Power Systems – Multiple Choice Questions (MCQs)

1. 25. A load factor close to unity indicates:

   • A. Highly fluctuating load
   • B. Constant load
   • C. Low power consumption
   • D. High reactive power

2. 26. Which type of relay is most suitable for long transmission lines?

   • A. Reactance relay
   • B. Impedance relay
   • C. Mho relay
   • D. Overcurrent relay

3. 27. The cost of energy generation in a power plant decreases with:

   • A. Decrease in load factor
   • B. Increase in plant capacity
   • C. Increase in load factor
   • D. Decrease in plant capacity

4. 28. What is the significance of the critical clearing time in transient stability analysis?

   • A. Time required to clear a fault without loss of synchronism
   • B. Time taken for a circuit breaker to open
   • C. Time for the system to recover from a disturbance
   • D. Time delay of a relay

5. 29. Which of the following is a non-renewable energy source?

   • A. Solar
   • B. Wind
   • C. Coal
   • D. Geothermal

6. 30. The function of a prime mover in a power plant is to:

   • A. Generate electricity
   • B. Convert heat energy to mechanical energy
   • C. Regulate voltage
   • D. Store fuel

7. 31. The use of bundled conductors in transmission lines primarily aims to:

   • A. Reduce resistance
   • B. Increase inductance
   • C. Reduce corona loss
   • D. Increase capacitance

8. 32. What is the primary role of a synchronous generator in a power system?

   • A. To absorb reactive power
   • B. To generate active power
   • C. To regulate voltage
   • D. To provide fault current

9. 33. The concept of 'spinning reserve' refers to:

   • A. Generators not yet connected to the grid
   • B. Generators operating at full capacity
   • C. Generators connected to the grid and ready to supply power instantly
   • D. Backup generators in maintenance

10. 34. Which type of substation typically steps up voltage for transmission?

    • A. Generating substation
    • B. Receiving substation
    • C. Distribution substation
    • D. Switching substation

11. 35. A protective relay's selectivity means:

    • A. It operates only for internal faults
    • B. It operates for external faults
    • C. It operates for any fault in the system
    • D. It can distinguish between different types of faults

12. 36. The voltage regulation of a transmission line is zero when the load is:

    • A. Resistive
    • B. Inductive
    • C. Capacitive
    • D. Unity power factor