Vulnerability Assessment Of Cyber Physical Power System For Malicious Attack

As the pivot for the conversion of various energy,the smart grid is the central link of the energy Internet.Its operation status is related to national economy,people’s livelihood and homeland security,and the core of smart grid is cyber physical system.Since all industries require power supply as an operating support,it is particularly important to ensure the reliable operation of cyber physical power system.In recent years,malicious attack on power system occur frequently at home and abroad.How to deal with such incidents actively and reduce the occurrence of cascading failures and large-scale blackouts has become an urgent problem.Therefore,it is of great practical significance to study the vulnerability assessment of cyber physical power system for malicious attack.Based on the above background,this thesis studies the modeling method of cyber physical power system,the risk propagation mechanism of malicious attack,and the vulnerability assessment of power system.The main research contents as follows:(1)From the perspective of cyber-physical fusion,considering the association and coupling characteristics of power grid,communication network and information network,a hierarchical modeling method for cyber physical power system is proposed.First,based on the power flow equation,considering communication transmission and information decision-making process,the layered model of power grid,communication network and information network is established.In view of the monitoring function of information network and the direction of information transmission,an upward/downward communication channel model responsible for information transmission is established.Then use the interface model to associate the power grid,communication network and information network,obtain an integrated model of cyber physical power system considering multilayer coupling.It shows the functional relationships of the power grid,communication network and information network.(2)Based on the cyber physical system model considering the multilayer coupling characteristics,first,classify malicious attack,and point out the attack paths of different malicious attack,analyze the impact of malicious attack on the system operation-control process qualitatively.Then propose a parameterized representation method for risk propagation of malicious attack of the cyber physical power system.Furthermore,study the mechanism and formulaic expressions of deliberate attack and three typical cyber attack(denial of service attack,false data injection attack and replay attack).By updating the model parameters to analyze the direct/indirect impact of different malicious attack on the system quantitatively.(3)From the perspective of preventing malicious attack,based on a background of cooperative attack,a two-view vulnerability assessment method based on mixed integer linear programming is proposed.First,based on the method of DC power flow and topology analysis,the dynamic evolution process of cascading failure caused by attacking primary power equipment is simulated,and the loss of load at a certain time after the accident is taken as the vulnerability assessment index.Then,taking into account the cumulative effect of time of load loss,considering the repair time and its differences after different types of equipment are damaged,simulate the power recovery process,and estimate the power outage caused by a disruptive behavior within a fixed time window,as another index for vulnerability assessment.It is convenient to show the cross-effects of attack intentions from different angle,and to evaluate the vulnerability of power system more comprehensively under the threat of malicious attack.