Electrical Cables Multiple Choice Questions and Answers for Practice

16. In a cable the voltage stress is maximum at

1. sheath
2. insulator
3. surface of the conductor
4. core of the conductor

17. In a cable, the maximum stress under operating conditions is at

1. insulation layer
2. sheath
3. armour
4. conductor surface

18. In cables the charging current

1. lags the voltage by 90°
2. leads the voltage by 90°
3. lags the voltage by 180°
4. leads the voltage by 180°

19. In capacitance grading of cables we use a....................dielectric

1. composite
2. porous
3. homogeneous
4. hygroscopic

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

1. blue
2. black
3. brown
4. none of the above

21. In single core cables armouring is not done to

1. avoid excessive sheath losses
2. make it flexible
3. either of the above
4. none of the above

22. In the cables, sheaths are used to

1. prevent the moisture from entering the cable
2. provide enough strength
3. provide proper insulation
4. none of the above

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

1. the resistance of the conductor
2. the inductance of conductors
3. the capacitances of insulated conductors
4. all above parameters

24. Is a cable is to be designed for use on 1000 kV, which insulation would you prefer ?

1. Polyvinyle chloride
2. Vulcanised rubber
3. Impregnated paper
4. Compressed SFe gas

25. Low tension cables are generally used upto

1. 200 V
2. 500 V
3. 700 V
4. 1000 V

26. Pressure cables are generally not used beyond

1. 11 kV
2. 33 kV
3. 66 kV
4. 132 kV

27. PVC stands for

1. polyvinyl chloride
2. post varnish conductor
3. pressed and varnished cloth
4. positive voltage conductor

28. Solid type cables are considered unreliable beyond 66 kV because

1. insulation may melt due to higher temperature
2. skin effect dominates on the conduc¬tor
3. of corona loss between conductor and sheath material
4. there is a danger of breakdown of insulation due to the presence of voids

29. The advantage of cables over overhead transmission lines is

1. easy maintenance
2. low cost
3. can be used in congested areas
4. can be used in high voltage circuits

30. The advantage of oil filled cables is

1. more perfect impregnation
2. smaller overall size
3. no ionisation, oxidation and formation of voids
4. all of the above