基于加权网络模型的电网连锁故障分析

摘要

本文基于复杂网络理论提出了一种评估电网发生连锁故障的新方法,运用复杂网络理论来分析电网有助于从电网架构上研究连锁故障.首先,以输电线路和变压器的阻抗模值为边权构建了电网加权拓扑模型,并给出评价电网中心性的指标;其次,基于线路断开瞬间线路传输功率优先分配到邻近线路的原则,提出评估电网发生连锁故障的阈值模型;最后,以IEEE 118节点系统为例,通过计算反映其中心性的指标值,找出了IEEE 118节点系统的中心节点,验证了加权拓扑模型在反映节点中心性方面优于无权拓扑模型,与实际网路也更接近.在此基础上,针对四种攻击网络的典型模式,运用阈值模型计算该系统发生连锁故障的临界阈值,揭示了电网发生连锁故障的机理.%A new method for the assessment of cascading failures in power grids is presented.This method is helpful to investigating cascading failures from the configuration of power grids by using complex networks theory.The topological model of power grids is established by defining the impedance of transmission lines and transformers as connection weights.The indices of centrality characteristics of power grids are given.The critical threshold model of cascading failures in power grids is explored based on the principle that a failed edge causes redistribution of instant power flow only to its neighboring edges.Taking IEEE 118-bus test system as example,we find its central vertexes by calculating those indices of centrality characteristics of power grids.The weighted model is more efficient than conventional ones in exhibiting vertexes,and closer in characteristics to real transmission grids.By using the system threshold model,we calculate the threshold value of cascading failure in grids under four typical attacking modes,revealing the mechanism of cascading failures.