ECONOMIC OPERATION OF POWER SYSTEMUNIT11. Load factor of a power station is defined as (a) maximum demand/average load(b) average load x maximum demand (c) average load/maximum demand(d) (average load x capacity factor)

Ans: c

2. Load factor of a power station is genera (a) equal to unity(b) less than unity (c) more than unity(d) equal to zero Diversity factor is always Ans: b

3. The load factor of domestic load is usually (a) 10 to 15%(b) 30 to 40% (c) 50 to 60% (d) 60 to 70% Ans: a

4. Annual depreciation cost is calculated by (a)sinkingfund method(b)straight line method(c) both (a) and (b)(d) none of the above Ans: c

5. Depreciation charges are high in case of (a) thermal plant(b) diesel plant(c) hydroelectric plant Ans: a

6. Demand factor is defined as (a)average load/maximum load(b)maximum demand/connected load (c) connected load/maximum demand (d) average load x maximum loadAns: b

7. High load factor indicates(a) cost of generation per unit power is increased (b) total plant capacity is utilised for most of the time(c) total plant capacity is not properly utilised for most of the time (d) none of the aboveAns: b

8. A load curve indicates

(a) average power used during the period(b) average kWh (kW) energy consumption during the period (c) either of the above(d) none of the above

Ans: b

9. Approximate estimation of power demand can be made by(a) load survey method (b) statistical methods (c) mathematical method (d) economic parameters (e) all of the aboveAns: e

10. Annual depreciation as per straight line method, is calculated by (a)the capital cost divided by number of year of life(b)the capital cost minus the salvage value, is divided by the number of years of life

(c) increasing a uniform sum of money per annum at stipulated rate of interest(d) none of the above Ans: b

UNIT 21. A consumer has to pay lesser fixed charges in (a)flat rate tariff(b)two part tariff(c) maximum demand tariff (d) any of the aboveAns: c

2. In two part tariff, variation in load factor will affect (a) fixed charges(b) operating or running charges (c) both (a) and (b)(d) either (a) or (b)Ans: b

3. In Hopknison demand rate or two part tariff the demand rate or fixed charges are (a)dependent upon the energy consumed(b)dependent upon the maximum demand of the consumer(c) both (a) and (b)(d) neither (a) nor (b)Ans: b

4. Which plant can never have 100 percent load factor ? (a) Peak load plant(b) Base load plant

(c) Nuclear power plant

(d) Hydro electric plantAns: a

5. The area under a load curve gives (a) average demand(b) energy consumed (c) maximum demand(d) none of the aboveAns: b

6. Different generating stations use following prime movers (a) diesel engine(b) hydraulic turbine (c) gas turbine(d) steam turbine (e) any of the above Ans: e

7. Diversity factor has direct effect on the (a) fixed cost of unit generated(b) running cost of unit generated (c) both (a) and (b)(d) neither (a) nor (b)Ans: a8. Following power plant has instant starting (a)nuclear power plant(b) hydro power plant (c)diesel power plant (d) both (b) and (c)(e) none of the aboveAns: d

9. Which of the following generating station has minimum ruining cost ?(a) Nuclear (b) Hydro (c) Thermal (d) Diesel Ans: b

10. Power plant having maximum demand more than the installed rated capacity will have utilisation factor(a) equal to unity (b) less than unity (c) more than unity(d) none of the above Ans: c

UNIT 31. Load curve is useful in deciding the (a) operating schedule of generating units (b) sizes of generating units(c) total installed capacity of the plant (d) all of the aboveAns: d

2. Load curve of a power plant has always (a)zero slope(b)positive slope (c) negative slope(d) any combination of (a), (b) and (c)Ans: d

3. The increased load during summer months is due to (a)increased business activity(b)increased water supply

(c) increased use of fans and air conditioners (d) none of the aboveAns: c

4. Which of the following equipment provides fluctuating load ? (a)Exhaust fan(b)Lathe machine

(c) Welding transformer (d) All of the above

Ans: c

5. offers the highest electric load. (a) Television set(b) Toaster

(c) Vacuum cleaner (d) Washing machine Ans: b

6. With reference to a power station which of the following is not a fixed cost ?(a) Fuel cost(b) Interest on capital(c) Insurance charges(d) DepreciationAns: a

