基于改进LeaderRank算法的电网连锁故障关键线路辨识方法

Identification of Critical Lines of Power Grid Cascading Failures Based on Modified LeaderRank Algorithm

针对现有连锁故障关键线路辨识方法在具体量化单元作用及方法复杂度上的不足,结合复杂网络理论结构分析方法与电网连锁故障后果近似分析方法,提出一种基于改进LeaderRank算法的关键线路辨识方法。首先,介绍了原LeaderRank算法,并指出其直接应用于电网关键线路辨识的不足所在;然后,针对原算法不足之处,提出基于线路量化关系的电网衍生网络以及利用小概率事件近似简化的事故链模型;最后,基于上述模型构建改进LeaderRank算法,对电网关键线路进行辨识。IEEE39节点系统与实际系统仿真实验表明,经小概率事件近似简化处理的连锁故障模型计算效率大幅提高,且结合LeaderRank算法能更全面反映单元在系统中的作用,即包括系统结构关系,线路单元受影响程度及线路单元断开造成后果,验证了所提算法的合理性与有效性。该分析方法基于复杂网络理论将电网拓扑结构转化为电网衍生网络,结合简化事故链模型,不仅反映了线路断开造成后果的严重程度,更反映了线路自身的脆弱性,可综合衡量一条线路在电网中的关键程度。

To address the shortcomings of the existing cascading fault critical line identification methods in the specific quantization unit function and method complexity,combined with the complex network theoretical structure analysis method and the power grid cascading failure consequence approximate analysis method,a critical line identification method based on the improved LeaderRank algorithm is proposed.Firstly,the original LeaderRank algorithm is introduced,and the shortcomings of its direct application to identify critical lines of the power grid are pointed out.Then,aimed at the shortcomings of the original algorithm,a derived network based on the quantitative relationship of lines and a simplified accident chain model based on small probability event approximation are proposed.Finally,an improved LeaderRank algorithm is constructed based on the above model to identify critical lines of the power grid.The examples of IEEE39 system and actual power system show that the computational efficiency of the cascading failure model is significantly improved by using small probability event approximation.Moreover,combined with LeaderRank algorithm,it can more fully reflect the role of the unit in the system,including the system structure relationship,the degree of influence of the line unit,and the consequences of disconnection of the line unit.Thus the validity and effectiveness of the proposed method can be verified.The analysis method,which is based on the complex network theory to transform the grid topology into a derived network and is combined with a simplified accident chain model,not only reflects the severity of the consequences caused by the disconnection of the line,but also reflects the vulnerability of the line itself.The proposed method can comprehensively measure the criticality of a line in the power grid.