中文摘要：

传统确定性电力系统安全评估方法难以考虑电力系统的随机性，难以实时、定量和直观地提供电网安全健康状态的诊断信息。文章引入了电网脆弱性的概念，拓展了传统的电力系统安全性概念，并考虑预想事故发生的概率，采用暂态能量函数法从暂态安全角度定量评估了电力系统的脆弱性，给出了电力系统的脆弱性指标和闽值。算例分析结果表明该方法在保证安全分析结果正确性的同时节省了机时，验证了该方法的合理性与有效性。

英文摘要：

It is difficult for traditional certainty assessment method of power system security to consider the randomness of power system, so it is also difficult to offer real-time, quantitative and visual diagno4sis information of security and health status of power system. Introducing the concept of power system vulnerability the authors extend traditional concept of power system security; considering the occurrence probability of contingency, by use of transient energy function the vulnerability of power system is quantitatively assessed in the viewpoint of transient security, and the index and threshold value of power system vulnerability are given. Results of calculation example analysis validate the rationality and effectiveness of the proposed method; meanwhile, these results also show that the proposed method can ensure the correctness security analysis while the computing time is saved.