MCQOPTIONS
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MCQOPTIONS
This section includes 180 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering Questions knowledge and support exam preparation. Choose a topic below to get started.
| 151. |
What is frequency stability? |
| A. | To maintain steady frequency following severe disturbance resulting in the imbalance between transformer and load |
| B. | To maintain steady frequency following severe disturbances resulting in the imbalance between generators and load |
| C. | To maintain a steady frequency in all the protection components and the transmission lines. |
| D. | Both (a) and (b) |
| E. | All of these |
| Answer» C. To maintain a steady frequency in all the protection components and the transmission lines. | |
| 152. |
What is / are the major assumptions made in the calculation of swing equations? |
| A. | Damper windings are neglected |
| B. | The machine is lossless |
| C. | The machine has to run at synchronous speed |
| D. | Both (a) and (b) |
| E. | All of these |
| Answer» E. All of these | |
| 153. |
What is / are the cause(s) for transient disturbance? |
| A. | Sudden load changes |
| B. | Faults in the power system |
| C. | Switching operations |
| D. | All of these |
| E. | None of these |
| Answer» E. None of these | |
| 154. |
What is an oriented graph? |
| A. | A connection of network topology, represented by replacing all physical elements by lines. |
| B. | A graph in which the direction is assigned to each branch. |
| C. | A graph where at least one path exists between any two nodes of the graph. |
| D. | None of these |
| Answer» C. A graph where at least one path exists between any two nodes of the graph. | |
| 155. |
What information does the swing curve provide? |
| A. | Stability of the system. |
| B. | Performance of the machine |
| C. | The rotor performance |
| D. | All of these |
| E. | None of these |
| Answer» B. Performance of the machine | |
| 156. |
What happens to the zero sequence currents, if the neutral in the Y connection is absent? |
| A. | Minimum |
| B. | Zero |
| C. | Maximum |
| D. | ∞ |
| Answer» C. Maximum | |
| 157. |
What happens to the value of the fault current in case of SLG fault, if fault impedance is introduced? |
| A. | The fault current increase |
| B. | The fault current remains same as in case of SLG fault. |
| C. | The fault current becomes zero |
| D. | The fault current is reduced |
| Answer» E. | |
| 158. |
What happens if the neutral is not grounded in case of the single line to ground fault? |
| A. | Only the zero sequence impedance will be zero |
| B. | The zero sequence impedance will be infinite |
| C. | Fault current will be zero |
| D. | Both (b) and (c) |
| E. | All of these |
| Answer» E. All of these | |
| 159. |
What does the swing equation describe? |
| A. | The relative motion of rotor with the field windings of the machine |
| B. | The relative motion of the rotor with respect to stator field as a function of time. |
| C. | The relative motion of stator field with the rated frequency of the machine |
| D. | The performance curve of the machine |
| Answer» C. The relative motion of stator field with the rated frequency of the machine | |
| 160. |
What does the positive sequence component consist of? |
| A. | Three balanced phasors of equal magnitude and displaced by 120° |
| B. | Three unbalanced phasors displaced by 120° |
| C. | Three phasors with equal magnitude and zero displacement. |
| D. | None of these |
| Answer» B. Three unbalanced phasors displaced by 120° | |
| 161. |
What are zero sequence components? |
| A. | Three balanced phasors of equal magnitude and displaced by 120° |
| B. | Three balanced phasors displaced by 120° and having phase sequence opposite to that of the original phasors. |
| C. | Three phasors with equal magnitude and zero displacement. |
| D. | None of these |
| Answer» D. None of these | |
| 162. |
What are the types of unsymmetrical faults? |
| A. | Single line to ground fault |
| B. | Double line to ground fault |
| C. | Line to line fault |
| D. | All of these |
| E. | None of these |
| Answer» E. None of these | |
| 163. |
What are the main applications of the swing curves? |
| A. | Designing the rotor field windings |
| B. | Designing the protective devices |
| C. | Used to limit the size of the machine |
| D. | All of these |
| E. | None of these |
| Answer» C. Used to limit the size of the machine | |
| 164. |
What are the common assumptions made for the equal area criterion? |
| A. | The transmission line and machine resistances are neglected. |
