Q1. Base load of a power station refers to:
A. Maximum demand during the day
B. Average load over 24 hours
C. Load that remains constant throughout the day
D. Load occurring during peak hours
Correct Option: 3
Explanation:
Base load is the minimum load which remains almost constant throughout day and night. It exists continuously irrespective of load variations and is supplied by base load plants.
Q2. Which plant is most suitable to carry base load?
A. Diesel power plant
B. Gas turbine plant
C. Steam power plant
D. Pumped storage plant
Correct Option: 3
Explanation:
Steam power plants are designed for continuous operation, have low running cost per kWh and operate at high load factor, making them ideal for base load duty.
Q3. Peak load on a power station is best handled by:
A. Nuclear plant
B. Hydroelectric plant
C. Steam plant
D. Base load plant
Correct Option: 2
Explanation:
Peak load occurs for short duration and requires fast starting and stopping. Hydroelectric plants can start quickly and respond to sudden load changes.
Q4. Which load is present for the maximum duration in a power system?
A. Peak load
B. Variable load
C. Base load
D. Emergency load
Correct Option: 3
Explanation:
Base load exists throughout the entire day and forms the lowest constant portion of the load curve.
Q5. Base load plants generally operate at:
A. Low load factor
B. High load factor
C. Zero load factor
D. Variable load factor
Correct Option: 2
Explanation:
Since base load plants operate almost continuously near rated capacity, their average load is close to maximum demand, resulting in high load factor.
Q6. If maximum demand is 100 MW and base load is 60 MW, the base load percentage is:
A. 40%
B. 50%
C. 60%
D. 75%
Correct Option: 3
Explanation:
Base load percentage = (Base load / Maximum demand) × 100 = (60 / 100) × 100 = 60%.
Q7. The method of meeting peak load economically is by using:
A. Steam plant only
B. Diesel plant only
C. Hydroelectric plant
D. Nuclear plant
Correct Option: 3
Explanation:
Hydroelectric plants have zero fuel cost, fast starting capability and are economical for short-duration peak load operation.
Q8. Which plant has minimum starting time and is suitable for sudden load changes?
A. Steam power plant
B. Nuclear power plant
C. Hydroelectric power plant
D. Thermal plant
Correct Option: 3
Explanation:
Hydroelectric plants do not require boiler or fuel combustion, so they can start almost instantly and handle sudden load changes.
Q9. Load duration curve is used to determine:
A. Voltage regulation
B. Frequency control
C. Capacity and energy requirements
D. Short circuit level
Correct Option: 3
Explanation:
Load duration curve helps in deciding installed capacity, energy generation and selection of base and peak load plants.
Q10. If a station runs at full load for 8 hours and half load for 16 hours, load factor is:
A. 50%
B. 66.7%
C. 75%
D. 80%
Correct Option: 2
Explanation:
Average load = [(1×8) + (0.5×16)] / 24 = 16 / 24 = 0.667. Load factor = 66.7%.
Q11. Which plant is NOT suitable for meeting peak load?
A. Diesel plant
B. Gas turbine
C. Pumped storage
D. Nuclear plant
Correct Option: 4
Explanation:
Nuclear plants have very high capital cost and slow starting, hence they are designed only for continuous base load operation.
Q12. Spinning reserve is mainly used to:
A. Increase voltage
B. Improve power factor
C. Meet sudden load changes
D. Reduce losses
Correct Option: 3
Explanation:
Spinning reserve is the extra generating capacity already running and is used to meet sudden load increase or generator failure.
Q13. A power station has a maximum demand of 50 MW and average load of 25 MW. Load factor is:
A. 0.25
B. 0.4
C. 0.5
D. 0.75
Correct Option: 3
Explanation:
Load factor = Average load / Maximum demand = 25 / 50 = 0.5.
Q14. An interconnected grid system is mainly used to:
A. Reduce voltage
B. Improve reliability
C. Increase losses
D. Increase fuel cost
Correct Option: 2
Explanation:
Interconnection allows sharing of load and reserve capacity, improving reliability and continuity of power supply.
Q15. Major advantage of interconnected grid is:
A. Higher capital cost
B. Reduced diversity factor
C. Reduced reserve capacity
D. Increased transmission loss
Correct Option: 3
Explanation:
Due to diversity of loads, interconnected systems require less standby reserve capacity, reducing overall installed capacity.
Q16. Two stations of 100 MW each are interconnected. Individual reserve required was 20%. Reserve after interconnection is approximately:
A. 40 MW
B. 30 MW
C. 20 MW
D. 10 MW
Correct Option: 2
Explanation:
Individual reserve = 20% of 100 = 20 MW each. Total = 40 MW. After interconnection, reserve reduces to about 75% of total, i.e., approximately 30 MW.
Q17. Which factor increases when power systems are interconnected?
A. Load factor
B. Fuel cost
C. Operating cost
D. Transmission loss only
Correct Option: 1
Explanation:
Interconnection smooths load variations and increases average load relative to maximum demand, improving load factor.
Q18. If diversity factor of an interconnected system is 1.5 and sum of individual maximum demands is 300 MW, system maximum demand is:
A. 150 MW
B. 200 MW
C. 250 MW
D. 300 MW
Correct Option: 2
Explanation:
System maximum demand = Sum of individual demands / Diversity factor = 300 / 1.5 = 200 MW.
Q19. Average load = 40 MW, Maximum demand = 80 MW. Annual energy generated (in MU):
A. 350
B. 300
C. 280
D. 250
Correct Option: 1
Explanation:
Annual energy = Average load × 8760 = 40 × 8760 = 350.4 MU ≈ 350 MU.
Q20. A hydro plant supplies peak load of 30 MW for 4 hours daily. Annual energy supplied (in MU) is:
A. 30
B. 43.8
C. 60
D. 120
Correct Option: 2
Explanation:
Daily energy = 30 × 4 = 120 MWh. Annual energy = 120 × 365 = 43.8 MU.