Coordinated variable structure switching in smart power systems: attacks and mitigation

Recently, a class of cyber-physical attacks termed coordinated variable structure switching attacks has been identified for future smart grid systems. Here, an attacker who has remotely gained access to a circuit breaker or switch is able to disrupt power system operation by applying a state-dependent switching sequence. The sequence can be effectively designed employing variable structure systems theory. In this work, we extend this research to demonstrate an approach to mitigation within this variable structure system framework. Specifically, we study strategies employed by a power system operator in the face of a switching attack to steer the system to a stable equilibrium through persistent co-switching and by leveraging the existence of a stable sliding mode. We demonstrate how such co-switching can be designed for a variant of the WECC 3-machine, 9-bus system using linearized models and then employ simulations in MATLAB/Simulink and PSCAD to demonstrate its potential in practice.