MCQOPTIONS
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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. |
A three phase transformer has a nameplate rating of 30 MVA, 230Y/69Y kV with a leakage -reactance of 10% and the transformer connection is wye-wye. Choosing a base of 30MVA and 230 kV on high voltage side, the high voltage side impedance ____________ |
| A. | 1763.3 |
| B. | 158.7 |
| C. | 15.87 |
| D. | 176.3 |
| Answer» B. 158.7 | |
| 2. |
A three phase transformer has a nameplate rating of 30 MVA, 230Y/69Y kV with a leakage -reactance of 10% and the transformer connection is wye-wye. Choosing a base of 30MVA and 230 kV on high voltage side, the reactance of transformer in per units is __________ |
| A. | 0.1 |
| B. | 0.3 |
| C. | 0.03 |
| D. | 1.5 |
| Answer» B. 0.3 | |
| 3. |
A single phase TL has copper conductor of 0.775 cm2 cross section through which 200 kW at UPF at 330 V is to be maintained. If the efficiency of transmission line is 90%, then the minimum length of TL is ___________(in km and take specific resistance to be 1.785 /cm). |
| A. | 13.6 km |
| B. | 14 km |
| C. | 136 km |
| D. | 16.4 km |
| Answer» B. 14 km | |
| 4. |
A 50 Hz four pole turbo-generator rated 100 MVA, 11 kV has an inertia constant of 8 MJ/MVA. If the mechanical input is suddenly raised to 80 MW for an electrical load of 50MW, then the rotor acceleration is ____________ |
| A. | 337.5 |
| B. | 3.375 |
| C. | 457.5 |
| D. | 4.57 |
| Answer» B. 3.375 | |
| 5. |
A 100 MVA synchronous generator operates on full load at a frequency of 50 Hz. The load is suddenly reduced to 50 MW. Due to time lag in governor system, the steam valve begins to close after 0.4s. The change in the frequency is ________(H=5 kW-s/KVA). |
| A. | 1 |
| B. | 0.5 |
| C. | -1.5 |
| D. | 0.8 |
| Answer» B. 0.5 | |
| 6. |
A 275 kV TL has following line constants A=0.85 5o, B=200 75o. The active power angle such that the voltage to be maintained at the other end will be 275 kV ____________ |
| A. | 22 |
| B. | 16 |
| C. | 18 |
| D. | 24 |
| Answer» B. 16 | |
| 7. |
A 275 kV TL has following line constants A=0.85 5o, B=200 75o. The active power received if the voltage to be maintained is 275kV will be __________ |
| A. | 117.63 |
| B. | 220 |
| C. | 120 |
| D. | 115.25 |
| Answer» B. 220 | |
| 8. |
A single phase distributor of 1 km long has resistance and reactance per conductor of 0.1 and 0.15 respectively. If the far end voltage Vb=200V and current is at 100A at 0.8 lag. At the midpoint a current of 100A is tapped at a pf of 0.6 pf with ref to voltage Vm at mid point. The voltage magnitude at M is ________ |
| A. | 218V |
| B. | 200V |
| C. | 232V |
| D. | 220V |
| Answer» B. 200V | |