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Friday, 26 August 2016

Economics of Power Generation - Multiple Choice Questions

Economics of Power Generation - Multiple Choice Questions Points : Economics of Power Generation, multiple choice questions and answers, electrical objective type question answers, mcqs 1. In the diminishing value method for calculating depreciation, the annual depreciation charge is independent of
(i) useful life of equipment
(ii) scrap value
(iii) the rate of interest
(iv) initial value of equipment

2. A consumer who consumes more electrical energy should pay
(i) more fixed charges per unit
(ii) less fixed charges per unit
(iii) less running charges per unit
(iv) none of above

3. The fixed cost of energy generated
(i) depends on maximum demand
(ii) depends on units generated
(iii) independent of (i) and (ii)
(iv) none of above

4. The most fundamental method for calculating the depreciation of equipment is
(i) straight line method
(ii) diminishing value method
(iii) sinking fund method
(iv) none of above

5. The depreciation of equipment is
(i) more in early years
(ii) less in early years
(iii) same every year
(iv) none of above

6. When the load factor of a power station increases, the units (kWh) generated
(i) are increased
(ii) are decreased
(iii) remain the same
(iv) none of above

7. The annual deposit is ……. in sinking fund method as compared to straight line method.
(i) smaller
(ii) greater
(iii) the same
(iv) none of above

8. A factory draws an apparent power of 300 kVA at a lagging power factor of 0.65. The active power drawn by the factory is
(i) 285 kW
(ii) 228 kW
(iii) 185 kW
(iv) 195 kW

9. An ideal value of power factor is
(i) 1
(ii) 0.5
(iii) 0.8
(iv) 0.75

10. Alternators and transformers are rated in
(i) kVA
(ii) kW
(iii) kVAR
(iv) none of above

11. A load draws a power of 10 kW at a p.f. of 0707 lagging. The lagging kVAR drawn from the supply will be
(i) 5 kVAR
(ii) 20 WAR
(iii) 10 KVAR
(iv) 15 KVAR

12. The most economical power factor for a consumer is generally
(i) 0.95 lagging
(ii) 1
(iii) 0.6 lagging
(iv) 075 lagging

13. A transformer costing Rs. 90,000 has a useful life of 20 years. If the scrap value of the equipment is Rs. 10,000, the annual depreciation charge using straight line method is
(i) Rs. 8000
(ii) Rs. 4500
(iii) Rs5000
(iv) Rs.4000

14. The drawback of diminishing value method for calculating depreciation is that depreciation charges
(i) are small in early years
(ii) are high in later years
(iii) are independent of rate of interest
(iv) none of above

15. The lagging reactive power drawn by a load is zero. The power factor of the load is
(i) 0.5
(ii) 0.75
(iii) 1
(iv) none of above

16. A factory has a maximum load of 240 kW at 0.8 p.f. lagging with an annual consumption of 50,000 units. The tariff is Rs 50 per kVA of maximum demand plus 10 paise per unit. The flat rate of energy consumption is
(i) 30 paise
(ii) 50 paise
(iii) 40 paise
(iv) 25 paise

17. When power factor is Improved, the lagging kVAR drawn from the supply will
(i) increase
(ii) decrease
(iii) remain the same
(iv) none of above

18. If power factor is to be improved to 1 in Q. 36, the p.f. correction equipment should supply leading WAR equal to
(i) 10 kVAR
(ii) 5 KVAR
(iii) 15 kVAR
(iv) 20 kVAR

19. Arc and induction furnaces operate on
(i) very low lagging p.f.
(ii) very low leading p.f.
(iii) very high leading p.f.
(iv) none of above

20. The straight line method for calculating depreciation i based on the assumption that depreciation charge is
(i) constant every year
(ii) is more in early years
(iii) is Less in early years
(iv) is more in later years

21. The initial cost of an equipment is Rs 10,000 and its scrap value after useful life is zero. The annual rate of depreciation is 10%. Using diminishing value method, the depreciation charge for the second year is
(i) Rs. 1000
(ii) Rs.500
(iii) Rs. 900
(iv) Rs. 750

22. A generating plant has a maximum-capacity of 100 kW and costs Rs. 1,60,000. The annual fixed charges are 12%. If the toad factor is 50%. the fixed charges per kWh will be
(i) .5.24 paise
(ii) 7.82 paise
(iii) 4.38 paise
(iv) 3.82 paise

23. A factory draws an apparent power of 300 kVA at a p.f. of 0.65 lagging. What is the reactive power drawn at a p.f. of 0.85 lagging?
(i) 121 kVAR
(ii) 195 kVAR
(iii) 110 kVAR
(iv) 150 kVAR

24. When p.f. at the generating station is improved, the cost per unit
(i) decreases
(ii) increases
(iii) remains same
(iv) none of above

25. For a given active power and voltage, the current drawn is minimum when the value of power factor is
(i) 0.8 lag
(ii) 0.8 lead
(iii) 0.75 lag
(iv) 1

26. An alternator is rated at 1000 kVA. The maximum active power that can be drawn from it is
(i) 500kW
(ii) 750 kW
(iii) 800kW
(iv) 1000kW

27. When p.f. is improved, the kW capacity of alternators is
(i) increased
(ii) decreased
(iii) unaffected
(iv) none of above

28. An over-excited synchronous motor on no load is called
(i) alternator
(ii) induction motor
(iii) synchronous condenser
(iv) universal motor

29. When the power factor is unity, the relation between line current I and supply voltage V is
(i) 1 leads V by 90°
(ii) 1 lags V by 90°
(iii) 1 is in phase with V
(iv) none of above

20. When the power factor is increased
(i) active power increases
(ii) active power decreases
(iii) line current increases
(iv) line current decreases

21. Most of the loads are
(i) inductive
(ii) capacitive
(iii) resistive
(iv) none of above

22. Improving the power factor means making it
(i) close to unity
(ii) zero
(iii) less than 0.5
(iv) none of above

23. An alternator is supplying a load of 300 kW at a p.f. of 0.6 lagging. If the p.f. is raised to unity, how many more kW can alternator supply?
(i) 200kW
(ii) 100kW
(iii) 300 kW
(iv) 150 kW

24. A synchronous condenser improves p.f. by taking
(i) lagging kVAR
(ii) leading kVAR
(iii) both (i) and (ii)
(iv) none of above

25. The main reason for low power factor of supply system is due to the use of
(i) induction motors
(ii) resistive loads
(iii) synchronous motors
(iv) all correct

26. The best location of p.f. correction equipment to be installed on the transmission line is at the
(i) sending end
(ii) receiving end
(iii) middle of line
(iv) none of above

27 The smaller the lagging reactive power drawn by the circuit
(i) the higher is the p.f.
(ii) the smaller is the p.f.
(iii) the higher is the active power
(iv) none of above

28. The only motor that can be worked at leading power factor is
(i) 3-phase induction motor
(ii) 1 -phase induction motor
(iii) synchronous motor
(iv) none of above

29. For a large installation, it is better to apply
(i) individual correction to small motors
(ii) individual correction to large motors
(iii) bulk correction to large motors
(iv) none of above

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