Impact of inter-network assortativity on robustness against cascading failures in cyber–physical power systems

It is found larger inter-network assortativity can mitigate(aggravate) cascading failures under random(targeted) attacks in cyber–physical systems(CPSs) according to the limited extreme cases, such as the max–min, max–max, and complete random degree-based interdependent networks. However, it is unclear how the assortative interdependence influences the robustness of real infrastructure systems, especially the cyber–physical power systems(CPPSs). We develop a new model called POD based on an optimized load shedding policy to simulate the Power-loss failures, Out-of-control failures and Data-blocking failures in cascade process. By extending the RAndom Interacting Network(RAIN) model, CPPSs with different ‘one-to-one’ assortative interdependence can be generated and studied systematically. The simulation results show that the relationship between assortative interdependence and the robustness of systems is much more complicated than expected. Fragmentation and compatibility are introduced to explain these results, and we find slighter fragmentation and better compatibility make the CPPSs more robust against cascading failures. The interplay between fragmentation and compatibility plays an important role in estimating the influence of assortative interdependence on the CPPS robustness.