基于自组织临界理论的电网脆弱线路辨识

Vulnerable line identification of power grid based on self-organizing critical theory

为了辨识引发电力系统连锁故障的脆弱线路,从事故发展的角度出发,基于自组织临界理论的幂律特性构建了电网脆弱线路辨识模型。线路因保护的隐藏故障或过载而退出运行后,利用孤岛搜索辨识引发系统解列的关键线路,并对其处理以便重新潮流计算。综合改进的潮流分布熵、灵敏度分析理论及OPF模型对负荷水平和发电机出力进行调整,构成电网停电模拟模型。通过大量的仿真与统计,利用系统负荷损失量的幂律或幂律尾特性判断系统是否达到临界状态,同时,系统负荷损失量的数学期望越高,该自组织临界状态越危险,致使连锁故障的风险越高。以IEEE 39节点系统为仿真算例,验证了方法的正确性和有效性。

In order to identify vulnerable lines which lead to cascading failure of power system, the identification model is proposed based on the power law characteristic of the self-organizing critical theory from the perspective of the developing trend of the accident. When line is out of service due to overload or hidden failures in protection system, critical lines causing power system separation can be found based on the island search method, and islands will be processed to be convenient to power flow calculation. The simulation model of power system blackouts is built considering the improved distribution entropy of power flow and the theory of sensitivity analysis to adjust load level, and the OPF model to adjust generator output. Through a lot of simulation and statistics, the power law or power law tail characteristic of loss load of power system can be used to determine whether the system reaches the self-organizing critical state. While the mathematical expectation of loss load is higher, the self-organized critical state is more dangerous, and the risk of cascading failure is higher. The effectiveness of this method in identifying vulnerable lines of power grid has also been verified by simulation results of IEEE 39-bus system.