Why is DC excitation important in synchronous generators?

The importance of DC excitation in synchronous generator

The role of DC excitation in synchronous generators is crucial, mainly reflected in the following aspects:

• Maintenance voltage and reactive power output: When the synchronous generator is running normally, the DC excitation system is responsible for providing the generator with the excitation current required to maintain a certain voltage and a certain reactive power output. This is essential for the stability and reliability of the power system, as it ensures that the generator can maintain the ideal operating condition under different load conditions.

• Excitation regulation: By adjusting the DC excitation current, the terminal voltage of the generator can be changed (no load), so as to achieve grid-connection, and adjust the reactive power output to the grid during grid-connection. This helps to optimize the operational efficiency and stability of the power system.

• Response to failure: In the case of short circuit or sudden load change in the power system, the DC excitation system can carry out forced excitation or demagnetization operation to enhance the stability of the power system and prevent generator overload or voltage collapse .

• Advantages of brushless excitation system: the DC exciter is coaxial with the synchronous generator, and the brushless excitation system can be used, which eliminates the slip ring and carbon brush in the traditional excitation system, reduces the maintenance needs and the possibility of failure, and improves the reliability and long-term stability of the system.

• Adapt to different excitation modes: DC excitation is a common excitation mode of synchronous generators, which is suitable for a variety of excitation systems, including DC generator excitation, static rectifier excitation and rotary rectifier excitation, etc. These systems provide different advantages according to different application scenarios.

In summary, DC excitation plays a key role in synchronous generators, which not only ensures the stable operation of the power system, but also improves the flexibility and reliability of the system.