汽轮发电机时步有限元计算参数对大扰动仿真结果的影响

Influence of Calculation Parameters of Time-stepping Finite Element Method on Simulation Results in Turbo-generators Large Disturbance Process

为准确反映电网大扰动故障对系统动态稳定以及对发电机的影响,在充分考虑转子槽楔、阻尼导条、转子体以及端部梳齿环等阻尼作用的基础上,采用场-路-网耦合时步有限元法对单机-双回线-无穷大系统动态过程进行仿真计算,系统研究了定转子端部漏抗、涡流区域等效电导率以及剖分策略等共计10个计算参数在一定范围内的取值变化对极限切除时间、电磁转矩等多个机电量仿真结果的影响。揭示了定子端部漏抗对过渡过程中最大转矩,以及转子槽楔等效电导率对励磁电流与极限切除时间的计算结果有重要影响。为系统动态过程的仿真计算、参数辩识以及巨型发电机承受系统非正常运行能力等相关问题的研究提供依据。

In order to accurately describe the effects of large disturbance on the dynamic stability and the generator＇s characteristics in the power system, a field-circuit-network coupling time-stepping finite element method （T-S FEM） model is employed to calculate the dynamic response of the one machine double circuit line infinite system, considering the effects of slot wedge, damping, rotor core and the comb ring. This paper systematically analyzes how the 10 calculation parameters, such as end region leakage reactance, equivalent conductivity and mesh density, impact the critical clearing time, the electromagnetic torque and other electromechanical variables in the simulation. The result shows that stator end leakage inductance affects the maximum electromagnetic torque in the transient process evidently, while the equivalent conductivity of slot wedge has significant influence on the excitation current and critical clearing time. The analysis in this paper provides the basis for accurate system dynamic simulation, parameter identification and helps the study on capability of huge generators to endure the abnormal operation.