Simulation Study On Operation Action Of Asynchronized Turbogenerators Under Faults In The Excitation System

The performances of Asynchronized Turbogenerator(ASTG) are significantly better than those of conventional turbogenerator. Its appearance shows a new way to solve the problems of continuous over voltage on extra-high voltage transmission lines due to the surplus of reactive power and the stability of power systems with long distance transmission line.In this thesis, based on the basic operation principle of ASTG and the dual-passage excitation control principle the system simulation model of ASTG is established by the Saber simulation software. Simulation results when some faults in the excitation system are carried out during the steady state operation and the transient state operation for ASTG and the dynamical process is analyzed.The excitation system of ASTG is a two-axis excitation system, and the excitation current in the rotor windings can reverse. In this thesis, the faults in the excitation system include the partial faults, the loss of excitation at one winding of the rotor and the loss of excitation at both windings of the rotor. The results in this thesis show: the regulative performances of the active power and reactive power for ASTG with partial faults in the excitation system appear in good; the ASTG can return to the original steady state operation when the any working thyristors were damaged suddenly and this dynamical process is stable; the ASTG can maintain the active power output without a power unit tripping and the characteristics for ASTG appear in good order at the loss of excitation at both windings or one winding of the rotor, which show that the operation mode of ASTG is agility. The results in this thesis will be helpful to analyze the operation for ASTG when some faults occur in the excitation system.