Electrical Power Systems

448 Electrical Power Systems
(a) overheating of generator
(b) overheating of generator and neutral resistors of earthing transformer
(c) overheating of earthing transformer only
(d) none of the above.
12. The effect of electric shock in the human body will depend on
(a) line voltage (b) line current
(c) current flowing in the body (d) none of the above.
13. To protect the power transformer (Y – Y, with neutral grounded) against fault, the CT will
have
(a) D – D connection (b) D – Y connection
(c) Y – D connection (d) Y – Y connection.
14. The class C insulation can withstand
(a) 180ºC (b) 150ºC (c) 200ºC (d) 105ºC
15. The location of the lightning arresters is
(a) near the transformer (b) away from the transformer
(c) near the circuit breaker (d) away from the circuit breaker.
16. Which of the following distribution systems gives the greater reliability
(a) radial system (b) ring system
(c) DC three wire system (d) open loop system.
17. In the transformers
(a) high tension winding is used near the core
(b) high tension winding is used away from the core
(c) low tension winding is used near the core
(d) low tension winding is used away from the core.
18. The effect of series capacitor on a transmission line is to improve the
(a) steady state stability (b) transient stability
(c) (a) and (b) both (d) none of the above.
19. The power intended to be available even under emergency condition is called
(a) firm power (b) hot reserve (c) cold reserve (d) spinning reserve.
20. Two transmission lines of the surge impedance of 600 ohms each is linked by a cable. What
should be the surge impedance of the cable if there were no reflection at the junction?
(a) 300 ohms (b) 30 ohms (c) 600 ohms (d) 60 ohms.
21. or 11 KV underground system, it is possible to work upon a length of
(a) 800 miles (b) 100 miles (c) 400 miles (d) 10 miles.
22. Series capacitors are used to
(a) improve the line voltage
(b) compensate for line inductive reactance
(c) compensate for line capacitive reactance
(d) none of the above.
23. The short circuit in any windings of the transformer is the result of
(a) impulse voltage (b) insulation failure
(c) mechanical vibrations (d) loose connection.
24. Split–phase relaying responds to faults between turns of a transformer
(a) true (b) false.
25. Which of the following relays are used for phase fault on long line?
(a) impedance relays (b) reactance relays
(c) MHO relays (d) over current relays.