This set of Power Systems Multiple Choice Questions & Answers (MCQs) focuses on “Gas Turbine Power Plants & Types of Tariffs”.
1. The installation time for a gas turbine power plant is ______________
a) Comparatively less than thermal power plant
b) Comparatively more than thermal power plant
c) Equal to thermal power plant
d) Very much longer than thermal power plant
View Answer
Explanation: Gas turbine power plant is comparatively simpler in construction than thermal power plant. So, its installation time is less than a thermal power plant for same capacity.
2. Which of the following is not used in gas turbine power plant?
a) Compressor
b) Turbine
c) Combustion chamber
d) Condenser
View Answer
Explanation: Natural gas itself or mixture of natural gas and air is used as working medium in gas turbine power plant. Condenser is a device or arrangement used to condense low pressure steam already used by turbine. There is no steam in gas turbine power plant so no condenser is required.
3. Which component of gas turbine power plant is main cause of its low efficiency?
a) Gas turbine
b) Combustion chamber
c) Compressor
d) Starting motor
View Answer
Explanation: The overall efficiency of gas turbine is low, because a greater part of power developed by the turbine ( about 65%) is used in driving the compressor.
4. What is intercooling in gas turbine power plant?
a) Removal of heat from combustion gas between stages of turbine
b) Removal of heat from compressor between stages of compressor
c) Removal of heat from intake air
d) Removal of heat from exhaust air
View Answer
Explanation: Intercooling means removal of heat from compressed air between low pressure and high pressure compressor. Cooling the low pressure compressed air reduces the air volume and improves the thermal efficiency, air rate and work ratio.
5. What is the function of regenerator?
a) Eatery compresses the exhaust gases
b) It heats the compressed air
c) It regenerates the combustible gas from exhaust gas
d) It regenerates the combustible oil from exhaust gas
View Answer
Explanation: Regenerator is usually of shell and tube construction. Regenerator uses the heat of exhaust gas to heat compressed air before it is sent to combustion chamber. This reduces the fuel consumption and improves the cycle thermal efficiency.
6. Fuel other than natural gas i.e. solid and liquid fuels can be used in _______
a) open cycle gas turbine power plant
b) closed cycle gas turbine power plant
c) open and closed cycle gas turbine power plant
d) only natural gas is used in gas turbine power plant
View Answer
Explanation: In closed cycle gas turbine power plant the working medium is heated externally and the fuel is not mixed with working fluid. This ensures the use of any fuel such as inferior type or solid type fuel.
7. Which of the following gas turbine power plant can use working medium of required property?
a) Closed cycle gas turbine power plant
b) Open cycle gas turbine power plant
c) Open and closed cycle gas turbine power plant
d) No gas turbine power plant can use working medium of required property.
View Answer
Explanation: A working medium with physical properties superior to those of air such as helium and hydrogen can be used in closed cycle gas turbine power plant. This is because of airtight construction of this plant.
8. What is the tariff in case of power system?
a) The taxes which a power plant pay to Indian government
b) The taxes which a power plant pay to state government
c) The taxes which a Power Grid pay to Indian government
d) The schedule of rates are charged of supply of electricity for consumers
View Answer
Explanation: Tariff means the schedule of rates are charges tariff. In case of electric supply means the schedule of rates framed for supply of electrical energy to different classes of consumer.
9. An electricity supplier is charging for the electricity as per the total load connected, fixed number of hours. This type of tariff will be a ___________
a) Simple tariff
b) Flat demand tariff
c) Flat rate tariff
d) Block rate tariff
View Answer
Explanation: When the use of Electricity was mainly restricted to very few applications such as for lamps it is ee and the number of hours of use of lamp were fixed they were charged on the basis of total load connected in Kilowatt and the fixed number of hours of use district is known as flat demand tariff.
10. Which statement about simple tariff is true?
a) Charges are made as per the total load connected and of fixed duration of use
b) Charges are made on the basis of units consumed in a certain period
c) Different types of consumers are charged differently
d) Charges per kilowatt decreases with increase in unit consumed
View Answer
Explanation: In simple tariff cost of energy is charged on the basis of unit consumed cost per KWh is given by summing annual fixed cost and annual operating cost and dividing it by total number of units applied to the consumer per annum.
11. Identify the type of tariff the consumer is charged Rs 4 per unit if the consumer does not exceed 50 KWh, Rs 3.50 per unit if the consumer does not exceed 50 KWh but less than 200 kilowatt hour, and Rs 3 per KWh if consumer exceeds 200 kilowatt hour.
a) Flat demand tariff
b) Simple tariff
c) Flat rate tariff
d) Step rate tariff
View Answer
Explanation: Step rate tariff is a group of flat rate tariff of decreasing unit charges for higher range of conception. Charges per KWh are reduced for increas in power consumption above different predefined step levels. This type of tariff takes into account the fact of lower generation cost going to higher energy consumption consequent to improvement of load factor.
12. What is demand factor of commercial consumers?
a) Low
b) Low
c) High
d) More than 1
View Answer
Explanation: Demand factor is the ratio of maximum demand to connected load. As we know maximum demand cannot be greater than connected load so demand factor is always less than one. Commercial consumer generally used as most of disconnected loads so their demand factor is high.
13. If an industrial consumer consumes 50KW for 4 hours, 300KW for 15 hours and 60KW for 5 hours daily and the tariff rate is Rs 5/KWh. What is the energy consumption in a month of 30 days?
a) Rs 750000
b) Rs 475000
c) Rs 755000
d) Rs 470000
View Answer
Explanation: Energy Consumed in one day = (50×4 + 300×15 + 60×5)KWh = 5000 KWh
Energy Consumed in one month = 5000× 30
= 150000 KWh
Hence, Charge on one month = 150000 × 5
=750000 Rupees.
14. Monthly consumption of a consumer is 500KWh. What will be the monthly bill at the following rate?
First 100 unit Rs 0.6/KWh
Next 100 units Rs 0.5/KWh
Remaining units Rs 0.4/KWh
a) Rs 250
b) Rs 25
c) Rs 230
d) Rs 23
View Answer
Explanation: 500 KWh = (100 +100 + 300) KWh
Bill for one month consumption
= (100×0.6 + 100×0.5 + 300×0.4) Rupees
= 230 Rupees.
Sanfoundry Global Education & Learning Series – Power Systems.
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