Power Systems (Transmissions & Distribution) Expected MCQ PDF 5 For VIZAG MT Exam 2017

1)   What is the safety factor of an insulator?
a. Puncture strength * Flash over voltage
b. Puncture strength / Flash over voltage
c. Flash over voltage / Puncture strength
d. None of these

ANSWER: Puncture strength / Flash over voltage
2)   What is the desirable safety factor prescribed for the pin type of insulators?
a. 5
b. 13
c. 10
d. 2

ANSWER: 10
3)   Why is the
voltage rating of a multiple shell pin type insulator cannot be
increased beyond a limiting value?

a. The internal voltage distribution between shells becomes unequal
b. The leakage path resistance starts reducing
c. The disruptive critical voltage for the material of the insulator is reached
d. The puncture voltage of the material of the insulator is reached

ANSWER: The internal voltage distribution between shells becomes unequal
4)   What is the main type of distribution system in India?
a. Radial
b. Parallel
c. Network
d. All of these

ANSWER: Radial
5)   Which component connects the substation to the area where power is to be distributed?
a. Distributors
b. Service mains
c. Feeders
d. All of these

ANSWER: Feeders
6)   The cost of material used in a distribution circuit per kVA of the distributed power varies as
a. Square of linear dimensions of supply area.
b. Directly according to (supply area)2
c. Cube of linear dimensions of supply area
d. None of these

ANSWER: Directly according to (supply area)2
7)   Name the cable which connects the distributor to the consumer terminals.
a. Distributors
b. Service mains
c. Feeders
d. All of these

ANSWER: Service mains
8)   What is the permissible limit of voltage variations allowed in the distribution systems?
a. ± 2 %
b. ± 5 %
c. ± 10 %
d. ± 6 %

ANSWER: ± 6 %
9)   Where the radial systems are generally employed?
a. Where power is generated at low voltage
b. Where power is generated at high voltage
c. Where power is generated at low voltage and substation is located at the centre of the load
d. Where power is generated at high voltage and substation is located at the centre of the load

ANSWER: Where power is generated at low voltage and substation is located at the centre of the load
10)   What is the main advantage of ring main system over radial system?
i. Voltage drop in the feeder is less.
ii. Power factor is higher.
iii. Supply is more reliable.
Which among the above statements are correct?

a. i and ii only
b. ii and iii only
c. i and iii only
d. i, ii and iii

ANSWER: i and iii only
11)   The null point of a uniformly loaded distributor feed at equal voltage at both ends lies at
a. Mid point
b. Either end
c. Two third distance from one end
d. One fourth distance from one end

ANSWER: Mid point
12)   In a distribution system, which of the following items shares the major cost?
a. Conductors
b. Earthing systems
c. Distribution transformer
d. Insulators

ANSWER: Distribution transformer
13)   Which type of distribution is preferred in residential areas?
a. Single phase, two wire
b. Three phase, three wire
c. Three phase, four wire
d. Two phase, four wire

ANSWER: Three phase, four wire
14)   In a dc 3 wire distributor using having unequal loads on the two sides
a. Both balancers operate as generators.
b. Both balancers operate as motors.
c. Balancers connected to the lightly loaded sides operate as a generator.
d. Balancers connected to the heavily loaded sides operate as a generator.

ANSWER: Balancers connected to the heavily loaded sides operate as a generator.
15)   Why are the balancers fields cross connected in a three wire distribution system?
a. Equalise voltage on positive and negative outer
b. Boost the generated voltage
c. Make both machines operate as unloaded motors
d. All of these

ANSWER: Equalise voltage on positive and negative outer
16)   Which distribution system is energised by two or more generating stations or substations?
a. Radial systems
b. Interconnected systems
c. Ring main systems
d. All of these

ANSWER: Interconnected systems
17)   A three wire dc distribution makes available how many voltages?
a. One
b. Two
c. Three
d. All of these

ANSWER: Three
18)   If the
voltage of the system is about 230 V, then what would be the highest and
the lowest permissible voltage?

a. 242 and 214 V
b. 240 and 210 V
c. 244 and 216 V
d. 244 and 212 V

ANSWER: 244 and 216 V
19)   What is the loss factor in a distribution system?

