MCQOPTIONS
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MCQOPTIONS
This section includes 12 Mcqs, each offering curated multiple-choice questions to sharpen your Power Systems knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Magnetic blow out coils are generally used in |
| A. | air blast circuit breakers |
| B. | oil circuit breaker |
| C. | vacuum circuit breaker |
| D. | air break circuit breaker |
| Answer» E. | |
| 2. |
An 11 kV, 500 MVA circuit breaker suddenly closes on to a fault. Find rms value of the symmetrical breaking current. |
| A. | 32.24 kA |
| B. | 45.45 kA |
| C. | 26.24 kA |
| D. | 52.48 kA |
| Answer» D. 52.48 kA | |
| 3. |
In air-blast circuit breakers, the pressure of the air is of the order of: |
| A. | 100 mm Hg |
| B. | 1 kg / cm2 |
| C. | 20 kg / cm2 to 30 kg / cm2 |
| D. | 200 kg / cm2 to 300 kg / cm2 |
| Answer» D. 200 kg / cm2 to 300 kg / cm2 | |
| 4. |
A 3-phase circuit breaker is rated at 1500 A, 2000 MVA, 33 kV. Its making current will be |
| A. | 35 kA |
| B. | 49 kA |
| C. | 70 kA |
| D. | 89 kA |
| Answer» E. | |
| 5. |
A lightning arrester is usually located nearer to |
| A. | Transformer |
| B. | Isolator |
| C. | Busbar |
| D. | Circuit breaker |
| Answer» B. Isolator | |
| 6. |
A three-phase, 33 kV oil circuit breaker is rated 1200 A, 2000 MVA, 3 s. The symmetrical breaking current is |
| A. | 1200 A |
| B. | 3600 A |
| C. | 35 kA |
| D. | 104.8 kA |
| Answer» D. 104.8 kA | |
| 7. |
Find the making current for a circuit breaker rated at 1000 A, 3000 MVA, 66 kV, 3 sec, 3 – phase, oil circuit breaker |
| A. | 86.92 kA |
| B. | 66.92 kA |
| C. | 58.62 kA |
| D. | 76.52 kA |
| Answer» C. 58.62 kA | |
| 8. |
In general AC distribution systems, arc interruption in vacuum circuit breakers are designed to function in a time period of |
| A. | One cycle |
| B. | Two to three cycles |
| C. | Within ten cycles |
| D. | None of the above |
| Answer» B. Two to three cycles | |
| 9. |
In a 132 kV system, Phase to Ground capacitance is 0.01 μF and inductance is 4H. Calculate the critical resistance to be connected in order to eliminate restriking if a magnetizing current of 5 A is interrupted by the circuit |
| A. | 20 kΩ |
| B. | 10 kΩ |
| C. | 100 kΩ |
| D. | 200 kΩ |
| Answer» C. 100 kΩ | |
| 10. |
In which type of circuit breaker, the high-pressure air-blast is used as an arc extinguishing medium? |
| A. | Air magnetic circuit breakers |
| B. | Vacuum circuit breakers |
| C. | Air Blast circuit breakers |
| D. | Air electric circuit breakers |
| Answer» D. Air electric circuit breakers | |
| 11. |
Making capacity of Circuit breaker is |
| A. | Lesser than the asymmetrical breaking capacity |
| B. | Greater than the asymmetrical breaking capacity |
| C. | Equal to the symmetrical breaking capacity |
| D. | Equal to the asymmetrical breaking capacity |
| Answer» C. Equal to the symmetrical breaking capacity | |
| 12. |
Keeping in view the cost and overall effectiveness, the following circuit breaker is best suited for capacitor bank switching |
| A. | Vacuum |
| B. | Air Blast |
| C. | SF6 |
| D. | Oil |
| Answer» B. Air Blast | |