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GATE 2024 EE – Question 47

Power Systems · Voltage and Frequency control, Power factor correction · 2 marks · Multiple select

Which of the following options is/are correct for the Automatic Generation Control (AGC) and Automatic Voltage Regulator (AVR) installed with synchronous generators?

  1. AGC response has a local effect on frequency while AVR response has a global effect on voltage.
  2. AGC response has a global effect on frequency while AVR response has a local effect on voltage.
  3. AGC regulates the field current of the synchronous generator while AVR regulates the generator’s mechanical power input.
  4. AGC regulates the generator’s mechanical power input while AVR regulates the field current of the synchronous generator.

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Show answer and explanation

Correct answer: (B) AGC response has a global effect on frequency while AVR response has a local effect on voltage.; (D) AGC regulates the generator’s mechanical power input while AVR regulates the field current of the synchronous generator.

Explanation

Frequency is common to the whole interconnected system, so the AGC (load-frequency control) has a global effect, whereas voltage is a local quantity, so the AVR acts locally. AGC adjusts the prime mover's mechanical power input (governor set point), while the AVR adjusts the exciter and hence the field current.