This set of Power Systems Multiple Choice Questions & Answers (MCQs) focuses 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

View Answer

Explanation: 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

View Answer

Explanation: 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

View Answer

Explanation: 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

View Answer

Explanation: 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

View Answer

Explanation: 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

View Answer

Explanation: Let the power losses remain constant over the systems, then

2P

^{2}R/V

^{2}= 2P

^{2}R1/2*V

^{2}

or, R = R1/4;

As R = lρ/a;

a

_{1}= a/4;

So, V

_{1}/V

_{1}= 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

View Answer

Explanation: 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

View Answer

Explanation: Let the power losses remain constant over the systems, then

2P

^{2}R/V

^{2}= 2P

^{2}R1/V

^{2}

or, R1 = R

As R = lρ/a;

a

_{1}= a

So, V

_{1}/V

_{1}= a

_{1}*2l/a

_{1}= 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

View Answer

Explanation: 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

View Answer

Explanation: Vmax = V/√2 = (440/2)/√2 = 155.6 V.

**Sanfoundry Global Education & Learning Series – Power Systems.**

To practice all areas of Power Systems, __here is complete set of 1000+ Multiple Choice Questions and Answers__.

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