MCQOPTIONS
Saved Bookmarks
MCQOPTIONS
This section includes 8 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. |
Per unit impedance is equal to |
| A. | base impedance / actual impedance |
| B. | actual impedance / base impedance |
| C. | base MVA / base current |
| D. | base current / base MVA |
| Answer» C. base MVA / base current | |
| 2. |
On a base of 132 kV, 100 MVA, a transmission line has 0.2 per unit impedance. On a base of 220 kV, 50 MVA, it will have a per unit impedance of: |
| A. | \(0.2*\frac{{50}}{{100}}*{\left( {\frac{{220}}{{132}}} \right)^2}\) |
| B. | \(0.2*\frac{{100}}{{50}}*{\left( {\frac{{132}}{{220}}} \right)^2}\) |
| C. | \(0.2*\frac{{50}}{{100}}*{\left( {\frac{{132}}{{220}}} \right)^2}\) |
| D. | \(0.2*\frac{{100}}{{50}}*{\left( {\frac{{220}}{{132}}} \right)^2}\) |
| Answer» D. \(0.2*\frac{{100}}{{50}}*{\left( {\frac{{220}}{{132}}} \right)^2}\) | |
| 3. |
For a given base voltage and base volt-amperes, the per unit impedance value of an element is x. The per unit impedance value of this element when the voltage and volt-amperes bases are both doubled is |
| A. | 0.5x |
| B. | 2x |
| C. | 4x |
| D. | x |
| Answer» B. 2x | |
| 4. |
If the positive, negative and zero-sequence reactance of an element of a power system are 0.3, 0.3 and 0.8 p.u. respectively, then the element would be a? |
| A. | Synchronous generator |
| B. | Synchronous motor |
| C. | Static load |
| D. | Transmission line |
| Answer» E. | |
| 5. |
In an unbalanced three phase system, phase current Ia = 1∠(-90°) pu, negative sequence current Ib2 = 4 ∠(-150°) pu, zero sequence current IC0 = 3∠ 90° pu. The magnitude of phase current Ib in pu is |
| A. | 1 |
| B. | 7.81 |
| C. | 11.53 |
| D. | 13 |
| Answer» D. 13 | |
| 6. |
A 500 MVA, 11KV synchronous generator has 0.2 p.u. synchronous reactance. The p.u. synchronous reactance on the base values of 100 MVA and 22 KV is |
| A. | 0.16 |
| B. | 0.01 |
| C. | 4 |
| D. | 0.25 |
| Answer» C. 4 | |
| 7. |
For a fully transposed transmission line |
| A. | positive, negative and zero sequence impedances are equal. |
| B. | positive and negative sequence impedances are equal. |
| C. | zero and positive sequence impedances are equal. |
| D. | negative and zero sequence impedances are equal |
| Answer» C. zero and positive sequence impedances are equal. | |
| 8. |
A 25 MVA, 33 kV transformer has a pu impedance of 0.9. The pu impedance at a new base 50 MVA at 11 kV would be |
| A. | 10.4 |
| B. | 12.2 |
| C. | 14.4 |
| D. | 16.2 |
| Answer» E. | |