MCQ's of Power Systems

 01. Which of the following protects a cable against mechanical injury ?

1 point

(a) Bedding

(b) Sheath

(c) Armouring

(d) None of the above

02. Which of the following insulation is used in cables ?

1 point

(a) Varnished cambric

(b) Rubber

(c) Paper

(d) Any of the above

03. The thickness of the layer of insulation on the conductor, in cables, depends upon

1 point

(a) reactive power

(b) power factor

(c) voltage

(d) current carrying capacity

04. The insulating material for cables should

1 point

(a) be acid proof

(b) be non-inflammable

(c) be non-hygroscopic

(d) have all above properties

05. The current carrying capacity of cables in D.C. is more than that in A.C. mainly due to

1 point

(a) absence of harmonics

(b) non-existence of any stability limit

(c) smaller dielectric loss

(d) absence of ripples

06. In case of three core flexible cable the colour of the neutral is

1 point

(a) blue

(b) black

(c) brown

(d) none of the above

07. Conduit pipes are normally used to protect _____ cables.

1 point

(a) unsheathed cables

(b) armoured

(c) PVC sheathed cables

(d) all of the above

08. The minimum dielectric stress in a cable is at

1 point

(a) armour

(b) bedding

(c) conductor surface

(d) lead sheath

09. Dielectric strength of rubber is around

1 point

(a) 5 kV/mm

(b) 15 kV/mm

(c) 30 kV/mm

(d) 200 kV/mm

10. The surge resistance of cable is

1 point

(a) 5 ohms

(b) 20 ohms

(c) 50 ohms

(d) 100 ohms

11. PVC stands for

1 point

(a) polyvinyl chloride

(b) post varnish conductor

(c) pressed and varnished cloth

(d) positive voltage conductor

12. In the cables, the location of fault is usually found out by comparing

1 point

(a) the resistance of the conductor

(b) the inductance of conductors

(c) the capacitances of insulated conductors

(d) all above parameters

13. The material for armoring on cable is usually

1 point

(a) steel tape

(b) galvanised steel wire

(c) any of the above

(d) none of the above

14. The relative permittivity of rubber is

1 point

(a) between 2 and 3

(b) between 5 and 6

(c) between 8 and 10

(d) between 12 and 14

15. In cables the charging current

1 point

(a) lags the voltage by 90°

(b) leads the voltage by 90°

(c) lags the voltage by 180°

(d) leads the voltage by 180°

16. In the cables, sheaths are used to

1 point

(a) prevent the moisture from entering the cable

(b) provide enough strength

(e) provide proper insulation

(d) none of the above

17. In a cable the voltage stress is maximum at

1 point

(a) sheath

(b) insulator

(c) surface of the conductor

(d) core of the conductor

18. The advantage of cables over overhead transmission lines is

1 point

(a) easy maintenance

(b) low cost

(c) can be used in congested areas

(d) can be used in high voltage circuits

19. Which of the following distribution systems is more reliable ?

1 point

(a) Radial system

(b) Tree system

(c) Ring main system

(d) All are equally reliable

20. Transmission voltage of 11 kV is normally used for distances upto

1 point

(a) 20—25 km

(b) 40—50 km

(c) 60—70 km

(d) 80—100 km

Post a Comment

Previous Post Next Post