Power Systems – Multiple Choice Questions (MCQs)

1. 97. The power flow analysis in a power system is used to determine:

   • A. Voltage magnitudes and phase angles
   • B. Active and reactive power flows
   • C. System losses
   • D. All of the above

2. 98. What is the basic principle of operation of a differential relay?

   • A. Compares currents entering and leaving a protected zone
   • B. Measures impedance
   • C. Measures voltage
   • D. Measures frequency

3. 99. The term 'blackout' in a power system refers to:

   • A. A planned power outage
   • B. A temporary voltage sag
   • C. A complete loss of power over a wide area
   • D. A short-circuit event

4. 100. Which protective device is used to detect overcurrents and short circuits and automatically open the circuit?

   • A. Fuse
   • B. Circuit breaker
   • C. Isolator
   • D. Relay

5. 101. The voltage stability of a power system is primarily concerned with its ability to:

   • A. Maintain voltages at acceptable levels
   • B. Maintain frequency
   • C. Withstand short circuits
   • D. Restore power quickly

6. 102. The purpose of a series compensation in a transmission line is to:

   • A. Increase reactive power flow
   • B. Reduce series reactance
   • C. Increase series resistance
   • D. Improve power factor at the sending end

7. 103. What is the main function of a power system stabilizer (PSS)?

   • A. To improve transient stability
   • B. To control voltage
   • C. To regulate frequency
   • D. To limit fault current

8. 104. Which of the following is a common issue with overhead transmission lines but not underground cables?

   • A. Corona effect
   • B. Skin effect
   • C. Capacitive effect
   • D. Inductive effect

9. 105. The 'spinning reserve' is crucial for dealing with:

   • A. Planned outages
   • B. Sudden load changes or generator trips
   • C. Long-term load growth
   • D. Seasonal load variations

10. 106. Which of the following describes a 'smart grid'?

    • A. A traditional power grid with limited automation
    • B. An electrical grid that uses information and communication technology
    • C. A grid powered only by renewable energy
    • D. A grid with no human intervention