中文摘要：

针对计及励磁饱和环节的最优励磁控制系统，揭示了吸引域和系统分岔的物理意义及其相互关系，基于迭代搜索的计算策略，提出了以椭球吸引域体积为指标确定小扰动稳定域边界的新算法。与传统算法相比，该算法将可镇定扰动与状态空间吸引域的大小建立关联．确定的小扰动稳定域能提供注入空间和状态空间等多元信息。算例分析验证了算法的有效性，计算了恒阻抗、恒电流、恒功率3种不同负荷模型下的小扰动稳定域。研究表明．系统的负荷模型对饱和系统小扰动稳定域边界有一定的影响，使用恒阻抗模型获得的稳定域较小．使用恒电流模型获得的稳定域稍大。

英文摘要：

The physical meaning and correlation between RA （Region of Attraction） and system bifurcation are revealed for the linear optimal excitation control system with saturation element. Based on the iterative calculating search strategy,an algorithm with the volume of ellipsoidal RA as the criterion is proposed to determine the boundary of the SSSR（Small Signal Stability Region）,which establishes the bonds between disturbance and RA in state space. The SSSR contains information of state space,injection space and so on. Case analysis indicates its efficiency. SSSRs are calculated for different load models：constant impedance, constant current and constant power,which demonstrate that,the system load model has certain effect on the SSSR boundary of system with saturation：the SSSR of constant impedance model is smaller while the SSSR of constant current model is slightly larger.