Research On Operation Characteristics For The 1000MW Hydro-generator Under Conditions Of Saturation

1000MW hydro-generator has greater capacity than the 700MW hydro generator put into operation in the Three Gorges Power Station. The research on 1000MW hydro-generator is still at an early stage at home and abroad, so there are many problems in its design and analysis. When a generator has been designed, accurate calculation of the electrical operating characteristics would become more important, and so is the case of 1000MW hydro-generator. In order to get a variety of operating characteristics of the 1000MW hydro-generator, the nonlinear magnetic field distributions in different conditions are analyzed by finite element method in this paper.First of all, a two-dimensional geometric model of the 1000MW hydro-generator is established, and no-load characteristic is calculated by flux density harmonic method, the tooth flux method and flux linkage method respectively, which proves the rationality of the flux linkage method. Then with the flux linkage method, the operation characteristics at rated operating conditions are calculated. The methods of calculating basic reactances as well as the incremental reactances are deduced, and the reletive results of reactances at rated load are given.Then, several important steady-state operation characteristics for the 1000MW hydro-generator can be calculated using winding flux linkage method. The calculation methods of the short-circuit characteristic, zero power factor load characteristic, power-angle characteristic and U-shaped feature are given, then the basic reactances and incremental reactances at different operating point are calculated under condition of the active power regulation and reactive power regulation, on the base of calculated results, the variations of the calculated operating characteristics and reactances are analyzed. Finally, based on the theoretical analysis, nonlinear load characteristics of the 1000MW hydro-generating are calculated by finite element method. The characteristic curves are relationship between resultant current and air electromotive force. The load characteristics include d-axis saturation characteristics and q-axis saturation characteristics are calculated. To obtain a series of saturated nonlinear load characteristic curves under varied conditions, the different operation conditions, such as keeping field current and power angle constant, keeping power angle constant but different d-axis component current, keeping ratio of d axis resultant current to q axis current of stator constant, keeping ratio of field current to q axis current of stator and keeping power factor constant, respectively are analyzed in this paper. By calculating these saturation characteristics, the variation trends between saturation characteristics in different operation conditions are given.The work can provide a valuable reference for the design and performance study of the 1000MW hydro-generator in this paper, the methods and calculation results of the operating characteristics and the reactances will also be useful for the design and performance study of other generators.