基于网络依存关系的CPPS连锁故障分析及风险评估

信息系统的融合给电网安全运行带来了新的风险，因此有必要研究电力信息物理系统(cyber-physical power system, CPPS)连锁故障的产生及传播机理。首先建立CPPS部分相互依存模型，采用老化因素、潮流、隐性故障、偶然因素构建电网风险元，采用信息占用率、拓扑结构、网络攻击、节点负荷以及依存关系构建信息网风险元，从而将风险元理论应用于CPPS连锁故障预测过程。其次提出一种同时考虑两网失负荷率的风险计算方法，可以识别骨干层与接入层的关键节点。最后分析信息节点自身故障和网络攻击引起的信息节点失效对连锁故障的不同影响。算例分析表明：依存关系会促进故障在两网传播，增大系统的风险；对CPPS进行整体分析能较全面地评估连锁故障风险，识别关键信息节点；同时遭受网络攻击与信息节点自身故障的CPPS的平均风险最高，需采取措施提高其可靠性。

Cascading failure analysis and risk assessment of CPPS based on network dependency

The integration of an information network brings new risks to the safe operation of the power grid, so study of the generation and propagation mechanism of CPPS cascading failure is a matter of importance. First, a CPPS partial interdependence model is established, grid risk elements are constructed based on ageing factors, load flow, hidden failure and chance factors. Then information network risk elements are constructed based on information occupancy, topology, network attacks, node loads and dependencies, and risk element theory is applied to the CPPS cascading failure prediction process. Second, a risk calculation method considering the load loss rate of the two networks is proposed to identify the key nodes of the backbone layer and the access layer. Different effects of information node failure by information nodes and network attacks are analyzed. The analysis shows that the dependency relationship will promote the propagation of faults in two networks and increase the risks; the risk calculation method can comprehensively assess cascading failure risk and identify key information nodes; when a network attack is combined with the node''s own failure, the average risk of CPPS is the highest, measures should be taken to improve the reliability of CPPS.

This work is supported by the Natural Science Foundation of Anhui Province (No. 1808085ME142).