| Nowadays it put higher requirements for the stability of the system with the size of the grid expanded. Synchronous generator is an important component of power system, and its runtime behavior affects all aspects of the system, so its model and parameters were always be an important part of the study on modeling of power system. Accurate and reasonable synchronous generator model and parameters have great significance for analysis and calculation of dynamic behavior of power system. Aiming at synchronous generator, people established a variety of models with different levels. Different models corresponding to different types of parameters, the independence of parameters and the issues of whether the parameters correspond to the model have a relationship with the parameter identification of synchronous generator. It is one of theoretical basis of parameter identification of synchronous machine. Parameter identification of synchronous machine is both application and basic theoretical subject. Due to the presence of saturation, vortex and a series of complex physical phenomena in the synchronous machine, some of the parameters are nonlinear with varying work conditions. Therefore, the subject is more difficult.Aiming at the analysis of dynamic behavior of synchronous machine, it introduced third-order model of electromechanical transient stability, fifth-order model of comprehensive stability, six-order model of practical utility. Meanwhile, explained electromagnetic theory, analyzed issues of electromagnetic fields within the synchronous machine broadly from static field, eddy current field and motion field these three parts.Illustrated the significance of mathematical modeling, elaborated the principles of modeling of synchronous machine including magnetic saturation based on three-phase coordinate system, proposed a method to describe the phenomenon of magnetic saturation of the synchronous machine based on nonlinear inductance. Meanwhile, it introduced two specific ways to build the saturated model. One of which is using software of FLUX2D and finite element method to do the modeling of machine, the other one is using the equivalent circuit diagram of synchronous machine to reflect the effect of magnetic saturation.The paper introduced the least square method and standstill frequency response (SSFR) test, meanwhile, the gain and phase of different parameters with range frequencies were obtained by analyzing the SSFR curves. The model and the state-space equations of synchronous machine were simplified with the gain and phase to replace the relevant term in characteristic transfer functions which represented d, q-axis electromagnetic parameters. The experimental data process method was improved and the parameters of the machine were identified based on the status analysis of the machine at the open field winding and the open stator winding.The nonlinear saturation model and the state-space equations of silent-pole synchronous machine (SPSM) were established by the nonlinear characteristic of electromagnetic field with dynamic saturation inductance. The linear electromagnetic parameters of SPSM were obtained by conventional test and standstill frequency response test. The non-linear electromagnetic parameters of SPSM could be identified based on the proposed mathematical model and the linear parameters of SPSM. A simple stand-alone system was created by using MATLAB based on the mathematical model and identified parameters. The proposed method to identify the dynamic saturation parameters was verified by the research results. |
