| With massive sensors and complex communication networks,modern power system realizes real-time situational awareness and control service of the entire system to ensure security and stability.The deep integration of information and physics forms a complex cyberphysical power system(CPPS).CPPS guarantees the high efficiency of the power system control means,however,the deep coupling between the power system and the cyber system also leads to many problems.In recent years,the international situation has been complicated,natural disasters and cyber attacks have occurred frequently.Major power outages caused by this are obvious to all.CPPS is facing the threat of many extreme events.The occurrence of extreme events has caused huge economic losses to CPPS,and it also seriously threatens the safety of peoples lives and property.Therefore,it is of great significance to investigate deeply into the cyber-physical coupling properties and enhance the resilience of CPPS to ensure reliable power supply,protect peoples safety,and ensure national economic development.The resilience of CPPS is mainly reflected in pre-disaster prevention capabilities,disaster response and adaptation capabilities,and post-disaster rapid restoration capabilities.This paper studys from the time scale of extreme events,fully considers the cyber-physical coupling characteristics of CPPS,and studies the resilience enhancing methods from the three stages.The research of the three stages is continuous in time and progressive in content.The main research content and achievements are as follows:1)A routing optimization method for power communication network considering physical failure and network attack risk is proposed.Allocate more reliable communication links for each substation in the power system in pre-disaster prevention stage to ensure that the important remedial control commands of the power grid can be delivered reliably in the event of faults.Firstly,based on the dispatching instructions in various fault scenarios of the power system,an information flow associated load index is proposed.This index reflects the degree of coupling between cyber-physics,and is used to evaluate the importance of information flows.Secondly,taking account of the risk of physical failure and cyber attack risk,the reliability of the communication links is evaluated.Finally,a two-stage robust optimization model for power communication network routing is solved by the column constraint generation algorithm.Communication links with high reliability and low delay are allocated for important information flows to reduce the loss caused by the non-delivery of important scheduling instructions in case of failures.The simulation results of the standard IEEE-39 and IEEE-118 CPPS system illustrate the effectiveness of the routing optimization model for improving the resilience of CPPS.2)A cyber-physical coordinated emergency control method for large-scale network attacks is proposed.Firstly,the nodes’ observability and controllability after the cyber attack are modeled,and the response model of the cyber side is established.The cyber side adopts measures such as re-searching the routing paths for the substations with communication interruption to quickly recover communication and ensure the observability and controllability of power grid.Secondly,considering cyber-physical coupling properties,the power side response model is an optimal power flow model considering the cyber side limit,and the load loss is minimized through power flow regulation.In this way,the emergency control model of the cyber side and the physical side is established for overall solution,and the cyber-physics is decoupled through the Benders decomposition algorithm to reduce the difficulty of model solution.Finally,examples are given to illustrate the advantages of the proposed coordinated control model compared with the traditional model in reducing the load loss caused by cyber attacks and enhancing the resilience of CPPS in the response and adaptation phase.3)A coordinated cyber-physical restoration model considering the joint failure of cyber network and power grid is proposed.Firstly,considering the restoration process involving wind power and energy storage,a long-time scale load restoration model and cyber system restoration model are constructed.For the uncertainty of wind power,opportunity programming constraints are used,and the probability density function of wind power output is transformed into a clear equivalent.Secondly,the cyber-physical coupling forms such as the topological coupling between the transmission lines and the communication links,the power supply of the information nodes by the power nodes,and the transmission of the power system restoration commands by the cyber network are modeled in detail.Finally,a long-time scale cyber-physical coordinated recostoration model is established.The model is transformed into a mixed integer linear programming(MILP)model through linearization technology to effectively coordinate the restoration process of the power grid and the cyber network.Thereby the resilience of the CPPS in the restoration phase is improved. |
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