A Cyber-Physical Security Assessment Model for Distribution Grid with High Penetration of Electric Vehicle Charging Infrastructure

Distribution grid with electric vehicle (EV) charging infrastructure can be modeled as a coupled network consisting of the cyber network, distribution grid and traffic network. The interconnection of the coupled network allows attackers to launch cyber attacks and control numerous EVs to cause severe load fluctuations, thereby affecting the normal operation of the distribution grid and the traffic flow. To evaluate the cyber-physical security of the coupled network, we present a security assessment model formulated as a coupled Discrete Event System Specification (DEVS). In this model, the evolution of the coupled network is represented as state transitions triggered by events in a discrete-time process, while the interaction is achieved through event transmission, reception and processing. To determine the redistribution of states influenced by the selection of EV charging stations and moving paths, we propose a spatial-temporal evolution mechanism. Based on the assessment model, we propose an event-triggered simulation method. The efficiency of the proposed simulation method is evaluated by comparing it with the multi-layer synchronous simulation method. Compared with the existing security assessment models, the simulation results of our model are more accurate.