Research On Operation Behavior Of Synchronous Generator Under System Disturbance Conditions With Time-Stepping Finite Element Method

The Field-Circuit-Network Coupled Time-Stepping Finite Element Model (T-S FEM) was built for dynamic simulation of power system, in which the complicated non-linear factors are considered adequately. Based on this model, the influence of multiple non-linear factors on generator's operation behavior was studied under system disturbance conditions, and the influence of computation parameters of T-S FEM on simulation results was also analyzed. All of those can provide the theory and technical foundation to further build the simplified model for power system analysis. The main innovations are summarized as follows:1. In order to consider the influence of turbine generators' non-linear factors on the generator-grid system's transient process, a novel Field-Circuit-Network coupled T-S FEM for the system analysis was built, in which the non-linear factors such as saturation, field distortion and skin effect in rotor core, excitation winding and damping bar in dynamic process can be considered altogether.2. Aiming at the synchronous generators' concrete structure, the influence of preset factors such as structure, material parameters, time and space discrete density on the simulation result in T-S FEM are studied systematically. The relationship between T-S FEM simulation result and calculation parameters is revealed and the suitable value range for getting standard response in dynamic process is proposed.3. Combining the small signal characteristics value method and Prony analysis, the T-S FEM was adopted to reveal the relationship between multiple complicated non-linear factors and basic operation characteristics, such as rotor oscillator frequency, damping ratio, limit of the system static stability and so on. And the error resources are pointed out when the PARK equation based on factory parameters was adopted for simulation on some operation situation.4. The T-S FEM was adopted to analyze the maximum electromagnetic torque, maximum stator & exciting currents and critical clear time during big disturbance, The influence of complicated non-linear factors on the operation behavior and system stability were revealed, which can provide the theoretical basis for further research on the simple model to reflect the complicated non-linear function of the generators.