a. 0.3 * load factor + 0.7 (load factor)2
b. 0.5 * (load factor)
c. Load factor
d. 0.7 * load factor + 0.3 (load factor)2

ANSWER: 0.3 * load factor + 0.7 (load factor)2
20)   A uniformly
loaded dc distributor is fed at both ends with equal voltages. In
comparison to a similar distributor fed at one end only, what will be
the maximum voltage drop?

a. One fourth
b. Half
c. One third
d. One sixth

ANSWER: One fourth
21)   A uniformly
loaded dc distributor is fed at both ends with equal voltages. In
comparison to a similar distributor fed at one end only, what will be
the drop at the midpoint be?

a. One fourth
b. Half
c. One third
d. One sixth

ANSWER: One third
22)   Installation of capacitors at suitable locations and of optimum size in a distribution system results in
i. Improved voltage regulation.
ii. Reduction in distribution power losses.
iii. Reduction of kVA rating of distribution transformers.
Which among the above statements are correct?

a. i only
b. i and ii only
c. iii only
d. All of these

ANSWER: All of these
23)   What are boosters?
a. Is a high voltage and low circuit machine
b. Is a series wound dc generator driven by dc shunt motor
c. Is a low voltage and high current generator operating on straight or linear portion of its voltage current characteristics
d. Both (b) and (c)
e. None of these

ANSWER: Both (b) and (c)
24)   Why are the boosters inserted in the circuit?
a. Reduce current
b. Increase current
c. Reduce voltage drop
d. Compensate for voltage drop

ANSWER: Compensate for voltage drop
25)   Why is the floating neutral in a three phase supply considered as undesirable?
a. High voltage across the load
b. Low voltage across the load
c. Unequal line voltages across the load
d. None of above

ANSWER: Unequal line voltages across the load
26)   For purely domestic loads which type of distribution is employed?
a. Single phase two wire
b. 3 phase 3 wire
c. 3 phase 4 wire
d. None of these

ANSWER: Single phase two wire
27)   Which type of loads use 3 phase 4 wire ac system of distribution?
a. Balanced
b. Unbalanced
c. Both (a) and (b)
d. None of these

ANSWER: Unbalanced
28)   In a
balanced 3 phase, 4 wire ac system the phase sequence is RYB. If the
voltage of R phase = 230 ∠ 0° volts, then what will be the B phase?

a. 230 ∠ – 120°
b. 230 ∠ – 90°
c. 230 ∠ – 90°
d. 230 ∠ – 120°

ANSWER: 230 ∠ – 120°
29)   What are ground detectors?
a. Used for detecting earth faults for all cables
b. Used for detecting ground faults for underground cables
c. Used for detecting all types of fault in a underground cables
d. None of these

ANSWER: Used for detecting ground faults for underground cables
30)   An
industrial consumer has a load pattern of 2000 kW, 0.8 lag for 12 hours
and 1000 kW UPF for 12 hours. What is its load factor?

a. 10.5
b. 0.75
c. 0.6
d. 2.0

ANSWER: 0.75
31)   Where are the strain type of insulators used?
a. Low voltage overhead lines
b. Dead ends
c. Change in direction of the transmission lines
d. Both (b) and (c)

ANSWER: Both (b) and (c)
32)   Strain and Shackle type insulators are provided on which type of plane?
a. Vertical plane
b. Horizontal plane
c. On the surface
d. All of these

ANSWER: Vertical plane
33)   Which insulator is also called as spool type of insulators?
a. Pin type
b. Shackle type
c. Suspension type
d. Stay insulators

ANSWER: Shackle type

34)   Assembly of which type of insulators are used as strain type of insulators?
a. Pin type
b. Shackle type
c. Suspension type
d. None of these

ANSWER: Suspension type
35)   Which type of insulators is mainly used for low voltage overhead lines?
a. Pin type
b. Shackle type
c. Suspension type
d. None of these

ANSWER: Shackle type

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Power Systems (Transmissions & Distribution) Expected MCQ PDF 6 For VIZAG MT Exam 2017
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