| Advanced Metering Infrastructures(AMIs)unite smart meters,bidirectional communication and metering data management system enable two-way interactive communication between power grid and users side.AMIs mainly undertake the functions such as demand response,real-time price and fault detection of power measurement data transmission and other system modules.With the development of smart grid,they may also integrate more additional functions in the future.Advanced metering system apply open communication protocols to transmit electricity price,electricity consumption and control instructions and other sensitive information under the heterogeneous situation.However,AMIs have potential information security risk,is the research hot topic currently.Firstly,the difference between scheduling automation and substation automation system is compared in this paper,then the characteristics of advanced metering system network security protection are summarized.Secondly,this paper analyzes the possible purpose and the available means of invasion from the angle of attack side.Thirdly,the applicability of the commonly used network security protection is analyzed,which is based on the characteristics of the advanced measurement system.At last,intrusion detection method which can be applied to advanced metering system is put forward,with the modified anti-virus software,CPU computing resources and the smart meters with limited network communication bandwidth.Since utilization ratio of CPU and communication load can increase notably if smart meters are intruded by malwares.Therefore,it is possible to embed software in smart meters to collect CPU utilization ratio and communication load.Afterwards,these data could be uploaded to User Data Management Center together with electricity consumption data.The outlier detection system could determine threshold of outlier according to statistics of collected data.This is based on similarity principle,the same type and configuration of hardware should have the similar CPU loads,and the k-means clustering algorithm can accurately identify the abnormal CPU of the smart meter.Based on the new cloud security mechanism in recent years,a new method of smart meter virus detection approach is put forward.The processes in smart meters and data collectors are enumerated in cloud based anti-virus approach.Thereafter,Hash code of a process is calculated and utilized as ID code of a process.After this,the hash codes of a smart meter are uploaded together with electricity consumption data to User Data Management Center.Since they should have similar software in smart meters of the same type,the meters with notable different software process are identified as potential intruded meters.Under this situation,field crews could check state of the meter and collect software within the meter to determine the security of the meters.And the hash code of the malicious process could be listed in blacklist.Finally,the meters with process in blacklist could be identified as intruded meters.Hash code algorithm simulation shows that the calculation of smart meters in the typical process of hash signature by machine obey normal distribution with averages 497?s and variance 5.26?s,using the proposed method to detect the illegal software in the smart meters with limited computing resources. |
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