Security Risk Assessment and Defense Resource Allocation of Power System Under Synergetic Cyber Attacks

The Ukrainian blackout incident shows that security of electric cyber physical system (ECPS) is severely threatened by synergetic cyber attacks. Considering this issue, it is of practical significance to propose a risk assessment and defense resource allocation method related to the ECPS under synergetic cyber attacks. Based on analysis of the destruction mechanism of cyber attacks on the physical grid and the cyber attack defense measures of ECPS, this paper proposes a probabilistic expression of the synergetic cyber attacks based on attack-defense game theory. Furthermore, considering success rate and destruction degree, a risk assessment method of the ECPS under synergetic cyber attacks is proposed. Finally, a method determining the defense resource demand under a given risk situation and an optimal defense resource allocation method under the condition of limited defense resources are proposed. Application of these methods to the ECPS based on a 10-machine 39-bus system verifies effectiveness of these methods.