基于动态潮流的电网连锁故障模型及关键线路识别

Modeling Cascading Failures in Power Grid Based on Dynamic Power Flow and Vulnerable Line Identification

研究电力系统连锁故障机理有助于电网安全分析与控制,为此提出考虑发电机调速及负荷电压、频率特性的动态潮流连锁故障模式搜索方法。根据故障状态下雅克比矩阵对角元素值的变化,推导出系统电压稳定评估指标和系统处于电压崩溃临界点时的电压临界值。随着负载率的增大,系统电压稳定指标会逐渐下降,但临界值始终维持在0.5左右。将所提评估指标应用于电网关键线路辨识,对IEEE 39节点系统的仿真表明:所提线路关键性指标比传输功率和权重介数指标更为全面,PSASP时域仿真结果验证了所提方法的有效性。

Research on cascading failures in power grid is uesful for the study of security analysis and control. This paper proposed a search method for power system cascading outages based on dynamic power flow which considered the voltage and frequency dependence of loads and generator regulation characteristics. The voltage stability evaluation index of power system and its critical value were derived according to the variation of the Jacobian matrix diagonal elements when the operating point of a power system is close to a voltage collapse point. The voltage stability evaluation index of power system will decline gradually but its critical value will hold steady at around 0.5 when the load increases. The voltage stability evaluation index was applied to identification of vulnerable lines. The IEEE 39-bus system was used to illustrate the methodology, simulation results for the 39-bus system were compared with the results obtained by transmitted power and weighted line betweenness. The results show that the proposed evaluation index is more useful and the time-domain simulation results also verify that the proposed method is reasonable and valid.