Integrated Defense Mechanism Based on Attack Goals against Three Attack Strategies in Smart Grid

Cyber-physical systems (CPSs) are frequently subjected to multiple and simultaneous attacks; however, defenders are often unaware of what kind of attack strategy has been adopted by attackers. By simulating an attacker's behavior, we can predict and propose three possible attack strategies that can be combined with interdependence features and a knowledge of smart grid, i.e. Topology Structure Attack Strategy (TSAS), Socio-economic Attack Strategy (SEAS) and Power Flow Attack Strategy (PFAS). TSASs focus on node loss, SEASs concentrate on economic loss, and PFASs utilize the mechanism of power flow to trigger load-redistribution, inducing more node failures. Malicious attackers may choose different attack strategies. However, the defense mechanisms portrayed in many studies may only deal with one type of attack strategy. As such, we will divide cyber and physical nodes into four protection levels and design a coupling mode between different levels in order to establish an integrated defense mechanism against TSAS, SEAS or PFAS. Experimental results show that cyber and physical Attack Goals (AGs) that can achieve the expected attack effects have been explored and exploited by the attackers. When the same proportional AGs are successfully attacked, Coordinated Cyber-Physical Attacks (CCPAs) have a better attack effect than cyber-attacks or physical attacks. Finally, experimental results show that an integrated defense mechanism can not only mislead the attackers and cause them to select insignificant nodes as AGs, but that it can also improve the robustness of CPSs, enhancing their ability to deal with CCPAs.