What is the purpose of load sharing in parallel operation of alternators?
A Maintain Frequency
B Balance Voltage
C Improve Efficiency
D Distribute Power
Load sharing in parallel operation ensures that the power demand is evenly distributed across multiple alternators. This prevents overload on any single alternator and ensures reliable power supply by spreading the load among the units.
When alternators are operated in parallel, which of the following is crucial for their synchronization?
A Voltage Matching
B Rotor Speed
C Frequency Control
D Power Factor
For parallel operation, the alternators must have their voltages matched. Voltage matching ensures that the alternators operate in harmony, preventing electrical faults and ensuring stable power output across the system.
What happens if the frequency of two alternators is not synchronized during parallel operation?
A Overload
B Voltage Drop
C System Instability
D Power Loss
If the frequencies are not synchronized, one alternator will try to drive the other, causing instability. This can lead to system failures, including damaging electrical equipment and reducing overall reliability of the power grid.
What is the main requirement for the parallel operation of alternators?
A Same Speed
B Same Voltage
C Same Excitation
D Same Power Factor
For alternators to operate in parallel, their output voltages must be the same. Voltage synchronization ensures that the alternators can share the load effectively without causing fluctuations or instability in the power supply.
In load sharing between alternators, how is the total load divided?
A Based on Power Factor
B Based on Voltage
C Based on Rated Capacity
D Based on Rotor Speed
Load sharing is typically based on the rated capacity of each alternator. The larger-rated alternators will carry more load, while smaller ones share the load proportionally, ensuring efficient operation and preventing overload.
What could happen if an alternator in a parallel system operates at a lower voltage than others?
A It Will Not Contribute to Load
B It Will Overload
C It Will Supply More Power
D It Will Disconnect Automatically
If an alternator operates at a lower voltage, it will not contribute to the load. The alternator with lower voltage will be disconnected or not take part in supplying the load, as it cannot synchronize with the others.
What role do synchronizing lamps play in parallel operation of alternators?
A Match Frequency
B Monitor Power Output
C Indicate Voltage Drop
D Synchronize Voltage
Synchronizing lamps are used to match the voltages of the alternators during parallel operation. When the lamps flash in unison, it indicates that the alternators are synchronized and can safely be connected to the grid.
What is the primary cause of an alternator failing to share load in parallel operation?
A Excessive Load
B Incorrect Speed
C Incorrect Excitation
D Frequency Mismatch
If the excitation is incorrect, an alternator may not generate the required voltage and therefore cannot properly share the load in parallel operation. This results in inefficient power distribution and may cause system instability.
How does the parallel operation of alternators affect the overall system reliability?
A Reduces Power Factor
B Increases Reliability
C Reduces Efficiency
D Increases Complexity
Parallel operation increases system reliability by providing redundancy. If one alternator fails, the others continue to supply power, ensuring an uninterrupted power supply and reducing the risk of complete system failure.
What is the purpose of a governor in an alternator’s parallel operation?
A Control Load Sharing
B Control Frequency
C Synchronize Voltage
D Regulate Speed
The governor controls the rotor speed of the alternator to maintain synchronization with other units in parallel operation. By adjusting speed, the governor ensures that all alternators operate at the same frequency and contribute effectively to load sharing.
What happens if alternators in parallel operation have a significant power factor difference?
A Equal Voltage
B Increased Stability
C Uneven Load Sharing
D Increased Efficiency
A significant power factor difference between alternators in parallel operation causes uneven load sharing. The alternator with a lower power factor may draw more current, leading to inefficiency and potential overload on some units.
In a parallel operation, how is the voltage control achieved in alternators?
A By Changing Excitation
B By Adjusting Load
C By Adjusting Speed
D By Synchronizing Frequency
Voltage control in parallel operation is primarily achieved by adjusting the excitation of each alternator. By increasing or decreasing the excitation, the voltage can be matched across the system to ensure stable and balanced operation.
What is one of the key challenges in load sharing between multiple alternators?
A Maintaining Synchronization
B Ensuring Proper Excitation
C Maintaining Frequency
D Overloading One Unit
Ensuring proper excitation for each alternator is crucial in load sharing. If one alternator has inadequate excitation, it will not maintain the correct voltage, leading to improper load sharing and possible system instability.
How does an alternator’s excitation system affect load sharing in a parallel operation?
A It Controls Frequency
B It Prevents Overload
C It Regulates Voltage
D It Determines Load Contribution
The excitation system is critical in controlling the alternator’s output voltage. In parallel operation, the voltage regulation from the excitation system ensures that each alternator contributes to the load proportionally, maintaining balanced load sharing.
What is the main purpose of using a paralleling switchboard in alternator operation?
A Synchronization and Load Sharing
B Fault Detection
C Speed Regulation
D Voltage Control
A paralleling switchboard is used to synchronize alternators, allowing them to operate together and share the load. It ensures that voltage and frequency are matched before closing the circuit to prevent system damage.