| B. | Rotor speed of the machine is constant |
| C. | Mechanical input remains constant. |
| D. | All of these |
| E. | None of these |
| Answer» E. None of these | |
| 165. |
What are cross country faults? |
| A. | A fault occurring at any point of the power system |
| B. | Two or more faults occurring simultaneously on the power system |
| C. | Line to line fault |
| D. | All of these |
| E. | None of these |
| Answer» C. Line to line fault | |
| 166. |
To control which among the following is the regulating transformer used in a power system? |
| A. | Power flows |
| B. | Frequency |
| C. | Voltage |
| D. | Power factor |
| Answer» B. Frequency | |
| 167. |
The positive sequence current is always equal to ______________. |
| A. | Always zero |
| B. | 1/3 of the negative sequence current |
| C. | Negative sequence current |
| D. | 3 times the negative sequence current |
| Answer» D. 3 times the negative sequence current | |
| 168. |
Phase shift of symmetrical components happens in which among the following? |
| A. | Delta - delta |
| B. | Star – delta |
| C. | Delta – star |
| D. | Both (b) and (c) |
| E. | All of these |
| Answer» E. All of these | |
| 169. |
On what factors does the transient stability depend on? |
| A. | Initial operating state |
| B. | Severity of disturbances |
| C. | Voltage instability |
| D. | Both (a) and (b) |
| E. | All of these |
| Answer» E. All of these | |
| 170. |
In which portion of the transmission system is the occurrence of the fault more common? |
| A. | Alternators |
| B. | Transformers |
| C. | Transmission lines |
| D. | Underground cables |
| Answer» D. Underground cables | |
| 171. |
In what direction does the phasor get rotated if it is multiplied by the operator ‘a’? |
| A. | Anti clockwise |
| B. | Clockwise |
| C. | Gets rotated by 90° in the clockwise direction |
| D. | Gets rotated by 90° in the anticlockwise direction |
| Answer» B. Clockwise | |
| 172. |
In the manufacture of transformers, ANSI prescribes certain standards. What is this standard? |
| A. | High voltage side should lead the low voltage side by 30° with Y - Δ or Y - Δ connections. |
| B. | High voltage side should lead the low voltage side by 60° with Y - Δ or Y - Δ connections. |
| C. | High voltage side should lag the low voltage side by 30° with Y - Δ or Y - Δ connections. |
| D. | High voltage side should lag the low voltage side by 60° with Y - Δ or Y - Δ connections. |
| Answer» B. High voltage side should lead the low voltage side by 60° with Y - Δ or Y - Δ connections. | |
| 173. |
If the speed of the circuit breaker is 8 cycles or slower than that what will be the multiplying factor? |
| A. | 2.3 |
| B. | 1.0 |
| C. | 1.5 |
| D. | 1.7 |
| Answer» C. 1.5 | |
| 174. |
How is the voltage and frequency controlled in automatic generation control? |
| A. | By controlling the excitation |
| B. | By controlling the turbine action |
| C. | Turbine speed control for voltage and excitation control for frequency |
| D. | Excitation control for voltage and turbine speed control for voltage. |
| Answer» D. Excitation control for voltage and turbine speed control for voltage. | |
| 175. |
How are the zero sequence and negative sequence networks connected in case of LLG faults? |
| A. | Parallel |
| B. | Series |
| C. | Can be connected in either way |
| D. | Such type of connection does not exist |
| Answer» B. Series | |
| 176. |
For Y - Δ and Δ - Y transformers, the phase shift between the transformer windings is equal to “ n * 30° “. What does ‘n’ represent in the equation? |
| A. | Number of windings |
| B. | Number of turns |
| C. | Turns ratio |
| D. | Hour number |
| Answer» E. | |
| 177. |
For which among the following cases is the equal area criterion of stability used? |
| A. | One machine and infinite bus bar |
| B. | No load on bus bar |
| C. | Many machines and infinite bus bar |
| D. | All of these |
| E. | None of these |
| Answer» B. No load on bus bar | |
| 178. |
For what studies are the FDLF method used? |
| A. | Optimisation studies |
| B. | Multiple load flow studies |
| C. | Small size systems |
| D. | Both (a) and (b) |
| E. | All of these |
| Answer» E. All of these | |
| 179. |
For economic measure the generators at a power plant operate at _____________. |
| A. | Equal incremental cost |
| B. | Equal loads |
| C. | Equal power rating |
| D. | All of these |
| E. | None of these |
| Answer» B. Equal loads | |
| 180. |
At what value of ‘δ’ the maximum power transfer takes place? |
| A. | 45 ° |
| B. | 90 ° |
| C. | 120 ° |
| D. | 180 ° |
| Answer» C. 120 ° | |