Research On The Identification And Importance Evaluation Of Critical Nodes And Node Groups In A Cyber Physical Power System

With the advancement of technology in modern society,the integration of powerful technology with communication technology has facilitated the rapid development of a smart grid.This system,known as the Cyber-Physical Power System(CPPS),is a multi-level and complex network that involves information interaction and mutual assistance.However,the CPPS faces various challenges such as equipment failures,natural disasters,malicious attacks,and potential threats to the communication network.Thus,it is essential to understand the complex coupling relationship between the power network and the communication network.This article considers the interaction of a power network and communication network,models the Cyber-Physical Power System,and focuses on studying three scenarios based on the analysis mentioned above: important nodes,relatively important nodes,and important node groups.The specific research content is as follows:Firstly,we construct a network topology model of the Cyber-Physical Power System based on the complex network theory,which is essential for follow-up research.In our further studies,we will investigate the applicability of the Cyber-Physical Power System under different coupling methods.The proper coupling method is critical to ensuring optimal performance across all aspects of the Cyber-Physical Power System;Secondly,we combine the different characteristics of the two networks in the Cyber-Physical Power System,we also consider the interaction between the power network and the communication network in the Cyber-Physical Power System.We identify critical nodes in the system using information entropy and examine the network efficiency relative values and the degree of network damage as measurement indicators.To verify the effectiveness of the critical node method,we use both static and dynamic scenarios and analyze the verification process of important nodes using the seepage theory.We also take examples from the physical power information system corresponding to IEEE-30 and IEEE-118 node systems to validate the proposed method’s effectiveness and superiority.Thirdly,when a small number of critical nodes in the system are destroyed,we can identify and protect the relatively important nodes based on the information left by them,which can prevent the spread of faults.Therefore,we propose a relatively important node identification method based on relative weighted entropy for the Cyber-Physical Power System.We define the connection tightness indicators of any two nodes.To accurately measure the degree of difference between any two nodes,we define connection tightness indicators,which are combined with relative entropy to sort nodes and judge their relative importance.This method allows for the evaluation of relatively important nodes without distinguishing between power and communication,and it is also possible to identify nodes that are relatively important to one side of the Cyber-Physical Power System based on the importance of the network nodes on the other side;Finally,when we need to control a limited number of nodes in the vast Cyber-Physical Power System to manage a larger range of networks,it is beneficial to select a group of critical nodes.However,the critical node group is not merely a combination of the previously identified critical nodes.Therefore,we propose an important node group evaluation strategy based on the pinning control theory,which uses the minimum non-zero eigenvalue of the modified Laplacian matrix as the evaluation index.We use matrix analysis theory to summarize the two screening conditions to reduce the computational complexity,and we screen the critical node groups in the Cyber-Physical Power System.