Research On Vulnerability Evaluation And Cyber Attack Of Cyber-Physical System Of Distribution Network

With the widespread application of advanced sensor technique,intelligent control technique and new generation of information and communication technology in the distribution network,the traditional distribution network has gradually shown the characteristics of deep coupling between the information space and the physical space,and has gradually become the cyber physical system of the distribution network.However,while advanced information and communication technology brings convenience to the intelligent development of the distribution network,its potential information security risks may also be transmitted to the distribution system through information-physical coupling nodes and affect its reliability,safety and stability.Thence,in order to ensure the safe and steady operation of the power distribution system and deal with the problems of extensive access of large-scale intelligent terminal equipment in the future,it is of very important to fully excavate and identify the weak links in the space on both sides of the system and study the security risk assessment of the system under network attacks.Based on the above background,this article first sets up the security system framework model of the CPS system of distribution network.Through the functional equivalence of the nodes on both sides of the cyberspace and the physical space,a"partial one-to-one" dependent network model of the distribution network CPS system based on the dependent network theory is constructed.Then it realizes the coupling modeling of the system,and study the interaction characteristics and linking mechanism of the space on both sides;Secondly,considering the features of the actual operating topology and business features of the system,it proposes a node vulnerability assessment method based on combined weighting and TOPSIS algorithm,constructs the vulnerability evaluation indicators of the information side and the physical side from the aspects of business data type,node processing delay,real-time performance,packet loss rate and improved node degree,node compactness,injection power,etc,and use FAHP and entropy method to assign weights to indicators from subjective and objective perspectives.Based on the principle of minimum discriminant information,the comprehensive weighting of vulnerability index is completed,then use the TOPSIS algorithm to quantitatively calculate and sort the vulnerability of the nodes,and complete the comprehensive evaluation of the system nodes based on the dependency coupling matrix.The consequences of the example model indicate that the means proposed in this paper can synthetically think over the vulnerability of the space nodes on both sides,which has guiding significance for the vulnerability assessment of the system;Finally,on account of the CPS security architecture model of the distribution network,the risk quantitative assessment method considering the actual security protection conditions of the system under the cyber-attacking is researched.The possible security threats of the system are analyzed.And it establishes a potential attack data stream related to equipment security vulnerabilities with the circuit breaker as the attack target,uses the attack graph "series-parallel" model to realize the traversal modeling of the attack path and the calculation of the attack success probability;And taking the misoperation of the circuit breaker in the normal operation state and the load loss caused by the refusal operation in the fault state as the consequence of the attack,the risk evaluation model in the information security domain is used to quantify the risk value of the system.The calculation example shows that the factors that affect the system security risk are not only related to the success rate of the attack,but also related to the physical consequences of the successful attack.