Dipartimento di Ingegneria informatica, automatica e gestionale

This study presents a robust defence strategy in reaction to destabilising cyber-physical attacks launched against linear time invariant systems and its application to power systems. The proposed protection scheme aims at making the dynamics of a selected subsystem decoupled from the dynamics of the subsystem targeted by the attack. The standard decoupling methods are made robust, in spite of poor information about plant parameters and lack of state measurement, with the aid of an extended observer. In this way, it is possible to keep the protected dynamics arbitrarily close to the one of a suitably chosen stable system, so long as the dynamics being targeted by the attack remain within the prescribed bounds. The proposed defence strategy is presented in the context of modern power systems, wherein generators and transmission networks are operated by different players and shown to be effective using the Western System Coordinating Council 9-bus test power network.