提出使用电气介数分析电网连锁故障传播机制的方法，研究不同电气介数节点失效对系统连通性和输电能力的影响。同时提出基于生成介数的连锁故障积极防御方法。理论分析表明所提方法基于基尔霍夫定律，克服了已有模型假设潮流只沿母线间最短路径流动的不足，物理背景更符合电力系统实际。IEEE 39节点系统算例显示，电气介数阈值较低时单一节点故障极易引发系统连锁故障，提高介数阈值可相对减弱这种风险，但仍无法改变电网在高电气介数节点故障面前极为脆弱的本质。在故障初期，根据生成介数主动切除极少量不重要节点，可以较小代价显著抑制连锁故障的蔓延，且简单经济。对西北网的计算也证明了上述结论。

Analysis of cascading failure mechanism in power grid was presented based on electric betweenness, in which relationship among electric betweenness of nodes, connective loss and transmission capability of power system was studied especially. Whereafter，generated betweenness was introduced to make active defence against the cascading failure. Academic analysis shows the presented method is more reasonable in power system than existed models because it is based on Kirchhoff’s law rather than supposing power flow being transferred only along the shortest path. Numeric example of IEEE 39-bus system shows faults of single node can cause cascading failure easily when the threshold of electric betweenness in power system is low, while such risk is reduced partially by improving of the threshold. However, the system is still vulnerable even with high threshold but under fault of nodes with high electric betweenness. Moreover, it shows the cascading failure is restrained remarkably by intentional removal of very few nodes according to their generated betweenness when original fault occurs. Corresponding conclusions were also confirmed by the analysis of China Northwest system.

国家重点基础研究专项经费项目(2004CB217905)；国家自然科学基金项目(50777052)。