为研究电网连锁故障机理,同时判别出连锁故障传播过程中的关键脆弱元件,从熵的基本原理出发,结合过负荷与断线扰动下潮流的分布特性,提出了基于潮流熵的脆弱元件评估模型。通过对新英格兰10机39节点系统的模拟计算,节点单位过负荷扰动下,节点的潮流分布熵越小,越容易导致系统支路越限,节点越脆弱;支路受"发电机—负荷"节点对的潮流冲击越大、支路潮流转移熵越小,支路越脆弱,在连锁故障中起到关键传播作用;与基于介数、风险等方法的脆弱元件判别结果相比,基于潮流熵的脆弱元件评估模型物理意义明确,计算速度快,脆弱元件集符合实际情况。
To study the mechanism of cascading failures in a power grid and find out the key vulnerable components propagating cascading failures,based on the basic principle of entropy and the distribution of power flow due to overload and removal of components,the components vulnerability assessment method of power flow entropy is proposed.Simulation results on the IEEE 39-bus system indicate that the smaller the distribution entropy of power flow is,the more vulnerable the node is.It also shows that the smaller the transfer entropy of power flow and the larger the impact by power flow of 'generator-load' nodes is,the more vulnerable the branch is.The vulnerable components play a key role in the propagation of cascading failures.Compared with vulnerable components evaluation results obtained by methods based on betweenness and risks,the vulnerability assessment model of power flow entropy has a clearer physical meaning,faster calculation,and is more realistic.