Research On The Impact Of Coordinated Cyber-attack On The Physical Power System And Its Security Risk Assessment

With the development of modern communication technology,the integration of the power system and the electric information network is becoming closer and closer,which results in a united electric cyber physical system(ECPS).ECPS can realize functions such as fast fault removal and optimal power flow control through information analysis and decision-making.At the same time,when the power cyber network is attacked,the physical power system is likely to cause catastrophic accidents.For instance,in 2015,a large-scale blackout occurred in the Ukrainian power grid that lasted for several hours,due to cyber attacks on multiple 220 kV substations.And in 2019,the Guli Hydropower Station,which accounts for 40% of Venezuela's electricity generation,and the corresponding control center were suffered from cyber attacks,resulting in a major blackout that affects 18 states in this country.In this paper,this kind of coordinated attack against multiple cyber nodes corresponding to key physical nodes is defined as coordinated cyber attack.These cyber-physical security incidents have shown that the security of the ECPS is threatened severely by coordinated cyber attacks.It is practically meaningful to analyze the mechanism of coordinated cyber attacks and propose a method for risk assessment and defense resource allocation.In view of the above problems,this paper carries on the related research in the following two aspects:(1)From the analysis of existing information security incidents,the current cyber attacks show the following characteristics: The attacker will conduct coordinated attacks on multiple key information nodes.The coordinated cyber attack directly triggers power outages by disrupting the dynamic control functions of ECPS,and hides the attack facts and expands the scale of power outages by destroying the situational awareness function of ECPS.This paper also simulates the impact of cyber attacks on ECPS by simulation software OPNET and PSS/E.According to the simulation analysis,cyber attack against a single node can only have a limited impact on the power system,while a coordinated cyber attack can cause a blackout.(2)This paper proposes the probabilistic expression of the coordinated cyber attacks from the attack-defense game theory.A risk assessment method of ECPS under coordinated cyber attacks is proposed,considering the success rate and degree of destruction.Finally,the optimal allocation methods of defense resources are proposed for the two situations of firm risk with sufficient defense resources and minimum risk with limited defense resources.The application of these methods to the ECPS,which is based on the New England 10-machine 39-bus system,verifies the effectiveness of these methods.Based on the above analysis,only by synthetically analyzing all kinds of coordinated coordinated cyber attack scenarios can the risks faced by ECPS under cyber attack be evaluated comprehensively,and then the defense resource allocation scheme that can effectively resist all kinds of information attack can be obtained.