汽轮发电机不同模型小扰动特性

Small Disturbance Characteristics of the Different Turbine Generator Models

电力系统仿真分析常用的几种同步发电机实用模型是在Park方程基础上引入不同假设条件得到的。不少文献假设参数满足xaf xD=xaD xfD(q轴同理)而得到所谓的假设A模型,而将满足xad=xaf=xaD=xfD关系的实用模型称为假设B模型,对假设B模型进一步简化得到假设B-1模型。为了分析不同实用模型小扰动仿真结果的准确性,本文将其与时步有限元仿真结果进行对比:首先研究了各模型假设条件的物理意义,揭示出不同假设条件的根本区别在于是否计及励磁绕组和阻尼绕组之间的互漏磁链;然后以300MW汽轮发电机单机无穷大系统为例,对比了三种实用模型和时步有限元的小扰动仿真结果,重点分析了由大齿导条、转子导电槽楔构成的阻尼绕组和导磁导电的转子实心体分别作用和共同作用下的小扰动仿真结果;最后通过对小扰动特性指标进行对比分析得出假设A模型的仿真结果与时步有限元最接近。研究结果为电力系统仿真中合理选择汽轮发电机模型提供了重要参考。

The practical models of turbine generator used in power system simulation are derived from Park equations by introducing different assumed conditions. The so-called assumed A practical model is obtained by postulating XafXD=XaDXfD in several literatures, while assumed B practical model is obtained by postulating Xad=X^f=XaD=XfD. The B-1 practical model is obtained based on assumed B by further hypothesis. In order to analyse the accuracy of simulation results, the small-disturbance characteristics calculated by practical models are compared with time step finite element method（TSFEM）. Firstly, the physical significance of different assumed condition is studied. The essential distinction of different assumed conditions is considering the mutual leakage flux linkage between exciting winding and damping winding or not; Then, take single machine infinite system for example, the small-disturbance characteristic calculated by different models are compared under the different damping structures. Finally, the small-disturbance characteristic calculated by assumed A is closed to T-S FEM through comparing small-disturbance characteristics index. The result provides reasonable reference to select practical model in power system simulation.