upvotes • 14:57mins

Anvesh Sameer

1. The surge impedance of 50 miles long underground cable is 50 ohms. For a 25 miles length it will be: (a) 25 ohms (b) 50 ohms (c) 100 ohms (d) None of the above. 2. For a load flow solution the quantities normally specified at a voltage controlled bus are: (a) P and Q (b) P and |V| (c) Q and |V| (d) P and δ. 3. For reducing tower footing resistance it is better to use: (a) Chemical and ground rods only (b) Chemical and counterpoise only (c) Ground rod and counterpoise only (d) Chemical, ground rods and counterpoise. 4. The positive, negative and zero sequence impedances of a solidly grounded system under steady state condition always follow the relations: (a) Z1 > Z2 > Z0 (b) Z1 < Z2 < Z0 (c) Z0 < Z1 < Z2 (d) None of the above. 5. Mho relay is normally used for the protection of: (a) Long transmission lines (b) Medium length lines (c) Short length lines (d) No length criterion. 6. Reactance relay is normally preferred for protection against: (a) Earth faults only (b) Phase faults only (c) None of the above. 7. If the fault current is 2000 amps, the relay setting 50% and the C.T. ratio is 400/5, then the plug setting multiplier will be: (a) 25 amps (b) 15 amps (c) 50 amps (d) None of the above.