Research On Low-cost Multi-stage Attack Strategy For Power Cyber Physical System

With the development of smart grid,modern power system has evolved from traditional primary equipment network to power cyber physical system with deep integration of information network and power grid.While the information network significantly improves the operation efficiency of power system,the attacks cross domain relations also bring new risks to the stable operation of power system.In recent years,the attacks on power grid at home and abroad show that the targeted attacks on power system is gradually mature,the attack mode is more hidden and extensive,the attack range is highly spread.In practice,the attack cost can affect the attackers’ decision-making to a certain extent,considering the attack cost factors,it is of great significance to study the attack mode and attack behavior characteristics on power system to improve the ability to resist attacks.At the same time,few studies consider the possibility of attackers’ multi-stage attacks on power grid,while the 2019 Venezuela outage shows that attacker can launch multi-stage attacks on the power grid in a variety of ways.Therefore,considering the attack cost factor,this paper proposes a low-cost multi-stage attack strategy for power cyber physical system,and evaluates the risk of low-cost multi-stage attack scenario.The main research work is as follows:Based on the complex network theory,the topological model of power cyber physical system is carried out,and the dynamic models of power network and information network are established respectively.On this basis,the interaction between cyber layer and physical layer and the mechanism of cascading failure are analyzed.Based on the topological and operation characteristics,the attack cost index is defined to identify the low attack cost lines with weak protection measures and vulnerable to attack in the power grid,and then a multi-stage attack strategy for low attack cost lines is proposed.Taking IEEE 118 bus system and a provincial power system as examples,the effectiveness of the strategy is verified:a few periodic attacks on low attack cost lines can also cause blackouts.and the attack cost is obviously lower;The increase of failure probability of information node weakens the ability of information network to suppress cascading failures,and further improves the harm of multi-stage attack.Considering the attack cost and the choice tendency of the attacker,the probability of each attack scheme selected by the attacker is calculated based on the attack profit and loss principle,the attack cost index is used to measure the success probability of multi-stage attack,and a risk assessment model is established for the low-cost multi-stage attack scenario of power cyber physical system.Finally,the risk assessment is carried out for IEEE 118 node system and a provincial power system.The results show that the risk assessment model can reflect the attacker’s choice tendency to cause great harm to the power grid at a lower cost,and reveal the high-risk low-cost multi-stage attack scheme;The high-risk and high-order attack scheme identification method based on high-risk and low-order attack scheme can identify the highrisk attack path of the attacker in the next stage,which has a certain reference value for path prediction and active defense of multi-stage attack.