Modelling and Vulnerability Analysis of Cyber-Physical Power Systems Based on Interdependent Networks

The strong coupling between the power grid and communication systems may contribute to failure propagation, which may easily lead to cascading failures or blackouts. In this paper, in order to quantitatively analyse the impact of interdependency on power system vulnerability, we put forward a "degree-electrical degree" independent model of cyber-physical power systems (CPPS), a new type of assortative link, through identifying the important nodes in a power grid based on the proposed index-electrical degree, and coupling them with the nodes in a communication system with a high degree, based on one-to-one correspondence. Using the double-star communication system and the IEEE 118-bus power grid to form an artificial interdependent network, we evaluated and compare the holistic vulnerability of CPPS under random attack and malicious attack, separately based on three kinds of interdependent models: "degree-betweenness", "degree-electrical degree" and "random link". The simulation results demonstrated that different link patterns, coupling degrees and attack types all can influence the vulnerability of CPPS. The CPPS with a "degree-electrical degree" interdependent model proposed in this paper presented a higher robustness in the face of random attack, and moreover performed better than the degree-betweenness interdependent model in the face of malicious attack.