MCQOPTIONS
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MCQOPTIONS
This section includes 10 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. |
How can one think of reducing the earth capacitance of line? |
| A. | Using guard ring |
| B. | Using special designed earth capacitances |
| C. | Implementing parallel insulator lines |
| D. | Any of the mentioned |
| Answer» B. Using special designed earth capacitances | |
| 2. |
For a 400 kV, 50 Hz five pin insulator setup provides the protection with an efficiency of 87.4%. The same setup is now meant to be used at the frequency of 60 Hz, the updated string efficiency of the system will be ____________ |
| A. | 87.4 |
| B. | 91 |
| C. | 82% |
| D. | 86% |
| Answer» B. 91 | |
| 3. |
If the frequency of the transmission line is changed from 50 Hz to 100 Hz, then the string efficiency ____________ |
| A. | remains unchanged |
| B. | increases |
| C. | decreases |
| D. | May or may not increase depending on the parameters |
| Answer» B. increases | |
| 4. |
The pin type insulators are generally not used for the voltage range exceeding ____________ |
| A. | 33kV |
| B. | 66kV |
| C. | 25kV |
| D. | 11kV |
| Answer» B. 66kV | |
| 5. |
For a line-man while measuring the string efficiency of the insulator installation done, observes that it shows a reading of 100%. This means ___________________ |
| A. | equal potential across each insulator disc |
| B. | one of the insulator disc is shorted |
| C. | zero potential across each disc |
| D. | none of the mentioned |
| Answer» B. one of the insulator disc is shorted | |
| 6. |
A string of insulators consisting of 7 units. The voltage across the bottom most unit is 25% of the total voltage. The string efficiency of this system will be |
| A. | 57.14 % |
| B. | 50.6 % |
| C. | 80.4 % |
| D. | 67.7 % |
| Answer» B. 50.6 % | |
| 7. |
The capacitance grading method is one of the most practical and most widely used method in Indian transmission system. |
| A. | True |
| B. | False |
| Answer» C. | |
| 8. |
How does grading neutralize the potential distribution across the units of the suspension insulators? |
| A. | By forming capacitances to cancel the charging current from link pins |
| B. | By forming capacitances with link pin to cancel the charging current from them |
| C. | By increasing the capacitance of lower insulator units |
| D. | By decreasing the capacitance of lower insulator units |
| Answer» B. By forming capacitances with link pin to cancel the charging current from them | |
| 9. |
For a string of five suspension insulators is to be fitted with a grading ring. If the pin to earth capacitances are equal to C, then the value of line to pin capacitance of first and last capacitance(from top) is |
| A. | 0.25C, 4C |
| B. | 0.667C, 3C |
| C. | 1.5C, 1.5C |
| D. | 4C,0.25 |
| Answer» B. 0.667C, 3C | |
| 10. |
For a string of five suspension insulators is to be fitted with a grading ring. If the pin to earth capacitances is equal to C, then the value of line to pin capacitance of first capacitance is |
| A. | 0.25C |
| B. | 0.667C |
| C. | 1.5C |
| D. | 4C |
| Answer» B. 0.667C | |