Application And Study On Self-Excited Excitation System In Large Turbine Generators

The synchronous generator is one of the main resources of reactive power in power system operation, the reactive power output of generator can be changed through the adjustment of exciting current to maintain the terminal voltage of generator. The characters of excitation system of synchronous generator plays an important role in power system operation, an excellent excitation system can guarantee the quality of voltage effectively and improve the stability of power system operation. With the increase of the capacity of single generator and the scale of power network, higher requirements to the reliability and dynamic quality of the excitation control for generator set and power system are needed. Based on the development of excitation controller at home and abroad as well as the engineering practical situation of 2x300MW generator sets of the thermal power in Shaanxi Huxian No.2 Power Plant, the functions and characters as well as the problems appeared during operation of UNITROR 5000 excitation system produced by ABB company are analyzed in the paper.In the paper, the development and trend of excitation system to be used in large thermal power generator sets at home and abroad are introduced, the comparison between relative merits is carried out in detail, then the paper clearly points out that the self-excited excitation system has the obvious characters as faster speed response and shorter axial system as well as economic running, therefore, the system should be promoted widely. Simultaneously, the paper compares and analyzes the three normal excitation control methods and obtains that the PID+PSS control has a good adaptability, and it can be used in faster excitation system and normal excitation system. Moreover, in accordance with the choice of excitation system in Shaanxi Huxian No.2 Power Plant, the functions and characters as well as the practical application in engineering of UNITROR 5000 excitation system produced by ABB company are introduced. Finally, through the tuning of AVR and PSS parameters of the generator excitation adjuster and the effect test of PSS in Huxian No.2 Power Plant, it can be proved that adopting self-excited system and PID control is a kind of safe and reliable excitation method.