250+ TOP MCQs on Distribution Systems – 1 and Answers

Power Systems Multiple Choice Questions on “Distribution Systems – 1”.

1. A transmission and distribution engineer needed to design the sub transmission substation. The tapping component needed will be _______________
A. feeder
B. distributor
C. transmitter
s) tap-changing transformer

Answer: A
Clarification: For the sub transmission level, there is no tapping at various level does not take place. For this a feeder is used.

2. While designing the distribution to locality of one lac population with medium dense load requirement, we can employ ___________
A. radial system
B. parallel system
C. ring main system
D. any of the mentioned

Answer: A
Clarification: A radial system is used for the medium requirement of loading and a medium dense population as it becomes easier to install and operate.

3. A _________ distribution system is more reliable than the ______ distribution system.
A. parallel, radial
B. parallel, ring
C. radial, parallel
D. ring, parallel

Answer: A
Clarification: A parallel distribution system has two end feeding and an alternative of parallel line, so in case there is a fault, the isolator can isolate the faulty part and let the healthy system operate.

4. For the figure shown, having a 2-wire dc system where mid point is earthed, having resistance of 20 ohms, with a power transmitted of 5 MW at the voltage level of 440 kV.
The power loss of the distribution system will be ___________
A. 5165 W
B. 515 kW
C. 10330 W
D. 2583 W

Answer: A
Clarification: I = P/V = 5000000/440000 = 11.36 A
Power loss = 2I2*R = 2* 11.362*20 = 5165 W.

5. For the figure shown, having a 2-wire dc system where mid point is unearthed, having resistance of 20 ohms, with a power transmitted of 5 MW at the voltage level of 440 kV.
The power loss of the distribution system will be ___________
A. 5165 W
B. 515 kW
C. 10330 W
D. 2583 W

Answer: D
Clarification: I = P/V = 5000000/440000 = 11.36 A
Power loss = I2*R = 2* 11.362*20 = 2583 W.

6. A DC 2-wire system with mid-point earthed having cross-sectional area of each conductor be ‘a’ and resistance ‘R1’. If the DC tow wire replaces the system, then the ratio of volume of each conductor V1/V2 will be ___________
A. ¼
B. ½
C. 4
D. 2

Answer: A
Clarification: Let the power losses remain constant over the systems, then
2P²R/V² = 2P²R1/2*V²
or, R = R1/4;
As R = lρ/a;
a₁ = a/4;
So, V₁/V₁ = 1/4.

7. While designing the distribution sub stations by the designer, it is required to use the _______ for the discrete power tapping.
A. distributor
B. power transformer
C. distribution transformer
D. feeder

Answer: A
Clarification: For the discrete tapping of the power the consumer level it is the distributor which is employed at the sub stations and consumer levels.

8. A DC 2-wire system with mid-point earthed having cross-sectional area of each conductor be ‘a’ and resistance ‘R1’. If this is replaced by monopolar system, then saving of copper will be ______
A. ½
B.b¼
C. 2
D. 4

Answer: A
Clarification: Let the power losses remain constant over the systems, then
2P²R/V² = 2P²R1/V²
or, R1 = R
As R = lρ/a;
a₁ = a
So, V₁/V₁ = a₁*2l/a₁ = 1/2.

9. For the single phase 2-wire system, the maximum voltage between the outer wires and earth is ______________
A. V/√2
B. √2V
C. V
D. 2V

Answer: A
Clarification: The midpoint voltage will be V/√2.

10. For the given distribution system the maximum voltage at the midpoint will be ________
A. 155.6 V
B. 311.12 V
C. 622 V
D. 220 V

Answer: A
Clarification: Vmax = V/√2 = (440/2)/√2 = 155.6 V.