Aux 1 Unit 15 Q1

1 / 6

What device is installed on main breakers to prevent a generator from operating outside its designated frequency range when running in parallel?

C) Load shedding relay

A) Under/over-frequency relay

B) Voltage regulator

D) Power factor meter

2 / 6

What is the importance of an under/over-frequency relay in the protection of a.c. generators running in parallel?

A) To increase the generator's current

B) To ensure the generator operates within its designated frequency range, preventing damage and ensuring stable parallel operation with other generators

C) To measure the generator's voltage

D) To synchronize the generator with the main grid

3 / 6

Why is a reverse power relay necessary when a.c. generators are running in parallel?

D) To increase the generator's frequency

C) To monitor the generator's load

A) To adjust the generator's voltage output

B) To prevent a generator from drawing power instead of supplying it, which can lead to mechanical damage or destabilization of the power system

4 / 6

Which device is crucial for detecting reverse power flow in a generator running in parallel with others?

B) Over-voltage relay

D) Phase sequence indicator

C) Load sharing relay

A) Reverse power relay

5 / 6

How does the combination of overcurrent relay, reverse power relay, and under/over-frequency relay contribute to the safe operation of generators in parallel?

D) By reducing the generator's power output

A) By monitoring the generator's physical size

C) By increasing the generator's load capacity

B) By providing comprehensive protection against overcurrent, reverse power flow, and frequency deviations, ensuring the generators operate safely and efficiently in parallel

6 / 6

Why is an overcurrent relay fitted to the main breakers of a.c. generators running in parallel?

B) To protect the generator from damage by disconnecting it in the event of excessive current, which could occur due to faults or overload conditions

C) To synchronize the generator with the grid

D) To monitor the generator's temperature

A) To increase the generator's output

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