中文摘要：

将电力网络拓扑结构与系统潮流相结合，提出了一种能反映这两方面特性的预想事故自动选择的新方法。传统的预想事故自动选择方法着眼于电力系统潮流。实际上，网架的拓扑结构对电力系统的能量传输同样重要。将电力系统网络等值为无向加权网络，以线路的阻抗幅值作为边的权值，通过计算任意两点间的最短路径得出各边和节点的介数，用介数来反映元件在网络拓扑中的重要程度。用线路流过的功率来反映目前线路的负载程度，两者结合，得到本方法的排序指标。IEEE30节点系统的算例分析结果表明本方法能较好地反映元件对系统的重要程度，对严重故障具有较高的捕获率，能够有效地减少静态安全分析的计算量。

英文摘要：

A new Automatic Contingency Selection （ACS） method considering topological characteristics and load flow of the power system is proposed in this paper. The traditional methods of ACS just focused on the load flow of the power system. In fact, the topological characteristics of power system play an important role in the energy transmission. The new index （betweenness） is used to evaluate the importance of the branches, transformers and generators in the topology. So this new performance index can be used to evaluate the importance of the components for the automatic contingency selection. Using this new index, topological characteristics and load flow of the components are both considered. The IEEE 30-bus system is used as an example system to test the correctness and efficiency of the proposed index. The simulation results indicate that this new index and the proposed method are simple and effective.