This paper proposes a novel approach to estimate the steady-state angle stability limit (SSASL) by using the nonlinear power system dynamic model in the modal space. Through two linear changes of coordinates and a simplification introduced by the steady-state condition, the nonlinear power system dynamic model is transformed into a number of single-machine-like power systems whose power-angle curves can be derived and used for estimating the SSASL. The proposed approach estimates the SSASL of angles at all machines and all buses without the need for manually specifying the scenario, i.e. setting sink and source areas, and also without the need for solving multiple nonlinear power flows. Case studies on 9-bus and 39-bus power systems demonstrate that the proposed approach is always able to capture the aperiodic instability in an online environment, showing promising performance in the online monitoring of the steady-state angle stability over the traditional power flow-based analysis.

中文翻译：

---

电力系统稳态在线监测的模态空间方法

本文提出了一种通过在模态空间中使用非线性电力系统动态模型来估计稳态角稳定极限 (SSASL) 的新方法。通过两次坐标线性变化和稳态条件引入的简化，将非线性电力系统动态模型转化为多个类似单机的电力系统，其功率角曲线可用于估计SSASL . 所提出的方法估计所有机器和所有总线的角度 SSASL，无需手动指定场景，即设置汇和源区域，也无需求解多个非线性潮流。9 母线和 39 母线电力系统的案例研究表明，所提出的方法始终能够捕捉在线环境中的非周期性不稳定性，