面向互联电网连锁故障安全防控的关键支路辨识

Identification of Key Branches for Safety Prevention and Control of Cascading Failures in Interconnected Power Grids

随着电网互联紧密程度的提高,抵御连锁性故障成为关键问题。在一定场景下,电网关键载流支路故障会引发过载型连锁反应,威胁系统安全运行,对于此类关键线路的筛选和辨识具有重要意义。据此,在考虑无功电压的改进直流潮流模型的基础上,推导和构建了过载型连锁故障动态演化模型。该模型考虑连锁故障过程中系统功率平衡和电压稳定装置的调节作用以及系统的校正控制措施,并较为准确地模拟支路失效后互联系统连锁故障的动态演化过程,进而研判连锁故障对系统功能和结构的影响。在此基础上,提出了电网载流支路的重要度评估指标,通过大规模连锁故障模拟计算,获得各载流支路的重要度指标,最终实现电网关键支路的有效辨识。以IEEE 39节点系统为算例,验证了所提模型和方法的有效性。

With the improvement of the interconnection of power grid, resisting the cascading faults becomes a key problem. In a certain scenario, the key current-carrying branch accidents of power grid will lead to overload cascading faults, threatening the safe operation of the system, which is of great significance to the screening and identification of such critical lines. On the basis of improving the DC power flow model of reactive voltage, the dynamic evolution model of overload-type cascading faults is deduced and constructed. The model takes into account the adjusting effects of power balance and voltage stability devices and the corrective control measures of the system, and accurately simulates the dynamic evolution of the cascading faults of the interconnected system after branch failures, so as to analyze the influence of cascading faults on the system function and structure. On this basis, the importance evaluation index of current-carrying branches of power grid is proposed, and the importance index of each current-carrying branch is obtained through large-scale cascading fault simulation calculation, and finally the effective identification of key branches of power grid is realized. Taking the IEEE 39-bus system as an example, the effectiveness of the proposed model and method is verified.