Research On Excitation Of The High-low Voltage Rectifier

With the development of economy, power supply in China is far behind demand. Therefore, power plants are currently constructed rapidly. As the largest scaled power station, the Three Gorges power station will act as a key role in the national power system. As known, the stability of large power station has great impact on the power system. The synchronous generator excitation which is of the most importance in the generator will effect on the dynamic and static stability of the generator. Therefore, the research of the key technology of the excitation is more important in terms of the power system stability. To keep the multiple of excitation voltage in the constrained current operation, the power converter in generator excitation has a big trigger angle when the generator is in rated state. There will bring some serious problems for excitation, such as: the more voltage harmonization, the higher voltage in the phase conversion of thyristor. This paper analyses the high-low voltage converter excitation in chapter 2 and chapter 3. This paper investigates the differences between the new excitation and the traditional excitation and proposes the construction of the high-low voltage converter excitation. Furthermore, According to the study of the characteristics of the new excitation system, two individual operations of the excitation system are put forward, and the theory of the operation is discussed, and relevant formulae under different operation are derived. Based on the simulation of MATLAB, the instantaneous waveforms of the excitation voltage under different operating modes of the high-low voltage converter excitation are studied. As a result, there are no negative impacts on the generator control, and this novel excitation system is effective. The excitation controller is an important component of an excitation system. This paper analyses the principle and characteristics of the excitation controller of the Three Gorges power station generator in chapter 4. The differences of this excitation controller and other excitation controllers are investigated. A simulation model of an infinite system to a generator is set up for the purpose of the investigation of super-huge unit of the Three Gorges power station generator. The comparison between the proposed excitation controller and other two excitation controllers are carried out and some valuable viewpoints are available for the purpose of the dynamic simulation of the excitation system of the Three Gorges generator unit. In the end, the excitation control method adopted by the generator units used by later stage of the Three Gorges Projects is discussed.