基于脆弱支路筛选的电网连锁故障多目标预防策略

针对电力系统中由线路故障引发的连锁故障现象，文中提出了一种基于脆弱支路筛选的电网连锁故障多目标预防策略。首先，提出一种改进的支路安全指标和系统安全指标，并引入泰尔熵指数对电力系统中各支路进行脆弱性评估，以此量化某支路故障退出运行后对电网运行安全性的影响；然后，根据支路脆弱性排序筛选出发生初始故障退出运行后对电网运行安全性影响较严重的几条支路，建立预想事故集；最后，建立兼顾系统安全指标和电网电压稳定，且能应对多种初始故障场景的电力系统连锁故障预防控制模型，并使用非支配排序遗传算法(non-dominated sorting genetic algorithm-Ⅱ,NSGA-Ⅱ)求解该模型。基于IEEE 39节点系统进行仿真分析，结果表明所提预防策略能获得更安全合理的发电机组出力方案，且证明了支路负载率差异对脆弱支路辨识的重要性。

A multi-objective prevention strategy for grid cascading failure based on vulnerable lines screening

To address the phenomenon of cascading failures caused by line faults in power systems, this paper proposes a multi-objective prevention strategy for grid cascading failures based on vulnerable lines screening. First, an improved branch safety index and system safety index are proposed, and the Thiel entropy index is introduced to assess the vulnerability of each line in the power system, so as to quantify the impact of a line failure on the safety of grid operation. Further, several lines with a more serious impact on the safety of grid operation are screened out according to the lines vulnerability ranking to establish a set of expected accidents. Finally, a preventive control model is developed that takes into account system safety indicators and grid voltage stability, and is able to cope with a variety of initial fault scenarios. The model is solved using NSGA-II, and the simulation analysis of the IEEE39 node system shows the importance of line load factor differences for the identification of vulnerable lines, and demonstrates that the proposed prevention strategy leads to a safer and more reasonable generator set output programme.