Study On Synchronous-generator's Magnetic Field Nonlinear Characteristics And Operational Characteristics

In this paper calculation methods of various characteristics curves considering magnetic field nonlinear effect of synchronous generators is systematically studied. The comparison between the results and those without consideration of nonlinear effect is given. The magnetic field nonlinear effect on the operating characteristics is analyzed and the possible factors causing the nonlinear phenomenon is presented. Considering the effect of three-variable differential method is used to estimate the field current and power angle.The main results of research in this paper are:The stability and accuracy of the FEM calculation program are validated with the reference of the test report on the leading operation of 1 # generator in Fengzhen power station.Through the extensive calculation, the effects of the ferro-magnetic saturation and field distortion on operating characteristics and the generator parameters are further studied based on the former literatures. The no load curve and zero power loading curve are obtained. Different poti reactances are calculated when field currents are different. The power angle characteristics are acquired and compared with the unsaturated curves. It is concluded that the stability limit of the power angle is less than 90 degree. Reactive power regulating curves are calculated and compared with those curves when saturation effect is not considered, The result is that U type curves are deviated to the right.Based on current resolving method of nonlinear finite element equations, the magnetic field distribution of typical operations are obtained. Through the analysis of calculating results, this paper presents the effect of the synchronous generator operational parameters on the magnetic field non-linearity.According to the calculation results, the three-variable differential method is applied to estimate the field current and power angle of the synchronous generator.