Research On Loss Excitation Fault Character For 1000MW Turbo-Generator

With the increase of the voltage level of the power system and the high parameterization of automation, the large capacity generator becomes the main unit, so the generator fault will directly affect the normal and stable operation of power system. The loss of excitation fault is one of serious accidents of large turbo generator, which will directly affect the stability of the power system and generator,even to make the generator out of the grid. After the loss of excitation fault of large turbo generator, the stator current increase, the rotor is over voltage, the asynchronous torque become large, the stator winding heating and the surface temperature of the rotor is too high, these reasons restrict the asynchronous operation. In this paper,from the variations of electrical quantities in the rotor and stator, rotor eddy current loss distribution, and rotor temperature field to study the loss of excitation fault of the turbo generator.In this paper, the research object is a 1000 MW turbo generator in Shanghai Turbo-generator Co. Limited. Based on Matlab/Simulink software to study on the dynamic characteristics of turbine generator’s loss of excitation. According to the theory of electromagnetism and heat transfer,using Ansoft Maxwell software and the integrated simulation platform Ansys Workbench to research the following aspects:Firstly,based on Matlab/Simulink to build the simulation model of the single machine infinite bus system, compared with the traditional method to confirm the advantages of this method; Then,based on the load reduction measures, to simulate the generator on the excitation with the winding open circuit and short circuit fault, comparison the influence of two kinds of faults on the electric quantity of the stator and rotor, from the curves of the stady-state operation to analyze the way which benefits the stable operation and the maintaining stability between the generator and the grid when the load down to a certain extent.Secondly, based on the Finite Element software Ansoft Maxwell to build the 1000 MW level turbo generator. By using these data from the Matlab/Simulink,load the stator current and the rotor speed to the Finite Element simulation model. Calculation of rotor eddy current loss to obtain the cloud chart after loss of excitation, and view the eddy loss distribution, providing the calculated data for the study of rotor temperature field simulation.Finally, using the loss of the results calculated from the Finite Element software Ansoft Maxwell, combined with Ansys Workbench software, based on the coupling between the electromagnetic field and temperature field to analyze the rotor temperature. Through the analysis of the electromagnetic and temperature,viewed the results of the calculation, and integrated evaluation of the generator’s capacity with the loss of excitation and asynchronous running.