How is a synchronous generator connected to a power grid to provide real and reactive power?
1 Answer
A synchronous generator is connected to a power grid in a specific manner to provide both real and reactive power. Real power is the actual power that does useful work and is measured in watts (W), while reactive power is the power required to establish and maintain the electromagnetic fields in the transmission system and is measured in volt-amperes reactive (VAR).
To connect a synchronous generator to a power grid and provide real and reactive power, the generator is synchronized with the grid's voltage and frequency. Here's a step-by-step explanation of the process:
Synchronization:
The generator's prime mover (usually a turbine) is brought up to the required operating speed.
The generator's voltage and frequency are adjusted to match those of the power grid to which it will be connected. This is typically done using automatic voltage regulators (AVRs) and governor control systems.
The generator's circuit breaker is kept open during this process to prevent any sudden power flow.
Voltage and Frequency Matching:
The automatic voltage regulator (AVR) adjusts the generator's output voltage to match the grid voltage.
The governor control system adjusts the generator's mechanical power input to maintain the generator's rotational speed, thus matching the frequency of the grid.
Synchronization Check:
Synchronization is verified by monitoring the phase angle difference between the generator's voltage and the grid voltage. When the phase difference is close to zero, synchronization is achieved.
Closing the Circuit Breaker:
Once synchronization is verified, the generator's circuit breaker is closed. This allows the generator to start feeding power into the grid.
Real and Reactive Power Injection:
As the generator is now connected to the grid, it supplies real power to the grid by converting the mechanical power from its prime mover into electrical power. This real power contributes to the total power available in the grid for doing useful work.
The generator also provides reactive power to the grid. This is achieved by controlling the generator's field current using the AVR. By adjusting the field current, the generator can inject or absorb reactive power to help maintain voltage levels and support the grid's stability.
Power Factor Control:
Power factor is a measure of how effectively real power is being utilized in a system. It's the cosine of the angle between real power and apparent power (the combination of real and reactive power).
Utilities and power generators often aim to maintain a specific power factor to optimize power transmission efficiency. The AVR and reactive power control mechanisms help manage the power factor.
By following these steps and using control systems like the AVR and governor, a synchronous generator can be connected to a power grid to provide both real and reactive power, contributing to the grid's overall stability and functionality.
To connect a synchronous generator to a power grid and provide real and reactive power, the generator is synchronized with the grid's voltage and frequency. Here's a step-by-step explanation of the process:
Synchronization:
The generator's prime mover (usually a turbine) is brought up to the required operating speed.
The generator's voltage and frequency are adjusted to match those of the power grid to which it will be connected. This is typically done using automatic voltage regulators (AVRs) and governor control systems.
The generator's circuit breaker is kept open during this process to prevent any sudden power flow.
Voltage and Frequency Matching:
The automatic voltage regulator (AVR) adjusts the generator's output voltage to match the grid voltage.
The governor control system adjusts the generator's mechanical power input to maintain the generator's rotational speed, thus matching the frequency of the grid.
Synchronization Check:
Synchronization is verified by monitoring the phase angle difference between the generator's voltage and the grid voltage. When the phase difference is close to zero, synchronization is achieved.
Closing the Circuit Breaker:
Once synchronization is verified, the generator's circuit breaker is closed. This allows the generator to start feeding power into the grid.
Real and Reactive Power Injection:
As the generator is now connected to the grid, it supplies real power to the grid by converting the mechanical power from its prime mover into electrical power. This real power contributes to the total power available in the grid for doing useful work.
The generator also provides reactive power to the grid. This is achieved by controlling the generator's field current using the AVR. By adjusting the field current, the generator can inject or absorb reactive power to help maintain voltage levels and support the grid's stability.
Power Factor Control:
Power factor is a measure of how effectively real power is being utilized in a system. It's the cosine of the angle between real power and apparent power (the combination of real and reactive power).
Utilities and power generators often aim to maintain a specific power factor to optimize power transmission efficiency. The AVR and reactive power control mechanisms help manage the power factor.
By following these steps and using control systems like the AVR and governor, a synchronous generator can be connected to a power grid to provide both real and reactive power, contributing to the grid's overall stability and functionality.