7. _______ is invariably used as base load plant.(a) Diesel engine plant(b) Nuclear power plant(c) Gas turbine plant(d) Pumped storage plantAns b

8. In two part tariff, variation in load factor will affect(a) Fixed charges(b)Operating or running charges (c) both(a) and(b) (d) either (a) or (b)Ans : b

9. In Hopknison demand rate or two part tariff the demand rate or fixed charges are(a) Dependent upon the energy consumed(b) Dependent upon the maximum demand of the consumer(c) both(a) and(b)(d) neither(a)nor(b)Ans: b

10. Which plant can never have 100 percent load factor ?(a) Peak load plant(b) Base load plant(c) Nuclear power plant(d) Hydro electric plant Ans: a

UNIT 41. In which of the following power plants the maintenance cost is usually high ? (a) Nuclear power plant(b) Hydro-electric power plants (c) Thermal power plants(d)Diesel engine power plants Ans: c

2. ________ is invariably used for peak load (a) Nuclear power plant(b) Steam turbine plant (c) Pumped storage plant (d) None of the above Ans: c

3. Which of the following is not an operating cost ? (a)Maintenance cost(b)Fuel cost

(c) Salaries of high officials (d) Salaries of operating staff Ans: d

4. The are a under a load curve gives(a) Average demand(b) Energy consumed(c) Maximum demand(d) None of the above Ans:b

5. Different generating stations use following prime movers(a) Diesel engine(b) Hydraulic turbine(c) Gas turbine(d) Steam turbine(e) Any of the above Ans:e

6. Diversity factor has direct effect on the(a) Fixed cost of unit generated(b) Running cost of unit generated(c) both(a) and(b)(d) neither(a)nor(b)Ans: a

7.Load curve helps in deciding(a) total installed capacity of the plant(b) sizes of the generating units(c) operating schedule of generating units(d) all of the aboveAns:d

8. . Which of the following is the disadvantage due to lowpower factor ? (a) Poor voltage regulation(b) Increased transmission losses

(c) High cost of equipment for a given load (d) All of the aboveAns: d

9. Satic capacitors are rated in terms of (a) kW(b) kWh (c) kVAR(d) none of the above Ans: c

10. Which of the following is the disadvantage due to low power factor ? (a) Poor voltage regulation(b) Increased transmission losses(c) High cost of equipment for a given load (d) All of the aboveAns: d

Unit 51. Which of the following is the disadvantage of a synchronous condenser ? (a) High maintenance cost(b) Continuous losses in motor (c) Noise(d) All of the above Ans: d

2. A synchronous condenser is virtually which of the following ? (a) Induction motor (b) Under excited synchronous motor (c) Over excited synchronous motor (d) D.C. generator(e) None of the above Ans: c

3. For a power plant which of the following constitutes running cost ? (a)Cost of wages(b)Cost of fuel(c) Cost of lubricants (d) All of the above Ans: d

4. In an interconnected system, the diversity factor of the whole system (a) remains unchanged(b) decreases (c) increases (d)none of the above Ans: c

5. Generators for peak load plants are usually designed for maximum efficiency at (a) 25 to 50 percent full load(b) 50 to 75 percent full load (c) full load(d) 25 percent overload Ans: b6. ________ will be least affected due to charge in supply voltage frequency. (a) Electric clock(b) Mixer grinder (c) Ceiling fan (d) Room heater Ans: d

7. The connected load of a IVMIM uir consumer is around (a) 5 kW(b) 40 k\V (c) 80 kW (d) 120 kW Ans: a

8. Which of the following is not necessarily an advantage of interconnecting various power stations ?(a) Improved frequency of power supplied (b) Reduction in total installed capacity (c) Increased reliability(d) Economy in operation of plants Ans: a

9. Most efficient plants are normally used as (a) peak load plants(b) base load plants (c) either (a) or (b) (d) none of the above Ans:

10. For a diesel generating station the useful life is expected to be around (a) 15 to 20 years(b) 20 to 50 years (c) 50 to 75 years (d) 75 to 100 years Ans: a